Visceral mass and reticulorumen volume of differing biological types of... by Eddie L Fredrickson

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Visceral mass and reticulorumen volume of differing biological types of beef cattle
by Eddie L Fredrickson
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in
Range Science
Montana State University
© Copyright by Eddie L Fredrickson (1987)
Abstract:
A study was conducted to determine if differences in visceral organ mass and potential reticulorumen
volume occur among beef cow biological types differing in milk production potential. During 1985» 6
pregnant, 6 to 9 yr old lactating cows of 5 biological types were used. These include: Straightbred
Herefords (HH) , 50% Angus-50% Hereford (AH), 25% Simmental-75% Hereford (1S3H), 50%
Simmental-50% Hereford (SH) and 75% Simmental-25% Hereford (3S1H). In 1986 , 6 pregnant, 3 yr
old lactating cows of 4 biological types were examined: HH, 50% Tarentaise-50% Hereford (TH), 50%
Tarentaise-(25% Simmental-25% Hereford) or 50% Tarentaise-(37.5% Simmental-12.5%
Hereford)(T(SH)) and 50% Charolais-(25% Simmental-25% Hereford) or 50% Charolais-(37 • 3%
Simmental-12.5% Hereford) (C(SH)). In the summer of 1985 fecal organic matter output was estimated
with a CrgCL dilution technique (all cows) and total fecal collections (HH and 3a1H). Total fecal
collections were obtained from all cows in 1986. Esophageal fistula collections were collected each
fecal collection to estimate organic matter intake (OMI). Weightiheight ratios were used to determine
body condition scores, and milk production estimates were obtained using a weigh-suckle-weigh
technique. Weights of the spleen, heart, lungs, kidney, kidney fat, reticulorumen weight and volume
and liver were measured 5 weeks after weaning in 1 985 and at weaning in 1986. Potential
reticulorumen volume was determined to be the water filled capacity at slaughter. Differences (P>.10)
in reticulorumen volume or OMI were not evident either year. In 1985 liver weight was greatest
(P<.10) for the 3S1H and BH, and kidney weight was higher (P<.10) for the 3S1H. Cows with larger
livers and kidneys also had lower (P<.10) condition scores and kidney fat weights. During 1986 milk
production at weaning was greatest (P<.10) for the T(SH) and TH. Condition scores and body fat
measurements did not differ (P>.10) in 1986. Kidney and spleen weights were highest (P< .10) for the
C(SH) and tended to be high for the T(SH). Differences in kidney weight could be accounted for by
differences in body weight, but differences in spleen weights are not understood. Differences in organ
weights in 1985 appear to reflect milk production potential, while organ weights during 1986 possibly
reflect both body size and milk production potential. Further research regarding metabolic activity per
unit of tissue weight may further assist in understanding differences among biological types. VISCERAL MASS AND RETICULORUMEN VOLUME
OF DIFFERING BIOLOGICAL TYPES OF
BEEF CATTLE
by
E d d ie L . F r e d r i c k s o n
A t h e s i s s u b m itte d i n p a r t i a l f u l f i l l m e n t
o f t h e r e q u i r e m e n ts f o r t h e d e g r e e
of
M a s te r o f S c ie n c e
in
. Z
Range S c ie n c e
MONTANA STATE UNIVERSITY
B ozem an, M ontana
June 1987
MAIN Ub.
Go^-cSO
ii
APPROVAL
o f a t h e s i s s u b m itte d by
E d d ie L . F r e d r i c k s o n
T h is t h e s i s h a s b e e n r e a d by e a c h member o f t h e t h e s i s c o m m itte e
and h a s b e e n fo 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 lis h u s a 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 is s io n t o t h e C o lle g e o f G r a d u a te S t u d i e s .
Im. a r i%AD a te |
]
C h a i r p e r s o n , G ra d u a te C om m ittee
A pproved f o r t h e M ajor D e p a rtm e n t
c
H ead, M ajor D e p a rtm e n t
D a te
A pproved f o r t
(? D a te
2 C G ra d u a te Dean
A
,.
ill
STATEMENT OF PERMISSION TO COPY
In
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t n e s i s may be g r a n t e d by my m a jo r p r o f e s s o r , o r i n h i s a b s e n c e , by th e
D i r e c t o r o f t h e L i b r a r i e s w hen, i n t h e o p i n io n o f e i t h e r ,
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Any c o p y in g o r u se o f
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iv
ACKNOWLEDGEMENTS
I
w ould l i k e t o d e d i c a t e t h e e f f o r t s
g r a n d p a r e n t s Mr.
and M rs.
C h a r le s W. F r e d r i c k s o n .
h a v e b e l i e v e d i n m e, and i n my d e s i r e
s c ie n c e .
o f th e l a s t
to
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tw o y e a r s t o
fin e
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p u r s u e an e d u c a t i o n i n r a n g e
My g r a t i t u d e to w a rd them i s beyond w o rd s .
my
V
TABLE OF CONTENTS
P age
LIST OF TABLES................................................................................................
ABSTRACT.......... ............................................................................'................,•-------• ..............
v iii ,
INTRODUCTION......................................... .................. ...........................................................•
I
LITERATURE REVIEW..........................................................................
I n t r o d u c t i o n ...................................................................................................
M a in te n a n c e Demand.........................................................................................................
V i s c e r a l O rgan M ass.......................................................................................................
A c tiv e T i s s u e s ............ ................................................................................
I n t a k e ......................................................................................................
R e tic u lo ru m e n v o lu m e .......... ........................................................................................
F a t i g u e ............................................................................
3
4
7
11
16
MATERIALS AND METHODS....................................................................................
1
M eth o d o lo g y Used i n 1 9 8 5 ................................................................................
M eth o d o lo g y Used i n 1 9 8 6 .......................................................................................
S t a t i s t i c a l A n a l y s i s .......... ......................................................................................
19
23
24
RESULTS......................................................................................................................................
1 9 8 5 ....................................................... ............- ....................... ....................................
1986 ................................................................................................
DISCUSSION.............................................
F o ra g e I n t a k e ..................................................................................................................
M ilk P r o d u c t i o n .............................................................................................................
O rgan M a ss.........................................................................................................................
R e tic u lo ru m e n Volum e.....................................................................
G e n e ra l D i s c u s s i o n ......................................................................................................
LITERATURE CITED...............................................................................................................
APPENDIX............................................................................................................................
26
26
42
42
44
45
47
50
60
vi
LIST OF TABLES
T a b le
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Page
T r a i t s o f b e e f cow b i o l o g i c a l t y p e s ,
1 9 8 5 . . . . ..................................
20
Body w e i g h t , body c o n d i t i o n , h ip h e i g h t , k id n e y f a t w e ig h t
. and h o t c a r c a s s w e ig h t o f f i v e d i f f e r e n t b e e f cow b i o l o g i c a l
t y p e s , 1 9 8 5 ............................
26
A verage d a i l y m ilk p r o d u c t i o n ( k g /d ) f o r f i v e b e e f cow
b i o l o g i c a l t y p e s , 1 9 8 5 ......................................................
C a lf a v e ra g e d a i l y g a in (k g ) from dams o f f i v e b e e f cow
b i o l o g i c a l t y p e s , 1 9 8 5 .................................
'
.
27
28
t
S te p w is e r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p r o d u c t i o n p r i o r
w e a n in g , 1 9 8 5 .........................................................
29
A v erag e d a i l y g a in (k g ) f o r f i v e d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1 9 8 5 ......................................
29
O rg a n ic m a t t e r i n t a k e p e r day (O M I/d, k g ) , and OMI/d a s
a p e r c e n t o f body w e ig h t (%BW) f o r f i v e d i f f e r e n t b e e f
cow b i o l o g i c a l t y p e s , 1 9 8 5 . . ............ ......................... .................. - ..............
30
S te p w is e r e g r e s s i o n c o e f f i c i e n t s f o r o r g a n i c m a t t e r i n t a k e
p r i o r t o w e a n in g , 1 9 8 5 ...................................................................
31
O rgan m ass o f f i v e d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s ,
1 9 8 5 ............................
32
O rgan m ass a s a p e r c e n t o f body w e i g h t, o f f i v e d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1 9 8 5 . . . . ..........................................................
32
P o t e n t i a l r e t i c u l o r u m e n volum e o f f i v e d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1 9 8 5 ..............................................................
33
Body w e i g h t, h i p h e i g h t , and h o t c a r c a s s w e ig h t o f f o u r
d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s , 1986 ...........................................
34
K id n ey f a t w e ig h t, b a c k f a t t h i c k n e s s and m a r b lin g s c o r e
o f f o u r d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s , 19 8 6 . . . . ..............
34
A v erag e d a i l y m ilk p r o d u c t i o n ( k g /d ) f o r f o u r b e e f cow
b i o l o g i c a l t y p e s , 1986 ...................... ' . ................................................... ...........
35
C a l f a v e ra g e d a i l y g a in (Kg) from dams o f f o u r d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1986 ....................................................................
36
vii
LIST OF TABLES - C o n tin u e d
T a b le
16
17
18
19
20
21
22
23
24
25
P age
S te p w is e r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p r o d u c t i o n a t .
w e a n in g , 1986 ......................................................................................................... .. •
37
S te p w is e r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p r o d u c t i o n a t
w e a n in g , 1986 .................................... "•................................ .....................................
37
A verage d a i l y g a in (k g ) o f f o u r d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s . 1986 ............................
38
O rg a n ic m a t t e r i n t a k e p e r day (O M I/d, k g ) , and OMI/d a s
a p e r c e n t o f body w e ig h (%BW) f o r f o u r b e e f cow b i o l o g i c a l
t y p e s , 1986 .......................
