Comparison of Finnish Landrace crossbred ewes with Columbia, Rambouillet, and Targhee on western
range
by Robert David Lewis
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in
Animal Science
Montana State University
© Copyright by Robert David Lewis (1984)
Abstract:
Effects of crossing 1/2 Finnish Landrace and 1/2 Rambouillet (FxR) rams with Columbia (C),
Rambouillet (R), and Targhee (T) ewes on productivity traits under western range spring lambing
management were evaluated. From 1975 to 1978, 563 whiteface (WF) ewes composed of C, R, and T,
bred to either FxR or WF (of the same breed) rams produced 821 lambs. Ewes bred to FxR had similar
levels of prolificacy and individual lamb weights at birth, 60 d, and 120 d (weaning) as those bred to
WF rams. Lambs sired by FxR had 7.3% higher survivability to 60 d than those sired by WF (P<.01),
resulting in 4.1 kg more lamb weaned per ewe lambing for ewes bred to FxR rams (P<.01).
From 1976 to 1982, 146 FxR-sired ewes (1/4Fx) and 143 WF-sired ewes were exposed to Suffolk rams
to lamb beginning at T yr of age through to 6 yr of age, for a total of 1264 lambing opportunities. At 1
yr of age 1/4Fx ewes had higher fertility (P<.01) than WF ewes (37.7$ vs 1.3$). Prolificacy (lambs per
ewe lambing) for 1/4Fx ewes was 1.10 lambs, and total kg of lamb weaned per 1/4Fx ewe exposed was
14.0 kg. No differences in fertility were found between mature (ages 2 to 6 yr) 1/4Fx and WF ewes.
Prolificacy for mature 1/4Fx was .36 lambs higher than that for WF ewes (P<.01). Superiority of 1/4Fx
ewes for litter size at 60 d and 120 d per ewe exposed was .24 and .22 lambs, respectively (P<.01).
Lambs from mature 1/4Fx dams were lighter at birth (P<.01), but not significantly different at 60 d and
120 d than those from mature WF dams. Survival to 60 d was 4.6% higher for lambs from 1/4Fx dams
(P<.05), and 7.6$ higher for lambs from 1/4Fx dams when adjusted for birth weight (P<.01). Litter
weights at 60 d and 120 d per ewe exposed were 3.9 kg and 4.3 kg heavier for 1/4Fx than WF ewes
(P<.01). Fleeces from 1/4Fx ewes ages 1 to 6 were lighter and coarser than those from WF ewes
(P<.01), but had similar staple lengths. COMPARISON OF FINNISH LANDRACE CROSSBRED EWES
WITH COLUMBIA, RAMBQUILLET, AND
TARGHEE ON WESTERN RANGE
by
Robert David Lewis
A t h e s i s sumbmitted i n p a r t i a l f u l f i l l m e n t
of th e re q u ire m e n ts f o r th e degree
of
M aster of Science
in
Animal Science
MONTANA STATE UNIVERSITY
Bozeman, Montana
June 1984
ii
APPROVAL
o f a t h e s i s s u b m it te d by
R o b ert David Lewis
T h is t h e s i s h a s been r e a d by each member o f t h e t h e s i s c o m m itte e
a n d h a s b e e n f o u n d t o be s a t i s f a c t o r y r e g a r d i n g c o n t e n t , E n g l i s h
u sa g e , f o r m a t , c i t a t i o n s , b i b l i o g r a p h i c s t y l e , and c o n s i s t e n c y , and i s
r e a d y f o r s u b m i s s i o n t o th e C o lle g e o f G ra d u a te S t u d i e s .
A pproval f o r t h e M ajor D epartm ent
(o ^
D ate
-Q-H
Head, Major D epartm ent
Approved f o r th e C o lle g e o f G ra d u a te S t u d i e s
^
D a te
G ra d u a te D ean
_
iii
STATEMENT OF PERMISSION TO USE
In
p re se n tin g
th is
th e sis
in
p a rtia l
f u l f i l l m e n t of th e
r e q u i r e m e n t s f o r a m a s t e r ’s d e g r e e a t M ontana S t a t e U n i v e r s i t y ,
I
a g re e t h a t th e L ib r a r y s h a l l make i t a v a i l a b l e to b o rro w ers under th e
r u l e s of th e L ib ra ry .
B r i e f q u o t a t i o n s from t h i s t h e s i s a r e a llo w a b le
w ith o u t s p e c i a l p e rm is s io n , provided t h a t a c c u r a te acknowledgement Of
so u rce i s made.
P e rm iss io n f o r e x te n s iv e q u o t a t i o n from or r e p r o d u c t io n o f t h i s
t h e s i s may be g ra n te d by ,my major p r o f e s s o r , or i n h i s absence, by the
D ir e c t o r of L i b r a r i e s when, i n th e o p in io n of e i t h e r , th e proposed use
of th e m a t e r i a l i s f o r s c h o l a r l y purposes.
m a te ria l
Any copying or use of the
i n t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d
w ith o u t my w r i t t e n p erm issio n .
iv
ACKNOWLEDGEMENTS
I w ish to e x p r e s s my s i n c e r e thanks t o Dr. P. J. B urfening and Dr.
D. D. K ress f o r t h e i r guidance, encouragem ent, and p a tie n c e throughout
my g ra d u a te program. A p p re c ia tio n i s extended t o Dr. M. D. Huffman and
Dr. W. W. Kezar f o r t h e i r counsel and i n s t r u c t i o n .
S p e c i a l t h a n k s a r e e x p r e s s e d t o Ms. D. M. Doede f o r h e r s u p p o r t
and f r i e n d s h i p which made the s u c c e s s of my g ra d u a te program p o s s i b le ,
and
to
Mr.
D.
E.
T r o w b r id g e
fo r
h is
a ssista n c e
w ith
c o m p u te r
programming.
Thanks a r e e x t e n d e d t o Dr. J. L. Van Horn, Mr. K. L. C olem an, and
th e
sta ff
of
th e
Red B l u f f
R esearch
Ranch f o r
m an ag em en t and
c o l l e c t i o n of d ata.
I w ish to o f f e r my s i n c e r e g r a t i t u d e t o my f a m i l i e s , f a r and near,
w ith o u t whose d e d i c a t i o n t o my e d u c a t i o n my g r a d u a t e p ro g ra m w ould
n e i t h e r have been a tte m p te d nor completed.
L a s t ly , I e x p r e s s my most s p e c i a l thanks and a d m ir a ti o n t o my w if e .
Sarah.
V
TABLE OF CONTENTS
Page
LIST OF ...........................................................................................................................
v ii
ABSTRACT............................................................................................................................
ix
1.
INTRODUCTION......................... ...........................................................
1
2. LITERATURE REVIEW..................................................................................................
6
F e r t i l i t y . . . . . . ..................................................................................................
P r o l i f i c a c y . ........................................................................................................
S u r v i v a b i l i t y .................................... .................................................................
I n d iv i d u a l Progeny Weaning Weight Performance..................................
Composite R eproductive P e rfo rm a n c e ........................................................
Wool.........................................................................................................................
6
3. MATERIALS AND METHODS...........................................................
15
19
23
26
29
P o p u la t io n s ..........................................................................................................
Management.................................................................................. ..........................
T r a i t s S tu d ie d ......................................................................................
S t a t i s t i c a l Methods...........................................................
29
31
32
33
4 . RESULTS AND DISCUSSION.......................................................................................
36
Mature Ewe and Progeny Performance i n Phase I ...............................
Breed Group o f S i r e E f f e c t s .................................................................
Breed Group of Ewe E f f e c t s ........................
Other Main E f f e c t s ............................................
Ewe Lamb and Progeny Performance i n Phase I I ..................................
F e r t i l i t y and P r o l i f i c a c y .....................................................................
Progeny Perform ance..................................................................................
■Composite T r a i t s . .......................................................
Mature Ewe and Progeny Performance i n Phase I I ..........................
Breed Group o f Ewe E f f e c t s ...................................
Age of Ewe and I n t e r a c t i o n E f f e c t s .................................................
Breed Group o f S i r e E f f e c t s .......................................................
Other Main E f f e c t s ..................................................................................
36
36
42
42
36
43
44
46
4?
4?
58
60
62
vi
TABLE OF CONTENTS-C o n tin u e d
Page
Wool P r o d u c tio n .................................................................................................
Grease F leece W e ig h t........................................
F le e c e Grade...................... '..........................................................................
S ta p l e Length............................................
D is c u s s i o n .....................................................................................................
REFERENCES
C IT E D .............................................
62
62
64
65
66
68
v ii
LIST OF TABLES
Table
1
2
3
4
5
6
7
8
9
10
11
12
Page
Comparison o f 1/2 and 1/4 Finn C rosses w ith S tandard
Breeds f o r F e r t i l i t y i n Ewe Lambs...................................................
10
T o ta l Number of Phase I Ewes Lambing by Year and Age
a t Lambing......................................
30
T o ta l Number o f Phase I I Ewes Exposed i n P revious
Breeding Season by Year and Age a t Lambing.................................
30
Mean Squares from Analyses o f V ariance f o r Phase I
Ewe R eproductive T r a i t s per Ewe Lambing (1975 - 1 9 7 8 ) . . . .
37
Mean Squares from Analyses o f V ariance f o r Phase I
I n d iv i d u a l Progeny T r a i t s (1975 - 1978)......................................
38
L e a s t-S q u a re s Means and S tandard E r r o r s f o r Phase I
Ewe R eproductive T r a i t s p er Ewe Lambing (1975 - 1 9 7 8 ) . . . .
39
L e a s t-S q u a re s Means and S tandard E r r o r s f o r Phase I
Progeny T r a i t s (1975 - 1978)......... ....................................................
40
Mean Squares from Analyses o f V ariance f o r Phase I I
Ewe P ro d u c tio n T r a i t s (1976 - 19 8 2 )...............................................
41
L e a st-S q u a re s Means and S tandard E r r o r s f o r Phase I I
Fx Ewe Lamb R eproductive T r a i t s (1976 - 1979).........................
44
Mean Squares from Analyses o f V ariance f o r Phase I I
I n d iv i d u a l Progeny T r a i t s from Fx Ewe Lambs
(1976 - 1.979)...............................................................................................
45
L e a st-S q u a re s Means and S tan d a rd E r r o r s f o r Phase I I
I n d i v i d u a l Progeny T r a i t s from Fx Ewe Lambs
. (1976 T 1979).................... ...........................................................................
45
L e a s t-S q u a re s Means and S tan d a rd E r r o r s f o r Phase I I
Fx Ewe Lamb Composite R eproductive T r a i t s p er Ewe
Exposed (1976 - 1979)..............'...................................................
46
I
v iii
LIST OF TABLES-Continued
T ab le
13
14
15
16
17
18
19
20
21
22
23
Page
L e a s t-S q u a r e s Means and S tan d ard E rro r s f o r F e r t i l i t y
of Phase I I Mature Ewes (1976 - 19 8 2 )......................................
48
L e a s t-S q u a re s Means and S tan d a rd E r r o r s f o r P r o l i f i c a c y
of Phase I I Mature Ewes (1976 - 1982)..........................................
49
Mean S q u ares from A n a ly se s o f V a r ia n c e f o r Phase I I .
Mature Ewe Progeny T r a i t s (1977 - 19 8 2 )......................................
51
L e a s t-S q u a re s Means and S tandard E r r o r s f o r I n d i v i d u a l
Lamb Performance from Dams Ages 2 through 6
(1977 - 1982) .......... ..................................... ..............................................
52
L e a st-S q u a re s Means.and S tan d a rd E r r o r s f o r L i t t e r S ize
a t 60 Days p e r Ewe Exposed (LS60, 1977 - 1982).......................
54
L e a st-S q u a re s Means and S tan d a rd E r r o r s f o r L i t t e r Weight
a t 60 Days per Ewe Exposed (LW60, 1977 - 1 9 8 2 ) . . ..................
55
L e a st-S q u a re s Means and S tan d a rd E r r o r s f o r Phase I I
L i t t e r S ize a t 120 Days per Ewe Exposed
(LSI20, 1977 - 1982).................................................................................
56
L e a s t-S q u a re s Means and S tan d a rd E r r o r s f o r Phase I I
L i t t e r Weight a t 120 Days per Ewe Lambing
( LWI20, 1977 - 1.982)..........................................................
57
L e a st-S q u a re s Means and S tan d a rd E r r o r s f o r Phase I I
Mature Ewe P ro d u c tio n and I n d i v i d u a l Lamb Performance
by B re e d Group o f S i r e (1976 - 19 8 2 )...............................
61
Mean Squares from V ariance A nalyses f o r Ewe Wool
P ro d u c tio n T r a i t s (1976 - 19 8 2 )........................................................
63
L e a s t-S q u a r e s Means and S tan d ard E rro r s f o r Phase I I
Wool C h a r a c te r s , Ages I to 6 (1976 - 1982)...........................
63
ix
ABSTRACT
E f f e c t s o f c r o s s in g 1/2 F in n is h Landrace and 1/2 R am b o u illet (FxR)
r a m s w i t h C o lu m b ia (C), R a m b o u i l l e t (R), and T a rg h e e (T) ew es on
p r o d u c t i v i t y t r a i t s under w e s te r n range s p r in g lam bing management were
e v a lu a te d . From 1975 t o 1978, 563 w h ite f a c e (WF) ewes composed of C,
R, and T, b r e d t o e i t h e r FxR o r WF ( o f t h e same b r e e d ) r a m s p r o d u c e d
821 la m b s . Ewes b r e d t o FxR had s i m i l a r l e v e l s o f p r o l i f i c a c y and
i n d i v i d u a l lam b w e i g h t s a t b i r t h , 60 d, and 120 d ( w e a n in g ) a s t h o s e
b r e d t o WF ra m s . Lambs s i r e d by FxR had 7.3% h i g h e r s u r v i v a b i l i t y t o
60 d t h a n t h o s e s i r e d by WF (P < .01), r e s u l t i n g i n 4.1 kg m ore lam b
weaned per ewe lam bing f o r ewes bred to FxR rams (P<.01).
From 1976 t o 1982, 146 F x R - s i r e d ew es ( 1 /4 F x ) and 143 W F - s ir e d
ew es w e r e e x p o s e d t o S u f f o l k r a m s t o la m b b e g i n n i n g a t I y r o f age
through to 6 y r of age, f o r a t o t a l o f 1264 lam bing o p p o r t u n i t i e s . At
I y r o f a g e 1 / 4 F x ew es h ad h i g h e r f e r t i l i t y (P<.01) t h a n WF ew es
(37.7% v s 1.3%). P r o l i f i c a c y ( la m b s p e r ewe l a m b in g ) f o r 1 /4 F x ew es
was 1.10 lam bs, and t o t a l kg o f lamb weaned p er 1/4Fx ewe exposed was
14.0 kg. No d i f f e r e n c e s i n f e r t i l i t y were found between m ature (ages 2
t o 6 y r) 1/4Fx and WF ewes. P r o l i f i c a c y f o r m ature 1/4Fx was .36 lambs
h i g h e r t h a n t h a t f o r WF ew es (P<.01). S u p e r i o r i t y o f 1 /4 F x ew es f o r
l i t t e r s i z e a t 60 d and 120 d p e r ewe e x p o s e d w as .24 and .22 la m b s ,
r e s p e c t i v e l y (P<.01).
Lambs fro m m a t u r e 1 /4 F x dam s w e r e l i g h t e r a t b i r t h (P < .01), b u t
not s i g n i f i c a n t l y d i f f e r e n t a t 60 d and 120 d than th o s e from m ature
WF dams. S u r v i v a l t o 60 d w as 4.6% h i g h e r f o r la m b s fro m 1 /4 F x dams
(P<.05), and 7.6% h i g h e r f o r la m b s f r o m 1 /4 F x dams when a d j u s t e d f o r
b i r t h w eig h t (P<.01). L i t t e r w e ig h ts a t 60 d and 120 d p e r ewe exposed
w ere 3.9 kg and 4.3 kg h e a v i e r f o r 1/4Fx th a n WF ewes (P<.01). F le e c e s
from 1/4Fx ewes ages I to 6 were l i g h t e r and c o a r s e r th a n th o se from
WF ewes (PC.01), but had s i m i l a r s t a p l e le n g th s .
I
CHAPTER I
.
INTRODUCTION
R eproductive e f f i c i e n c y o f th e ewe, t o t a l k ilo g ra m s o f lamb weaned
p e r ewe i n
im p o rta n t
th e flo c k
fa c to r
( S i d w e l l and M i l l e r ,
a ffe c tin g
p ro fita b ility
19 7 1 a),
is
t h e m o st
i n c o m m e r c i a l sh e e p
p r o d u c t i o n s y s t e m s i n t h e U n i t e d S t a t e s ( D ic k e r s o n and G lim p , 1975;
P arker and Pope, 1983; S id w e ll and M i l l e r , 1971a). L i t t e r s i z e , number
o f la m b s
p roduced p er
p a rtu ritio n ,
r e p r o d u c t iv e e f f i c i e n c y (Bradford,
r e g io n (Arizona,
Colorado,
Idaho,
is
a m a jo r
com ponent of
1972a). L i t t e r s i z e i n th e Mountain
Montana, Nevada, New Mexico,
Utah,
and Wyoming), which co m p rises 36% o f th e t o t a l sheep p o p u la tio n in, th e
U.S., h a s i n c r e a s e d by o n ly
.057 lam bs per. p a r t u r i t i o n (ap proxim ately
6 % ) from 1958 t o 1981 ( P a r k e r ,
1981). Such l i m i t e d g r o w th i n any
i n d u s t r y 's most im p o r ta n t economic t r a i t demands a t t e n t i o n from the
r e s e a r c h community.
R e p ro d u c tiv e e f f i c i e n c y
may be i n c r e a s e d by im p r o v e m e n t s i n
m an ag em e n t, n u t r i t i o n , and g e n e t i c s . C o n s i d e r a t i o n o f a l l o f t h e s e
a r e a s i n t h e w e s te r n ra n g e la n d environm ent i s beyond th e scope of t h i s
paper; e f f o r t s w i l l be c o n c e n tr a te d on improvement through th e use of
g e n e tic s . New te c h n o lo g ie s loom on th e h o riz o n ; y e t ,
a t th e p re s e n t,
two methods a r e a v a i l a b l e t o the com m ercial range sheep manager f o r
g e n e t i c im p r o v e m e n t : (I). s e l e c t i o n among b r e e d i n g a n i m a l s b a s e d on
in d iv id u a ls a n d /o r r e l a t i v e
p erfo rm an ce and,
(2) u t i l i z a t i o n
of
2
g e n e t i c d i v e r s i t y between breeds i n c r o s s b r e e d in g schemes (Dickerson,
1969; T urner,
1969).
Both o f t h e s e t e c h n i q u e s h a v e b e e n u n d e r s t u d y and i n p r a c t i c e
u n d e r d i f f e r e n t m anagem ent s y s t e m s a r o u n d t h e w o r l d f o r many y e a r s
( N i t t e r , 1978). Improvements i n r e p r o d u c t iv e e f f i c i e n c y from s e l e c t i o n
s t r a t e g i e s dep en d on t h e r e p e a t a b i l i t y and h e r i t a b i l i t y a s s o c i a t e d
w ith th e components under s e l e c t i o n (Turner* 1969; F a lc o n e r,
p a r t i a l l i s t o f components provided by B radford (1972)
a t pu b erty ,
1981). A
i n c l u d e s : age
frequency of p a r t u r i t i o n ( f e r t i l i t y and i n t e r v a l to f i r s t
p o st-p artu m
(p ro lific a c y ),
e stru s),
num ber o f la m b s
produced
per
p a rtu ritio n
s u r v iv a l of th e lambs, and le n g t h of r e p r o d u c t iv e l i f e .
As t r a d i t i o n a l management in v o lv e s b re e d in g ewes f i r s t a s y e a r l i n g s
and s u b se q u e n tly on an annual b a s is ,
c h o ic e s f o r s e l e c t i o n s t r a t e g i e s
have focused on f e r t i l i t y and p r o l i f i c a c y .
I n a r e v i e w , T u r n e r (1969) r e p o r t e d r e p e a t a b i l i t y f o r f e r t i l i t y
a t .08 t o .09, and h e r i t a b i l i t y a t 0 t o .03. More r e c e n t l y , C la r k e and
Hohenboken (1983) fo u n d t h e h e r i t a b i l i t y t o be .02 i n a c r o s s b r e d
p o p u la tio n . E s ti m a t e s of such low m agnitude would s u g g e s t g a in s from
s e l e c t i o n t o be slow. S h e lto n (1962) r e p o r t e d g a in s from c u l l i n g open
2 - y r - o l d s o f .05 la m b s p e r ewe b r e d p e r y r . T u r n e r (1966) r e p o r t e d
g a i n s o f o n ly .005 and .059 i n tw o f l o c k s , c o n c l u d i n g t h a t s e l e c t i o n
f o r f e r t i l i t y (or a g a i n s t i t s converse, b a rre n n e s s ) i s i n e f f e c t u a l .
H e r i t a b i l i t y e s t i m a t e s f o r p r o l i f i c a c y a r e a l s o q u i t e low i n
magnitude. I n a re v ie w , T urner (1969) r e p o r t e d an average e s t i m a t e to
be .1 5 ; o t h e r v a l u e s h a v e b e e n .06 t o .16 i n w e s t e r n f i n e w ool sh e e p
( S h e l t o n and M e n z ie s ,
1970; B a s u t h a k u r e t a l . ,
1973),
and .12 i n
3
c r o s s b r e d s ( C la r k e and H ohenboken, 1983). R e p e a t i b i l i t y e s t i m a t e s
rev ie w e d
by T u r n e r f a l l
b o th
a b o v e and
below
th e h e r i t a b i l i t y
e s t i m a t e s . B r a d f o r d ( 1972a) s u g g e s t s t h a t a n e g a t i v e e n v i r o n m e n t a l
c o r r e l a t i o n m ight e x i s t between c o n s e c u tiv e r e c o r d s due t o ewes who
r a i s e d t w i n s b e i n g i n p o o r e r c o n d i t i o n a t m a t i n g t h a n ew es r a i s i n g
o n ly I lamb. Again w ith such low e s t i m a t e s re s p o n s e to s e l e c t i o n w i l l
be slow. Turner (1969) and B urfening (unpublished d a ta ) both r e p o r te d
an ann u al
d iv e rg e n c e
p ro lific a c y of
b e tw e e n l i n e s
se le c te d
fo r
h ig h
and
low
.023 lambs per ewe exposed. I n th e l a t t e r experim ent
no d i f f e r e n c e s w e re fo u n d b e t w e e n h i g h and c o n t r o l l i n e s .