38
S te p w is e r e g r e s s i o n c o e f f i c i e n t s f o r o r g a n i c m a t t e r i n t a k e
a t w e a n in g , 1986 ................................................................
39
O rgan m ass o f f o u r d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s ,
1986................................................................................. - ....................................
. 40
O rgan m ass a s a p e r c e n t o f body w e ig h t ($BW) o f f o u r
d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s , 1986 ...........................................
40
P o t e n t i a l r e t i c u l o r u m e n volum e o f f o u r d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s ..........................
41
L e a st s q u a re s a n a ly s is o f v a ria n c e o f o rg a n ic
m a t t e r i n t a k e (O M I), 1 9 8 5 ...............................
61
L e a st s q u a re s a n a ly s i s o f v a ria n c e o f o rg a n ic
m a t t e r i n t a k e (O M I), 1 9 8 6 ..............
61
v iii
ABSTRACT
A s tu d y w as c o n d u c te d t o d e te r m in e i f d i f f e r e n c e s i n v i s c e r a l
o r g a n m ass and p o t e n t i a l r e t i c u l o r u m e n volum e o c c u r among b e e f cow
b i o l o g i c a l t y p e s d i f f e r i n g i n m ilk p r o d u c t i o n p o t e n t i a l .
D u rin g 1 9 8 5 ,
6 p r e g n a n t , 6 t o 9 y r o ld l a c t a t i n g cow s o f 5 b i o l o g i c a l t y p e s w ere
used.
T h e se i n c l u d e : S t r a i g h t b r e d H e r e f o r d s ( H H ), 50% A n g u s-5 0 %
H e r e f o r d (A H ), 25% S im m ental--? 5% H e r e fo r d (1 S 3 H ), 50% S im m e n ta l- 50%
H e r e fo r d (SH) and 75% S im m ental-25% H e r e f o r d ( 3 S 1 H ) .
In 1986, 6
p r e g n a n t , 3 y r o l d l a c t a t i n g cows o f 4 b i o l o g i c a l t y p e s w e re e x a m in e d :
HH, 50% T a r e n t a i se-50% H e r e fo r d (T H ), 50% T a r e n t a i se -(2 5 % S im m ental-25%
H e r e f o r d ) o r 50% T a r e n t a i s e - (37-5% S im m e n ta l- 12.5% H e r e f o r d ) ( T (S H )) and
50% C h a r o la is -( 2 5 % S im m ental-25% H e r e f o r d ) o r 50% C h a r o l a i s - ( 3 7 • 3%
S im m e n ta l-1 2 .5 % H e r e f o r d ) (C ( S H ) ) . I n t h e summer o f 1985 f e c a l o r g a n i c
m a t t e r o u tp u t w as e s t i m a t e d w ith a C r 2 Og d i l u t i o n t e c h n i q u e ( a l l cow s)
and t o t a l f e c a l c o l l e c t i o n s (HH and 3 S 1H ).
T o ta l f e c a l c o ll e c t i o n s
w e re o b t a i n e d fro m a l l cows i n 1 9 8 6 .
E so p h ag eal f i s t u l a c o l l e c t i o n s
w ere c o l l e c t e d e a c h f e c a l c o l l e c t i o n t o e s t i m a t e o r g a n i c m a t t e r i n t a k e
( O M I).
W e ig h tih e ig h t r a t i o s w e re u s e d t o d e te r m in e body c o n d i t i o n
s c o r e s , and m ilk p r o d u c t i o n e s t i m a t e s w ere o b t a i n e d u s in g a w e i g h s u c k l e - w eig h t e c h n i q u e .
W e ig h ts o f t h e s p l e e n , h e a r t , l u n g s , k i d n e y ,
k id n e y f a t , r e t i c u l o r u m e n w e ig h t and volum e and l i v e r w e re m e a su re d
5
w e e k s a f t e r w e a n in g i n 1 985 a n d a t w e a n in g i n 1 9 8 6 .
P o te n tia l
r e t i c u l o r u m e n volum e was d e te r m in e d t o be t h e w a t e r f i l l e d c a p a c i t y a t
s l a u g h t e r . D i f f e r e n c e s ( P X I O ) i n r e t i c u l o r u m e n vo lu m e o r OMI w e re n o t
e v id e n t e i t h e r y e a r .
I n 1985 l i v e r w e ig h t w as g r e a t e s t (P < .1 0 ) f o r th e
3S1H and SH, an d k id n e y w e ig h t was h i g h e r (P < .1 0 ) f o r t h e 3S1H.
Cows
w i t h l a r g e r l i v e r s and k i d n e y s a l s o h a d lo w e r (P < .1 0 ) c o n d i t i o n s c o r e s
and k id n e y f a t w e i g h t s .
D u rin g 1986 m ilk p r o d u c t i o n a t w e a n in g w as
g r e a t e s t (P < .1 0 ) f o r t h e T(SH) and TH.
C o n d itio n s c o r e s and body f a t
m e a s u re m e n ts d i d n o t d i f f e r ( P X 1 0 ) i n 1 9 8 6 . K id n e y and s p le e n w e i g h ts
w e re h i g h e s t (P < .1 0 ) f o r t h e C(SH) and te n d e d t o b e h i g h f o r th e T (S H ).
D i f f e r e n c e s i n k id n e y w e ig h t c o u ld be a c c o u n te d f o r by d i f f e r e n c e s i n
body w e i g h t , b u t d i f f e r e n c e s i n s p l e e n w e ig h ts a r e n o t u n d e r s t o o d .
D i f f e r e n c e s i n o r g a n w e ig h ts i n 1985 a p p e a r t o r e f l e c t m ilk p r o d u c t i o n
p o t e n t i a l , w h ile o r g a n w e i g h ts d u r in g 1986 p o s s i b l y r e f l e c t b o th body
s i z e and m ilk p r o d u c tio n p o t e n t i a l .
F u r t h e r r e s e a r c h re g a rd in g
m e t a b o li c a c t i v i t y p e r u n i t o f t i s s u e w e ig h t may f u r t h e r a s s i s t i n
u n d e r s t a n d in g d i f f e r e n c e s among b i o l o g i c a l t y p e s .
I
INTRODUCTION
A goal
" m a x im iz e
1 9 8 6 ).
of
th e
th e
c o w -c a lf
p o unds
of
th e s e
tra its
have
h ig h e r
e n e rg y
re q u ire m e n ts
m ust
n u tritio n a lly
re s tric tiv e
c o n d itio n
m a jo r
be
and
fa c to r
n e c e ssa ry to
beef
per
cow i n
ra n g e la n d s
th e
h e rd "
m et
cow
p ro d u ce
a
ra n g e la n d
l o w e r in g
b ecause
(T hom as,
b e e f cow t y p e s
w ith
h ig h e r
e ffic ie n c y
o v e ra ll
th e
of
Cow
w e a n in g
T h ese
th a t
d e m a n d in g .
p e rfo rm a n c e
o f te n
by
in
e n e rg y
e ffic ie n c y
is
and
it
of d iffe rin g
g e n o ty p e
is
th e s e
r e p ro d u c tiv e
e n e rg e tic s
h ig h e r
A d e c lin e
can o c c u r i f
h e rd
im p o rta n t
1 9 8 4 ).
e n v iro n m e n t
T h is d e c l i n e i n
b e t t e r u n d e r s ta n d
ty p e s
(N E C ,
e n e rg e tic a lly
re p ro d u c tiv e
in
c a lv e s
to
H ow ever, h i g h e r p r o d u c in g b e e f cow t y p e s
in
and
is
f o r m ilk p r o d u c t i o n and body s i z e .
re q u ire m e n ts
r e q u i r e m e n ts a r e n o t m e t.
th e
w eaned
o f te n
w e ig h ts (S m ith e t a l . , 19 7 6 ) .
body
w e s te rn
To a c h ie v e t h i s g o a l p r o d u c e r s h a v e i n tr o d u c e d
w ith
a ls o
on
c a lf
w ith h i g h e r g e n e t i c p o t e n t i a l
ty p e s
o p e ra to r
m akes
b io lo g ic a l
e n v iro n m e n ta l
in te ra c tio n s .
A p p ro x im a te ly
70% o f
th e m e ta b o liz a b le
t h e a n im a l f o r m a in te n a n c e
e n e rg y
in ta k e
( F e r r e l and J e n k i n s , 1 9 8 5 ).
is
u se d by
The r e m a in in g
e n e rg y i s u s e d f o r a c t i v i t y , g r o w th , and c a l f p r o d u c t i o n .
T ess e t a l .
(1 9 8 4 )
w as
re p o rte d
fa s tin g
heat
p ro d u c tio n
of
m a in te n a n c e
r e l a t e d t o t h e w e ig h t o f p r o t e i n i n t h e v i s c e r a o f p i g s .
re s p o n s ib le
fo r
p ro te in
and g a s t r o i n t e s t i n a l
t u r n o v e r and i o n
t r a c t h a v e p ro v e n t o
tra n s p o rt
h ig h ly
V ita l o rg an s
such a s
th e
liv e r
be o f m a jo r im p o r ta n c e . F o r
e x a m p le , l i v e r e x p e n d i t u r e s i n n o n l a c t a t i n g d a i r y cows w as e s t i m a t e d a t
3,369
k c a l/d ,
and
a c c o u n te d
fo r
2 2 .5 %
of
to ta l
a n im a l
e n e rg y
2
3,369
k c a l/d ,
e x p e n d itu re s
w e ig h ts
(S m ith
m ay
be
e x p e n d itu re s
th e s e
ana
a c c o u n te d
fo r
and B a ld w in ,
re la te d
b e tw e en
c h a n g e s may b e
to
1 9 7 4 ).
of
in
and
to ta l
T h erefo re
d iffe re n c e s
la c ta tin g
fo u n d
2 2 .5 %
in
d a ta
tis s u e s
b e tw e e n r a n g e
of th is
b e e f cow t y p e s i s
s o r t may r e f l e c t
among cow t y p e s .