(1972) r e p o r t e d on a New Z e a la n d l o n g - t e r m
C la r k e
s e l e c t i o n e x p erim en t
i n i t i a t e d i n 1948. The h ig h l i n e , s e l e c t e d f o r m u l t i p l e lam bings, had
an a n n u a l r a t e o f im p r o v e m e n t o f .018 t o .019 la m b s p e r ewe p e r y r
above the c o n t r o l l i n e ,
s e l e c t e d f o r g e n e ra l appearance.
As a r e s u l t o f t h e slow g a i n s due t o s e l e c t i o n ,
focused
on u t i l i z a t i o n
of g e n e tic
d iv e rsity
re s e a rc h has
b e tw e e n
breeds
in
c r o s s b r e e d i n g s c h e m e s f o r i n c r e a s i n g r e p r o d u c t i v e e f f i c i e n c y . The
F in n is h Landrace (Finn) and th e Romanov have s u r f a c e d a s seem ingly th e
most p r o l i f i c breeds (Bradford,
1972a). R eports of d i r e c t com parisons
b e tw e e n t h e two b r e e d s a r e fe w . Goot e t a l . ,
s ig n ific a n t d iffe re n c e s in f e r t i l i t y
(1979) r e p o r t e d
and p r o l i f i c a c y
no
b e tw e e n Fl
p ro g e n y p r o d u c e d by F in n and Romanov ra m s c r o s s e d w i t h M erino and
Awassi ewes. However, d i f f e r e n c e s did e x i s t between progeny f o r wool
t r a i t s . Romanov c r o s s e s had s i g n i f i c a n t l y lo w e r wool g ra d e s and h ig h e r
in c id e n c e of kemp f i b e r s th a n th e Finn c r o s s e s , r e s u l t i n g i n a poorer
q u a lity fle e c e .
4
P u re F i n n s a r e n o te d f o r t h e i r e a r l y age a t p u b e r t y and l a r g e
litte rs.
I n F in la n d ,
Finn ewe lam bs have an average 96.1% co n ce p tio n
r a t e and h a v e l i t t e r s i z e s o f 1.80, 2 . 3 9 , and 2.75 a t 1 , 2 and 3+ y r
of age, r e s p e c t i v e l y (Maij a l a and O stepberg, 1977).
Under d i f f e r e n t
B rita in ,
m anagem ent and e n v i r o n m e n t a l
co n d itio n s in
p u r e F in n ewe la m b s had a s i m i l a r c o n c e p t i o n r a t e ,
93%;
h o w e v e r, l i t t e r s i z e s w e r e c o n s i d e r a b l y h i g h e r a t 2 . 0 , 3. 0 , and 3.4
f o r a g e s I , 2 and 3+ y r , r e s p e c t i v e l y (D onald and Read, I 967). T hese
r e s u l t s may be due to th e i m p o r t a t i o n o f sheep more i n t e n s e l y s e l e c t e d
f o r p r o l i f i c a c y r a t h e r t h a n s h e e p m ore r e p r e s e n t a t i v e o f th e b r e e d .
C ro ssb red F in n s i n B r i t a i n have a l s o
shown s u p e r i o r p r o l i f i c a c y
com pared t o t h r e e t r a d i t i o n a l c r o s s b r e d g r o u p s . At a g e s I , 2 and 3+
y r , f e m a l e p ro g e n y from F in n s i r e and S c o t t i s h B l a c k f a c e ew es had
l i t t e r s i z e s o f 1.5, 2.0 , and 2.3, r e s p e c t i v e l y , w h i l e t h e c r o s s b r e d
a v e r a g e s fro m B o r d e r L e i c e s t e r , Clun F o r e s t , and D o r s e t Horn s i r e s
w e r e 1.1, 1.6, and 1.6, r e s p e c t i v e l y (D onald e t a l . , 1968).
E v a l u a t i o n o f F in n c r o s s e s (Fx) i n t h e U.S. b e g a n i n I 970 a t t h e
U.S. M eat and A nim al R e s e a r c h C e n t e r , Clay C e n t e r , N e b r a s k a . Under
p a s tu r e c o n d i tio n s c r o s s e s w ere made u s in g Finn and R am b o u ille t s i r e s
w ith
s e v e n b r e e d s o f ew es.
At I y r
o f age Fx ew es had h i g h e r
co n ce p tio n r a t e s th a n R a m b o u illet c r o s s e s (Rx), 85% vs 66%, and h ig h e r
t h a n p u r e b r e d a v e r a g e , 58%. At a g e s I , 2, 3, and 4 y r l i t t e r s i z e s
w e r e h i g h e r f o r Fx t h a n Rx, 1.55, 1.94, 2 .0 3 , and 2.25 vs 1.06, 1.38,
1.68,
1.51, r e s p e c t i v e l y ,
and h i g h e r th a n p u r e b r e d a v e r a g e ,
1.08,
I .3 2 , 1.52, 1.73, r e s p e c t i v e l y . O v e r a l l r e p r o d u c t i v e p e r f o r m a n c e f o r
the Fx was 28% g r e a t e r th a n th e R am bouillet c r o s s e s (D ickerson,
1977).
5
Under w e s te r n range c o n d i tio n s Fx s u p e r i o r i t y over th e average of
p u reb red Columbia,
R am b o u illet, and Targhees i n co n c e p tio n r a t e a t I
y r o f age w as e v e n m ore d r a m a t i c , 90.6% vs. 24.0%. L i t t e r s i z e was
a l s o s i g n i f i c a n t l y h i g h e r f o r Fx e w e s ,
1. 2 3 , 1.53 a t a g e s I ,
Knight,
'
2 , and 3+ y r ,
1.53,
1.90,
re sp e c tiv e ly
2.25 v s .
1.06,
( E r c a n b r a c k and
unp u b lish e d d ata).
The p r e li m i n a r y r e s u l t s c i t e d above i n d i c a t e t h a t u t i l i z a t i o n of
c r o s s b r e e d i n g s c h e m e s i n v o l v i n g F in n b r e e d i n g may be an a t t r a c t i v e
a lte rn a tiv e
for
im p ro v in g
c o n d itio n s.
The p r i m a r y
re p ro d u c tiv e
o b je c tiv e
of
e ffic ie n c y
th is
stu d y
is
under
to
ran g e
com pare
r e p r o d u c t iv e e f f i c i e n c y and wool p ro d u c tio n o f ewes composed o f 1/4
F in n b r e e d i n g w i t h s t r a i g h t b r e d C o lu m b ia , R a m b o u i l l e t , and T a rg h e e
ewes on w e s te r n range. The secondary o b j e c t i v e i s t o a n a ly z e breed of
s i r e e f f e c t s (F in n x R a m b o u i l l e t v s . s t r a i g h t b r e d r a m s )
k ilo g ra m s o f lamb weaned p e r ewe lambing.
on t o t a l
6
CHAPTER 2
LITERATURE REVIEW
F e rtility
In t h i s paper,
fe rtility
i s d e f i n e d a s t h e p r o p o r t i o n o f ew es
l a m b i n g r e l a t i v e t o ew es e x p o s e d t o t h e ram ( N i t t e r ,
1978). I n a
review of Finn c r o s s b r e d perform ance i n numerous c o u n t r i e s ,
M a ija la
and O s t e r b e r g ( 1977) fo u n d F in n b r e e d i n g c o n t r i b u t e d t o i n c r e a s e d
f e r t i l i t y o n l y i n ewe la m b s (ew es l a m b i n g a t a p p r o x i m a t e l y I y r of
age). I n B r i t a i n , B arker (1975) r e p o r t e d s l i g h t l y n e g a t i v e , a l t h o u g h
non—s i g n i f i c a n t , d i f f e r e n c e s i n f e r t i l i t y f o r m ature ewes between Finn
c r o s s e s and p u r e b r e d s . T hese r e s u l t s a r e i n a g r e e m e n t w i t h s t u d i e s
c o n d u c t e d u n d e r s e m i - i n t e n s i v e m anagem ent i n t h e U.S.
in v o lv in g
1/4Finn c r o s s e s (1/4Fx) compared w ith D orset x R am b o u illet (Thomas and
W hitem an, 1979); and I / 2 F in n ( I / 2Fx) compared w ith Border L e i c e s t e r
c r o s s e s ( O l t e n a c u and B o y la n , 1981a). H ow ever, u n d e r w e s t e r n r a n g e
c o n d itio n s
at
H o p elan d ,
C a lifo rn ia ,
1 /2 F x (x W h i t e f a c e ) have
d em o n strated s i g n i f i c a n t l y h ig h e r f e r t i l i t y a t ages 2 th ro u g h 5 than
1 /2 S u ffo lk (x W h ite face ), 98$ vs. 88$, r e s p e c t i v e l y (D ickerson,
1977).
E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d d a t a ) r e p o r t s i m i l a r r e s u l t s ,
a lth o u g h not s i g n i f i c a n t ,
b e t w e e n 1/2 F x (x W h iteface) and W hiteface
b reed s ag es 2 through 7 on w e s te r n range.
F e r t i l i t y i n ewe la m b s i s l a r g e l y a f u n c t i o n o f age a t p u b e r t y
(N itte r,
1978). Puberty may be d e f in e d a s t h a t p o in t when r e p r o d u c t io n
7
i s f i r s t p o s s i b le . Age a t p u berty i s u s u a l l y determ in e d by o b s e r v a tio n
o f f i r s t b e h a v io r a l e s t r u s (D ickerson and L a s t e r ,
1975;
Drymundssonf
1981). A l i s t o f f a c t o r s a f f e c t i n g age a t p u b e r t y w ould a t l e a s t
in c lu d e breed,
n u tritio n ,
breed-cross, year,
d a y lig h t,
and
d a te o f b i r t h ,
te m p e ra tu re
w eig h t a t breeding,
(L a ste r
et
a l.,
1972;
Drymundsson, 1981). Review of each of th e s e a r e a s i s beyond the scope
o f t h i s paper,
e f f o r t s w i l l be c o n c e n tr a te d on breed and b r e e d - c r o s s
effects.
Age a t p u b e r t y i n ewe la m b s i s
n o t o n ly o f i n t e r e s t f o r t h e
p o t e n t i a l o f r e d u c i n g t h e num ber o f n o n - p r o d u c t i v e ew es i n a f l o c k ,
b u t a l s o f o r i t s e f f e c t s on l i f e t i m e r e p r o d u c t i v e p e r f o r m a n c e . On
w e s t e r n r a n g e ewe la m b s who d i s p l a y b e h a v i o r a l e s t r u s d u r i n g t h e i r
f i r s t b re e d in g season,
but bred to lamb f i r s t a t 2- y r - o l d ,
have been
r e p o r te d to be more p ro d u c tiv e a t su b se q u en t ages th a n lam bs f a i l i n g
t o c y c l e ( H u l e t e t a l . , I 969; B u r f e n i n g e t a l . , 1972).
S e v e ra l s t u d i e s have r e p o r t e d s m a ll s i g n i f i c a n t breed d i f f e r e n c e s
i n ewe lambs o b ta in in g p u b erty i n t h e i r f i r s t b re e d in g " s e a s o n (Hulet
e t a l . , 1969; S o u th a n e t a l . , 1971; B u r f e n i n g e t a l . ,
1974). Due t o
w id e v a r i a t i o n s i n m anagem ent and e n v i r o n m e n t a t v a r i o u s r e s e a r c h
s ite s,
l a r g e d i f f e r e n c e s e x i s t b e t w e e n r e p o r t e d m eans among and
b e tw e e n b r e e d s (D rym undsson, 1981). R e s u l t s i n t h e l i t e r a t u r e may
r a n g e fr o m 0% i n e s t r u s d u r i n g f i r s t b r e e d i n g s e a s o n f o r M erin o ewe
la m b s i n A u s t r a l i a (W atson and Gamble, 1961), and 24% f o r C olum bia,
R am b o u illet, and Targhee ewe lambs on w e s te r n range (fiurfening e t a l.,
1972),
t o 90.0% and 51.4% ewe la m b s l a m b i n g a t 12 mo o f age f o r
8
S u f f o l k and T a r g h e e u n d e r s e m i - i n t e n s i v e m anagem ent ( O l t e n a c u and
Boylan, 1981a).
S tu d ie s in v o l v in g pure F inns i n d i c a t e c o n s i s t e n t l y high f e r t i l i t y
i n ewe la m b s i n v a r i o u s e n v i r o n m e n t s .
M a i j a l a (1977) r e p o r t s i n
F i n l a n d t h a t o v e r 90% o f t h e F in n ewe la m b s a r e b r e d t o la m b a t I y r
of age, and lam bs on a h ig h l e v e l of n u t r i t i o n breed a t 5 mo. S i m i l a r
i n d i c a t i o n s o f f e r t i l i t y were found i n S c o tla n d where 97% o f th e pure
F in n ewe l a m b s e x h i b i t e d e s t r u s a t 6 mo o f ag e (Land e t a l . , 1974).
R ep o rts o f
s u ch l a r g e
breed
d iffe re n c e s
in
age a t
p u b e rty
and
f e r t i l i t y i n ewe lam bs h a s l e d r e s e a r c h e r s t o ask "how” and "to what
degree" w i l l
in c o rp o ra tio n
o f F in n i n t o
sta n d a rd
breeds a f f e c t
f e r t i l i t y i n c r o s s b r e d progeny.
I n a s t u d y i n v o l v i n g F in n c r o s s e s (Fx) and R a m b o u i l l e t c r o s s e s
(Rx) w i t h s e v e n s t a n d a r d b r e e d s ( S u f f o l k , H a m p s h ire , R a m b o u i l l e t ,
D o r s e t , T a r g h e e , C o r r i e d a l e , and C o a rs e W ool), D i c k e r s o n and L a s t e r
(1975) r e p o r t e d s i g n i f i c a n t l y lo w er age a t p u b erty f o r Fx over Rx, 219
d and 238 d, r e s p e c t i v e l y . I n t h i s s t u d y la m b s w e r e b o r n e i t h e r i n
F e b r u a r y o r A p r i l and e x p o s e d t o v a s e c t b m i z e d ra m s f o r a b o u t 10 wk
p r i o r to November 10th. No breed by d a te i n t e r a c t i o n was r e p o r te d . Fx
la m b s w e r e 4 kg l i g h t e r a t p u b e r t y , b u t d i d n o t w e ig h s i g n i f i c a n t l y
l e s s th a n Rx a t 230 d o f age. The number of Fx lambs r e a c h in g puberty
by November IO th g r e a t l y e x c e e d e d t h e Rx la m b s ,
resp e c tiv e ly .
70.2% v s 36.4%,
While acknow ledging high r e p o r t s of f e r t i l i t y by Donald
and Read (1 9 6 7 ), D i c k e r s o n and L a s t e r s u g g e s t e d h e t e r o s i s p l a y e d a
l a r g e r r o l e th a n average gene e f f e c t s i n th e s u p e r i o r i t y of Fx lambs.
T h is s u g g e s t i o n was b a s e d on d a t a i n d i c a t i n g 41% m ore 1 /2 F x r e a c h e d
9
p u b e rty
by November
IO th
t h a n 3 /4 F x ( 3 /4 F x w e r e
n o t m e n tio n e d
e l s e w h e r e i n t h e s t u d y ) . Due t o a l a c k o f p u r e F i n n s , a h e t e r o s i s
e s t i m a t e was a v a i l a b l e only f o r Rx: 8$, n o n - s i g n i f i c a n t .
On the c o n tr a r y ,
C e d illo and Hohenboken (1977) found no d i f f e r e n c e
i n p e rc e n ta g e r e a c h in g p u b e rty or average age a t f i r s t e s t r u s between
S u f f o l k and C o lu m b ia ewe la m b s s i r e d by F in n ra m s v s t h o s e s i r e by
D orset,
Targhee,
C o r r ie d a le,
and Coarse Wool rams. But,
i n t h i s same
study a l a r g e d i f f e r e n c e i n f e r t i l i t y between Fx and s ta n d a r d c r o s s e s
was observed, 72% and 38%, r e s p e c t i v e l y .
While th e l i t t l e d a t a a v a i l a b l e on th e a f f e c t of Finn b re e d in g on
age a t p u b e r t y i s c o n t r a d i c t o r y , much e v i d e n c e e x i s t s u p p o r t i n g Fx
su p e rio rity fo r f e r t i l i t y
i n ewe lambs over purebred s ta n d a rd breeds
(see t a b l e I). Unweighted
av e ra g e s o f f e r t i l i t y f o r Fx ( e i t h e r 1/2 or*
1 /4 ) and s t a n d a r d p u r e b r e d s , w i t h w h ic h t h e F i n n s w ere c r o s s e d , a r e
l i s t e d w i t h i n th e r e s p e c t i v e s t u d ie s . Only i n one study,
Magid e t a l.
(1 9 8 1 b ), w e re Fx n o t r e p o r t e d s i g n i f i c a n t l y s u p e r i o r .
T h is s t u d y
co m p ared ewe la m b s s i r e d by e i t h e r B o r d e r L e i c e s t e r o r F in n r a m s ;
purebred com parisons were n o t r e p o r te d .
B ased on s i m i l a r l e v e l s f o r f e r t i l i t y f o r p u r e F i n n s (81%) and
F in n x M erin o (76%),
Land e t a l .
(1974) c o n c lu d e d t h a t t h e t r a i t
show ed h e t e r o s i s (87.7%) a t l e a s t " s u p e r f i c i a l l y " . I n t h e o n ly s tu d y
i n v o l v i n g p u r e F i n n s i n t h e U.S., O l t e n a c u and B o y la n (1 981 a) a l s o
r e p o r t e d s i m i l a r l e v e l s o f f e r t i l i t y b e t w e e n p u r e F i n n s (95.0%) and
F in n s c r o s s e d w i t h T a r g h e e , M in n e s o ta 100, and S u f f o l k : 9 4 .7, 94.1,
and 87.0,. r e s p e c t i v e l y .
Reported l e v e l s o f f e r t i l i t y
f o r th e Targhee,
M in n e s o ta 100, and S u f f o l k w e r e 5 1 .4 , 7 4 .7, and 90.0, r e s p e c t i v e l y ;
TABLE I .
Finn
Breeding
1/2
1/2
1/2
1/2
1/2
1/2
1/4
1/4
1/4
•
COMPARISON OF 1 / 2 AND 1 / 4 FINN CROSSES WITH STANDARD BREEDS FOR F E R T IL IT Y IN EWE LAMBS
S tandard Breeds
Involved i n Crosses
F e r t i l i t y (?)
Fx
S td.
R eference
Ml 00, S u f f o lk , Targhee
Columbia, R am bouillet, Targhee
S u f f o lk , R am bouillet, Targhee
C o r r ie d a le , D orset, Hampshire
Coarse Wool
Tasmanian Merino
Hampshire, R a m b o u ille t,Targhee
D o rse t, Targhee, C o rrie d a le
Coarse Wool
D orsetxR am bouillet
Columbia, R am bouillet, Targhee
Ml 00, S u f f o lk , Targhee
91.9
90.6
84
71.7
24.0
51
O ltenacu and Boylan (1981 a)
Ercanbrack and Knight (unpublished d a t a )
L a s t e r e t a l . , (1972)
81
78
72
5
78*
38
Land e t a l . (1974)
Magid e t a l . (1981b)
C e d illo and Hohenboken (1977)
80.5
76.1
79.2
56.5
24.0
71.7
Thomas and Whiteman (1979)
Ercanbrack and Knight (unpublished d a ta )
O ltenacu and Boylan (1981 a)
E s tim a te e q u a ls average of Finn and Border L e i c e s t e r c r o s s e s . Authors r e p o r te d no s i g n i f i c a n t
d i f f e r e n c e between Finn and Border L e i c e s t e r c r o s s ewe lam bs; purebred e s ti m a t e s not r e p o r te d .
11
e s t i m a t e s o f h e t e r o s i s w ere 29.5, 10.8, and -,5.9, r e s p e c t i v e l y .
These
r e s u l t s combined w ith th o se from Land e t a l . (1974) p o in t t o a s tr o n g
l i n k between i n c r e a s i n g e s t i m a t e s o f h e t e r o s i s f o r Finn c r o s s e s and
d e c r e a s in g f e r t i l i t y i n th e p u re b re d s i n c o r p o r a te d i n th e cro ss.
P ro lific a c y
In a d d i t i o n t o e a r l y age a t pu b erty , pure F inns a r e most noted f o r
e x c e p t i o n a l l y h ig h p r o l i f i c a c y ( l i t t e r s i z e ) , num ber o f la m b s b o rn
(dead or a l i v e ) p e r ewe lambing. The average l i t t e r s i z e f o r ewe lambs
i n F i n l a n d a v e r a g e s fro m 1.6 t h r o u g h 1.90 (Goot and M a i j a l a ,
M a i j a l a and O s t e r b e r g ,
1 977;
1977) i s w e l l above m a t u r e s h e e p o f any
s t a n d a r d b r e e d i n t h e U.S. M a i j a l a and O s t e r b e r g (I 977) r e p o r t t h a t
t h e l a r g e l i t t e r s i z e s c o n t i n u e t o i n c r e a s e w i t h age up t o 3 y r s o f
age., w i t h a v e r a g e s o f 2.39 and 2.75 f o r a g e s 2 and 3 y r . From ag e 3
onto a t l e a s t 8 y r old th e l i t t e r s i z e re m a in s c o n s ta n t.
U n w e ig h te d m eans o f p u r e F in n p e r f o r m a n c e i n o t h e r E u ro p e a n
c o u n t r i e s (not i n c lu d in g B r i t a i n ) ,
under v a r io u s management system s,
ag reed w ith th e r e s u l t s in F in la n d ,
a l t h o u g h t h e r e w as a s l i g h t
d e c l i n e a t 6 y r o f age. L i t t e r s i z e s w e r e 1.84, 2 .4 5 , and 2.82 f o r
a g e s I , 2 and 3+ y r , r e s p e c t i v e l y ( M a i j a l a and O s t e r b e r g , 1977). I n
B rita in ,
Donald and Read (1967) r e p o r t e d s i m i l a r r e s u l t s o f in c r e a s in g
l i t t e r s i z e t o 3 y r o f a g e , 2 .0 , 3 .0 , 3 .3 , 3 .4 , 3.4 f o r ew es a g e s I ,
2, 3, 4 and 5 y r , r e s p e c t i v e l y . I n t h e U.S.,
r e s u l t s f o r p u r e F in n s
a r e l i m i t e d t o one s t u d y r e p o r t i n g o n ly t h e f i r s t 3 y r . Yet th e d a t a
i s i n c l o s e a g r e e m e n t w i t h t h o s e r e p o r t e d by M a i j a l a and O s t e r b e r g
(1977); average l i t t e r s i z e was 156.8, 271.0, and 300.4 lambs born per
12
10O ew es e x p o s e d f o r a g e s 1 , 2 and 3 y r , r e s p e c t i v e l y ( O l t e n a c u and
Boylan, 1981a).