The f i r s t
changes in
tis s u e
co w s.
beef
l a c t a t i o n p o t e n t i a l s ( F e r r e l and J e n k i n s , 1 9 8 4 ) .
th e s e
e n e rg y
m a in te n a n c e
n o n la c ta tin g
n o n la c ta tin g
a n im a l
e n e rg y
A d d itio n a lly ,
cow s w ith
d iffe re n t
I n f o r m a t i o n c o m p a rin g
u n a v a ila b le .
H ow ever,
d i f f e r e n c e s i n m a in te n a n c e r e q u i r e m e n ts
o b je c tiv e
of
th is
s tu d y
w as t o
m e a su re
v i t a l o r g a n m ass o f ra n g e b e e f cow s w ith e m p h a s is on m ore m e t a b o l i c a l l y
a c t i v e t i s s u e s and r e l a t e any d i f f e r e n c e s t o
b e e f cow t y p e s o f v a r y i n g
f o r a g e i n t a k e and m ilk p r o d u c t i o n .
A lth o u g h
th e re
is
a
many
la rg e
g a s tro in te s tin a l
fill
fa c to rs
am o u n ts
tra c t
may
of
fill
m ech an ism s l i m i t i n t a k e
lim it
d a ta
in ta k e
w h ic h
of
low
s u g g e s ts
upon f o r a g e i n t a k e
o f low q u a l i t y
q u a lity
th e
ro u g h a g e
i m p o r ta n c e
(Van S o e s t ,
1 9 8 3 ).
of
If
f o r a g e s t h e n a n im a ls w i t h
v a r y i n g i n t a k e am o u n ts may a l s o h a v e d i f f e r i n g r e t i c u l o r u m e n c a p a c i t i e s
t o accom pany t h e i n c r e a s e i n
by W agner e t a l .
fo ra g e
in ta k e s
f o r a g e c o n s u m p tio n .
I n an e a r l i e r
s tu d y
( 1 9 8 6 ) , h i g h e r p r o d u c in g b i o l o g i c a l t y p e s had g r e a t e r
th a n
lo w e r
p ro d u c in g
d i g e s t i b i l i t i e s w e re b elo w 60 t o 65%.
cow
ty p e s
w hen
fo ra g e
A s e c o n d o b j e c t i v e w as t o r e l a t e
p o t e n t i a l r e t i c u l o r u m e n volum e w i t h cow ty p e and f o r a g e i n t a k e and t o
d e te r m in e i f r e t i c u l o r u m e n volum e v a r i e s w ith f o r a g e i n t a k e .
T h e se two
o b j e c t i v e s w ould a llo w u s t o b e t t e r c h a r a c t 6 r i z e d i f f e r e n c e s among b e e f
cow b i o l o g i c a l t y p e s and m a tc h a b i o l o g i c a l
e n v ir o n m e n ta l c o n d i t i o n s .
ty p e t o a s p e c i f i c s e t o f
3
LITERATURE REVIEW
In tro d u c tio n
O p tim a l b e e f cow p r o d u c t i v i t y
th e
e n e rg y
tra n s fe r
fro m
th e
fro m
p la n t
ra n g e la n d s
com m unity
to
is
d e p e n d a n t upon
d e s ire d
S p e c i f i c a l l y t h i s m eans p o u n d s o f c a l f w eaned p e r cow i n
th e
s a lv a g e
v a lu e
of
th e
p r o d u c in g
a n im a ls .
p ro d u c ts .
t h e h e rd and
To p ro d u c e
a
454 kg
s l a u g h t e r s t e e r G re g o ry (1 9 7 2 ) e s t i m a t e d t h a t 65% o f t h e n u t r i e n t s a r e
u s e d t o s u p p o r t t h e c a l f t o w e a n in g a g e .
F o r th e m a jo r ity o f p ro d u c e rs
th is
in
n u trie n t
r e q u ir e m e n t
e n v ir o n m e n ts ,
B e s id e s
s o la r
each
w ith
m a n i p u la t in g
e n e rg y
e ffic ie n c y
in
of
m u st
a
th e
u n iq u e
p la n t
a d e s ira b le
e n e rg y
be
m et
set
of
com m unity
fo rm ,
u tiliz a tio n
a
v a rie ty
a ttrib u te s
to
of
and
a c h ie v e
ra n g e la n d
c o n s tra in ts .
m a x im a l
u s a b le
c o n s i d e r a t i o n m ust be g iv e n t o
by
th e
beef
cow h e r d
fo r
th e
o p tim a l
p ro d u c tio n .
E n e rg y
u tiliz a tio n
by t h e
p r o d u c in g b e e f cow c a n be p a r t i t i o n e d
i n t o m a in te n a n c e , g r o w th , t r a v e l , g e s t a t i o n and l a c t a t i o n
H o w ev er,
a rtific ia l
among a l l
beef
as
as
s u g g e s te d
e n e rg y
C a s e b o lt,
1 9 8 4 ),
Koong e t
m e ta b o lis m
p h y s io lo g ic a l
cow b i o l o g i c a l
by
ra te
of
in
(1 9 8 5 )
in v o lv e s
p ro ce sse s.
ty p e s
a l.
m ilk
m a tu rity
a
B e c a u se
com plex
p a rtitio n in g
is
in te rre la tio n s h ip
o f th e v a r i a b i l i t y
p ro d u c tio n
( L a s te r
th is
(C o o k , 1 9 7 0 ).
(H o tte r
e t.a l.,
et
1 9 7 6 ),
a l.,
body
among
1978;
s iz e
(S m ith e t . a l . , 1976; H o t t e r e t . a l . , 1 9 7 8 ) , body c o m p o s itio n ( F e r r e l and
J e n k in s ,
1 9 8 4 ),
re q u ire m e n ts
fo ra g e
(F e rre l
in ta k e
and
(W agner
e t.a l.,
J e n k in s ,
1986)
1985)
th e
and
m a in te n a n c e
e x te n t
and
4
in te rre la tio n s h ip
To a c h ie v e
among t h e s e
o p tim a l
p ro d u c tio n
t h e r a n g e e n v iro n m e n t t o
p o te n tia l.
p h y s io lo g ic a l
s u ffic ie n t
p r o c e s s e s m u st a l s o
v a ry .
e n e rg y m ust be d e r i v e d
su p p o rt each b io lo g ic a l
t y p e 's
fro m
p h y s io lo g ic a l
A g r e a t e r u n d e r s t a n d in g o f t h e m ech an ism s i n f l u e n c i n g t h e
e x p r e s s i o n o f t h i s p h y s i o l o g i c a l p o t e n t i a l i n r e l a t i o n t o e n e rg y i n p u t s
r e q u i r e d i n a r a n g e e n v iro n m e n t i s n e e d e d .
in
id e n tific a tio n
and
p o s s ib le
T h is i n f o r m a t i o n may a s s i s t
m a n ip u la tio n
of
b io lo g ic a l
ty p e s
e n e r g e t i c demand t o m a tc h t h e o f t e n l i m i t i n g r a n g e e n v ir o n m e n t.
T h is r e v ie w o f l i t e r a t u r e
w i l l be p r e s e n t e d i n
r e q u i r e m e n ts
v is c e ra l
fo r
o rg an
th re e
p a rts .
m a in te n a n c e .
m ass
and
its
d i f f e r e n c e s among b i o l o g i c a l
e x am in e
re tic u lo ru m e n
m echanism
to
s a tis fy
w h ic h a d d r e s s e s
The f i r s t
T he
th e
p a r t w i l l d i s c u s s e n e rg y
fo llo w in g
p o s s ib le
re la tio n
t y p e s o f b e e f cow s.
volum e d i f f e r e n c e s
e n e rg e tic
s t u d y 's o b j e c t i v e s
p a rt
to
w ill
e n e rg e tic
The t h i r d
among b i o l o g i c a l
demand when
ru m in a l
a d d re ss
fill
demand
p a rt w ill
ty p e s a s a
is
lim itin g
in ta k e .
M a in te n a n c e Demand
When e n e rg y u t i l i z a t i o n i s p a r t i t i o n e d a s s u g g e s te d by Cook (19 7 0 )
t h e e n e r g y f o r body s t a s i s o r m a in te n a n c e r e q u ir e m e n t i s
70 t o 75% o f t h e t o t a l a n n u a l e n e rg y r e q u ir e m e n ts
1 9 8 5 ).
e n e rg y
a p p r o x im a te ly
( F e r r e l and J e n k i n s ,
H ow ever, e s t i m a t e s by F e r r e l and J e n k i n s (1 9 8 5 ) o f t o t a l a n n u a l
r e q u i r e m e n ts o f d i f f e r i n g b i o l o g i c a l
c o n s id e ra b ly .
t y p e s o f b e e f cow s v a r i e d
T h e se e s t i m a t e s o f e n e rg y r e q u i r e d f o r m a in te n a n c e w ere
d e r i v e d fro m f o u r b i o l o g i c a l t y p e s ; Angus X H e r e fo r d (AHX), C h a r o l a i s X
5
Angus o r H e r e fo r d
(C X ), J e r s e y
Angus o r H e r e f o r d (S X ).