Of major concern t o com m ercial sheep managers
i s how w e ll t h i s
breed s u p e r i o r i t y i s t r a n s m i t t e d to progeny i n c r o s s b r e e d in g schemes.
The f i r s t F in n c r o s s b r e e d i n g p r o j e c t i n B r i t a i n d e m o n s t r a t e d c l e a r
s u p e r i o r i t y f o r l i t t e r s i z e o f 1 /2 F x o v e r s t a n d a r d b r e e d s . Fx ew es
a v e r a g e d 1.52, 2. 0 2 , and 2.30 la m b s b o r n p e r ewe l a m b i n g a t I , 2
and
3 y r of age; and, d i f f e r e n c e s between Fx and s ta n d a rd b reed s in c r e a s e d
w ith age:
.4 8 ,
.5 5 ,
and .79 a t a g e s I ,
2 and 3 y r ,
re sp e c tiv e ly
(D onald e t a l . , 1968). A l a t e r s tu d y i n B r i t a i n i n v o l v i n g d i f f e r e n t
b r e e d s fo u n d t h e same p a t t e r n . But t h e d i f f e r e n c e s w e r e s m a l l e r and
d i d n o t i n c r e a s e a s d r a m a t i c a l l y w i t h ag e . Fx m inus s t a n d a r d b r e e d
(Border L e i c e s t e r ,
S u ffo lk ,
and Clun F o r e s t) average was .30, .32, .39
f o r ages I , 2 and 3, r e s p e c t i v e l y (B arker, 1975).
S e v e r a l e x p e r i m e n t s c o n d u c t e d i n t h e U.S. have fo u n d s i m i l a r
r e s u l t s t o t h o s e i n B r i t a i n . L a s t e r e t a l . (1972) r e p o r t e d on. ewe
la m b s
from
cro sses
in v o lv in g
seven
b r e e d s o f dam and e i t h e r
R a m b o u i l l e t o r F in n s i r e s . Fx ew es la m b s h ad .58 m ore la m b s p e r ewe
l a m b i n g t h a n Rx ewe la m b s and .52 m ore t h a n p u r e b r e d . C e d i l l o e t a l .
(1977) r e p o r t e d a d i f f e r e n c e o f .44 b e tw e e n Fx and s t a n d a r d c r o s s e s
( D o r s e t , C h e v i o t , and Romney c r o s s e d w i t h C o lu m b ia and S u f f o l k ) ewe
la m b s . I n a more e x t e n s i v e s t u d y , O l t e n a c u and B o y la n (1 9 8 1 a ) fo u n d
l a r g e and s h a r p ly i n c r e a s i n g d i f f e r e n c e s i n l i t t e r s i z e betw een Fx and
th e
average
of
M in n e so ta
100
(Ml 0 0 ) ,
S u ffo lk ,
and
T arghee
p u r e b r e d s : .5 1 , .7 5 , and .86 a t a g e s I , 2 and 3. y r , r e s p e c t i v e l y .
13
Two s t u d i e s
under
h arsher
c o n d itio n s
on t h e
w e s te r n ran g e
d e m o n stra te t h a t Fx s u p e r i o r i t y f o r p r o l i f i c a c y i s n o t r e a l i z e d
only
i n s e m i - i n t e n s i v e m anagem ent s c h e m e s. At H o p land, C a l i f o r n i a t h e
average d i f f e r e n c e f o r ag es 2 through 5 between 1/2Fx and w h ite breeds
w as .60 ( D i c k e r s o n , 1977). E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d d a t a )
r e p o r t e d l a r g e d i f f e r e n c e s b e t w e e n 1 /2 F x and s t a n d a r d w h i t e - f a c e
breeds (Columbia, Targhee, and R am b o u illet) on w e s te r n r a n g e . . Fx ewes
e x c e e d e d th e s t a n d a r d b r e e d s by .47 a t I y r o f ag e. S u b s e q u e n t b r e e d
group d i f f e r e n c e s were n e a r l y i d e n t i c a l ,
.71 f o r ages 2 through. 7 yr.
S i m i l a r i t y b e tw e e n r e s u l t s u n d e r w e s t e r n r a n g e and s e m i - i n t e n s i v e
m an ag em e n t, a r e i n a g r e e m e n t w i t h c o n c l u s i o n s d raw n by Meyer and
Bradford (1973). Finn x Targhee and Targhees both on high and low feed
l e v e l s d em o n strated no t r e a tm e n t x genotype i n t e r a c t i o n f o r f e r t i l i t y
and p r o l i f i c a c y . The r e s e a r c h e r s c o n c l u d e d t h a t f e e d l e v e l s a r e o f
l i t t l e im p o rtan ce f o r e v a l u a t i o n of r e p r o d u c tiv e t r a i t s .
R e s u lts from s t u d i e s in v o lv in g 1/4Fx ewes a t v a r io u s ag es show a
r e d u c t io n i n p r o l i f i c a c y from 1/2Fx; however,
1/4Fx w ere s t i l l found
to be s u p e r i o r to the p u reb red s. The s m a l l e s t breed group d if f e r e n c e ,
was r e p o r t e d by Thomas and W h item a n (1979) u n d e r s e m i - i n t e n s i v e
management f o r ewe lam bs. 1/4Fx average l i t t e r s i z e was 1.1.7 compared
to
1.08 f o r R a m b o u i l l e t x D o r s e t s ,
a n o n -s ig n ific a n t d iffe re n c e
o f .09. Also under s e m i - i n t e n s i v e management, 1/4Fx ewes, produced by
b a c k c r o s s i n g 1 /2 F x w i t h t h e s t a n d a r d b r e e d s , w ere s u p e r i o r t o t h e
s t a n d a r d b r e e d s . 1/4 F x ewe la m b s s i g n i f i c a n t l y e x c e e d e d s t a n d a r d s
by .2 4 ;
w h ile l i t t e r
s i z e s from 2 y r o l d 1/4 F x w e r e .12 h i g h e r ,
alth o u g h n o n - s i g n i f i c a n t ( O ltenacu and Boylan,
1981),
14
Iro n ic a lly ,
under h a r s h e r w e s te r n range management, o v e r a l l breed
means f o r both 1/4Fx and sta n d a rd b reed s w ere much h ig h e r than under
s e m i - i n t e n s i v e management. I n a d d i t i o n , d i f f e r e n c e s betw een 1/4Fx and
s t a n d a r d b r e e d s w e re g r e a t e r i n m a g n itu d e . A c r o s s a g e s 2 t o 5 y r a t
Hopland, l i t t e r s i z e s were .32 h ig h e r f o r 1/4Fx (D ickerson, 1977). The
d i f f e r e n c e r e p o r t e d by E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d d a t a ) f o r
ewe lambs was h a l f as g r e a t , .16, but s i g n i f i c a n t . The amount by which
I / 4Fx e x c e e d e d t h e s t a n d a r d b r e e d s a t l a t e r a g e s (2 th o u g h 7 y r )
rem ained c o n s ta n t,
Cl e a r l y ,
.38 average.
t h e F in n h a s t h e a b i l i t y
to t r a n s m i t i t s
s u p e rio r
p r o l i f i c a c y to c r o s s b r e d progeny under v a r y in g management system s and
a t d e g r e e s o f b r e e d i n g a s .l o w a s 1 /4 . The q u e s t i o n now m ust be a s k e d
a s t o what g e n e t i c mechanism i s t h i s d i f f e r e n c e a t t r i b u t e d - h e t e r o s i s
or a d d i t i v e gene e f f e c t ?
In
an
ex p erim en t
in v o lv in g
pure
F in n s,
M e r in o s ,
and t h e i r
r e c i p r o c a l c r o s s e s , average p r o l i f i c a c y f o r ag es 2 through 4 was 2.68,
1. 0 0 , and 1.70, r e s p e c t i v e l y . E s t i m a t e d
h e t e r o s i s , c r o s s b r e d mean
m in u s t h e p a r e n t a l mean a s a p r o p o r t i o n o f th e p a r e n t a l mean, was
■7.6%.
T h erefo re,
be a t t r i b u t e d
no h e t e r o s i s was p r e s e n t and th e s u p e r i o r i t y could
t o a d d i t i v e g en e e f f e c t s
(Land e t
a l.,
1974).
r e s u l t s o f O ltenacu and Boylan (1981) a r e i n s tr o n g agreem ent.
d ata
d e m o n stra te d
sig n ific a n t.
h e te ro sis
( 10. 1%) a t
I yr
of
age,
but
The
Their
non­
However, a t ages 2 and 3 y r h e t e r o s i s was z e ro . The mean
o f t h e 1/4 F x a t I y r o f a g e f e l l a l m o s t e x a c t l y h a l f way b e tw e e n th e
m id -p a re n t v a lu e and th e s ta n d a rd breed average,
1.01 (1/4Fx) and 0.97
15
(m id -p a re n t). However, a t age 2 yr, th e 1/4Fx were lo w e r th a n th e mid­
p a r e n t v a lu e ,
but n o n - s i g n i f i c a n t .
There do e x i s t r e p o r t s i n th e l i t e r a t u r e of p o s i t i v e h e t e r o s i s f o r
p r o l i f i c a c y (T urner,
1969; S id w e ll and M i l l e r ,
1971a); however, most
average about 3% and a r e n o n - s i g n i f i c a n t ( H i t t e r ,
e s t i m a t e t h i s a u t h o r r e v i e w e d , 30%,
s ig n ific a n t
1978).
The h ig h e s t
i n v o l v e d Fx e w es, b u t was non­
(H ohen b o k en and C o c h ra n ,
1 97 6 ).
T h erefo re,
w h ile
d i f f e r e n c e s between Fx and s ta n d a rd b re e d s may v ary w ith environm ent
and age, th e com m ercial producer may ex p ec t, i n g e n e r a l, l i t t e r s i z e s
t o i n c r e a s e by t h e same p r o p o r t i o n o f F in n b r e e d i n g due t o a d d i t i v e
gene e f f e c t s .
S u rv iv a b ility
U tiliz a tio n
o f F in n b r e e d i n g t o i n c r e a s e
p ro lific a c y
may be
unw arranted i f c o r r e s p o n d in g l a r g e d e c r e a s e s i n s u r v i v a b i l i t y fro m
b irth
t o w e a n in g e x i s t .
F acto rs a f f e c tin g s u r v iv a b ility
(o r th e
converse, m o r t a l i t y ) i n lam bs a r e n u m e ro u s and o f t e n u n a c c o u n t a b l e .
Any l i s t o f f a c t o r s w o u ld
i n c l u d e b r e e d , b i r t h w e i g h t o f t h e la m b ,
n u t r i t i o n (p re-p artu m and p o s t-p a rtu m ), l i t t e r s i z e , age of ewe, sex,
season, and management system (B radford, 1972b; Jakubee, 1977). A ll of
th e s e f a c t o r s a r e im p o r ta n t to the com m ercial sheep p ro d u cer; however,
t h i s r e v i e w w i l l c o n c e n t r a t e on t h e g e n e t i c f a c t o r s : b i r t h weigh];,
l i t t e r size,
and breed.
S u b s t a n t i a l e f f e c t s o f l i t t e r s i z e on p o s t-p a rtu m lamb m o r t a l i t y
have been r e p o r t e d i n th e l i t e r a t u r e under v a r io u s environm ents. Under
adverse c o n d i tio n s tw in s have been found t o have 68% h ig h e r m o r t a l i t y
r a t e s than s i n g l e s (Sm ith, 1974). But, under more i n t e n s i v e management
16
i n w h ic h m o r t a l i t y r a t e s a r e l o w e r , t w i n s may h a v e i n e x c e s s o f 80$
h ig h e r m o r t a l i t y th a n s i n g l e s ( S id w e ll e t a l . ,
1962; S i d w e l l and
M i l l e r , 1971a; O l t e n a c u and B o y la n , 1981). The e f f e c t i s e v e n m ore
d r a m a t i c f o r la m b s b o r n a s t r i p l e t s ,
m o r t a l i t y th a n tw in s and s i n g l e s ,
o v e r 50$ and 2 00$ h i g h e r
r e s p e c t i v e l y (O ltenacu and Boylan,
1981).
I n a w e ll-p la n n e d study under two env iro n m en ts ( s e m i - i n t e n s i v e and
open p a s tu r e ) ,
P u rse r and. Young (1964) concluded t h a t m u l t i p l e b i r t h s
had no d i r e c t e f f e c t on s u r v i v a b i l i t y , but r a t h e r b i r t h w e ig h t was th e
m a j o r f a c t o r . Lambs o f e q u a l b i r t h w e i g h t , r e g a r d l e s s o f ty p e of
b irth ,
had equal s u r v i v a l .
Numerous s t u d i e s have r e p o r t e d e f f e c t s of
l i t t e r s i z e on i n d i v i d u a l b i r t h w e ig h ts ; tw in s w eighing on average 15
t o 20$ l e s s t h a n s i n g l e s ( P u r s e r and Young, 1964; B r a d f o r d , 1972b;
S i d w e l l and M i l l e r , 1971b, Magid e t a l . , 1981a), and t r i p l e t s 30 to
35$ l e s s t h a n s i n g l e s ( R a s t o g i e t a l . ,
1975; Magid e t a l . ,
1981a;
O ltenacu and Boylan, 1981b)
As p u r e F i n n s h a v e much h i g h e r l i t t e r s i z e s t h a n m o s t s t a n d a r d
breeds,
b i r t h w e i g h t s and s u r v i v a b i l i t y w ould be e x p e c t e d t o be
s u b s t a n t i a l l y lo w e r . M a i j a l a and O s t e r b e r g ( 1977) r e p o r t e d av erage,
b i r t h w eig h t of pure F inns a c r o s s a l l ages, and a t v a r i o u s l o c a t i o n s ,
t o be 2.57 kg. A lth o u g h n o t an a c c u r a t e c o m p a r is o n , b i r t h w e i g h t s i n
t h e U.S. a v e r a g e 4 t o 5 kg ( S i d w e l l and M i l l e r , 1971b; R a s t o g i , 1975;
D ickerson e t a l . , 1975). D e s p ite th e much lo w er b i r t h w e ig h ts , M a ija la
and O s t e r b e r g ( 1977) r e p o r t e d m o r t a l i t y a c r o s s a l l a g e s o f dams and
litte r
s i z e s , b e t w e e n b i r t h and 2 wk o f ag e , t o be 10 t o 15$. The
e f f e c t s o f l i t t e r s i z e and age o f dam w e re s i g n i f i c a n t .
M o rta lity
17
r a t e s o f lambs from y e a r l i n g s were tw ic e a s high as t h a t from m ature
ewes a t every l i t t e r s iz e . Lambs born a s q u i n t u p l e t s t o y e a r l i n g s had
m o r t a li ty - r a t e s i n e x c e ss o f 70/6.
Donald and Read (1967) r e p o r t e d s i m i l a r e s t i m a t e s f o r b i r t h w eight
o f p u r e F in n la m b s i n B r i t a i n . A verage b i r t h w e i g h t f o r s i n g l e s and
t w i n s was 2.8 kg and 2.2 kg, r e s p e c t i v e l y . I n c l u d i n g la m b s dead a t
b i r t h , F in n s had 38/6 m o r t a l i t y fro m b i r t h t o w e a n in g . D e s p i t e s e m i i n t e n s i v e m a n ag em e n t, m o r t a l i t y f o r la m b s b o rn a l i v e fro m b i r t h to
w e a n in g w as 255», a v e r a g e d a c r o s s a l l a g e s o f dam and l i t t e r s i z e s .
They a t t r i b u t e d th e high death l o s s e s t o low b i r t h w e ig h ts.
B ir th w e ig h ts fo r
p u r e F in n s h e e p i n
t h e U.S.
are
in
c lo se
agreem ent w ith th e r e s u l t s r e p o r t e d i n F in la n d and B r i t a i n . I n d iv id u a l
pure Finn lam bs from ewes had an average b i r t h w eig h t o f 2.60 kg, 1.00
(28/6) kg l e s s t h a n t h e s t a n d a r d b r e e d s (Ml 00, T a r g h e e , and S u f f o l k )
a c r o s s ages I , 2 and 3 y r (Oltenacu and Boylan, 1981b). As th e s e means
a r e a d ju s te d f o r type of b i r t h and p u re Finns had much l a r g e r l i t t e r
s i z e s , th e a c t u a l d i f f e r e n c e i n means would be l a r g e r . The d i f f e r e n c e
r e p o r t e d i n t h i s s t u d y may r e f l e c t t h e s m a l l e r m a t u r e w e i g h t o f t h e
F in n ewe, a l t h o u g h F in n la m b s a r e s m a l l r e l a t i v e t o m a t u r e ewe s i z e
( B r a d f o r d , 1972b).
I n c o r p o r a t i o n o f F in n b r e e d i n g i n t o s t a n d a r d b r e e d s h a s a l s o
served to reduce b i r t h w e ig h ts a t a l l ages. In B r i t a i n ,
1 /2 F x ew es
w ere found t o have c o n s i s t e n t l y lo w er b i r t h w e ig h ts th a n purebreds a t
ag es I , 2 and 3 yr. U nadjusted f o r type o f b i r t h the d i f f e r e n c e was on
a v e r a g e .5 kg (12%) l e s s t h a n p u r e b r e d a v e r a g e (D onald e t a l . , 1968;
B ark er, 1975).
18
Most o f t h e e s t i m a t e s o f d i f f e r e n c e s i n t h e U.S. f a l l b e tw e e n .3
and .9 kg l e s s f o r
t h e 1/2 F x t h a n s t a n d a r d b r e e d s ( D i c k e r s o n e t a l . ,
1 975; Magid e t a l . , I 981; O l t e n a c u and B o y la n , 1981, C o c h ra n e t a l . ,
1982,
E r c a n b r a c k and K n ig h t,
u n p u b lish e d d a ta ).
B ut one r e p o r t
i n v o l v i n g F i n n x Panama (FP) and Panama (P) p u r e b r e d s f o u n d S u f f o l k
s i r e d la m b s fro m FP ew es t o be s i g n i f i c a n t l y h e a v i e r a t b i r t h th a n
la m b s fro m P ew es by .89 kg (Dahmen e t a l . , 1 979). The s t u d y d i d n o t
r e p o r t i f type of b i r t h was in c lu d e d i n th e model. E s ti m a t e s f o r IA F x
a r e i n t e r m e d i a t e between 1/2Fx and p u re b re d s , ran g in g from .3 to .6 kg
l e s s t h a n t h e p u r e b r e d s ( O lte n a c u and B o y la n , 1981; C o c h ra n e t a l . ,
1992; Ercanbrack and Knight, u npublished d a ta ).
B ased on t h e l o w e r e s t i m a t e s o f b i r t h w e i g h t f o r l a m b s fro m Fx
dams, one would ex p ec t s u r v i v a b i l i t y to be lo w er as w e ll. But, d e s p i t e
sig n ific a n t
d iffe re n c e s
in
b irth
w e ig h t,
th is
au th o r
fo u n d
no
e s t i m a t e s o f s i g n i f i c a n t l y lo w er s u r v i v a b i l i t y i n lambs from 1/2Fx or
I M F x ew es a g e 2 y r o r o l d e r when ty p e o f b i r t h was n o t i n c l u d e d i n
th e model (Donald e t a l . ,
1968; B arker,
1975; D ickerson,
1977; Thomas
and W h item a n , 1979; C o ch ran e t a l . , I 982). Only two s t u d i e s r e p o r t e d
s i g n i f i c a n t l y l o w e r s u r v i v a b i l i t y f o r la m b s fro m Fx y e a r l i n g dams.
D onald e t a l . (1969) and B a r k e r (1975) b o th r e p o r t e d a b o u t 9% l o w e r
s u r v i v a b i l i t y f o r Fx th a n p urebreds when weaned a t about 90 d of age.
Although s t a t i s t i c a l l y n o n - s i g n i f i c a n t ,
s i m i l a r r e s u l t s w ere r e p o r te d
by D ickerson (1977) and Thomas and Whiteman (1979).
C o n f li c ti n g ,
but
s t a t i s t i c a l l y n o n - s i g n i f i c a n t r e s u l t s w e r e fo u n d by E r c a n b r a c k and
Knight (unpublished d a ta ) when lambs w ere r e a r e d on w e s te r n range and
weaned a t a p p ro x im a te ly 120 d of age . Lambs from 1/2Fx y e a r l i n g ewes
19
had 3/5 h ig h e r s u r v i v a b i l i t y th a n purebreds. These r e s u l t s may b ia s Fx
s u r v i v a b i l i t y upwards due t o th e management procedure which c r e d i t s a
ewe w i t h h a l f a la m b when s u c c e s s f u l l y r e a r e d by a n o t h e r ewe o r
a rtific ia lly .
E s t i m a t e s o f s u r v i v a b i l i t y u s i n g m o d e ls w h ic h i n c l u d e ty p e o f
b i r t h show i n c r e a s e d s u r v i v a b i l i t y w i t h i n c r e a s i n g a m o u n ts o f F in n
breeding.
O ltenacu and Boylan (1981a) found s ta n d a r d breeds and 1/4Fx
t o have s i m i l a r s u r v i v a l r a t e s f o r p e r c e n t of t o t a l born t o weaning;
however, 1/2Fx and p u re F inns exceeded s ta n d a r d breeds by 9% and 25%,
r e s p e c t i v e l y . H ow ever, D i c k e r s o n e t a l . (1975) r e p o r t e d ev e n more
d r a m a t i c d i f f e r e n c e s ; 1 /2 F x e x c e e d e d b o th Rx and p u r e b r e d s by more
t h a n 30%. I n c o n t r a s t ,
H ohenboken and C l a r k e (1981) f o u n d l o w e r
s u r v i v a l r a t e s f o r la m b s fro m 1 /2 F x dam s; a l t h o u g h ,
due t o t h e i r
s u p e r i o r p r o l i f i c a c y , . the Finn s u r v i v a b i l i t y was b ia sed downwards as
a l l la m b s i n e x c e s s o f 2 w e re rem o v e d fro m t h e dam and c o u n t e d a s
dead.
The l i t e r a t u r e r e v i e w e d s u g g e s t , t h a t no l a r g e breed d i f f e r e n c e s
e x i s t b e tw e e n F in n c r o s s b r e d s and s t a n d a r d
breeds,
or
t h a t any
m a t e r n a l h e t e r o s i s i s p r e s e n t . These c o n c l u s i o n s a g r e e w i t h o t h e r
r e p o r t s i n th e l i t e r a t u r e t h a t l i t t l e
t o no h e t e r o s i s has been found
in v o l v in g o t h e r s ta n d a rd breed c r o s s e s (Sidwe l I e t a l . ,
1962; S id w e ll
and M i l l e r , 1971a; R asto g i e t a l . , 1975; Hohenboken and Cochran, 1976;
N itte r,
1978).
J
20
I n d i v i d u a l Progeny Weaning Weight Perfnrmannm
The l a s t com ponent o f r e p r o d u c t i v e e f f i c i e n c y , i n d i v i d u a l lam b
weaning w eight perform ance, o f t e n r e c e i v e s th e most a t t e n t i o n from the
p ro d u c e r; how ever,
t h e t o t a l k i l o g r a m s o f lam b w eaned i s m ore a
f u n c t i o n of th e t o t a l number o f lam bs weanec? than th e i n d i v i d u a l lamb
w e ig h ts (Sidwe l I and M i l l e r ,
1971a). A com posite view o f th e p revious
s e c t i o n s of t h i s re v ie w would c l e a r l y s u g g e s t th e Finn c o n t r i b u t i o n to
t o t a l number of lambs weaned i s im p o r ta n t. Now th e q u e s t i o n becomes
w hether the g a in s r e a l i z e d i n number weaned from c r o s s b r e d Finns a re
negated or dampened by poor weaning w e ig h t performance.
Any l i s t o f t h e f a c t o r s a f f e c t i n g t h e w e a n in g w e i g h t o f la m b s
would a t l e a s t in c lu d e , breed, sex, type of b i r t h / r e a r i n g , age of dam,
age o f lamb, n u t r i t i o n ,
season, and management. Of th e en v iro n m e n ta l
f a c t o r s , ■ty p e o f b i r t h / r e a r i n g h a s t h e l a r g e s t e f f e c t on w e a n in g
w eight. A ll s t u d i e s have shown a n e g a tiv e e f f e c t on w eaning w eight due
to in c r e a s in g
re p o rts
th a t
ty p e
of b i r t h / r e a r i n g
w e a n in g
w e ig h ts
of
(B radford,
tw in s
reared
1972b).
as
B radford
s in g le s
fa ll
i n t e r m e d i a t e to w e ig h ts o f tw in s r e a r e d a s tw in s and s i n g l e s r e a r e d as
sin g le s,
s u g g e s tin g a permanent en v iro n m e n ta l e f f e c t due to type of
b i r t h . B ut, e v i d e n c e p u t f o r t h by Doney and Munro (1962) i n d i c a t e s
d i f f e r e n c e s i n w e a n in g w e i g h t a r e n o t due d i r e c t l y t o t y p e o f b i r t h
but
ra th e r
b irth
w e i g h t w hich i s
a fu n c tio n of l i t t e r
siz e
as
d i s c u s s e d e a r l i e r . The r e s e a r c h e r s f o u n d no d i f f e r e n c e i p w e a p in g
w e ig h t a t 90 d o f age between s i n g l e s r e a r e d as s i n g l e s and tw in s when
r e a r e d a s s i n g l e s from I d of age when a d j u s t e d f o r b i r t h w eight.
21
Due t o . a
la rg e
am ount
of v a r i a t i o n
in
m anagem ent no v a l i d
e s t i m a t e s a r e a v a i l a b l e f o r pure Finn i n d i v i d u a l w eaning w e ig h ts i n
F in la n d ; however, i n a review of e x p e rim e n ts in v o lv in g p u re Finn sheep
i n E u ro p e , M a i j a l a and O s t e r b e r g (1977) r e p o r t e d an a v e r a g e o f 18 kg
a t 90 d o f age.
A ll s t u d i e s r e v i e w e d by t h i s a u t h o r h a v e shown r e d u c e d lam b
weaning w e ig h ts due to th e i n c o r p o r a t i o n o f Finn b re e d in g when means
a r e u n a d ju ste d f o r type of b i r t h / r e a r i n g .
Barker (1975) found s i n g l e
and tw in lam bs from 1/2Fx dams l i g h t e r a t 70 d of age than purebreds.
The p u r e b r e d s u p e r i o r i t y i n c r e a s e d w i t h age r a n g i n g f r o m 1.1 kg f o r
t w i n s fr o m y e a r l i n g s t o 3.4 f o r s i n g l e s a t a g e s 3 and 4 y r . S i m i l a r
r e s u l t s h a v e b e e n r e p o r t e d i n t h e U.S. u n d e r b o th s e m i - i n t e n s i v e
management and w e s te r n range. Lambs from Fx ewes were
1.3 t o 2.7 kg
l e s s t h a n p u r e b r e d s a t 70 t o 105 d o f age ( C e d i l l o e t a l . ,
1977;
D i c k e r s o n , 1977). B u t i n c o n t r a d i c t i o n t o B a r k e r ( 1 9 7 5 ), when o n ly
s i n g l e s w e r e co m p ared D i c k e r s o n f o u n d no breed d i f f e r e n c e s e x is te d .
A lso i n
c o n tra d ic tio n ,
Magid
et
al.
(1981)
re p o rte d
no
breed
d i f f e r e n c e s between u n a d ju ste d weaning w e ig h ts o f lambs a t 50 d o f age
fro m Fx and B o r d e r L e i c e s t e r s i r e d ew es. T hese r e s u l t s may i n d i c a t e
th a t
th e l i m i t a t i o n s o f
th e m a te rn a l
e n v i r o n m e n t h a v e n o t been
exceeded a t such an e a r l y weaning d ate.
Thomas and W h item an (1979) a l s o fo u n d u n a d j u s t e d w e i g h t s t o be
s i g n i f i c a n t l y lo w e r f o r lam bs from Fx ewes when compared w i t h Dorset x
R a m b o u i l l e t . B ut, once t h e m odel i n c l u d e d ty p e o f b i r t h / r e a r i n g t h e
w e i g h t s w e re n o t s i g n i f i c a n t l y d i f f e r e n t . I n a g r e e m e n t w i t h t h e s e
r e s u l t s , O l t e n a c u and B o y l a n (1981b) r e p o r t e d no d i f f e r e n c e b e tw e e n
22
la m b s fro m p u r e F i n n s , I / 2Fx, and t h e t h r e e s t a n d a r d b r e e d s (M100,
Targhee,
and S u ffo lk ) when a d j u s t e d f o r type o f b i r t h / r e a r i n g .
from I A F x w ere s i g n i f i c a n t l y h e a v ie r th a n s ta n d a r d b reed s,
Lambs
but only
by 1.0 kg. E x clu sio n o f th e S u f f o lk breed from the s ta n d a r d breed and
Fx m eans r e s u l t s i n la m b s fro m p u r e F i n n s ,
e x c e e d in g
t h o s e fro m
1 /2 F x , and I A F x dams
T a rg h e e and M100 by 2 .0 ,
1.4,
and 2.3 kg,
re sp e c tiv e ly .
T h i s a u t h o r fo u n d no u n a d j u s t e d e s t i m a t e s o f m a te r n a l h e t e r o s i s
f o r i n d i v i d u a l la m b w e a n in g w e i g h t fro m
b re e d in g i n th e l i t e r a t u r e .
s t u d i e s i n v o l v i n g F in n
E s tim a te s i n t h e l i t e r a t u r e f o r m a tern al
h e t e r o s i s range from 0 t o 8% i n s t u d i e s in v o l v in g s ta n d a rd breeds, and
a r e c o n s i d e r e d o f m i n im a l i m p o r t a n c e ( S i d w e l l and M i l l e r ,
1971b;
Hohenboken and Cochran, 1976; Jakubec, 1977; N i t t e r , 1978).
Most o f th e s t u d i e s review ed above have u t i l i z e d a "meat" breed as
th e
sire
of th e
p ro g e n y fro m
t h e Fx and p u r e b r e d
r e s u l t i n g p r o g e n y a r e o n ly I A F x o r 1 /8 F x ,
dams.
As th e
d e p e n d i n g on t h e F in n
b r e e d i n g i n t h e dam, o n ly s m a l l d i f f e r e n c e s i n i n d i v i d u a l w e a n in g
w e ig h ts a d j u s t e d f o r type of b i r t h
a r e expected. The m ajor cause f o r
r e d u c t i o n s i n la m b w e i g h t s r e m a i n s l i t t e r s i z e , and t h e a s s o c i a t e d
l e s s th a n optimum environm ent f o r lamb grow th (Thomas and Whiteman,
1979).
T herefore,
perform ance
are
r e d u c t i o n s i n i n d i v i d u a l lam b w e a n in g , w e i g h t
to
be
e x p ec ted
under
any
s y s te m
of
b reed in g ,
n u t r i t i o n , o r management which s e r v e s t o in c r e a s e p r o l i f i c a c y .
)
23
Composite R eproductive Performance
I n c r e a s i n g p r o l i f i c a c y and f e r t i l i t y
f o r the com mercial sheep producer.
are in te rm e d ia te o b je c tiv e s
I n th e f i n a l a n a l y s i s ,
e v a lu a tio n
of th e c o n t r i b u t i o n t o r e p r o d u c t iv e perform ance of v a r y in g l e v e l s of
F in n b r e e d i n g w i t h s t a n d a r d b r e e d s m u s t c e n t e r on a c o m p o s i te o f
r e p r o d u c t iv e perform ance,
th e t o t a l k ilo g ra m s o f lamb weaned per ewe
exposed a t a l l ages.
U n f o r tu n a te ly ,
n o t a l l th e components o f th e th e above com posite
measurement a r e a v a i l a b l e i n each study, no r i s th e r e agreem ent among
sy stem s
of
a c c re d ita tio n
for
rearin g .
E stim a te s
of
pure
Finn,
perform ance a r e l i m i t e d to an average o f l i t t e r w e ig h ts a c r o s s F inland
u n d e r v a r i o u s m anagem ent s y s t e m s .
M a i j a l a and O s t e r b e r g
(1977)
r e p o r t e d t o t a l k ilo g ra m s per ewe lam bing f o r 2- y r - o l d and o ld e r ewes
o f 2 9 .1 , 4 5 .9 , 6 2 .8 , 8 7 . 8 , and 95.1 f o r l i t t e r s i z e s o f 1 , 2 , 3 , 4 and
5, r e s p e c t i v e l y . A v erag e l i t t e r w e i g h t a t 150 d o f a g e wa$ 7 1 kg. As
re p o rte d
e a rlie r,
fe rtility
fo r
p u r e F in n s h e e p i n
F in la n d
is
e x c e p t i o n a l l y h i g h ; t h e r e f o r e , e s t i m a t e s b a s e d on a p e r ewe e x p o s e d
b a s i s would n o t be c o n s id e r a b ly low er. These r e s u l t s a r e g a th e re d from
s m a ll system s of i n t e n s i v e management where s u p p le m e n ta tio n o f lambs
from l a r g e l i t t e r s i s r e g u l a r l y p r a c t ic e d .
On a p e r ewe l a m b i n g b a s i s , D onald e t a l . (1968) r e p o r t e d o n ly
s l i g h t d i f f e r e n c e s i n t o t a l l i t t e r w e i g h t b e tw e e n p u r e F i n n s and
s t a n d a r d b r e e d s ; h o w e v e r , a t a g e s 2 and 3 y r p u r e F i n n s r a i s e d 5.9 kg
and 9.5 kg m ore la m b , r e s p e c t i v e l y . T hese r e s u l t s r e f l e c t s m a l l e r
d i f f e r e n c e s i n p r o lif ic a c y - and h ig h e r lamb m o r t a l i t y r a t e s f o r Finn
24
y e a r l i n g s th a n s ta n d a r d breeds.
L arger d i f f e r e n c e s i n p r o l i f i c a c y a t
l a t e r ag es r e s u l t e d i n l a r g e d i f f e r e n c e s i n l i t t e r w eight.
Under s e m i - i n t e n s i v e m anagem ent i n t h e U.S.
p u r e F i n n s have
g r e a t l y e x c e e d e d s t a n d a r d b r e e d s ' (M l00, S u f f o l k , and T a rg h e e ) f o r
com posite r e p r o d u c t iv e perform ance. Y e a rlin g F inns weaned a t 70 d 10.7
kg (117%) m ore la m b t h a n t h e s t a n d a r d b r e e d s p e r ewe m a te d . Much o f
th is
d iffe re n c e
c o u ld
be a t t i b u t e d
to
su p e rio rity
f e r t i l i t y a t I y r of age. But, a t 2 y r of age
breeds
o f F in n s f o r
Finns exceeded sta n d a rd
by 19.6 kg (104%); F inn s u p e r i o r i t y f o r p r o l i f i c a c y being th e
m a jo r f a c t o r .
( O l t e n a c u and B o y la n ,
1981b).
From a c o m m e r c ia l
p ro d u cers v ie w p o in t th e s e r e s u l t s may be b ia se d i n f a v o r of th e Finns,
a s th e w e ig h ts of a l l lam bs r e a r e d a r t i f i c i a l l y were a c c r e d i t e d to th e
ewe.
C ro ssb red p erfo rm a n ce i n B r i t a i n w as r e p o r te d by B ark er (1975) on
a p er ewe ex p o sed b a s is .
Fx a d v a n ta g e o v er p u reb red s i n
t o t a l w e ig h t
w e a n e d w a s s i g n i f i c a n t o n l y a t I y r o f a g e (+3.3 k g ) . A t a g e s 2 and 3
y r th e Fx a d v a n ta g e w as s l i g h t l y p o s i t i v e ,
but n o n - s i g n i f i c a n t . B arker
c o n clu d e d
i n c r e a s i n g t o t a l k ilo g r a m s
th a t
th e F in n ’s
c o n t r ib u t io n
in
o f lamb weaned per ewe exposed i s p r i m a r i l y by i n c r e a s i n g f e r t i l i t y i n
ewe lambs.
T h is c o n c l u s i o n i s i n a g r e e m e n t w i t h t h e r e s u l t s r e p o r t e d by
Thomas and W hitem an (1979) f o r
management,
1 /4 F x ewes u n d e r s e m i - i n t e n s i v e
and by Hohenboken and Cochran (1981) f o r 1/2Fx ewes under
h i l l c o n d itio n s . Thomas and Whiteman found t o t a l w eig h t weaned a t 70 d
o f age f o r 1/4Fx y e a r l i n g ewes t o exceeded D orset x R a m b o q ille t by 3.5
kg, w h ile d i f f e r e n c e s a t 2 and 3 y r of age were only s l i g h t l y p o s i t i v e
25
and n o n - s i g n i f i c a n t .
These r e s u l t s l e d t o t h e c o n c l u s i o n t h a t t h e
m a j o r a d v a n t a g e o f 1/4 F in n b r e e d i n g i s i n c r e a s e d f e r t i l i t y i n ewe
lambs. Hohenboken an< Clarke (1981) fount} a 10 kg s u p e r i o r i t y f o r lamb
p r o d u c t i o n fr o m y e a r l i n g 1/2F x ew es o v e r s t a n d a r d b r e e d s ,
and no
d i f f e r e n c e s a t l a t e r a g e s . B u t, u n d e r m ore f a v o r i b l e c o n d i t i o n s on
i r r i g a t e d p a s tu r e 1/2Fx exceeded s ta n d a r d s a t a l l ag es r e s u l t i n g i n a
c u m m u la t iv e d i f f e r e n c e o f +36kg (27%) by age 5 y r . T hese r e s u l t s a r e
r e p o r t e d on a per ewe e n t e r i n g the e x p erim en t b a s i s , and would r e f l e c t
h a rd in e ss of
t h e ewe a s w e l l
th e re p r o d u c tiv e t r a i t s
d is c u s s e d
e a r l i e r . I n a d d i t i o n , ewes r e c e iv e d c r e d i t i n t h i s study only f o r the
w e ig h t o f lamb they a c t u a l l y r e a r e d th e m selv es.
Under w e s te r n range c o n d itio n s , E rcanbrack and Knight (unpublished
d a t a ) a l s o fo u n d 1/2 F x and 1/4F x t o e x c e e d p u r e b r e d s a t I y r o f age
f o r c o m p o s i t e r e p r o d u c t i v e p e r f o r m a n c e by 23.5 kg (452%) 13.8 kg
(265%),
resp ectiv ely .
The magnitude o f th e d i f f e r e n c e d ecre ase d from
a g e s 2 to 6 y r w ith a s l i g h t in c r e a s e a t age 7 y r. D if f e r e n c e s a t a l l
ages between Finn c r o s s e s and p u re b re d s were h ig h ly s i g n i f i c a n t .
The
cum mulative advantage o f 1/2Fx and 1/4Fx over ages I th ro u g h 7 y r was
107.8 kg (50%) and 63.5 kg (30%), r e s p e c t i v e l y . As m e n t i o n e d e a r l i e r
i n t h i s re v ie w ,
ewes were c r e d i t e d w ith h a l f th e w eig h t of a l l t h e i r
lambs r e a r e d a r t i f i c i a l l y or by a n o th e r ewe.
Due to v a r y in g system s of a c c r e d i t a t i o n and a n a l y s i s th e v e r d i c t
on th e F inns c o n t r i b u t i o n t o c r o s s b r e e d in g schemes in v o l v in g s ta n d a rd
b r e e d s i s n o t c l e a r . B u t, a l l t h e l i t e r a t u r e d o es p o i n t t o a c l e a r
s u p e r i o r i t y of F inns and Fx f o r f e r t i l i t y i n ewe lambs which r e s u l t s
i n in c r e a s e d k ilo g r a m s o f lamb weaned per ewe lamb exposed. I p term s
26
o f c o m m e r c i a l s h e e p o p e r a t i o n s , u t i l i z a t i o n o f F in n b r e e d i n g w i l l
red u ce the number o f u n p ro d u ctiv e ewes i n th e flo c k .
Wool
This rev ie w has been p r i m a r i l y aimed a t th e p o t e n t i a l c o n t r i b u t i o n
of the Finn breed to w ard s i n c r e a s i n g r e p r o d u c t i v e e f f i c i e n c y due to
t h e l a r g e p r o p o r t i o n o f g r o s s in c o m e d e r i v e d fro m t h e s a l e o f lam b
com pared t o w o o l. N e v e r t h e l e s s ,
t h e q u a l i t y and q u a n t i t y o f wool
produced re m a in s e c o n o m ic a lly im p o r ta n t t o th e w e s te r n range producer,
and should n o t bo overlooked i n e v a l u a t i n g any in tro d u c e d breed.
I n F i n l a n d t h e q u a n t i t y and q u a l i t y o f wool a r e c o n s i d e r e d o f
secondary im p o rta n c e ,
and b r e e d s o t h e r t h a n t h e F in n a r e b e t t e r
adapted f o r th e p ro d u c tio n of wool.
Pure F inns i n F in la n d produce on
a v e r a g e 2,7 kg o f g r e a s e w ool p e r y r , h a v e l o n g s t a p l e l e n g t h s , and
h a v e a g r a d e a v e r a g e a ro u n d 3 / 8 b lo o d ( M a i j a l a and O s t e r b e r g , 1977).
S i m i l a r r e s u l t s were r e p o r t e d from B r i t a i n where pure F in n s had f l e e c e
w e i g h t s o f 2.2 kg w i t h 3 / 8 t o 1 /2 b lo o d g r a d e s (D onald and Read,
1967).
I n t h e U.S. O l t e n a c u and B o y la n (1981b) r e p o r t e d a v e r a g e g r e a s e
f l e e c e w e i g h t s f o r p u r e F i n n s o f 2.0 kg and 2.2 kg f o r a g e s I. and 2
y r , r e s p e c t i v e l y , compared to
s ta n d a r d breed av era g es (Ml 00, S uffolk,
and T a r g h e e ) o f 3.2 kg and 3.4 kg. From t h e s e
e s t i m a t e s p u r e F in n s
have ap p ro x im a te ly 35% l i g h t e r g re a s e f l e e c e w eight.
Wool g ra d e s f o r
the pure Finn f e l l between 1/4 and 3/8 blood; grades f o r th e purebred
v a r i e d w id e ly due t o t h e breeds involved.
27
I n th e same study,
1/2Fx $wes had f l e e c e w e ig h ts s l i g h t l y h ig h e r
th a n th e m id - p a r e n t v a lu e ,
tra it.
d e m o n s tr a tin g about
8%
h e t e r o s i s f o r th e
E s t i m a t e s o f h e t e r o s i s f o r g r e a s e f l e e c e w e i g h t h a v e been
r e p o r t e d b e f o r e r a n g i n g fr o m 0 t o 27%; h o w e v e r , S i d w e l l and M i l l e r
(1971c) concluded t h a t more s t u d i e s w ere r e q u i r e d b e f o r e e s t a b l i s h i n g
the e x i s t e n c e of h e t e r o s i s i n wool t r a i t s .
The s u p e r i o r i t y o v e r t h e m i d - p a r e n t mean was m a i n t a i n e d i n t h e
1/4 F x a s t h e i r a v e r a g e w e i g h t s w e re t h e same a s t h e 1 /2 F x a t b o th I
and 2 y r o f age. 1 /2 F x w ool g r a d e s w e r e s i m i l a r t o p u r e F i n n s , w h i l e
th e 1/4Fx were no c o a r s e r th a n the s ta n d a rd breeds. Breed d i f f e r e n c e s
i n q u a l i t y and q u a n t i t y w e re c o n s i s t e n t a c r o s s a g e s I , 2 , and 3 y r
( l i m i t e d d a ta r e p o r t e d f o r age 3).
I n a study in v o lv in g ewes from S u f f o lk and Columbia dams crossed
w i t h e i t h e r F in n , D o r s e t ,
C h e v i o t,
o r Romney s i r e s ,
no c r o s s b r e d
d i f f e r e n c e s e x i s t e d f o r wool g r a d e . D e s p i t e h a v i n g s i m i l a r s t a p l e
l e n g t h s t o Romenys, Fx ew es had s i g n i f i c a n t l y l i g h t e r w e i g h t s ( - .3
kg) t h a n t h e c r o s s b r e d a v e r a g e . S i m i l a r i t y i n w ool g r a d e s i s t o be
expected a s a l l the o th e r s i r e b re e d s t y p i c a l l y have g ra d e s averaging
from 1/4 to 3 /8 .