X Angus o r H e r e fo r d
E ach cow was n i n e y e a r s o l d , and w as k e p t i n a
n o n p re g n a n t, n o n la c ta tin g c o n d itio n .
f o r m a in te n a n c e w as 1 3 0 ,
AHX,
( J X ) , S im m en tal X
129,
CX, JX and SX co w s,
The m e t a b o l i z a b l e e n e r g y r e q u i r e d
1 4 5 , and
160 k c a l x k g
r e s p e c tiv e ly .
T h e ir
re s u lts
'7 5 x d -1
in d ic a te
fo r
th a t
m ilk p r o d u c t i o n p o t e n t i a l and m a in te n a n c e e n e rg y demand may be r e l a t e d
f o r m a tu re
cows e v e n when t h e
p h y s io lo g ic a l
demand o f l a c t a t i o n
and
g e s ta tio n a re n o t e v id e n t.
R e s e a rc h i n v o l v i n g e n e r g y r e q u i r e m e n ts among b i o l o g i c a l t y p e s h a s
been
v a ria b le .
m e ta b o lis m
fo u n d
no
B rody
b e tw e e n
d a iry
d iffe re n c e
c ro ssb re d s te e r s .
(1 9 4 5 )
d id
not
and b e e f
in
fin d
d iffe re n c e s
b ree d s.
e ffic ie n c y
K lo s te rm a n
am ong
R u s s e l and W rig h t
H e re fo rd ,
in
et
re s tin g
a l.
(1 9 6 8 )
C h a ro la is
and
(1 9 8 3 ) r e p o r t e d no d i f f e r e n c e
in
m a in te n a n c e m e ta b o lis m b e tw e e n B lu e G rey and H e r e fo r d X F r i e s i a n cow s.
W e b ste r
F rie s ia n
et
a l.
(.1974)
p re d ic te d
post
a b s o rp tiv e
m e ta b o lis m
s t e e r s t o be p r o p o r t i o n a l l y 0 .0 6 tim e s g r e a t e r th a n
X Angus s t e e r s .
of
F rie s a in
V ercoe (1 9 7 0 ) and F r i s c h and V erc o e (1 9 7 6 ) d e te r m in e d
Bos t a u r u s ( H e r e f o r d X S h o r th o r n and t h e r e c i p r o c a l c r o s s ) s t e e r s h ad a
10
to
w e ig h t
fo u n d
15% g r e a t e r
(MBW) t h a n
H o ls te in
H e r e fo r d
m a in te n a n c e
per
Bos i n d i c u s X Bos t a u r u s
s te e rs
s te e rs .
r e q u ir e m e n t
to
have
A d d itio n a l
an
b%
s te e rs .
in c re a s e
re fe re n c e s
u n it
in
c ite d
m e t a b o li c
G a rre tt
(1 9 7 1 )
m a in te n a n c e
by F e r r e l
body
over
and J e n k i n s
(1 9 8 5 ) s u g g e s t e d Bos i n d i c u s h a v e lo w e r m e t a b o li c r e q u i r e m e n t s p e r u n i t
MBW th a n
p o te n tia l
Bos
have
ta u ru s .
h ig h e r
B io lo g ic a l
m a in te n a n c e
t y p e s w ith
a h ig h m ilk
re q u ire m e n ts ,
th a n b i o l o g i c a l t y p e s w i t h medium m ilk p o t e n t i a l .
when
p ro d u c tio n
s c a le d
to
MBW,
W e b s te r (1983.) f e l t
6
th a t
fa s tin g
m e ta b o lis m
of c a ttle
c o u ld
b e ra n k e d
a c c o r d in g t o
th e ir
r e s p e c t i v e l e v e l o f p r o d u c t i o n ; d a i r y cow s > b e e f b u l l s > b e e f s t e e r s >
b e e f h e i f e r s > Z eb u .
C hanges
a s s o c ia te d
in
p h y s io lo g ic a l
w ith
c a lc u la te d
la c ta tin g
la rg e
r e q u ir e m e n t
n o n p reg n a n t
n o n p reg n a n t H e re fo rd
la s t
flu x e s
trim e s te r
in
of
e n e rg e tic
e n e rg y
H e re fo rd
fo r
co w s
m a tu r e
dem and.
m a in te n a n c e
as
when f e t a l
g ro w th
(Bauman and
C u rrie ,
a s s o c i a t e d w ith t h e p o s tp a r tu m i n t e r v a l ,
is
beef
cow a r e
F o r e x a m p le ,
th e
31% h i g h e r
fo r
is
co m p ared
a b o u t 75% g r e a t e r i n t h e
a n im a l
th e
cow s ( N e v i l l e and M c C u llo u g h ,
o f g e s ta tio n
r e q u i r e m e n ts a r e
n o n p reg n a n t
of
s ta tu s
to
n o n la c ta tin g ,
1969) •
D u rin g t h e
g re a te s t,
n u trie n t
p r e g n a n t a n im a l t h a n i n t h e
1.980).
O th e r
e n e rg y
c o s ts
su c h a s i n v o l u t i o n , a l s o h a v e
a com pounding e f f e c t w ith p e a k m e t a b o li c dem ands a s s o c i a t e d w ith e a r l y
la c ta tio n .
M a in te n a n c e
w ith
d e c re a s in g
W r ig h t,
r e q u i r e m e n ts
body
1 9 8 3 ).
In
c o n d itio n
in
c o n d itio n
th r o u g h
su bsequent
th e
c o n d itio n
a d d itio n
N o rth e rn
th e
d e c re a se
have
been
(K lo s te m a n
G re a t
P la in s
(Adam s,
re p ro d u c tiv e
d e te r m in e d
et
cows e n t e r i n g
w in te r
in
a ls o
a l.,
to
19 6 8 ;
d e c re a se
R ussel
t h e w i n t e r m o n th s i n
o fte n
re ta in e d
1 9 8 7 ) , w hich o f t e n
p e rfo rm a n c e
poor
re s u lts
( B e llo w s
and
and
poor
body
in
a
S h o rt,
1 9 7 8 ) , m ilk p r o d u c t i o n and c a l f g ro w th ( C o r a h , 1 9 8 0 ).
E ffe c ts
m e ta b o lis m
shown t o
of
of
e n v ir o n m e n t
beef
cow s.
a ffe c t re s tin g
a ls o
P rio r
cau se
s h ifts
e x p o s u re
m e t a b o li c r a t e s .
to
in
c o ld
th e
m a in te n a n c e
te m p e ra tu re s
Cows k e p t i n
c o ld
have
c h a m b e rs
w ith e x p o s u re o f 20 C h a d a r e s t i n g m e t a b o li c r a t e o f a p p r o x im a te ly 70
kcal
x W
x
d~\
w h e re a s
cows e x p o s e d
to
-2 0
C had
a
re s tin g
7
m e ta b o lis m
of
a p p r o x im a te ly
110 k c a l
M a in te n a n c e e n e rg y i n c r e a s e s due t o
x W” " ^
x
d“ ^
th e d i s s i p a ti o n
(Y oung,
1 9 7 5 ).
o f h e a t w ith h e a t
s t r e s s , h a v e b e e n n o te d ( M o r r is o n , 19 8 3 )•
D a ily e n e rg y e x p e n d i t u r e s a s s o c i a t e d w ith
tra v e l
and g r a z i n g
fo r
t h e f r e e ro a m in g b e e f cow a r e s i g n i f i c a n t l y
h i g h e r th a n f o r t h e h o u se d
cow ( B l a x t e r ,
e x p e n d itu re s
1 9 6 2 ).
E s tim a te s
ro a m in g a n im a l a r e v a r i a b l e .
of
e n e rg y
fo r
th e
fre e
H a v s ta d a n d M alech ek (1 9 8 2 ) b e l i e v e d t h i s
i n c r e a s e may be a s h ig h a s 40%, w h ile O s u j i (1 9 7 4 ) g i v e s a r a n g e o f 25
t o 50%.
O th e r e s t i m a t e s a r e a s h ig h a s 100% ( O s u j i , 1 9 7 4 ) .
The e f f e c t
o f p re v io u s n u t r i t i o n
b e e n d e m o n s tr a te d i n r a t s
a l.,
1 9 8 6 ).
in d ic a te d
h ig h
a
C hanges i n
th e s e
a s p re v io u s le v e l
c o r r e s p o n d in g
body
s iz e
in c re a s e
d id
m a in te n a n c e r e q u i r e m e n t ,
heat
p ro d u c tio n
has
( F e r r e l and K oong, 1982) an d s h e e p ( F e r r e l e t
A summary o f
th a t
on f a s t i n g
not
in
e x p e r im e n ts
by Koong e t
of n u tritio n
w as v a r i e d
m a in te n a n c e
appear
to
be a
a l.
fro m low t o
re q u ire m e n t
fa c to r
in
(1 9 8 5 )
o c c u rre d .
c h a n g in g t h e
s i n c e a l l a n im a ls w e re ra n d o m ly r e a s s i g n e d t o
d i f f e r e n t n u t r i t i o n a l l e v e l s midway th r o u g h t h e s t u d y .