I n com parison w ith Columbia,
R am b o u illet,
and Targhee breeds on
w e s te r n ra n g e , 1/2Fx and 1/4Fx had c o n s i s t e n t l y l i g h t e r f l e e c e w e ig h ts
a t a g e s I t h r o u g h 7 y r t h a n t h e w h i t e f a c e b r e e d s by 1.10 kg and .48
k g, r e s p e c t i v e l y . D i f f e r e n c e s i n g r a d e s w e re c o n s i s t e n t a c r o s s a l l
ages,
1/2Fx w ere of lo w er grade w ith 1/4Fx i n t e r m e d i a t e (Ercanbrack
and Knight,
u npublished d ata). But, i n a p re v io u s study in v o l v in g the
28
same g r o u p s o f s h e e p Drpmmond e t a l . (1982) fo u n d no d i f f e r e n c e s i n
q u a l i t y o f y a r n s o r f a b r i c s produced by th e th r e e breed groups.
' A s t u d y i n v o l v i n g Panama and F i n n x Panama ew es Dahmen e t a l .
(1978) r e p o r t e d average Panama g r e a s e f l e e c e w eight t o exceed the Fx
by 1.1 kg and 1.5 kg a t I and 2 y r o f age. At 2 y r o f age Fx ew es w a re
fo u n d t o h a v e s i g n i f i c a n t l y s m a l l e r a v e r a g e f i b e r d i a m e t e r ( f i n e r
f l e e c e ) , ev e n th o u g h v i s u a l e s t i m a t e s had p r e v i o u s l y r a n k e d t h e Fx
lo w e r i n wool grade th a n th e Panama.
29
CHAPTER 2
MATERIALS AND METHODS
P o p u la tio n s
From I 974 t h r o u g h 1977 a t t h e M ontana A g r i c u l t u r a l E x p e r im e n t
S t a t i o n , Red B l u f f R e s e a r c h Ranch, N o r r i s , Mt., a p p r o x i m a t e l y 240
w e s t e r n r a n g e ew es o f a g e s 2 t h r o u g h 6 y r , com posed o f c o m p a r a b le
n u m b e rs o f C o lu m b ia (C),
R a m b o u i l l e t (R),
and T a rg h e e (T),
w e re
exposed t o F in n is h Landrace x R a m b o u ille t rams (FxR).
The (FxR) rams
were o b ta in e d from th e U. S. Sheep Experim ent S ta t io n ,
Dubois, Idaho.
I n a d d i t i o n , a p p ro x im a te ly 360 s t r a i g h t b r e d , w h ite fa c e ewes (WF) ages
o f 2 t h r o u g h 6 y r , cpm posed o f C, R, and T i n n e a r l y e q u ^ l n u m b e rs ,
w ere m a in ta in e d a s c o n t r o l s , ^o c r o s s e s w ere made between t h e t h r e e WF
g r o u p s . P e r f o r m a n c e o f t h e 563 ew es w h ic h la m b e d and o f t h e i r 821
progeny was d e s ig n a te d "Phase I" o f t h i s study ( t a b l e 2).
All h e a l th y fe m a le 1/4Fx lam bs from Phase I were r e t a i n e d i n the
f l o q k e a c h y e a r , t o t a l l i n g 146 f o r 4 y r . Each y e a r a p p r o x i m a t e l y t h e
same number o f WF lam bs a s 1/4Fx lam bs, r e p r e s e n t i n g a l l t h r e e breeds
comparably,
were s e l e c t e d randomly from th e c o n tr o l group,
143 f o r 4 y r .
to ta llin g
P h ase I I o f t h i s s t u d y i n v o l v e d t h e la m b and wool
p r o d u c t i o n o f 289 ew es fro m t h e s i x b r e e d g r o u p s , C, R, T, (FxR)xC,
(FxR)xR, and (FxR)xT, f o r a t o t a l o f 1264 s p r in g lam bing o p p o r t u n i t i e s
from I 976 t o 1982 a c r o s s a g e s I t o 6 y r ( T a b l e 3). B e g i n n in g a s ewe
lambs,
a t a p p r o x i m a t e l y 7 mo o f a g e ,
b o t h 1/4F x and WF ew es w e re
30
TABLE 2. TOTAL NUMBER OF PHASE I EWES
LAMBING
LAMBING BY YEAR
AND AGE
AT
Age a t lambing
Year
2
3
4
5
6
1975
18
26
23
20
——
87
1976
51
46
47
27
22
193
1977
51
57
33
32
17
190
1978
18
34
32
9
138
163
135
88
T otal
Total
93
39
TABLE 3. TOTAL NUMBER OF PHASE I I EWES EXPOSED IN PREVIOUS
SEASON BY YEAR AND AGE IN YEARS AT LAMBING
563
BREEDING
Age a t lambing
Year
I
2
3
4
5
6
1976
42
—
——
—
—
—
42
1977
88
38
—
——
——
—
126
1978
80
84
35
—
—
—
199
1979
79
84
73
42
—
—
278
1980
——
73
77
65
39
—
254
1981
——
—
58
67
55
33
213
1982
——
——
—
51
56
45
152
243
225
150
78
1264
TOTAL
289
279
Total
31
exposed to S u f f o lk rams th roughout th e b re e d in g season f o r y e a r s 1976
t o 1979. From 1980 t o 1982 ewes were randomly d iv id e d i n t o two groups
and exposed t o e i t h e r FxT o r S u f f o lk rams.
Management
A ll P h ase I and I I m a t u r e ew es ( a g e s 2 th r o u g h 6 y r ) from each
breed group were herded a s one band on th e range th roughout th e y ear
w i t h t h e e x c e p t i o n o f b r e e d i n g and l a m b i n g s e a s o n s . Ewe la m b s w ere
m anaged s e p a r a t e l y fro m w e a n in g u n t i l m i d - A p r i l on a f t e r m a t h hay
meadows r e c e i v i n g an a d d i t i o n a l 150 g. of supplem ent (ap p ro x im ate ly
1556 p r o t e i n , 7356 TDN) composed of b a r le y (62.556), w h e a tm ill run (30$),
cane m o lasse s (6.25$), u re a (1$), t r a c e m i n e r a ls (.25$), and D icalcium
Phosphate (.25$) w ith v it a m i n s A and D added (.25$).
From th e second week i n November to th e end o f December, a l l ewes
w e re b re d i n s m a l l p a s t u r e s .
Common "sh e d l a m b in g " p r a c t i c e s w ere
f o l l o w e d a t l a m b i n g , m i d - A p r i l t h r o u g h May, e x c e p t i n 1976 and 1977
when 65 and 80 P hase I ew es la m b ed on open p a s t u r e .
At t h i s t i m e
l a m b 's i d e n t i f i c a t i o n , dam 's i d e n t i f i c a t i o n , s e x , b i r t h d a t e , b i r t h
w eight (BWT), and type of b i r t h were re c o r d e d ;
a l l lam bs were docked
and male lambs were c a s t r a t e d . B ir th d a te and w eight f o r th e 205 Phase
I la m b s b o rn on p a s t u r e w ere n o t r e c o r d e d . Lambs w e re w e ig h e d t w i c e
s u b se q u e n tly ,
once i n th e m iddle of June (ap p ro x im ate ly 60 d of age,
WT60) and a g a in th e l a s t week i n August a t weaning (ap p ro x im a te ly 120
d o f age,
WTI20). Ewes were shorn d u rin g th e f i r s t week o f A pril each
y e a r e x c e p t i n I 981 when s h e a r i n g o c c u r r e d i n t h e l a s t week o f May.
Ewes were removed from Phase I I p r i o r to b reed in g a t s i x y e a r s of age,
32
o r a t e a r l i e r a g e s due t o u n s o u n d n e s s su c h a s m a s t i t i s ,
e t c . . . ; no
ewes w ere removed based on perform ance.
The r a n g e s i t e i s c h a r a c t e r i z e d by a 25 t o 35 cm p r e c i p i t a t i o n
zone,
w i t h san d y and s i l t y
s o ils,
d o m i n a te d by I d a h o f e s c u e and
b lu e b u n c h w h e a t^ g ra s s , aqd c l a s s i f i e d i n good c o n d i t i o n . D u r in g t h e
b reed in g seaso n th e ewes were f lu s h e d w i t h f i r s t c u t t i n g g r a s s hay and
g r a i n . D u r in g g e s t a t i o n ew es r e c e i v e d .2 kg p e r h e a d p e r day o f t h e
same supplem ent a s th e ewe lambs. Only under s e v e re w in te r c o n d itio n s
when snow a c c u m u l a t i o n p r e v e n t e d g r a z i n g d i d t h e ew es r e c e i v e hay
( a p p r o x i m a t e l y 5 d p e r y e a r ) . S t a r t i n g A p r i l I e a c h y e a r t h e ew es
r e c e iv e d an a d d i t i o n a l 1/2 kg of b a r le y p er sheep. In th e lam bing pens
f i r s t c u t t i n g hay was provided f r e e choice.
A fte r th e lam bing perio d
ewes were r e tu r n e d t o th e range.
T r a i t s S tudied
T r a i t s a s s o c i a t e d w i t h b r e e d g ro u p d i f f e r e n c e s i n o v e r a l l lamb
p ro d u c tio n , t o t a l k ilo g ra m s o f lamb weaned per ewe exposed, and wool
p r o d u c t i o n w e r e o f p r i m a r y i n t e r e s t . C om ponents o f la m b p r o d u c t i o n
measured ;Ln t h i s study c o n s is te d of ewe f e r t i l i t y ,
lamb s u r v i v a b i l i t y ,
ewe p r o l i f i c a c y ,
and i n d i v i d u a l lamb w eig h ts. For t,he purposes of
t h i s ex p erim en t f e r t i l i t y
was d e f i n e d a s t h e p e r c e n t a g e o f ew es
lam bing o f those exposed f o r breeding. Ewe p r o l i f i c a c y was d e fin e d as
the number o f lambs born per ewe lam bing. S u r v i v a b i l i t y was measured
a t m i d - l a c t a t i o n (S60), a t a p p ro x im a te ly 60 d, and a t w eaning (S120),
a p p ro x im a te ly
120 d o f
age.
S u rv iv a b ility
was
d e fin e d
p e rc e n ta g e of lambs a t th e r e s p e c t i v e ages o f those born,
as
th e
and coded 0
33
and I f o r dead and a l i v e ,
resp e c tiv e ly ,
f o s s e s in c lu d e d s t i l l b i r t h s ,
lam bs removed from th e ewe to be r e a r e d a r t i f i c i a l l y or by a n o th e r ewe
n o t i n t h e s t u d y , and la m b s t h a t d i e d p r i o r t o w e i g h i n g . C o m p o s ite
t r a i t s f o r re p ro d u c tiv e perform ance c o n s is te d of l i t t e r
s i z e and
l i t t e r w e i g h t a t m i d - l a c t a t i o n (LS60 and LW60), and l i t t e r s i z e and
l i t t e r w e i g h t a t y e a n i n g (L S I20 and LWI? p ). C o m p o s ite t r a i t s
yere
m e a su re d on a p e r ewe l a m b i n g b a s i s i n P h ase I and on a p e r ewe
exposed b a s i s i n Phase I I .
Wool c h a r a c t e r i s t i c s s tu d ie d in c lu d e d k ilo g ra m s o f g re a s e f l e e c e
w e i g h t , g r a d e , and f i b e r l e n g t h . F l e e c e s w e re g r a d e d b a s e d on th e
" b lo o d " s c a l e and t h e n coded I t h r o u g h 5: F in e ( I ) , 1 /2 ( 2 ) , 3 / 8 (3 ),
1 /4 (4 ), and lo w 1 /^ (5). L e n g t h s w ere coded a s S t a p l e ( I ) , F r e n c h
( 2 ) , and C l o t h i n g (3).
S t a t i s t i c a l Methods
A ll d a t a w e re a n a l y z e d a c c o r d i n g t o t h e p r o c e d u r e d e s c r i b e d by
Harvey (1975) f o r l e a s t s q u a r e s a n a l y s i s of d a t a w ith unequal s u b c la s s
n u m bers.
The f i x e d - e f f e c t s m odel f o r P h ase I and I I m a t u r e ewe
r e p r o d u c tiv e perform ance in c lu d e d th e f a c t o r s breed group of ewe (B),
breed group q f lam b's s i r e (S), age o f ewe a t lam bing (A), and y e a r of
lam bing (Y). A ll p o s s i b le two-way i n t e r a c t i o n s b e tw e e n m a in e f f e c t s
were t e s t e d (P<.10) i n p r e li m i n a r y a n a ly se s.
R e s u lts i n d i c a t e d BxA to
be th e o n ly i n t e r a c t i o n s i g n i f i c a n t f o r any o f t h e t r a i t s ; RxA was
in c lu d e d i n a l l a n a ly s e s ,
except LW60 and LWI20 i n Phase L Composite
t r a i t s f o r t o t a l k i l o g r a m s r e a r e d t o 60 and 120 d o f a g e p e r ewe
34
exposed w ere not a d j u s t e d f o r sex,
type of b i r t h / r e a r i n g ,
and d a te of
b irth .
The b a s ip f i x e d - e f f e c t s model f o r Phase I and I I i n d i v i d u a l lamb
s u r v iv a l, and w eig h t t r a i t s f o r m ature ewe progeny in c lu d e d th e f a c t o r s
b r e e d g ro u p o f dam (B ), b r e e d g ro u p o f s i r e ( S ) , age o f dam (A), y e a r
(Y), sex (X), and type of b i r t h / r e a r i n g (BR). P r e lim in a ry a n a l y s i s f o r
s i g n i f i c a n c e (P<.10) o f a l l p o s s i b l e tw o-w ay i n t e r a c t i o n s i n d i c a t e d
t h a t BxY end SxY s h o u ld be i n c l u d e d i n t h e f i x e d - e f f e c t s m o d e ls f o r
P hase I ,
and t h a t AxBR be i n c l u d e d i n
t h e m o d e ls f o r P hase I I .
Q u a d ra tic r e g r e s s i o n on b i r t h w e ig h t was in c lu d e d i n th e models f o r
e ac h t r a i t o t h e r t h a n b i r t h w e i g h t and s u r v i v a l from 60 t o 120 d. I n
Phase I , 205 lam bs, born on p a s tu r e , had no b i r t h w eig h t re c o rd e d , and
con seq u en tly were not in c lu d e d i n th e a n a l y s i s o f i n d i v i d u a l progeny
p e r f o r m a n c e . ( A n a l y s i s o f c o m p o s i t e t r a i t s , l e t t e r s i g e and w e i g h t ,
f o r Phase I ewes in c lu d e d a l l 8 2 1 lambs born.) Q u ad ratic r e g r e s s i o n on
b i r t h d a te was in c lu d e d i n model f o r b i r t h w eig h t; l i n e a r r e g r e s s i o n
on b i r t h d a t e was in c lu d e d i n th e f i x e d - e f f e c t s models f o r 60 and 120
d w e ig h ts. A d d itio n a l a n a ly s e s of a l l t r a i t s was conducted w ith type
o f b i r t h / r e a r i n g main e f f e c t and r e g r e s s i o n on b i r t h w eig h t removed
from th e model.
As a r e s u l t o f o n l y tw o ewe la m b s o u t o f 143 c o n c e i v i n g fro m t h e
WF g r o u p , a s e p a r a t e a n a l y s i s o f v a r i a n c e f o r ewe la m b r e p r o d u c t i v e
perform ance
was c o n d u c t e d . The f i x e d - e f f e c t s m odel f o r ewe lam b
r e p r o d u c t iv e perform ance in c lu d e d breed group (B),
y e a r (Y),
and BxY
i n t e r a c t i o n . F i x e d —e f f e c t s m odel f o r ewe la m b i n d i v i d u a l p ro g en y
35
t r a i t s i n c l u d e d B, Y, X, ty p e o f b i r t h / r e a r i n g , and r e g r e s s i o n s on
b i r t b d a t e ( l i n e a r ) and b ir t h w e i g h t ( q u a d r a tic ) .
The f i x e d - e f f e c t s model f o r wool p ro d u c tio n t r a i t s in c lu d e d breed
g ro u p o f ew e’s dam (D), b r e e d g r o u p o f ew e’s s i r e
(S)t
age
p o ssib le
of
ewe
(A).
P re lim in a ry
a n a ly sis
of
a ll
y e a r (Y), and
tw o-w py
i n t e r a c t i o n s i n d i c a t e d t h a t DxS, DxY, SxY, and SxA should be in c lu d e d
i n th e f i x e d e f f e c t s model.
T e s t o f s i g n i f i c a n c e p r o c e d u r e s d e s c r i b e d by H arvey (1975) f o r
a n a ly sis
v a ria b le s.
of v a ria n c e
a ssu m e
norm al
d istrib u tio n s
D i s t r i b u i t o n s f o r ewe f e r t i l i t y
of
dependent
and la m b s u r v i v a l a r e
b in o m ia l; and a l s o , p r o l i f i c a c y does n o t f o llo w a normal d i s t r i b u t i o n .
C o n seq u en tly ,
te sts
of
sig n ific a n c e
a c c u r a t e l y d e s c r ib e th e p o p u la tio n s .
fo r
th e se
tra its
may n o t
36
CHAPTER 3
RESULTS AND DISCUSSION
M ature Ewe and P rogeny P eform an oe i n P hase I
B reed Group o f S ir e E f f e c t s
Mean s q u a re s from a n a l y s i s o f v a r ia n c e f o r Phase I a r e p re s e n te d
in
t a b l e s 4 and 5.
in d iv id u a l
p ro g e n y
L ea st-sq u a res
perform ance
m eans f o r
by
breed
ewe p r o d u c t i o n and
g ro u p o f
sire
(S) a r e
p r e s e n t e d i n t a b l e s 6 and ?• Ewes b r e d t o FxR ra m s e x h i b i t e d n e a r l y
id e n tic a l le v e ls of p r o lif ic a c y ,
had l a r g e r ,
but not s i g n i f i c a n t ,
l i t t e r s i z e s and w e i g h t s a t 60 d, and w eaned more lambs. (P<.1 0) and
more t o t a l k ilo g ra m s of lamb p e r ewe lam bing (P<.05) th a n ewes bred to
WF ra m s . Land e t a l . (I 974) r e p o r t e d no d i f f e r e n c e s i p f e r t i l i t y or
p r o l i f i c a c y between ewes bred t o e i t h e r F inn or Tasmanian Merino rams,
e v e n th o u g h ew es o f t h e two b r e e d s d i f f e r g r e a t l y i n p r o l i f i c a c y .
F u rth e rm o re ,
B radford
(1972b) i n d i c a t e s
th a t d if f e r e n c e s in
p r o l i f i c a c y a r e more a f u n c t i o n o f g e n o t y p e o f t h e dam r a t h e r t h a n
genotype of th e o f f s p r in g .
B irth
lig h te r.
w e i g h t s o f la m b s s i r e d
Magid e t
al.
by FxR w e re n o t s i g n i f i c a n t l y
(1981) fo u n d
pure
F in n
sire s
to
produce
c r o s s b r e d lam bs w ith l i g h t e r BWT th a n Border L e i c e s t e r rams. D espite
l i g h t e r BWT ( n o n - s i g n i f i c a n t ) , 1 /4 F x la m b s had b e t t e r s u r v i v a b i l i t y
(P < .0 1 ) from
b irth
to
60 d
t h a n WF l a m b s ;
how ever,
in c re a se d
TABLE 4 .
MEAN
SQUARES
FROM
LAMBING ( 1 9 7 5 -
ANALYSES
OF
VARIANCE
FOR
PHASE I
EWE
REPRODUCTIVE TRAITS PER
EWE
1978)a
Source
df
P ro lificacy
LS60
LW60
LSI 20
LWI20
Breed o f dam (B)
Breed of s i r e (S)
Year (Y)
Age of dam (A)
BxA
E r r o r MS
E rro r df
2
I
3
4
8
.992*
.008
'1 6 6 , ,
3.606
.421 +
.221
544
1.680**
.7011
.5 3 8 ,,
4.355
.439
.283
544
693**
1.664**
1.012+
2444**
1718
4.125
.269
.295
544
5257
———
319
552
a LS60, l i t t e r s i z e a t 60 d ;
w eight a t 120 d.
t p < . io
%
1915
———
95
552
LW60, l i t t e r w eight a t 60 d; LSI20, l i t t e r s i z e a t 120 d; LWI20, l i t t e r
FROM ANALYSES OF VARIANCE
TABLE 5. MEAN SQUARES
- 1978)a
FOR PHASE I INDIVIDUAL PROGENY TRAITS TRAITS (1975
Source
df
BWT
S60
WT60
SI 20
WTI20
Breed o f dam (B)
Breed of s i r e (S)
Year (Y)
Age of dam (A)
Sex (X)
Type of b i r t h /
r e a r i n g (BR)"
BxY
SxY
R eg ressio n s
BDT ( l i n e a r )
BWT ( l i n e a r )
BWT ( q u a d .)
E r r o r MS
E rro r df
2
I
3
4
I
6.66**
'1 2 5 ,,
.793**
•330
•476“
1.214
45.85**
•0 1 ,,
6 5.31%
57.62**
40.99
.025
.035
.067
.035
.033
171.8**
1 .3 ,,
244.1 *
92.6
218.2
.419+
———
—
——
455.30**
———
—
——
.095
———
———
732.6**
———
———
##
1 2 6 2 .0 9 ,,
524.99
4.65
6.18
499
———
———
——
.056
502
713.6%
933.3**
19.5
12.5
489
1(2)
6
3
I
I
I
4 .0 4 “
6 . 09; ,
9.54**
90.80**
.84
1.27
»»
23.626*
———
———
.38
592
——
2.897
———
.110
601
a BDT, b i r t h d a t e ; BWT, b i r t h w e i g h t ; S60, s u r v i v a l t o 60; WT60, w e i g h t a t 60 d ; SI 20, s u r v i v a l to
120; WTI20, w eig h t a t 120 d.
^ d e g r e e s o f fre e d o m i n p a r e n t h e s i s f o r WT60, SI 20, and WTI20 m o d e ls ; r e a r i n g w as coded 11 ( s i n g l e
r e a r e d s i n g l e ) , 21 (tw in r e a r e d a s s i n g l e ) , and 22 (tw in r e a r e d
a s twin). T r i p l e t s were coded as
tw in s due to s m a ll numbers.
*
PC.10
PC.05
P<.01
UJ
CD
TABLE 6 .