V i s c e r a l O rgan Mass
I n o r d e r t o u n d e r s t a n d t h e i n f l u e n c e m a in te n a n c e e n e rg y demand may
h a v e on v i s c e r a l t i s s u e s
e n e rg y
e s s e n tia lly
e n e rg y i s
it
is
re p re s e n ts
i m p o r ta n t t o
th e
used f o r c i r c u l a t i o n ,
"co st
rem em ber t h a t m a in te n a n c e
of life "
re s p ira to ry
( D a le ,
fu n c tio n ,
19 8 4 ) .
c e llu la r
T h is
re p a ir
and r e p l a c e m e n t, membrane t r a n s p o r t , dynam ic e q u i l i b r i u m and many o t h e r
fu n c tio n s
at
b o th
th e
c e llu la r
and
tis s u e
le v e l.
B ecause
of
th e
8
v a ry in g
ro le
e n e rg e tic
(L o b le y
of v ita l
o rg an s
c o s t.
D a ta
a l.,
1980;
et
in
m a in te n a n c e
p re s e n te d
each
by B a ld w in e t
E d d e ls to n e
and
o rg an , h a s
a l.
H olzm an,
(1 9 8 0 )
19 8 1 ;
its
own
and o t h e r s
C anas
et
a l.,
1982) d e m o n s tr a te d t h a t i n d i v i d u a l t i s s u e s e a c h h a v e a u n iq u e m e t a b o li c
dem and.
I n w ork by C anas e t a l .
(1 9 8 2 ) h e a t p r o d u c t i o n p e r gram o f t i s s u e
i n r a t s w as 10 tim e s g r e a t e r i n
th e
w e ig h t
a c tiv itie s
and
re s tin g
in te s tin e s
w ere
o x id a tiv e
g re a te r
in
liv e r
la c ta tin g
th a n i n
of
m u s c le . B o th t h e
th e
s u b je c ts
h e a rt,
th a n
in
liv e r
and
n o n la c ta tin g
a n im a ls . F u r th e r m o r e , a 24% i n c r e a s e i n m a in te n a n c e e n e rg y r e q u i r e m e n ts
w ere e x p la i n e d
liv e r.
S tu d ie s
c o n s u m p tio n
in
a c c o u n te d f o r
le s s
by d i f f e r i n g
et
a l.
by
E d d e ls to n e
n e w b o rn
15 and
(1 9 8 4 )
r e l a t i v e w e i g h ts o f t h e h e a r t ,
and
la m b s
H o ltzm an
fo u n d
th a t
11%, r e s p e c t i v e l y ,
d e te r m in e d
fa s tin g
(1 9 8 1 )
th e
of
heat
tis s u e
liv e r
o f th e t o t a l
k id n e y and
and
GI
oxygen
tra c t
ox y g en consum ed,
p ro d u c tio n
w as
h ig h ly
c o r r e l a t e d t o t h e w e ig h t o f p r o t e i n i n t h e v i s c e r a and b lo o d i n p i g s .
G a rlic k
m e t a b o li c
et
ra te
a l.
in
(1 9 7 6 ),
p ig s ,
t u r n o v e r and s y n t h e s i s .
c itin g
ra ts
In h is
s tu d y w ith
s y n t h e s i s w as g r e a t e s t
liv e r
GI
s y n th e s is
th e
tra c t
e x h ib it
(L o b le y e t a l . ,
p ro te in
s y n th e s is
in
s tu d ie s ,
and man w e re h i g h l y
o f p ro te in
and
o th e r
th e
1 9 8 0 ).
th e
c a ttle
in th e v is c e r a .
g re a te s t
ra te
of
s ta te d
re la te d
th e
th a t
to
th e
p ro te in
fra c tio n a l ra te
Of t h e v i s c e r a t h e
fra c tio n a l
p ro te in
M u scle a c c o u n te d f o r t h e m a j o r i t y o f
w h o le
a n im a l.
L o b le y
et
a l.
(1 9 8 0 )
b e l i e v e d t h e w ork o f p r o t e i n s y n t h e s i s r e p r e s e n t s a maximum o f 30% o f
th e
to ta l
a n im a l
e n e rg y
e x p e n d itu re s .
B a ld w in
and
S m ith
(1 9 7 5 )
9
s u g g e s te d
p ro te in
m e ta b o lis m
a c c o u n ts
fo r
20
to
25% o f
liv e r
e n e rg y
e x p e n d itu re s .
The a c t i v e m ovement o f i o n s a c r o s s b i o l o g i c a l m em branes i s a n o t h e r
s ig n ific a n t
so u rc e
of
e n e rg y
M c B rid e
u tiliz a tio n
M illig a n
and
(1 9 8 5 ),
tra n s p o rt
o f Na+ and K+ , s t a t e d
in
d e s c rib in g
th e
th e
in
v is c e ra
v itro
p e r c e n ta g e
of
c a ttle .
m e a s u re m e n ts
of re s p ira tio n
fo r
due t o
t r a n s p o r t f o r s k e l e t a l m u s c le , d u o d e n a l e p i t h e l i u m and h e p a t o c y t e s w ere
26 t o 46%, 28 t o 61%, and 18 t o 54%, r e s p e c t i v e l y .
The n e rv o u s s y s te m
and
th e s e
k id n e y
e s tim a te d
h ad
even
v a lu e s
h ig h e r
b e in g
cost
50 t o
of
tra n s p o rtin g
60% (B a k e r and C o n n e lly ,
( B a la b a n e t a l . , 1 9 8 0 ) , r e s p e c t i v e l y .
a c tiv ity
1966)
w ith
and 70%
M ajo r s i t e s o f Na+ , K+ - ATPase
(enzym e c a t a l y z i n g t h e a c t i v e pum ping o f Na+ and K+ a c r o s s t h e
p la s m a m em brane) a r e
s y s te m
io n s ,
and
in
duodenal
c o n s u m p tio n
10 t o
h e p a to c y te s
(M cB ride
c o n s u m p tio n
of
th e
k id n e y ,
liv e r,
e p ith e liu m .
42% f o r
th e
fed
and M i l l i g a n ,
O2 b e tw e e n
la c ta tin g
T h is
a n im a l
s k e le ta l
a c tiv ity
over
1 9 8 5 a ).
and
m u sc le s,
In
d ry
in c re a s e d
th e
fa s te d
a s tu d y
e w e s,
n e rv o u s
O2
a n im a l
o f th e
Na+ , K+ -
in
liv e r
ATPase
d e p e n d e n t a c t i v i t y a c c o u n te d f o r 45 and 37% o f t h e O2 c o n s u m p tio n r a t e ,
r e s p e c t i v e l y , a n i n c r e a s e o f 22% w i t h l a c t a t i o n
1 9 8 5 b ).
I n c r e a s e s i n O2 c o n s u m p tio n by t h e l i v e r ,
k id n e y o f c o ld s t r e s s e d r a t s
- ATPase a c t i v i t y
s tu d ie s
(M cB ride and M i l l i g a n ,
th a t
w e re c o m p le te ly a c c o u n te d f o r by Na+ , K+
(G u e rn s e y and S t e v e n s ,
e n e rg e tic
cost
s k e l e t a l m u sc le and
of
19 7 7 )•
Na+ , K+ -
It
ap p e ars
ATPase a c t i v i t y
from t h e s e
is
c lo s e ly
t ie d to p h y s io lo g ic a l s ta t u s .
A f u r th e r in d ic a to r o f
p h y s io lo g ic a l s t a t u s i s
v is c e ra l
e n e rg e tic s
i n v a r y i n g b lo o d flo w r a t e s .
change
w ith
B lo o d flo w r a t e s
10
in c re a s e
50
la c ta tio n
to
in
in c re a s in g
60$
cows
ra te
m e ta b o liz a b le
B a ird ,
1 9 8 3 ).
b lo o d
f lo w
th e
d ig e s tiv e
(Lomax and B a i r d ,
of
flo w
e n e rg y
T h is
to
p ro d u c tio n .
to
to
th e
in ta k e
is
liv e r
to
th e
In a d d itio n
and
GI
and
a g re e m e n t w i t h
w ith
and
19 8 3 )•
( H u n tin g to n
in
in c re a s e
tra c t
tra c t
R e y n o ld ,
S e lle rs
in c re a s e s
in
liv e r
th e re
w ith
is
an
w ith
in c re a s e d
1986;
Lomax and
( 1965)
v o la tile
who
fo u n d
fa tty
a c id
I n c r e a s e d b lo o d flo w r a t e s i n d i c a t e h i g h e r O2 c o n s u m p tio n ,
g r e a t e r CO2 rem o v a l from t h e t i s s u e ,
an i n c r e a s e i n b lo o d m e t a b o l i t e s ,
and g r e a t e r w ork l o a d s i n v o l v i n g a c t i v i t i e s s u c h a s b lo o d p u r i f i c a t i o n
and b lo o d c e l l t u r n o v e r .
R e s e a rc h
in v o lv in g
changes
in
th e
o r g a n m ass o f
c a ttle
e f f e c t on m a in te n a n c e e n e rg y e x p e n d i t u r e s w as p r o b a b ly f i r s t
by S m ith and B a ld w in
(1 9 7 4 ).
in v o lv in g
e n e rg y
its
p e rfo rm e d
C i t i n g e a r l i e r w ork o f B a r c r o f t ( 1 9 4 7 ) ,
B ard ( 1 9 6 1 ) , L i n z e l l ( I 9 6 0 ) , N e u tz e e t a l .
(1 9 6 2 )
and
( 1 9 6 8 ) , and Wade and B is h o p
c o n s u m p tio n by t i s s u e s ,
th e y
d e te r m in e d t h a t
t h i s m ig h t b e e s p e c i a l l y t r u e o f t h e m ore m e t a b o l i c a l l y a c t i v e t i s s u e s .