LEAST-SQUARES MEANS
AND STANDARD ERRORS
FOR PHASE I EWE REPRODUCTIVE TRAITS PER EWE LAMBING
(1975 - 1978)a
E ffect
Breed Group o f S i r e b
FxR
WF
Breed Group of Dam
Columbia (C)
R am bouillet (R)
Targhee (T)
N
220
343
176
194
193
P ro lific a c y
LS60
LW60, kg
LSI 20
LWI20, kg
NS
NS
NS
26.8 ±. 0.9
25.4 ± 0.8
+
*
1.31 ± .04
1.21 + .04
1.50 + .04
1.49 ±. .03
•
1.35
1.27
**
••
••
1.41
1.50
1.58
1.24 ± .05
1.25 + .05
1.44 ± .05
24.8 ± 1.1
24.9 ± 1.0
28.5 ± 1.0
1.19 ± .05
1.21 ± .05
1.39 ± .05
±
±
±.
.04
.04
.04
±
±
.04
.04
48.1 ± 1.7
44.0 ± 1.6
43.8 ±. 1.9
43-7 + 1.8
50.6 ± 1 .8
a LS60, l i t t e r s i z e a t 60 d; LW60, l i t t e r w eight a t 60 d; LSI 20, l i t t e r s i z e a t 120 d ; LWI20, l i t t e r
w eight a t 120 d.
b FxR, Finn x R a m b o u ille t; WF, com posite of Columbia, R am bouillet, and Targhee.
NS, n o n - s i g n i f i c a n t (PXIO)
t PC.10
TABLE 7.
LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PHASE I PROGENY TRAITS (1975 - 1978)a
BWT
Mean, kg
E ffect
N
Breed Group
of Ramb
FxR
WF
NS
290 4.56 ± .06
326 4.64 ± .05
Breed Group
of Dam
Columbia (C)
R am bouillet (R)
Targhee (T)
*•
188 4.39 + .06
203 4.53 + .06
225 4.88 ± .06
WT60
S60
N
Mean,
%
•*
290 91.7 ± 2.6
326 84.4 ±. 2.6
NS
188 91.1 + 2 .9
203 86.5 ± 3.0
225 86.6 + 3.0
N
Mean, kg
NS
251 21.6 ± .3
265 21.6 + .3
•«
159 21.4 + .3
170 21.0 ± .3
187 22.3 ± .3
SI 20
N
Mean,
WTI20
%
NS
251 96.3 + .1
265 94.8 ± .1
NS
159 95.0 ± 1.6
170 94.9 ± 1.5
187 96.8 + 1.5
N
Mean, kg
NS
246 37.1 ± .4
259 37.0 ± .3
••
154 37.5 ± .4
166 35.8 ± .4
185 37.8 ± .4
a BWT, b i r t h w e ig h t; S60, s u r v i v a l from b i r t h t o 60 d; WT60, w eig h t a t 60 d of age; S120, s u r v iv a l to
I 20 d ; WTI 20, w e i g h t a t 120 d o f age.
b FxRf Finn x R a m b o u ille t; WFf composite of Columbia, R am b o u illetf and Targhee.
NS, non-s i g n i f i c a n t (P > .10)
t P<.10
TABLE 8. MEAN SQUARES
Source
Fx Ewe lambs:
Breed group (B)
Years (Y)
BxY
E r r o r MS
E rro r df
Mature ewes:
Breed group (B)
Years (Y)
Age (A)
S i r e (S)
BxA
E r r o r MS
E rro r df
df
FROM ANALYSES OF VARIANCE
F e rtility
2
3
6
•044
1.305
.103
.222
134
5
5
4
I
20
.086
.218
.144
.084
939
a LS60, l i t t e r s i z e a t 60 d;
w eig h t a t 120 d.
PC. 10
FOR
PHASE I I EWE PRODUCTION TRAITS (1976 - 1982)a
P ro lific a c y
LS60
LW60
.036
.063+
.183+
.090
43
•088
1.495
.312
.236
134
3.066*"
2.359
.625+
.198
.249
845
1.345+
.634+
.419
939
LSI 20
LWI20
36.2
732.9
135.4
109.8
134
. 0 3 9 ..
1.335
.241
.204
134
37
1929
296
255
134
1066.2**
3633.5**
938.9”
3277.0
250.4+
162.3
939
2.597”
4.075*
1.291*
2.040
.885
.412
939
1597”
8 0 2 7 .;
1878
321
365
347
939
LW60, l i t t e r w eight a t 60 d; LSI20, l i t t e r s i z e a t 120 d; LWI20, l i t t e r
s u r v i v a b i l i t y due t o i n d i v i d u a l h e t e r o s i s o f c r o s s b r e d la m b s o v e r
p urebred lam bs i s w e ll documented i n th e l i t e r a t u r e (D ickerson e t a l.,
1975; D ickerson and Glimp, 1975; W i tte r , 1978). Lambs s i r e d by FxR had
v i r t u a l l y the same average w e ig h ts a s lam bs s i r e d by WF ram s a t botl)
60 d and 120 d; and, s u r v i v a b i l i t y from 60 to 120 d was only s l i g h t l y
h i g h e r f p r 1/ftFx la m b s . T h e r e f o r e , t h e 4 k g a v e r a g e s u p e r i o r i t y i n
l i t t e r w eight of ewes s i r e d by FxR rams (P<.05) was due p r i m a r i l y to
improved s u r v i v a b i l i t y r e s u l t i n g from i n d i v i d u a l h e t e r o s i s .
Breed Group o f Ewe E f f e c t s
V a ria tio n
due
t o B w as l a r g e l y
due to h i g h e r l e v e l s
of
perform ance from T ewes f o r a l l t r a i t s e x c e p t S60 and SI 20 ( t a b l e s 6
and 7). Lambs from T ewes had h e a v i e r WT60 and WTI20 th a n lam bs from R
(PC.0 1), b u t w e re s i m i l a r t o la m b s fro m C ew es. B u t, t h e s u p e r i o r i t y
i n LW12Q d p e r ewe l a m b i n g (6 k^, PC.01) o v e r b o th G pnd R was c}]u^
m o stly to h ig h e r p r o l i f i c a c y .
Other Main E f f e c t s
Y ear (Y) a f f e c t e d LW60 (PC.01) and a l l
p ro g e n y t r a i t s
(PC.05)
e x c e p t S I 20 ( t a b l e 4). Age o f ewe (A) a f f e c t e d (PC.01) r e p r o d u c t i v e
and w e i g h t t r a i t s a s w e l l a s S60 (PC.0 1 ). P r o l i f i c a c y and c o m p o s i te
t r a i t s ( l i t t e r s i z e and w eig h t) in c r e a s e d t o 5 y r of age fo llo w e d by a
s l i g h t d e c lin e a t age 6 yr. L a rg e st d i f f e r e n c e s occured between age 2
and s u b s e q u e n t a g e s . Ewes l a m b i n g a t 5 y r o f ag e w eaned 20 kg more
la m b a t
120 d t h a n 2 - y r - o l d
ew es
(PC.01) due m o s t l y
to h ig h e r
p r o l i f i c a c y (.47 lambs, PC.01). B i r t h w e ig h t In c r e a s e d s t e a d i l y to age
43
6 y r ; how ever,
WT60 and WTI20 w ere h i g h e s t f o r la m b s fro m 4 - y r - o l d
ewes and d e c l in e d t h e r e a f t e r .
The o n ly i n t e r a c t i o n s a f f e c t i n g BWT w e r e BxY and SxY (P<.05) and
no tr e n d was e v id e n t. R eg ressio n on b i r t h d a te was h ig h ly s i g n i f i c a n t
fo r
BWT (.03 k g / d ) ,
r e s u l t i n g p e r h a p s fro m
b o th d i f f e r e n c e s i n
g e s t a t i o n l e n g t h s and a l o n g e r t i m e on h i g h p la n e o f n u t r i t i o n f o r
ewes lam bing l a t e i n t h e season.
Ewe Lamb and P rogeny P eform an ce i n Phase I I
F e r t i l i t y and P r o l i f i c a c y
E arly sex u al developem ent i s r e f l e c t e d i n f e r t i l i t y a t 7 months of
a g e w i t h l a m b i n g a t I y r o f ag e . Out o f 143 e x p o s u r e s o v e r 4 y r o n ly
tw o ew es fro m WF b r e e d g r o u p s la m b e d a t I y r o f ag e , co m p ared t o 55
o u t o f 146 f r p m 1/4 F x b r e e d gypups ovep t h e same p e r i o d (1.3? v s
3 7 . 7 ? p PC.OI). S u p e r i o r i t y o f 1 /4 F x e w e s o v e r WF b r e e d s and b r e e d
c r o s s e s f o r e a r l y sex u al development h as been r e p o r t e d p r e v io u s ly i n
t h e l i t e r a t u r e r a n g i n g fro m 7? t o 24? f e r t i l i t y f o r ewe la m b s u n d e r
s e m i - i n t e n s i v e management (Thomas and W h item a n , 1979; O l t e n a c u and
Boylan,
1981 a}, and up t o 52? pn w e s te r n range (Ercanbrack and Knight,
u n p u b lish e d
d ata).
Y ear a f f e c t e d
fe rtility
(PC.OI),
b u t was n o t
s i g n i f i c a n t f o r p r o l i f i c a c y ( t a b l e 8). L ev els o f f e r t i l i t y ranged from
16? i n
1977 t o 57? i n
1976.
A l t h o u g h B w as n o t
sig n ific a n t,
R a m b o u i l l e t c r o s s e s e x c e e d e d t h e p t h e r tw o b r e e d s f o r b o t h t r a i t s
( t a b l e 9). BxY i n t e r a c t i o n a p p r o a c h e d s i g n i f i c a n c e f o r p r o l i f i c a c y .
E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d d a t a ) fo u n d F in n x C o lu m b ia ewe
la m b s t o be i n f e r i o r i n f e r t i l i t y (PC.0 5 ) , 77.7? v s . 85.9? and 86.5?,
44
f o r F in n x RambouilJLet and F in n x T a r g h e e , r e s p e c t i v e l y ; b u t th e y
found no s i g n i f i c a n t d i f f e r e n c e s i n p r o l i f i c a c y .
TABLE 9. LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PHASE I I Fx EWE
LAMB REPRODUCTIVE TRAITS (1976 - 1979)
F e rtility
Brqed o f dam
Columbia (C)
R am bouillet (R)
Targpee (T)
Mean
N
Mean,
42
50
54
146
NS
41.7
45.5
39 .?
42.1
P ro lific a c y
%
±
±
+
+
8 .2
6.9
7.1
4 .3
N
Mean
16
21
18
55
NS
1.04 + .10
1.14 ±. .07
1.13 + .OJ
1.10 ± .05
T
NS, n o n - s i g n i f i c a n t (PX IO )
Progeny Performance
Mean s q u a re s from a n a ly s e s o f v a r ia n c e and l e a s t - s q u a r e s means by
brepd' of ewe f o r i n d i v i d u a l progeny t r q i t s a re p re s e n te d
i n t a b l e s 10
and 11, r e s p e c t i v e l y . Breed of ewe approached s i g n i f i c a n c e f o r BWf due
t o l a r g e r lam bs from (FxR)xT ewes. These r e s u l t s a r e i n agreem ent w ith
r e s u l t s fo u n d i n P h ase I o f t h i s s t u d y , w h e re s t r a i g h t b r e d T ewes
p r o d u c e d l a r g e r la m b s a t b i r t h t h a n e i t h e r R o r C (P < .01, t a b l e 7).
F or b o th WT60 and WTl 20 B was n o t s i g n i f i c a n t , c o n t r a r y t o P hase I
where lambp from T ewes were h e a v ie r a t both ages (P<.01). D ickerson
(1977) r e p o r t e d t h a t th e s u p e r i o r i t y of purebred T lambs over R lambs
was t r a n s m i t t e d t o c r o s s b r e d la m b s fr o m T and R dam s, a l t h o u g h i n
n e i t h e r cpse
d ifferen ces sig n ific a n t.
Type o f b i r t h / r e a r i n g a f f e c t e d BWT (P<.01) and WT60 (P <.01), b u t
d i d n o t s i g n i f i c a n t l y a f f e c t WTI20. N e v e r t h e l e s s , la m b s r e a r e d a s
s i n g l e s w e r e £ Jcg h e a v i e r t h a n t w i n e . Q u a d r a t i c r e g r e s s i o n on b i r t h
45
w e i g h t i n f l u e n c e d WTl 20 (P < .0 1), i n d i c a t i n g perhaps t h a t lambs w ith
h e a v i e r BWT had poorer subsequent perform ance to weaning due perhaps
to more d i f f i c u l t b i r t h s .
TABLE 10. MEAN SQUARES FROM ANALYSES OF VARIANCE FOR PHASE I I
INDIVIDUAL PROGENY TRAITS FROM Fx EWE LAMBS (1976 - 1979)a
Source
df
BWT, kg
WT60, kg
Breed of dam (B)
Year (Y)
Sex (X)
Type of b i r t h /
r e a r i n g (BR)b
R eg ressio n s
BDT ( l i n e a r )
BWT ( l i n e a r )
BWT (q u ad .)
E rro r MS
E rro r df
2
3
I
.853+
.455
1.496*
.048
3.591
.481
10 3
73.4
19.0+
11.635**
13.045*
10.9
.215
———
——”
.359
52
62.437**
21.746*
7.375
3.745
41
44.1*
48.5
101.0**
6.4
38
1(2)
I
I
I
WTI20, kg
'„
a BWT, b i r t h w eig h t; WT60, w eight a t 60 d; WTI20, w eight a t
120 d.
D d e g re e s of freedom i n p a r e n t h e s i s belong w ith models f o r
WT60 and WT120.
+ PC.10
»
:::
TABLE 11. LEAST-SQUARES
MEANS AND STANDARD ERRORS FOR PHASE I I
INDIVIDUAL PROGENY TRAITS FROM Fx EWE LAMBS (1976 - I 979)a
BWT
Breed Of Isweb
N
Mean, kg
WT60
N
Mean, kg
N
Mean, kg
16
21
16
53
NS
21.8 ±
21.8 ±
21.9 ±
21.8 ±
15
20
15
50
NS
36.1 ±
38.0 ±
37.5 ±
37.2 ±
+
(FxR) x C
(FxR) x R
(FxR) x T
Mean
17
24
20
61
3.73 ± .17
4.10 ± .14
4.15 ± .15
3.99 ±. .10
WTI20
.5
.6
.5
.3
a BWT, b i r t h w eig h t; WT60, weight a t 60 d; WT120, w eight a t 120 d.
b C = Columbia, F = F inn, R = R am bouillet, T = Targhee.
NS, n o n - s i g n i f i c a n t (P>.10)
+ PC.10
.8
.9
.8
.6
46
A l i m i t e d am ount o f d a t a p r e v e n t e d t h e u t i l i z a t i o n o f l e a s t s q u a re s methods f o r a n a l y s i s of s u r v i v a b i l i t y .
Out o f 61 lambs born,
53 s u rv iv e d t o ap p ro x im a te ly 60 d and 50 s u rv iv e d to ap p ro x im a te ly 120
d o f ag e . Lambs fro m C ew es had t h e h i g h e s t S60 r a t e s (94$) f o l l o w e d
by R (88$) and T (80$). One lamb from each breed group d ie d between 60
and I 20 d.
Composite T r a i t s
Composite t r a i t s f o r 1/4Fx ewe lamb r e p r o d u c t iv e perform ance a r e
r e p o r t e d i n t a b l e s 8 and 12. B reed o f ewe was n o n - s i g n i f i c a n t f o r
litte r
siz e
and w e i g h t
at
( w e a n in g ) p e r ewe e x p o s e d ,
fe rtility ,
b o th 60 d ( m i d - l a c t a t i o n )
re fle c tin g
and
120 d
th e la c k of B e f f e c t s f o r
p r o l i f i c a c y , and i n d i v i d u a l lamb w eights. Year a f f e c t e d a l l
f o u r com posite t r a i t s
(P<.01).
I n 1977 l i t t e r w eight per ewe exposed
was 17 kg l i g h t e r than th e p rev io u s year.
LW60
LSI 20
LWI20
42
50
54
146
NS
.42 ± .08
.45 ± .07
.36 ± .07
.41 ± .04
NS
9 .5 ± 1.8
9.4 ± 1.5
7 .8 ± 1.6
8.9 ± .9
NS
14.6 ± 2.8
14.4 ± 2.4
12.9 ± 2.4
14.0 ± 1.5
CO
LS60
O
Columbia (C)
R am bouillet (R)
Targhee (T)
Mean
N
-Cr
O
Breed of dam
1+ o5
TABLE 12. LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PHASE I I Fx
EWE LAMB COMPOSITE REPRODUCTIVE TRAITS PER EWE EXPOSED (1976
- 1979)*
.40 ± .07
.35 ± .07
.38 ± .04
a LS60, l i t t e r s i z e a t 60 d ; LW60, l i t t e r w eight a t 60 d ;
l i t t e r s i z e a t 120 d ; LWI20, l i t t e r w eig h t a t 120 d.
NS, n o n - s i g n i f i c a n t ( P > .10)
LS120,
47
M ature Ewe and Progeny P erfo rm a n ce i n P hase I I
B reed Group o f Ewe E f f e c t s
M eans' s q u a r e s fr o m
a n a l y s i s o f v a r i a n c e f o r r e p r o d u c t i v e and
c o m p o s ite t r a i t s o f m atu re ew es (a g e s 2 th ro u g h 6 y r ) a re p r e s e n te d i n
T a b le 8 . Mean s q u a r e s f o r w e i g h t and s u r v i v a b i l i t y o f p r o g e n y from
m ature ewes i s p r e s e n te d i n Table 15.
While l a r g e d i f f e r e n c e s i n f e r t i l i t y e x i s t e d between 1/4Fx and WF
ewe la m b s , B was n o t a s i g n i f i c a n t s o u r c e o f v a r i a t i o n i n t h e model
for f e r t i l i t y
i p m a t u r e ew es ( t a b l e 13). B reed g r o u p s w i t h I /4 F x
b r e e d i n g had h i g h e r l e v e l s
(P < .0 1) o f p r o l i f i c a c y
t h a n WF b r e e d
groups, a v e ra g in g a t .36 more lambs p e r ewe lam bing f o r ages 2 through
6 y r ( t a b l e 14).
S u p e r i o r i t y o f 1/4Fx f o r p r o l i f i c a c y was pronounced
a t a l l a^ee w ith no e v id e n t d e c l in e i n s u p e r i o r i t y w ith i n c r e a s i n g age
of
ewe
(ta ttle
14).
D ick erso n
( 1 977)
apd
E rcan b rack
and
K n ig h t
(unpublished d a ta ) r e p o r t e d average 1/4Fx s u p e r i o r i t y over WF breeds
on w e s t e r n r a n g e t o be .24 ( a g e s 2 t h r o u g h 5 y r ) and .38 ( a g e s 2
through 7 yr) lambs p er ewe lam bing,
r e s p e c t i v e l y ; and t h e magnitude
o f th e d i f f e r e n c e r e m a i n e d c o n s t a n t a t a l l a g e s . R e s e a r c h i n v o l v i n g
1/2Fx ewes h as shown g r e a t e r s u p e r i o r i t y i n p r o l i f i c a c y th a n r e s u l t s
f o r 1/4Fx, but po tr e n d of i n c r e a s i n g d i f f e r e n c e s w ith i n c r e a s i n g age
(D onald e t a l „ , 1968; Land e t a l . , 1974; B a r k e r , 1975; O l t e n a c u and
Boyl an, 1981).
B i r t h w eig h t f o r lambs from 1/4Fx m a tu re dams were .63 kg l i g h t e r
(P<.01) than lam bs from WF dams ( t a b l e s . 15 and 16). L i g h t e r BWT would
be e x p e c t e d due t o l a r g e r l i t t e r s i z e s ; h o w e v e r , when ty p e o f b i r t h
TABLE 1 3 .
LEAST-SQUARES MEANS AND STANDARD ERRORS FOR F E R T IL IT Y OF PHASE I I MATURE EWES ( 1 9 7 6 -
1982)
Age of ewe a t time o f lambing
2 yr
4 yr
3 yr
5 yr
Breed
Groupa
N
C
R
T
WF mean
44
43
51
138
94.9 ± 5.0
89.0 ± 5.1
91.2 ± 4 .7
91.7 ± 2.8
37
38
41
116
90.7 ±. 5.6
102.6 ± 5.5
108.4 ± 5.1
100.6 ± 3.1
33
38
41
112
103.6 ±
102.3 ±
98.9 ±
101.6 +
43
46
52
141
99.7 ± 5.3
89.5 + 5.2
101.1 ± 4 .8
96.8 ± 2.9
34
42
51
127
96.5 + 5 .8
105.8 ± 5 .2
83.8 + 4 .9
95.4 ± 3.0
30
36
47
113
91-3
108.8
90.3
96.8
+
±.
±
±.
279
94.5 ± 2 .3
243
(FxR)
(FxR)
(FxR)
IA Fx
Mean
x C
x R
x T
mean
a C1 C o lu m b ia ;
R,
Mean,,
N
%
R a m b o u i l l e t ; T,
Mean,
97.8
N
%
±
T a rg h e e ; F,
2.4
F in n ;
N
Mean,
6 .2
5.7
5.3
3.3
20
22
29
71
96.8
98.3
99.3
98.1
6.5
5.6
5.3
3.3
18
29
32
79
99.3 + 2.5
150
Mean,
225
breed
%
of s ire
lis te d
6 yr
N
Mean,
%
7.7
7.2
6.6
4.1
10
13
15
38
107.4
112.2
94.4
104.7
±10.5
± 9.5
± 8 .9
± 5.5
95.8 + 8.4
87.5 ± 6.7
92.1 ± 6.6
91.8 ± 4.1
8
16
16
40
77.8
76.7
96.5
83.7
±11.9
± 9.4
± 9.1
± 5.7
94.8
78
95.4 ± 4.1
firs t.
%
±
±
±
±
±
3.1
T ab le
14.
LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PROLIFICACY OF PHASE I I MATURE EWES ( 1 9 7 6 -
1982).