T h ese t i s s u e s
in c lu d e
g a s tro in te s tin a l
c a ttle ,
b o th
th e l i v e r ,
(G I) t r a c t .
la c ta tin g
and
h e a r t , mammary and co m p o n e n ts o f t h e
D a ta fro m two b i o l o g i c a l t y p e s o f d a i r y
n o n la c ta tin g ,
i n c r e a s e i n t i s s u e w e i g h ts w i t h l a c t a t i o n
la rg e r
body
s iz e
and g r e a t e r
la c ta tio n
d e m o n s tra te d
a
g e n e ra l
and i n b i o l o g i c a l t y p e s w i t h
p o te n tia l
( S m ith
and B a ld w in ,
1 9 7 4 ).
D a ta
of
o rg an
w e ig h ts
in
c o n ju n c tio n
w ith
a d d itio n a l
d a ta
r e g a r d i n g t i s s u e e n e rg y c o n s u m p tio n w ere u s e d t o e s t i m a t e t h e i n f l u e n c e
o f t i s s u e w e ig h ts upon m a in te n a n c e r e q u i r e m e n ts b e tw e e n l a c t a t i n g
n o n l a c t a t i n g cows (S m ith and B a ld w in , 1 9 7 4 ).
and
I n c r e a s e s w ith l a c t a t i o n
11
i n t h e w e i g h ts o f t h e GI t r a c t , l i v e r , h e a r t , mammary g l a n d , and o t h e r
c o m p o n e n ts
not
s p e c ifie d
(S m ith and B a ld w in ,
in c re a s e d
1 9 7 4 ).
m a in te n a n c e
The g r e a t e s t
r e q u i r e m e n ts
changes in
by
o r g a n w e ig h t and
p e r c e n t e n e rg y c o n s u m p tio n w as n o te d f o r t h e mammary, GI t r a c t ,
and h e a r t w i t h e s t i m a t e d
g re a te r,
change
re s p e c tiv e ly
in
in c re a s e
a b s o lu te
n o n la c ta tin g
to ta l
e n e rg y
22.5%
cow
c o n s u m p tio n b e in g
(S m ith and B a ld w in ,
o f 851 k c a l / d .
a c c o u n te d ^ f o r
tra c t,
e n e rg y
of
and
c o n s u m p tio n
In t h i s
th e
to ta l
25.6%
in
and h e a r t r e p r e s e n t e d
e n e rg y e x p e n d i t u r e s
s tu d y
w as
20 and
19%
However t h e g r e a t e s t
fo r
th e
e n e rg y
la c ta tin g
2 . 3 , 7 .2
liv e r
liv e r
w ith
an
t h e l i v e r e n e rg y e x p e n d i t u r e s
a n im a l
th e
50, 22,
1 9 7 4 ).
10%
e x p e n d itu re s
cow .
in
th e
The mammary,
and 10.0% , r e s p e c t i v e l y ,
GI
o f th e
f o r m a in te n a n c e i n t h e n o n l a c t a t i n g a n i m a l ,
and 3 . 6 , 8 .4 and 1 1 .9 , r e s p e c t i v e l y , i n t h e l a c t a t i n g a n im a l (S m ith and
B a ld w in , 1 9 7 4 ) .
A c tiv e T i s s u e s
The f u n c t i o n o f t h e h e a r t i s
t h e c i r c u l a t o r y s y s te m .
m ass i n
not
resp o n se
due t o
(Z a k ,
to
19 7 3 )•
W h ile t h e h e a r t i n t h e a d u l t a n im a l can c h a n g e
lo n g te rm
an in c r e a s e
t h e p r o p u l s i o n o f t h e b lo o d t h r o u g h
in
in c re a s e d
th e
w ork l o a d s t h i s
num ber o f
c e lls
P r e s e n t k n o w led g e o f t h e h e a r t i s
p resen t
c e lls
a lre a d y
in te rc e llu la r
th e re fo re
d e c re a se d
d iffe re n tia te d .
s tru c tu re s
such
a
g re a te r
e n e rg y
to
" n o rm a l"
m y o c a r d ia l
T h is
as
w ould
mean
m ito c h o n d ria
dem and.
c e lls
When t h e
w ill
in
g e n e ra lly
th e
h e a rt
t h a t m y o c a r d ia l c e l l s
do n o t r e g e n e r a t e i n t h e a d u l t a n im a l, b u t t h a t t h e r e i s
of
is
an
(Z a k ,
h e a r t 's
re tu rn
to
a e n la r g e m e n t
in c re a s e
1 9 7 3 ),
and
w o rk lo a d
n o rm al
in
is
s iz e
12
( B e z n a k , 19 6 9 )•
In th e
c a s e o f w o rk lo a d s b elo w n o rm a l a tr o p h y o f t h e
h e a r t c a n o c c u r ( K n ig h t, 1 9 6 7 ) .
The
s p le e n
se rv e s
as
a
s to ra g e
a re a
fo r
b lo o d
u n til
su c h
tim e
b lo o d i s n e e d e d f o r o t h e r f u n c t i o n s . . B e c a u se o f t h i s f u n c t i o n s i z e o f
th@ s p le e n c a n v a r y q u i c k l y w i t h i n a i n d i v i d u a l d e p e n d in g on t h e am ount
o f b lo o d i n t h e s p l e e n .
The s p l e e n i s n o t an e s s e n t i a l o r g a n a s o t h e r
o rg an s
fu n c tio n s
can
fu n c tio n s
assu m e
of
c o rp u s c le s ,
th e
its
s p le e n
in c lu d e ;
p ro d u c tio n
of
if
th e
re m o v a l
s p le e n
of
ly m p h o c y te s ,
e n e rg y
c o n s u m p tio n
of
th e
com pared t o o t h e r t i s s u e s
(B a rc ro ft,
Lung volum e and d i f f u s i o n
su rfa c e
p ro p o rtio n a l to
body w e ig h t
aged
rem o v e d .
or
dead
p ro d u c tio n
f o r m a tio n o f b i l e p ig m e n t and s t o r a g e o f i r o n
T he
is
lu n g s
of
O th e r
red
b lo o d
a n tib o d ie s ,
(S w e n so n , 1 9 8 3 ).
a p p e ars
to
be
m in im a l
as
1947; a s c i t e d by B l a x t e r , 19 6 2 ) .
a r e a f o r g a s e x c h a n g e a p p e a r s t o be
(R e e ce ,
1 9 8 3 ).
T h is i s
in d ic a te d
by th e
te n d e n c y to w a rd s i n c r e a s e d w id th and d e p th o f t h e b r i s k e t w ith h e a v i e r
b io lo g ic a l ty p e s .
The k i d n e y 's h ig h r a t e
o v e r a l l m e ta b o lis m .
o f b lo o d flo w
in d ic a te s
its
im p o r ta n c e t o
The a v e r a g e b lo o d flo w t o t h e k i d n e y s o f s h e e p and
g o a t s w as m e a su re d a s b e in g
550 ml x m in” ^ x
IOOg t i s s u e
.
B lood
f lo w s f o r t h e l i v e r and s k e l e t a l m u sc le a r e 320 and 5 ml x m in- ^ x IOOg
tis s u e - ^,
fu n c tio n
re s p e c tiv e ly
is
(V ern o n
m a in ta in in g
b lo o d
and
io n
P e a k e r,
1 9 8 3 ).
e q u ilib riu m ,
c o n t r i b u t i o n t o t h e e n e rg y e x p e n d ed by t h e s e o r g a n s .
p la y
a
ro le
e x c re tio n .
in
p ro te in
m e ta b o lis m ,
T w enty p e r c e n t
of
in c lu d in g
g ly c o g e n e s is
a t t r i b u t e d t o t h e k id n e y (80% i n t h e l i v e r ) .
u rea
in
th e
A m a jo r
a
k id n e y
s ig n ific a n t
The k id n e y s a l s o
c o n s e rv a tio n
fa s tin g
a n im a l
and
is
P r o d u c ti o n o f g l u c o s e i n
13
th e k id n e y an d t h e l i v e r
a s g lu c o s e
in c lu d e
is
s h o u ld i n c r e a s e s u b s t a n t i a l l y
a p rec u rso r fo r la c to s e .
m a in ta in in g
w a te r
b a la n c e ,
w ith l a c t a t i o n
O th e r f u n c t i o n s o f t h e k id n e y
e lim in a tio n
of
c o m p le x
o rg a n ic
com pounds and m e ta b o lis m and s e c r e t i o n o f e n d o c r in e s u b s t a n c e s .
L iv e r
fu n c tio n s
in c lu d e l i p i d
a re
d iv e rs e
and
m u ltifa c e te d .
T h e se
fu n c tio n s
m e ta b o lis m , c a r b o h y d r a te m e ta b o lis m , p r o t e i n m e ta b o lis m ,
horm one d e g r a d a t i o n an d p r o d u c t i o n , b i l e p r o d u c t i o n , b lo o d p u r i f i c a t i o n
and e l i m i n a t i o n
e n e rg e tic
th e
of
to x ic
s u b s ta n c e s .