Age of ewe iat time o f lambing
2 yi
N
Mean
C
R
T
WF mean
40
37
43
120
.99
1.12
1.14
1.08
±
+
+
zt
(FxR)
(FxR)
(FxR)
1/4Fx
41
38
50
129
1.48
1.44
1.43
1.45
±
zt
zt
±
249
Mean
a C,
x C
x R
x T
mean
C o lu m b ia ;
R,
4 yr
3 yir
Breed
Group3
N
Mean
N
Mean
.08
.09
.08
.05
31
36
41
108
1.24
1.16
1.34
1.25
.10
.09
.09
.05
32
35
39
106
1.39
1.40
1.45
1.41
.09
.09
.08
.05
31
39
41
111
1.65 zt .10
1.58 zt .09
1.72 ± .09
1.65 zt .05
26
35
42
103
1.67
1.79
1.67
1.71
1.27 zt .04
219
1.45 zt .04
209
1.56
R a m b o u i l l e t ; T,
zt
zt
zt
+
T a rg h e e ; F,
5 yr
N
Mean
.10
.09
.09
.05
18
19
27
64
1.34
1.50
1.76
1.54
±
.10
.09
.09
.05
Zt
.04
±
±
±
±
Zt
Zt
Zt
6 yr
N
Mean
.13
.12
.11
.07
10
13
14
37
1.50
1.43
1.75
1.56
±
+
zt
±
.17
.15
.14
.09
16
23
30
69
1.81 ;t .13
1.81 ± .11
1.73 zt .09
1.78 ± .07
6
13
15
34
2.18
1.80
1.83
1.94
±
zt
±
zt
.21
.14
.14
.09
133
1.66 ± .06
71
1.75 zt .08
F in n ; breed o f s i r e l i s t e d
±
zt
zt
zt
firs t.
50
was i n c l u d e d i n t h e m odel BWT f o r la m b s fro m I /4 F x dam s r e m a in e d
s m a l l e r by .34 kg (P < .0 1). R e s u l t s w e r e i n a g r e e m e n t w i t h B r a d f o r d
(1972) who found BWT f o r Finn lambs t o be s m a ll r e l a t i v e t o m ature ewe
s i z e a f t e r a d ju s tm e n t f o r type o f b i r t h . But r e s u l t s do n o t a g r e e w ith
E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d d a t a ) who fo u n d no s i g n i f i c a n t
d i f f e r e n c e s i n BWT betw een 1/4Fx and and WF b reed s when u n a d ju s te d f o r
type of b i r t h .
D e s p i t e l i g h t e r BWT,
la m b s fro m
1 /4 F x dams had .6 and .7 kg
h e a v i e r ( n o n - s i g n i f i c a n t ) WT60 and WTI20, r e s p e c t i v e l y , t h a n la m b s
from WF breeds ( t a b l e 16). When type of b i r t h / r e a r i n g was in c lu d e d i n
t h e m odel t h e d i f f e r e n c e s i n c r e a s e d t o 1.3 and 1.5 kg f o r WT60 and
WT l 20,
re sp e c tiv e ly
( P < .0 1).
O l t e n a c u and B o y la n (1981) fo u n d a
s i g n i f i c a n t a d j u s t e d w eig h t s u p e r i o r i t y o f 1.6 kg f o r lam bs from 1/4Fx
over WF breeds a t a p p ro x im a te ly 70 d o f age. D ipkerson (1977) r e p o r te d
u n a d j u s t e d la m b w e i g h t s f r o m 1/4F x dams t o be .4 kg h e a v i e r a t 105 d
o f age t h a n t h o s e fro m WF b r e e d s ( n o n - s i g n i f i c a n t ) . I n d i s a g r e e m e n t
w ith th e s e f i n d i n g s ,
Thomas and Whiteman (1979) found u n a d ju s te d lamb
w e a n in g w e i g h t s fro m
1 /4 F x dams t o be 1.5 kg l e s s t h a n D o r s e t x
R am b o u illet, but when type o f b i r t h / r e a r i n g was in c lu d e d i n th e model
no s i g n i f i c a n t d i f f e r e n c e s were e v id e n t. Amounts o f F inn b reed in g i n
e x c e s s o f 1/4 h a v e l o w e r e d u n a d j u s t e d w e a n in g w e i g h t s by 1.1 t o 3.5
kg, and h a v e had no s i g n i f i c a n t e f f e c t s when a d j u s t e d f o r ty p e o f
b i r t h / r e a r i n g (Donald e t a l . ,
1968; B ark er,
1975; D ickerson,
1977).
Lambs from 1/4Fx dams had 7.6% (P<.01) g r e a t e r S60 when q u a d r a t ic
r e g r e s s i o n on BWT w as i n c l u d e d i n t h e m o d e l ( t a b l e 16). Even though
BWT w ere s m a l l e r f o r lambs w ith F inn b re e d in g and s m a l l e r BWT cause
TABLE 1 5 .
MEAN SQUARES FROM ANALYSES OF VARIANCE FOR PHASE I I MATURE EWE PROGENY TRAITS ( 1 9 7 7 -
1982)a
Source
df
BWT, kg
S60
WT60, kg
Breed of dam (B)
Breed o f s i r e (S)
Year (Y)
Age of dam (A)
Sex (X)
Type of b i r t h /
r e a r i n g (BR)
A x BR
R eg ressio n s
BDT ( l i n e a r )
BDT ( q u a d .)
BWT ( l i n e a r )
BWT (quad.)
E rro r MS
E rror d f
5
I
5
4
I
3 .8 S ”
1 9 .3 5 .,
5.41%.
2 .1 5 ,,
39.20*
.384**
.2 0 4 ..
1.267
.0 2 0 .
.515
4 5 .2 %
5 5 .8 %
407.4*
18.2
3.8
.051
. 105._
.280**
.033
.036
63.7**
6.4
690.4%
5 0 .5 ,,
88.3
2(4)
7
95.49**
1.02
.273+
.170
250.5**
11.1 +
.028
.063
746.5%
27.5**
5 .6 6 ”
2.30
——
1631.6**
—
—
991.5**
5 .265%
2.338**
.104
1268
1400.6%
72.4
7.5
1069
—
.047
1072
1946.8**
35.1 +
13.7
952
a BWT, b i r t h w eig h t;
w eight a t 120 d.
t PC.10
I
I
I
I
S60,
——
.48
1268
s u r v i v a l to 60 d ;
WT60,
SI 20
WTI20, kg
w eight a t 60 d; SI20, s u r v i v a l to 120 d; WTI20,
TABLE 1 6 .
LEAST-SQUARES MEANS AND STANDARD
THROUGH 6 ( 1 9 7 7 - 1 9 8 2 ) a
BWT
Breed o f damb
N
Mean, kg
ERRORS FOR INDIVIDUAL LAMB PERFORMANCE FROM DAMS AGES
WT60
S60
N
Mean, ?
*#
*#
SI 20
Mean, kg
#*
4.14 + .14
4.53 ± .13
4.37 + .08
4.35 ± .08
86 • 0 +. 3.6
86.6 + 3.4
92.2 ± 3 .2
88.3 ± 2.0
125
143
199
467
20.2 + .5
20.7 ± .6
21.5 + .4
20.8 ± .3
(FxR)
(FxR)
(FxR)
1/4Fx
195
249
290
734
3.84 ± .08
4.08 ± .07
4.12 ± .07
4.01 ± .04
97.6 ± 3.3
97.1 ± 3.0
92.9 + 3.1
95.9 ±. 1.8
166
224
241
631
22.3 ± .4
22.1 ± .4
21.9 ± .4
4.18
o>
x C
x R
x T
mean
O v erall mean
1296
±
.03
-H
158
175
229
562
CU
Columbia (C)
R am bouillet (R)
Targhee (T)
WF mean
1.5
1098
Mean,
2
Wl 20
%
N
Mean, kg
**
NS
95.3 +
87.4 ±
93.9 ±
92.5 ±
3.7
3.4
5.6
2.6
117
123
180
420
33.1 ± .6
33.0 ± .8
34.7 + .6
33.6 ± .4
4.9
3.2
4.0
2.3
145
199
219
563
35.4 ± .6
34.8 ±. .5
35.1 ± .5
35.1 ±. .3
983
34.4 + .2
2 2 .1
±.
.2
92.6
94.2
87.5
91.8
±
±
±
±
21.5
±
.2
92.2 ± 2.2
a BWT, b i r t h w e ig h t; S60, s u r v i v a l t o 60 d ; WT60, w eight a t 60 d ; SI20, s u r v iv a l to 120 d; WT120,
w eight a t 120 d.
b C rosses d e s ig n a te d w ith l e t t e r s , breed of s i r e f i r s t ; F = F inn.
NS, n o n - s i g n i f i c a n t (P > .10)
PC.05
53
d e c r e a s e d s u r v i v a b i l i t y ( P u r s e r and Young, 1964), la m b s fro m 1/4 F x
dams had 4.6% (P<.05) g r e a t e r S60 when th e q u a d r a t i c r e g r e s s i o n on BWT
was removed from th e model. R eg ressio n s on BWT were n o t s i g n i f i c a n t
and w e re n o t i n c l u d e d i n t h e m odel f o r S120.
B reed o f ewe e f f e c t s
w e r e n o t s i g n i f i c a n t ; la m b s fro m WF b r e e d s h a v i n g s l i g h t l y b e t t e r
S I20. R e s u lts i n t h i s study f o r S60 a r e i n d is a g re e m e n t
s tu d ie s
w h ic h
fo u n d la m b s
from
1 /4 F x dam s t o
w ith p re v io u s
have s im ila r
s u r v i v a b i l i t y w ith s ta n d a r d p u re b re d s and c r o s s b r e d s (D ickerson,
O l t e n a c u and B o y la n ,
Knight,
1981;
C o ch ran e t a l . ,
1977;
1982; E r c a n b r a c k and
u npublished d ata).
Average LS60 ( m i d - l a c t a t i o n ) p e r ewe exposed o f 1/4Fx b reed groups
exceeded
t h e WF b r e e d a v e r a g e f o r a g e s 2 t h r o u g h 6 ( t a b l e
r e s u l t i n g i n an o v e r a l l d i f f e r e n c e
17),
o f .24 la m b s p e r ewe e x p o se d
(PC.01). L a r g e s t d i f f e r e n c e s o c c u r r e d a t a g e 2 y r w h e r e 1 /4 F x ewes
r e a r e d .46 m ore I ^mbs. S u p e r i o r i t y o f 1/4F% d e c l i n e d f o r 5 and 6 - y r old ewes p r i m a r i l y due to number o f lam bs r e a r e d by T ewes in c r e a s i n g
w ith age. Targhee ewes exceeded R and C a t a l l ages and 1/4Fx average
a t 5 and 6 y r o f a g e , a l t h o u g h n o t s i g n i f i c a n t l y . LS60 r a t h e r t h a n
i n d i v i d u a l lamb w e ig h ts was ,mostly r e s p o n s i b l e f o r 1/4Fx s u p e r i o r i t y
f o r LW60 p e r ewe e x p o s e d ( t a b l e 18). W e i g h ts w ere n o t a d j u s t e d f o r
s e x , age o f la m b , o r t y p e o f b i r t h / r e a r i n g .
A veraged a c r o s s a g e s 2
t h r o u g h 6 y r , 1/4 F x e x c e e d e d WF b r e e d s by 3.9 kg (P<.01). The l a r g e s t
d i f f e r e n c e o ccu rred a t age 2 y r (8.2 kg), and th e s m a l l e s t a t age 6 yr
(1.4 kg).
TABLE 1 7 . LEAST-SQUARES MEANS AND STANDARD ERRORS FOR L ITTER S IZ E AT 6 0 DAYS
1977 - 1982)
PER EWE
EXPOSED
(L S 60,
Age of ewe a t time of lambing
2 yr
Breed Groupa
N
Mean
4 yr
3 yr
N
N
Mean
6 yr
5 yr
Mean
N
Mean
N
Mean
Columbia (C)
Ram bouillet (R)
Targhee (T)
WF mean
44
43
51
138
.68 ± .10
.79 ± .10
• 86 ±_ *10
.77 ± .06
37
38
41
116
.97 ± .11
.94 ± .11
1.19 ± .11
1.03 ± .06
33
38
41
112
1.14 ± .12
1.09 ± .11
1.17 ± .11
1.13 ± .06
20
22
29
71
1 .09 ± .15
1.12 + .14
I .47 ± .13
I .23 ± .08
10
13
15
38
1.20 ± .21
1.03 ± .19
1.50 ± .17
1.24 + .11
(FxR)
(FxR)
(FxR)
1/4Fx
43
46
52
141
1.25 ± .11
1.17 ± .10
1.30 ±. .10
1.24 + .06
34
42
51
127
1.32 ± .12
1.44 ± .11
1.25 ± .10
1.34 ± .06
30
36
47
113
1.12
1.58
1.29
1.33
+
+
±.
±.
.13
.11
.10
.06
18
29
32
79
1.58 ± .16
1.24 ± .13
1.33 ± .12
1.38 ± .08
8
16
16
40
1.46
1.30
1.25
1.34
279
1.01 dt .05
243
1.19
.05
225
1.23
±
.05
150
I .31 ± .06
78
1.29 ± .09
x C
x R
x T
mean
O v e ra ll mean
a C ro sses d e s ig n a te d w ith l e t t e r s ,
±
breed o f s i r e
firs t,
F = F in n .
±
+
±
±
.24
.17
.17
.11
TABLE 1 8 .
LEAST-SQUARES MEANS
1977 - 1982)
AND STANDARD ERRORS FOR LITTER WEIGHT AT 6 0 DAYS PER EWE EXPOSED (LW60,
Age of ewe a t time of lambing
2 yr
Breed Groupa
N
Mean, kg
3 yr
N
4 yr
N
Mean,, k:g
5 yr
6 yr
Mean, kg
N
Mean,» kg
N
Mean,, kg
44
43
51
138
13.7 ± 2.0
18.5 ± 2.0
18.9 ± 1.9
17.0 ± 1.1
37
38
41
116
20.8
21.8
29.0
23.9
+
+
+
+
2 .2
2 .2
2.1
1.3
33
38
41
112
25.4
26.4
27.7
26.5
+
+
±
+
2 .3
2 .2
2.1
1.3
20
22
29
71
24.0 ± 3.0
21.3 ± 2 .8
30.2 ± 2.5
25.2 + .1 .6
10
13
15
38
25.0
21.7
31.6
26.1
(FxR)
(FxR)
(FxR)
1/4Fx
43
46
52
141
25.5 ± 2.0
23.1 ± 2.0
26.9 dL 1.9
25.2 ± 1.1
34
42
51
127
27.3
29.5
25.8
27.5
±
±
±
±
2.3
2.1
1.9
1.2
30
36
47
113
24.8
32.5
28.1
28.5
±
±
±
±
2.5
2.2
2 .0
1.3
18
29
32
79
29.9 ±. 3.1
27.2 ± 2.5
30.8 ± 2.4
29.3 ± 1.5
8
16
16
40
30.9 ± 4.6
27.1 ± 3.4
24.6 ± 3.4
27.5 ± 2.1
279
21.1 ± 1.0
243
25.7 ± 1.1
225
27.5
±
1.2
150
27.0
78
26.8
O verall mean
a C ro sses d e s ig n a te d w ith l e t t e r s ,
breed o f
sire
firs t;
F = F in n .
+
±
±
±
4.1
3.7
3.4
2.1
Hru
O
x C
x R
x T
mean
■H
Columbia (C)
Ram bouillet (R)
Targhee (T)
WF mean
Ul
Ul
TABLE 1 9 .
LEAST-SQUARES MEANS
EXPOSED ( L S I 2 0 , 1 9 7 7 -
AND STANDARD
1982)
ERRORS FOR
PHASE I I L ITTER S I Z E AT 1 20 DAYS
PER
EWE
Age of‘ ewe a t time of lambing
2 yr
Breed Groupa
N
Mean
4 yr
3 yj
N
N
Mean
5 yr
6 yr
Mean
N
Mean
N
Mean
Columbia (C)
R am bouillet (R)
Targhee (T)
WF mean
44
43
51
138
.69 ±. .10
.73 ± .10
.84 ± .10
.75 ± .06
37
38
41
116
.91 ± .11
.88 ± .11
1.11 ± .11
.97 ± .06
33
38
41
112
1.03 ± .12
1.05 + .11
1.11 ± .11
1.06 ± .06
20
22
29
71
1.03 ± .15
.93 ± .14
1.35 ± .13
1.10 ± .07
10
13
15
38
1.15 + .21
•91 ± .19
1.32 ± .17
1.13 ± .11
(FxR)
(FxR)
(FxR)
1/4Fx
43
46
52
141
1.11 + .10
1.06 ±. .10
1.16 ± .10
1.11 ± .06
34
42
51
127
1.22 ± .11
1.36 ± .11
1.17 ± .10
1.25 ± .06
30
36
47
113
1.07 ± .12
1.44 ± .11
1.18 ± .10
1.23 ± .06
18
29
32
79
1.33 + .16
1.18 + .13
1.28 ± .12
1.26 + .07
8
16
16
40
1.30 ± .23
1.20 ± .17
1.21 ± .17
1.24 + .11
279
.93 ± .05
243
1.11
225
1.15
150
1.18 ±. .06
78
1.18
x C
x R
x T
mean
O v e ra ll mean
a C r o sse s d e s ig n a t e d w ith l e t t e r s ,
±
.05
±
breed o f s i r e f i r s t ; F = F in n
.05
±
.09
TABLE 2 0 .
LEAST-SQUARES MEANS AND STANDARD
LAMBING ( LWI2 0 , 1 9 7 7 - 1 9 8 2 )
ERRORS
FOR PHASE I I L ITTER WEIGHT AT 1 2 0 DAYS
PER
EWE
Age of ewe a t time of lambing
2 yr
Breed Group3
N
4 yr
3 yr
Mean, kg
N
Mean, kg
N
5 yr
6 yr
Mean, kg
N
Mean, kg
N
Mean, kg
Columbia (C)
R am bouillet (R)
Targhee (T)
WF mean
44
43
51
138
24.3 + 2 .8
26.8 ±_ 2 .9
28.5 ± 2 .7
26.5 ± 1.6
37
38
41
116
30.5 ± 3.1
31.9 ± 3.1
41.0 ± 2 .9
34.5 ± 1.7
33
38
41
112
35.9 ± 3.3
38.5 ± 3.1
39.0 ± 3.0
37.8 + 1.8
20
22
29
71
37.2
34.1
46.7
39.3
±
±
±
±
4 .2
4.0
3.5
2 .2
10
13
15
38
40.5
34.3
44.3
39.7
±
±
±
±
5.8
5.1
4.8
3.0
(FxR)
(FxR)
(FxR)
1/4Fx
43
46
52
141
36.7 ± 2 .9
33.3 + 2 .8
38.0 + 2 .7
36.0 ± 1.6
34
42
51
127
40.2 ± 3.2
42.9 ± 2 .9
37.7 ± 2 .7
40.3 + 1.7
30
36
47
113
37.2
44.5
39.1
40.3
3.5
3.1
2.8
I .8
18
29
32
79
42.9
39.8
44.4
42.4
±
±
±
+
4.4
3.6
3.3
2.1
8
16
16
40
41.2
40.1
39.5
40.3
±
±
±
±
6.4
4.7
4.8
3.0
279
31.1
1.4
243
37.4 jl 1.5
225
39.1 ± 1.6
150
40.9 ± 2.0
78
40.0 ± 2.8
x C
x R
x T
mean
O v e ra ll mean
±
a C r o sse s d e s ig n a t e d w ith l e t t e r s ,
±
±
±
±
b reed o f s i r e f i r s t ; F = F in n .
58
T re n d s e s t a b l i s h e d f o r LS60
and LW60 co n tin u e d through weaning
due p r i m a r i l y t o no s i g n i f i c a n t e f f e c t on S I 20 due t o b r e e d o f ewe.
Average m ature 1/4Fx s u p e r i o r i t y f o r LSI20 and LWI20 p e r ewe exposed
w as
.2 2 ,
la m b s (P<.01) and 4.3 kg (P <.01), r e s p e c t i v e l y . T hese r e s u l t s
r e p r e s e n t an a v e r a g e i n c r e a s e , due t o 1 /4 F x b r e e d i n g , i n LSI 20 and
LW120 o f
22%
and 12%, r e s p e c t i v e l y . Ercanbrack and Knight (unpublished
d a t a ) fo u n d i n c o r p o r a t i o n o f 1 /4 F x b r e e d i n g i n t o t h e same WF b r e e d
groups as in v o lv e d i n t h i s study t o i n c r e a s e l i t t e r w e ig h t a t weaning
by 8.3 kg (24%) on a v e r a g e f o r ew es 2 t o 7 y r o f age. O th e r s t u d i e s
h a v e r e p o r t e d o n ly s l i g h t , . n o n - s i g n i f i c a n t 1/4F x s u p e r i o r i t y f o r
m ature ewes (D ickerson, 1977; Thomas and Whiteman, 1979; Magid e t a l . ,
1981b ) .
Age o f Ewe and I n t e r a c t i o n E f f e c t s .
Although age of ewe (A) was n o t a s i g n i f i c a n t source of v a r i a t i o n
i n th e model f o r f e r t i l i t y ,
th e BxA i n t e r a c t i o n was im p o r ta n t (P<.01).
At 2 y r o f age 1 /4 F x b r e e d g r o u p s had s l i g h t l y h i g h e r f e r t i l i t y t h a n
WF b r e e d s ,
but th is
d i f f e r e n c e w as r e v e r s e d
at
3 y r of age.
S u p e r i o r i t y o f WF ewes continued t o i n c r e a s e a t subsequent ages ( t a b l e
13). Ijn c o n t r a s t ,
p r e v i o u s r e s e a r c h h a s i n d i c a t e d no s i g n i f i c a n t
d e c l i n e s i n Fx f e r t i l i t y a t l a t e r ages, r a t h e r Fx f e r t i l i t y i s n e a r ly
i d e n t i c a l to s ta n d a r d b re e d s a t a l l ag es p a s t I y r (B a rk e r,
1975;
M a ija la and O stq rberg, 1977; Thomas and Whiteman, 1979; Magid e t a l . ,
1981; E rcanbrack and Knight, u npublished d ata).
Age of ewe s i g n i f i c a n t l y a f f e c t e d p r o l i f i c a c y and com posite t r a i t s
( t a b l e 8). Average l i t t e r s i z e s a t b i r t h in c r e a s e d s t e a d i l y from 2 to
59
6 y r o f a g e , r e s u l t i n g i n a d i f f e r e n c e o f .5 la m b s p e r ewe la m b in g
between th e two ages (P<..01, t a b l e 13). E f f e c t s due to A on com posite
t r a i t s f o r LS60 and LSI20 p er exposed r e s u l t e d p rim ary from A e f f e c t s
on p r o l i f i c a c y a s A had no e f f e c t on f e r t i l i t y and S60 and S I20. Breed
o f ewe x ag e o f ewe i n t e r a c t i o n a p p r o a c h e d s i g n i f i c a n c e f o r LS60
(PC.IO) due to combining f l u c t u a t i o n s i n p r o l i f i c a c y and §60 o f 4 - y r ° l d (FxR)xC and (FxR)xR, as w e ll as a s te a d y o v e r a l l improvement of T
ewe perform ance from age 2 t o 6 yr. Breed of ewe x age o f ewe e f f e c t s
on LW60 was due t o LS60 r a t h e r t h a n BxA e f f e c t s on i n d i v i d u a l lam b
w e ig h ts. A n a ly s is o f combined I A F x breed groups vs. WF breed groups
i n d i c a t e s no BxA i n t e r a c t i o n .
B ir t h w eig h t, a d j u s t e d f o r type of b i r t h , a l s o in c r e a s e d w ith each
y r i n age r e s u l t i n g i n lambe from 6- y r - o l d ewes w eighing on average .6
kg h e a v i e r
th a n th o s e
fro m R - y r - p l d s .
Age o f ewe a l s o a f f e c t e d
i n d i v i d u a l WT60 and WT120 (PC.OI), C o n t r a r y t o BWT, la m b w e i g h t s
i n c r e a s e d w ith age of ewe up to 3 y r old th e n d e c lin e d w ith i n c r e a s in g
age. T hese r e s u l t s a r e i n a g r e e m e n t w i t h D i c k e r s o n e t a l . (1975) who
found a s tr o n g c u r v i l i n e a r r e l a t i o n s h i p between age of ewe w ith 4 and
IQ wk la m b w e i g h t s .
Age o f ewe a f f e c t e d LW60 and LWI20 p e r ewe
e x p o s e d ( P ^ .0 1 ), and l a r g e l y r e f l e c t e d d i f f e r e n c e s b e t w e e n 2 - y r - o l d
and o ld e r ewes due to the c o n f l i c t i n g e f f e c t s of age on th e components
o f l i t t e r w e i g h t i n o l d e r ew es. A verage LW60 and LWI20 o f 3 t o 6- y r old ewes exceeded' 2- y r - o l d s by 6 ^nd 8 kg, r e s p e c t i v e l y ( t a b l e s 18 and
20).
Age o f ewe x ty p e o f b i r t h / r e a r i n g a f f e c t e d WTI20 (P<,01) and
approached s i g n i f i c a n c e f o r WT60 (P<.10). I n t e r a c t i o n e f f e c t s were due
60
p r i m a r i l y to w eig h t f l u c t u a t i o n s f o r lambs born a s t r i p l e t s and r e a r e d
a s s i n g l e s o r t w i n s . Lamb n u m b e rs i n t h e s e c a t e g o r i e s w e re s m a l l .
E f f e c t of A on s i n g l e s r e a r e d a s s i n g l e s and tw in s r e a r e d a s tw in s was
n e a r ly i d e n t i c a l .
B reed Group o f S ir e E f f e c t s
Due t o u t i l i z a t i o n
o f FxT ra m s i n a d d i t i o n t o
S u f f o l k ra m s
commencing I n th e f a l l o f 1980, breed o f s i r e e f f e c t s were in c lu d e d i n
a l l models f o r m a tu re ewe r e p r o d u c t iv e and i n d i v i d u a l progeny t r a i t s
( t a b l e 21). I n P hase I , F x R - s i r e d la m b s d i d n o t show s i g n i f i c a n t l y
h e a v ie r BWT, WT60, or WTI20 th a n W F-sired lambs. But i n com parison to
S u f f o i k s , F x T - s i r e d la m b s had l i g h t e r BWT (P < .0 1) and WT60 (P < .0 1),
but only .5 kg l i g h t e r WTI20. Oltenacu apd Boylan (1981b) found Finn x
^ u f f 9^
d^®? bred t o S u f f p lk rpms produced h e a v i e r BWT (+.3 kg, P<.05)
but not s i g n i f i c a n t l y h e a v ie r weaning w e ig h ts a t 70 d o f age th a n when
b r e d t o F in n ra m s . D i c k e r s o n e t a l . (1975) fo u n d Fx la m b s t o h av e
l i g h t e r BWT (.8 kg) and l i g h t e r w e a n in g w e i g h t a t 70 d (1,4 Kg.) t h a n
S u f f o lk c r o s s lambs..
Ewes e x p o s e d t o . FxT r a m s had h i g h e r f e r t i l i t y (P<.01) and h i g h e r
p r o l i f i c a c y (P <.10) t h a n ew es e x p o s e d t o S u f f o l k rams,, i n d i c a t i n g
s u p e r i o r f e r t i l i z a t i o n r a t e s a n d / o r l o w e r embyro m o r t a l i t y i n ewes
exposed to FxT rams.
fe rtility
Due t o confounding o f SxY a d d i t i o n a l a n a ly s e s of
and p r o l i f i c a c y w e re c o n d u c te d in c lu d in g o n ly th e y r 1981
and 1982. Ewes s i r e d by FxT ra m s i n t h e s e tw o y e a r s had 13/6 h i g h e r
fe rtility
th a n S u f f o l k - s i r e d ewes (P<.01), but w ere 9% l e s s p r o l i f i c
(PC.10). P r e v i o u s r e s e a r c h by Land e t a l . (1974) fo u n d no d i f f e r e n c e s
61
in f e r t i l i t y
or p r o li f ic a c y
b e tw e e n ew es b r e d t o e i t h e r F in n o r
Tasmanian Merino rams. L i t t e r s s i r e d by FxT were h e a v i e r a t 60 d per
ewe exposed (PC.OI) th a n th o se s i r e d by S u ffo lk p r i m a r i l y as r e s u l t of
su p e rio r f e r t i l i t y .
Due t o l o w e r S60 ( n o n - s i g n i f i c a n t )
and SI 20
TABLE 21. LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PHASE I I MATURE
EWE PRODUCTION AND INDIVIDUAL LAMB PERFORMANCE BY BREED
GROUP OF SIRE (1976 - 1982)
S u f f o lk
Finn x Targhee
T rait
.03
.06
.07
804
712
804
89.8 ±. .01
1 .58 ± .04
1.14 ± .03
171
171
28.7 ± 1.3
1.16 ±. .07
804
804
22.6 ± .7
1.06 + .03
171
37.2
1.9
804
35.3
234
234
214
214
196
3.87 ± .08
94.1 ±. .3
.4
20.9
97.2 ± .3
33.5 ± .6
1062
1062
884
884
787
171
169
171
103.0
1.49
1.26
±
±.
±
O
Lamb performance
B ir t h weight
S u rv iv a l t o 60 NS
Weight a t 60 **
S u rv iv a l t o 120 NS
Weight a t 120 NS
Mean
Mean
-H
Ewe p r o d u c t i o n , _
F e rtility , %
P ro lific a c y +
L i t t e r s i z e a t 60 +
L i t t e r w eight
a t 60, kg **
L i t t e r s i z e a t 120
L i t t e r w eight
a t 120, kg NS
N
N
4.28 ±. .06
97.3 ±. .2
21.7 ± .3
99.7 ± .3
33.8 ± .5
NS, n o n - s i g n i f i c a n t (PX IO )
+
P4.10
P<.05
** PC.OI
( n o n - s i g n i f i c a n t ) o f FxT s i r e d lam bs, average FxT s i r e d l i t t e r w eights
at
120 d was o n l y
1.9 kg h e a v i e r
(n o n -sig n ific a n t).
Low er lam b
v i a b i l i t y due to in c r e a s e d Finn b re e d in g found i n t h i s study i s not i n
agreem ent w ith
p re v io u s re s e a rc h .
D ick erso n e t a l .
(1975) fo u n d
S u f f o l k s i r e d c r o s s b r e d la m b s t o h a v e 5$ l o w e r s u r v i v a b i l i t y (non­
s i g n i f i c a n t ) t h a n F in n s i r e d c r o s s b r e d la m b s . Magid e t a l .
(1981)
62
r e p o r te d Finn s i r e d t o exceed Border L e i c e s t e r s i r e d c ro s s b r e d lambs
by 12% i p s u r v i v a b i l i t y .
O ther Main E f f e c t s
Y ear e f f e c t s (Y) f o r f e r t i l i t y (P<.0 5 ) , p r o l i f i c a c y (P < .0 1 ), and
la m b w e i g h t s
(P<.01) c o n t r a d i c t p r e v i o u s r e s e a r c h w h ic h fo u n d Y
e f f e c t s f o r p r o l i f i c a c y and i n d i v i d u a l lamb perform ance t r a i t s , but no
s i g n i f i c a n t Y e f f e c t s f o r f e r t i l i t y (M agid e t a l . , . 1 9 8 1 ; E r c a n b r a c k
and JCnight, u n p u b l i s h e d d a t a ) . Y ear e f f e c t w e r e a l s o fo u n d f o r LW60
(P<,01) and a p p r o a c h e d s i g n i f i c a n c e f o r LW120.
Sex e f f e c t s
w e re
s i g n i f i c a n t f o r BWT, S60, and Wfl 20 ( t a b l e 14). M ale la m b s had .3 kg
and .6 kg h e a v i e r BWT and WT120, r e s p e c t i v e l y , t h a n ,fezqales; however,
S60 was 4% l o w e r f o r m a le s . S i m i l a r r e s u l t s f o r b i r t h and w e a n in g
w eig h t have been r e p o r t e d i n s t u d i e s i n v o l v in g lambs from Fx ewes, but
d i f f e r e n c e s i n su rv iv aty ijlity have been n o p - s i g n i f i c a n t (Magid e t a l .,
1981b; O ltenacu and Boylan, 1981a; Ercanbrack anb Knight,
unpublished
d ata).
Wool P ro d u ctio n
Grease F le e c e Weight
S i g n i f i c a n t so u rces o f v a r i a t i o n f o r g re a s e f l e e c e w e ig h t (FLWT)
o f P hase I l ew es a g e s I t h r o u g h 6 y r i n c l u d e d b r e e d o f dam (B), b r e e d
g ro y p o f s i r e (S ), y e a r (Y), age (A), and SxA i n t e r a c t i o n ( t a b l e 22).
Ewes s i r e d by WF r a m s h ad .4 kg h e a v i e r FLWT t h a n F x R -s i r e d ew es
(P<.01, t a b l e 23). These r e s u l t s a r e i n c lo s e agreement w ith th e study
by E r c a n b r a c k and K n ig h t ( u n p u b l i s h e d <iata) w h ich i n v o l y e d t h e same
63
dam breed groups and s i m i l a r s i r e breed groups. In t h a t study FLWTs of
I A F x ewes were .5 kg l i g h t e r (P<.05) than WF ewes f o r ag es I through
7 yr. L arger d i f f e r e n c e were r e p o r te d by D ickerson (1977) w ith s i m i l a r
TABLE 22. MEAN SQUARES FROM VARIANCE ANALYSES FOR EWE WOOL PRODUCTION
TRAITS (1976 - 1982)
df
Source
2
Breed of dam (B)
Breed o f s i r e (S)
I
6
Years (Y)
Age (A)
5
2
BxS
12
BxY
6
SxY
SxA
5
Remainder
1224
+
**
Grease
weight
F leece
grade
3.84*
21. 68**
66.29**
28.63**
2.39
.83
2 . 10+
10.05**
1.10
51.95**
15.99**
9 . 10**
12.87**
2 2 . 16**
1.44*
5.03**
1.13
.75
S ta p le
le n g th
1.674*
.5 9 5 ..
21.971
2.361**
1.487
.742*
1 .241
.684
.383
P<.10
PC.05
PC.01
TABLE 23. LEAST-SQUARES MEANS AND STANDARD ERRORS FOR PHASE I I
CHARACTERS, AGES I TO 6 (1976 - 1982)
WOOL
Lengthb
Grease w eight
Gradea
Mean
Mean
Breed group0
N
Mean, kg
Columbia (C)
Ram bouillet (R)
Targhee (T)
WF mean
188
199
231
618
4.07
3.80
3.75
3.87
±
+
±
±
.12
.10
.09
.07
2.75 ± .10
1.18 + .09
1.74 ± .08
1.89 ±. .06
1.42 ± .07
1.16 + .06
1.10 ± .05
1.23 ± .04
(FxR)
(FxR)
(FxR)
IA Fx
175
219
252
646
3.63
3.27
3.51
3.47
±
±
±
±
.12
.09
.10
.07
2.54 ± .10
1.79 ± .08
2.37 ± .08
2.23 ± .06
1.35 ± .07
1.25 + .06
1.28 ± .06
1.29 ± .04
x C
x R
x T
mean
a F leece grades coded I to 5: Fine ( I ) , 1/2 blood ( 2 ) , 3/8 blood ( 3 ) ,
1/4 blood ( 4 ) , low 1/4 blood (5)
b S ta p l e le n g th coded I t o 3: S ta p le ( I ) , French ( 2 ) , C lo th in g (3)
c C rosses d e s ig n a te d by l e t t e r s , breed o f s i r e f i r s t , Finn (F)
64
b r e e d g r o u p s . A verage FLWT f o r WF e w e s e x c e e d e d 1/4 F x e w e s by 1.1 kg
f o r ag es I and 2 y r. S tu d ie s in v o l v in g com parisons o f 1/2Fx and 1/4Fx
ewes w ith o th e r breeds have shown Fx ewes t o have FLWT ra n g in g from 0
t o 1.5 kg ( a v e r a g e .5 kg) l e s s t h a n s t a n d a r d b r e e d s ( C e d i l l o e t a l . ,
I 977; Dahmen e t a l . , 1978; M agid e t a l . , 1981b; O l t e n a c u and B o y la n ,
1981b ).
No SxA e f f e c t s
w ere r e p o r te d i n th e l i t e r a t u r e
c i t e d above;
h o w e v e r , i n t h i s s t u d y , SxA w as a n i m p o r t a n t e f f e c t (P<.01). At I y r
o f age 1 /4 F x ew e s had .7 kg h e a v i e r FLWTs t h a n WF e w e s , and a t 2 y r
FLWTs were s i m i l a r . WF s u p e r i o r i t y f o r FLWT in c r e a s e d t o 5 y r of age,
th e n showed a s l i g h t d e c l in e f o r 6- y r - o l d ewes. FLWT f o r 1/4Fx 2 - y r old ewes was s i m i l a r t o WF ewes ages 2 through 6 yr. S u p e r i o r i t y o f WF
ewes f o r ages 2 through. 6 y r l a r g l y r e f l e c t e d a d e c l in e i n 1/4Fx FLWTs
w ith age.
E f f e c t s due to breed o f dam f o llo w e d normal breed c h a r a c t e r i s t i c s
w i t h C ew es h a v i n g t h e h e a v i e s t FLWT and T and R b e i n g c o m p a r a b le .
BxS, BxY, and SxY i n t e r a c t i o n s w ere not s i g n i f i c a n t (PX05).
F le e c e G r a d e '
F l e e c e s fro m 1 /4 F x w e r e a b o u t 1 /3 o f a b lo o d c o u n t c o a r s e r t h a n
th o se from WF ewes (P<.01, t a b l e 23). B a l s o a f f e c t e d f l e e c e grade i n
th e expected manner w ith C ewes a v e ra g in g i n th e 3 /8 blood range, T i n
th e 1/2 blood ran g e, and R g ra d in g c lo s e to Fine. F le e c e s from (FxR)xC
ew es g r a d e d s i m i l a r i l y t o s t r a i g h t b r e d C, b u t w e r e a h a l f a b lo o d
c o u n t c o a r s e r t h a n t h e f i n e r w o o le d R and T. R e s u l t s a r e i n c l o s e
agreem ent th e study by Ercanbrack and Knight (unpublished d a ta ) which
65
i n v o l v e d t h e same dam b r e e d g r o u p s . The r e s u l t i n g BxS i n t e r a c t i o n
(P C .O I)
in d ic a te s
c ro s s b re e d in g
w ith
ram s
p o sse ssin g
c h a r a c t e r i s t i c a l l y c o a r s e r f l e e c e s th a n dam breeds w i l l lo w er f l e e c e
g ra d e s; however, c r o s s b r e e d in g w ith ewes of s i m i l a r f l e e c e g ra d e s h as
no e f f e c t .
C e d illo e t a l .
(1977) found no d if f e r e n c e i n f l e e c e grades
b e tw e e n ew es fro m C o lu m b ia and S u f f o l k dams c r o s s e d w i t h e i t h e r
D orset,
Cheviot,
Romney or Finn,
a l l o f which have ap p ro x im a te ly 3/8
blood f l e e c e grades.
BxY and SxY w ere im p o r ta n t (P<.05) i n t h e -model f o r f l e e c e grades,
b u t no t r e n d s w e r e e v i d e n t . U n lik e FLWT, SxA was n o t a s i g n i f i c a n t
i n t e r a c t i o n f o r g r a d e s ( t a b l e 2 2 ). B u t,
(P<.01),
age e f f e c t s w e r e p r e s e n t
and due l a r g e l y to d i f f e r e n c e s between y e a r l i n g s and m ature
ewes. These r e s u l t s a r e i n agreem ent w ith p re v io u s r e s e a r c h i n d i c a t i n g
a f f e c t s due t o age b u t no b r e e d x a g e i n t e r a c t i o n s (Dahmen e t a l . ,
1978; E rcanbrack and Knight, u npublished d a ta ).
!
S ta p le Length
In ag reem en t w ith p re v io u s r e p o r t s i n th e l i t e r a t u r e in v o lv in g
s i m i l a r s i r e and dam b r e e d s (Dahmen e t a l . , 1978; Drummond e t a l . ,
I 9 8 2 ), S d i d n o t s i g n i f i c a n t l y a f f e c t s t a p l e ( f i b e r ) l e n g t h i n t h i s
s t u d y . B ut i n c o m p a r is o n o f o n ly R and T ew es s i r e d by e i t h e r FxR o r
WF rams, s t a p l e le n g th was s l i g h t l y lo n g e r f o r 1/4Fx ewes ( t a b l e 23).
C and (FxR)xC ew es had s i m i l a r s t a p l e l e n g t h s r e s u l t i n g i n a BxS
in te ra c tio n
(P<.05). S t a p l e l e n g t h i n c r e a s e d w i t h age (P < .0 1 ), b u t
showed no SxA i n t e r a c t i o n .
66
D is c u s s io n
Im proved r e p r o d u c t iv e e f f i c i e n c y
L and race
in te n s iv e
b r e e d in g
w ith
m a n a g em en t
lite r a tu r e .
sta n d a r d
sy ste m s
Few r e p o r t s ,
th rou gh in c o r p o r a t io n o f F in n is h
b reeds
has
h ow ever,
b een
i,n t h e
w e ll
U.S.
under
d o c u m e n te d
s e m iin
th e
have b een p u b lis h e d e v a l u a t i n g th e
p e r f o r m a n c e o f F in n c r o s s e s u n d e r m o re h a r s h c o n d i t i o n s o n w e s t e r n
range.
R e s u lts p r e s e n te d i n t h i s study i n d i c a t e g a in s i n t o t a l k ilo g ra m s
o f la m b w eaned may be r e a l i z e d
t h r o u g h t h e a d d i t i o n o f 1 /4 F in n
b re e d in g i n t o t y p i c a l w e s te r n w h ite fa c e ewes d e s p i t e l e s s th a n optimum
n u t r i t i o n and management. Based on unw eighted average o f LWI20 from I
t h r o u g h 6 y r o f ag e , I /4 F x ew es w eaned 6 kg p e r ewe p e r y r m ore t h a n
WF ewes under the same c o n d itio n s .
Lamb p r o d u c tio n s u p e r i o r i t y of 1/4Fx ewes wa$ most e v id e n t a t age5
I , 2 and
3 y r . D i f f e r e n c e s a s ewe la m b s , l a m b i n g a t I y r o f a g e ,
re su lte d
e n tire ly
from
in c re a se s
in
fe rtility
(37.7#
vs.
1.3#).
I n c r e a s e d f e r t i l i t y a s ewe la m b s p r o v i d e d 1 /4 F x ew es w i t h a 14 kg
p ro d u c tio n ad v an tag e
b e f o r e WF ew es la m b e d f o r t h e f i r s t
ti m e .
A n a l y s i s by b r e e d o f dam show ed i n c r e a s e d l e v e l s o f p r o d u c t i o n i n
1 /4 F x ewe la m b s t o be i n d e p e n d e n t o f t h e WF b r e e d i n v o l v e d i n t h e
cross.
S u p e rio r
LWI20 a t
a g e s 2 and 3 y r r e s u l t e d
p r o l i f i c a c y r a t h e r th a n f e r t i l i t y
s ig n ific a n t,
fro m
in c re a s e d
a s i n ewe la m b s . A lth o u g h non­
e s t i m a t e s o f f e r t i l i t y i n m ature ewes d em o n stra te d 1/4Fx
ew es t o be a c t u a l l y i n f e r i o r t o WF ew es. D e c r e a s e s i n f e r t i l i t y i n
67
m ature 1/4Fx ewes may be a r e s u l t o f in c r e a s e d s t r e s s due t o lam bing
a t I y r o f ag e ; how ever, t h i s stu d y does n o t a d d r e s s t h i s q u e s tio n .
F or a g e s I and
2 y r I / 4 F x e w e s e x c e e d e d WF ew e s by an a v e r a g e o f .4
lam bs per ewe lam bing, r e s u l t i n g i n an 8 kg s u p e r i o r i t y i n LWI20.
A n a l y s i s o f P hase I w as i n c l u d e d i n t h i s s t u d y t o e s t i m a t e any
change i n t o t a l k ilo g ra m s o f lamb weaned due t o th e use of FxR rams t o
o b t a i n 1/4Fx ewes f o r f u t u r e p ro d u ctio n . The s u b s t i t u t i o n o f FxR f o r
WF ra m s show ed no e f f e c t s on i n d i v i d u a l la m b w e a n in g w e i g h t s , and
t o t a l k ilo g r a m s o f lamb weaned i n c r e a s e d by 4 kg. S u p e r i o r i t y i n LW120
fo r
ew es s i r e d
by FxR. r a m s r e s u l t e d
p rim a rily
fro m
h e te ro sis
i n c r e a s i n g S60 f o r c r o s s b r e d lambs. .
F i n n i s h L a n d r a c e a r e known f o r l i g h t e r c o a r s e r f l e e c e s t h a n WF
e w es, and r e d u c t i o n s i n w ool p r o d u c t i o n and q u a l i t y due t o 1 /4 F in n
b re e d in g w ere s i g n i f i c a n t i n t h i s study. L ig h te r f l e e c e w e ig h ts of .4
kg p e r ewe p e r y r r e s u l t i n g i n a n e t l o s s o f 2.4 kg o f w ool o v e r 6 y r ,
co m b in ed
w i t h a l e s s a t t r a c t i v e w ool c l i p , <Jue t o c o a r s e r f l e e c e s ,
re d u c e s the o v e r a l l g a in s from the u t i l i z a t i o n o f 1/4Fx ewes.
68
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