M ajor p r o c e s s e s a c c o u n t in g f o r
demand h a v e b e e n p r e v i o u s l y
liv e r
c a n be
s e v e re ly
m e n tio n e d .
im p a c te d b y
fa s tin g
S iz e
s in c e
m a jo r s i t e f o r s t o r a g e o f b o th p r o t e i n and g ly c o g e n .
fo r
2
to
8% o f
n u tritio n a l
th e
w et
w e ig h t
of
th e
a n im a l.
s ta tu s
24
h o u rs
th e
T h is
rese rv e
w ith in
a d d itio n ,
s ta r v a tio n o r p ro te in d e f ic ie n t d i e t s
days o f f a s tin g
fa s tin g
liv e r
d e p le te d
l o s s o f l i v e r p r o t e i n w ith
of
of
(B e itz
and w e ig h t o f
th e
liv e r
is
a
G ly c o g e n a c c o u n t s
d e p e n d in g
of
upon
g ly c o g e n
and A l l e n ,
can
1 9 8 3 ).
c a n c a u s e up t o
th e g r e a t e s t lo s s w ith in th e f i r s t
th e
be
In
a 40%.
se v era l
(V ern o n and P e a k e r , 1 9 8 3 ).
U n lik e o t h e r v i t a l o r g a n s o f t h e b e e f cow t h e rum en h a s r e c e i v e d a
v o lu m in o u s am ount o f a t t e n t i o n .
s p le e n
th e
rum en
is
a m u s c u la r
In c o n tra s t to
o rg an .
The
t h e l i v e r , k id n e y s and
rum en
is
n e c e ssa ry
m ix in g , e v a c u a t i o n and r e g u r g i t a t i o n c o n t r a c t i o n s t o f a c i l i t a t e
and
d ig e s tio n
of
th e
c o n tin u o u s b u t v a r y i n
ru m in a l
c o n te n ts .
o f a c t i v i t y an d r e s t
( R uckebusch, 1 9 8 0 ).
cow 6 t o
c o n tra c tio n s
( D z iu k ,
8 b ip h a s ic
1 9 8 3 ).
T hese
)
f r e q u e n c y and i n t e n s i t y
A d o u b lin g
of
p assag e
c o n tra c tio n s
b e h a v io ra l
a re
s ta te s
In a r e s t i n g , p o st a b s o rp tiv e
p er fiv e
th e
w ith
fo r
m in u te p e r i o d
re s tin g
ra te
is
s h o u ld
n o te d
fo r
occur
sh eep
14
d u r in g f e e d i n g ,
h ay
d ie ts
and t h e
over
cu b ed
num ber o f c o n t r a c t i o n s
hay
d ie ts
( R uckebusch,
a re
g r e a t e r f o r lo n g
1 9 8 0 ).
The e n e r g e t i c
demand a s s o c i a t e d w i t h i n c r e a s e d r u m in a l c o n t r a c t i o n s e x p l a i n s i n
th e
i n c r e a s e d w ork o f d i g e s t i o n
a s n o te d by O s u ji (1 9 7 3 ;
p a rt
a s c ite d
by
O s u j i , 1 9 7 4 ).
F e ll
and W eekes
(1 9 8 0 )
d is c o v e re d
a
c lo s e
re la tio n s h ip
fo o d i n t a k e an d t h e w e ig h t o f r u m in a l m u co sa .
In cre a se d
b e tw e e n
la c ta te
an d
p y r u v a t e f o r m a ti o n w h ic h o c c u r r e d d u r i n g p e r i o d s o f p e a k i n t a k e r a t h e r
th a n
d u r in g
peak
la c ta tio n
su g g est
th a t
th e
a c tiv ity
of
m ucosa i s m e d ia te d by i n t a k e r a t h e r th a n m e t a b o li c dem and.
change
in
r u m in a l
tis s u e
in v o lv e d .
e p ith e lia l
w e ig h t
was
However an
in c re a s e
due
in
to
c e ll
th e
r u m in a l
Most o f t h e
h y p e rtro p h y
of
th e
nu m b ers a c c o u n te d
fo r
some w e ig h t i n c r e a s e w i t h a h ig h c o s t o f m i t o t i c c e l l d i v i s i o n , y e t an
i n c r e a s e i n c e l l n um bers w as n o t a s e v i d e n t .
In ta k e
To m ee t t h e
consum e
z e ro ,
a
c h a n g in g e n e rg y dem ands o f m a in te n a n c e
c o r r e s p o n d in g
am ount
of
o r p o s i t i v e e n e rg y b a la n c e
o f fo o d consum ed i s
n u trie n t
and
a v a ila b ility
d e n s ity ,
p h y s ic a l
e n e rg y
( B a i l e and F o r b e s ,
d e p e n d a n t upon a t t r i b u t e s
c a lo ric
and
m e ta b o liz a b le
of
th e
to
m a in ta in
1 9 7 4 ) . The am ount
o f th e fo ra g e in c lu d in g
d ig e s tib ility
lim ita tio n s
a n im a ls m ust
of
th e
a n im a l.
fee d ,
In
fo ra g e
a
ra n g e
e n v iro n m e n t w h e re f e e d s a r e o f t e n f i b r o u s , b u lk y and o f v a r i a b l e
a v a ila b ility ,
th e
c a p a c ity
of
th e
ru m en ,
p assag e
ra te s
and
fa tig u e
15
r e s t r i c t i o n s a s s o c i a t e d w ith g r a z i n g becom e l i m i t i n g f a c t o r s o f f o r a g e
in ta k e .
N u m erous
w ith
re se a rc h e rs
th e
in c re a s e d
la c ta tin g
c ro ssb re d
cows o f t h e
cow s
fo u n d
demand
consum ed
a l.,
in
tw o
1971;
o ld
re s p e c tiv e ly .
h e ife rs
fo u n d
1 9 8 5 ).
49%
m o re
a s s o c ia te d
For
th a n
e x a m p le ,
n o n la c ta tin g
S im ila r
d iffe re n c e s
a n im a ls by o t h e r
H odgson
la c ta tin g
R o is e r e e t a l .
co nsum ed
fo ra g e
1 9 8 6 ).
consum ed 76 an d 43% m ore th a n n o n l a c t a t i n g
fa ll,
in ta k e
and n o n la c t a t i n g
A llis o n ,
e x p e rim e n ts
in
la c ta tio n .
40% m ore
(K ro n b e rg e t
(D ijk s tra ,
in c re a s e s
d u rin g
fo u n d b e tw e e n l a c t a t i n g
re se a rc h e rs
(1 9 8 1 )
n u trie n t
same h e r d
have been
have
cow s
and
J a m ie s o n
(M arched
a n im a ls d u r i n g
c a lv e d )
s p rin g
and
(1 9 8 0 ) fo u n d t h a t l a c t a t i n g 2 y e a r
fo ra g e
th a n
th e ir
n o n la c ta tin g
c o u n te rp a rts .
F o ra g e i n t a k e h a s a l s o b e e n fo u n d t o v a r y b e tw e e n b i o l o g i c a l t y p e s
on
summer r a n g e l a n d s .
s tra ig h tb re d
c o n su m e d
H e re fo rd s
1 .9
r e s p e c tiv e ly .
and
K ro n b e rg
et
a l.
(1 9 8 6 )
re p o rte d
(HH) and 3 / 4 S im m e n ta ls X 1 /4 H e r e f o r d s
2 .1 %
of
th e ir
W agner e t a l .
body
w e ig h t
per
in ta k e
d ig e s tib ility
d ig e s tib ility
s im ila r
d iffe re n c e s .
w as
( B W /d ),
In
h ig h e r,
W a g n e r 's
65%
in
s tu d y
(1 9 8 6 ) d i d n o t
d u rin g
v itro
1983
o rg a n ic
fo ra g e
m a tte r
(IVOMD), t h a n t h a t r e p o r t e d by K ro n b e rg i n 1982 (5 0 % ).
c o m p a ris o n
m e n tio n e d
m uch
day
(3S1H)
(1 9 8 6 ) t h e f o ll o w i n g y e a r , 1 9 8 3 , u s in g t h e
same b i o l o g i c a l t y p e s and r a n g e l a n d a s K ro n b e rg e t a l .
d e te c t
la c ta tin g
o f fiv e
p re v io u s ly
b io lo g ic a l
was made
by
t y p e s on t h e
W agner
et
a l.
sam e r a n g e l a n d
(1 9 8 6 )
A
as
d u r in g
1984.
B i o l o g i c a l t y p e s u s e d i n t h i s s tu d y i n c l u d e HH, Angus X H e r e fo r d
(A H ),
1 /4 S im m en tal X 3 / 4 (1 S 3 H ), H e r e fo r d S im m e n ta l X H e r e f o r d (SH) and 3S1H
16
la c ta tin g
2 .3 ,
co w s.
2 .5 ,
61%.
Mean f o r a g e i n t a k e f o r HHt AH, ISgH t SH and 3S1H was
2 .2 ,
2 .6 ,
2.8%
M ilk p r o d u c t i o n
cow s when m ilk
o f BWZdt
a c c o u n te d
p ro d u c tio n ,
re s p e c tiv e ly ,
f o r 60% o f t h e
when IVOMD a v e ra g e d
v a ria tio n
w e ig h t:h e ig h t r a t i o s
among t h e s e
and body w e ig h t w e re
u s e d a s c o v a r i a t e s i n a r e g r e s s i o n m o d e l.
R e tic u lo ru m e n Volume
A lo n g
h y p e r tr o p h y
w ith
d u r in g
re tic u lo ru m e n
S h o r th o r n
an
in c re a s e
in
la c ta tio n ,
v o lu m e .
m onozygous
volum e w ith l a c t a t i o n .
th e re
T u llo h
tw in s
re tic u lo ru m e n
to
is
an
( 19 6 6 a )
assess
a s s o c ia te d
u sed
d iffe re n c e s
g re a te r
m id
d ig e s ts ,
fo r
a ir
fille d
la c ta tin g
co w s.
la c ta tio n
la c ta tio n .
w ith
s m a lle r
A ir f i l l e d
by
in c re a s e
in
and
in
Je rse y
X
re tic u lo ru m e n
c a p a c i ti e s o f th e re tic u lo ru m e n f o r e a ch
l a c t a t i n g a n d n o n l a c t a t i n g tw in w e re o b t a i n e d .
d ry
Je rse y
cau sed
The w e ig h t o f t h e d i g e s t s i n t h e r e t i c u l o r u m e n ,
and t h e w a t e r an d a i r f i l l e d
and
w e ig h t
c a p a c ity
and w a t e r f i l l e d
The g r e a t e s t
d iffe re n c e s
e s tim a tio n s .
( U l y a t t and B a r t o n ,
1 9 6 4 ).
d iffe re n c e
fo u n d
c a p a c itie s re s u lte d
d id th e w a te r f i l l e d
W e ig h ts o f b o th t h e w e t
d u r in g
c a p a c ity
o c c u rre d
e a rly
i n much t h e
w ere
d u r in g
an d
la te
same t r e n d s a s
S i m i l a r r e s u l t s w e re fo u n d i n s h e e p
T u llo h
(1 9 6 6 b )
a ls o
fo u n d t h e l e n g t h
and
i n t e r n a l c ir c u m f e r e n c e o f t h e i n t e s t i n a l la m in a o f t h e s m a ll and l a r g e
i n t e s t i n e t o b e l a r g e r f o r l a c t a t i n g a n im a ls .
Work by C am pbell and F e l l ( 1964) fo u n d h y p e r tr o p h y o f t h e GI t r a c t
c o u ld
be
p re v e n te d
in
ra ts
am o u n ts a s n o n l a c t a t i n g r a t s .
if
la c ta tin g
a n im a ls
w e re
fe d
th e
same
T h is s u g g e s t s i n t a k e may b e a c a u s e o f
17 .
h y p e rtro p h y .
However M owatt (1 9 7 3 ; a s c i t e d
d iffe re n c e
in
p re c a lv in g
and
fo o d
re tic u lo ru m e n
in ta k e .
at
w a te r
p a rtu ritio n
fille d
w ith o u t
by F o r b e s , 1986 ) fo u n d a
c a p a c ity
a
b e tw e e n
c o r r e s p o n d in g
T h is w o u ld s u g g e s t o t h e r i n f l u e n c e s ,
tw o w eeks
d iffe re n c e
in
i n c l u d i n g h o rm o n a l
c o n t r o l , may a f f e c t h y p e r tr o p h y and r e t i c u l o r u m e n v o lu m e .
R e tic u lo ru m e n
v o lu m e
s h o u ld
a ls o
be
a v a i l a b l e s p a c e i n t h e a b d o m in a l c a v i t y .
lim ite d
by
th e
am ount
of
( I 98 O) e s t i m a t e d
N u tt e t . a l .
r u m in a l volum e w ith e x t e r n a l m a r k e rs o f Angus cows w ith v a r y i n g fra m e
s iz e s .
A p o s itiv e
re la tio n s h ip
w as fo u n d
b e tw e e n r u m in a l volum e and
fra m e s i z e .
I n a d d i t i o n cow s g r a z i n g lo w e r q u a l i t y p a s t u r e s h ad l a r g e r
rum ens w i t h
in c re a s e d
in ta k e .
T h is
re la tio n s h ip
w as n o t
fo u n d w ith
a n im a ls g r a z i n g h ig h q u a l i t y p a s t u r e s .
F a t ig u e
When
th e
e n e rg y
e x p e n d itu re s
of
s e e k in g
fo o d ,
h a r v e s t becom e g r e a t e r t h a n t h e e n e rg y consum ed i t
a n im a l w i l l
s u f f e ,r f a t i g u e
or
e x h a u s tio n .
T h e se
and
g ra z in g
re sp o n se s
tim e
a re
( A r n o ld .
a p p a re n tly
a
lik e ly
th a t
and
th e
As t h e q u a n t i t y o f . f o r a g e
l e s s e n s t h e r e i s a g e n e r a l i n c r e a s e i n b o th b i t e
1976)
is
p re h e n s io n
ra te
I9 6 0 ;
S c a r n e c c h ia
m eans
of
(C hacon e t a l . ,
et
s u s ta in in g
a l.,
in ta k e
1985) •
le v e ls
s i n c e a n im a ls a r e a b l e t o m a i n ta i n i n t a k e l e v e l s w i t h d e c l i n i n g f o r a g e
a v a ila b ility
a ttrib u te d
( H a v s ta d
to
et
fa tig u e
a l.,
1 9 8 3 ).
a p p e ars
to
H ow ever,
occur
when
a
d e c lin e
g ra z in g
a p p r o x im a te ly 1 0 .8 h ( S c a r n e c c h i a e t a l . , 1985) t o
in
tim e
in ta k e
exceeds
1 2 .0 h o u r s ( S t o b b s ,
18
1 9 7 5 ).
to
D i f f e r e n c e s i n t h e l e n g t h o f g r a z i n g tim e n e c e s s a r y f o r f a t i g u e
occur i s
lik e ly
to
d e p e n d upon a m u l t i p l i c i t y
f o r a g e d e n s i t y , s t r u c t u r e and t e n s i l e
s tre n g th .
of fa c to rs ,
su c h a s
19
MATERIALS AND METHODS
T h is r e s e a r c h p r o j e c t was c o n d u c te d d u r in g t h e sum m ers o f 1985 and
1986 i n
c o o p e r a t i o n w ith
t h e N o r th e r n A g r i c u l t u r a l E x p e rim e n t S t a t i o n
l o c a t e d n e a r H a v re , M o n tan a.
A lth o u g h t h e r e s e a r c h o b j e c t i v e s f o r b o th
y e a r s w e re t h e sam e, t e c h n i q u e s w e re m o d if ie d i n
a c cu ra cy
of
in fe re n c e s
d e riv e d
fro m
th e
1986 t o i n c r e a s e t h e
d a ta .
B ecause
of
th e s e
c h a n g e s , e a c h y e a r w i l l be t r e a t e d s e p a r a t e l y i n t h i s an d t h e f o l l o w i n g
s e c tio n .
M eth o d o lo g y Used I n 1985
D u rin g
from
each
N o rth e rn
1985
of
s ix ' p reg n a n t
fiv e
b io lo g ic a l
A g ric u ltu ra l
ty p e s in c lu d e d in t h i s
H e re fo rd
(A H ),
and l a c t a t i n g
1 /4
ty p e s
R e s e a rc h
w e re
C e n t e r 's
a n im a ls ,
ran d o m ly
c ro ssb re d
h e rd .
s tu d y w e re : s t r a i g h t b r e d H e r e f o r d
S im m e n ta l
X 3 /4
H e re fo rd
by e i t h e r
H av re L in e 4 ,
P o l le d
9 y r o ld ,
s e le c te d
(1 S 3 H ),
H e r e fo r d (SH) and 3 /4 S im m en tal X I / 4 H e r e fo r d (3 S 1 H ).
s ire d
6 to
fro m
th e
B io lo g ic a l
(H H ), Angus X
S im m en tal
X
A ll c a l v e s w e re
o r h o rn e d H e r e f o r d b u l l s .
T h ese
b i o l o g i c a l t y p e s w ere s e l e c t e d t o r e p r e s e n t d i f f e r e n c e s i n m a tu re s i z e
and
m ilk
p ro d u c tio n
(ta b le
I).
W ith in
th e s e
b io lo g ic a l
ty p e s
th e
i n c r e a s i n g S im m e n ta l i n f l u e n c e r e p r e s e n t e d a b e e f cow t y p e w ith h i g h e r
m ilk p r o d u c t i o n a n d l a r g e r body s i z e .
re p re s e n te d
a
p ro d u c tio n .
M anagem ent o f t h e h e r d w as d e s ig n e d t o
m anagem ent
s m a lle r
p r a c tic e s
b io lo g ic a l
The Angus an d H e r e f o r d i n f l u e n c e
commonly
u se d
cow
by
ty p e
c o w -c a lf
w ith
m o d e ra te
re p lic a te
p ro d u ce rs
in
m ilk
ty p ic a l
N o rth
20
C e n tra l
M o n tan a.
The
o v e ra ll
goal
of
th e
p ro je c t
w as
to
m easu re
â– 
•
'
â– â– 
m a t e r n a l c h a r a c t e r i s t i c s o f e a c h b i o l o g i c a l ty p e o v e r a 10 y e a r p e r i o d
( K r e s s e t a l . , 1 9 8 6 ).
T a b le I .
T r a i t s o f b e e f cow b i o l o g i c a l t y p e s , 1985ab
Body S i z e
M ilk P r o d u c ti o n
Cow Type
HH
+
++
AH
++
++
I S3 H
++
++
SH
+++
+++
3 SI H
++++
++++
a A d a p te d fro m K r e s s e t a l . ( 1 9 8 6 ) .
bMore + ' s = g r e a t e r m ilk p r o d u c t i o n o r body w e i g h t.
The s tu d y s i t e w as l o c a t e d i n t h e B earpaw M o u n ta in s a p p r o x im a te ly
32 km s o u t h e a s t o f H a v re , M o n tan a.
was 81 h a i n s i z e
The p a s t u r e u s e d d u r in g t h e s tu d y
w ith s l o p e s up t o 40%.
E l e v a t i o n o f t h e s tu d y s i t e
a v e r a g e s 1300 m w ith a n n u a l p r e c i p i t a t i o n r a n g i n g fro m 4 5 .7 t o 5 0 .8 cm.
The s i t e
s ilty
is
c la s s ifie d
ran g e
g la c ia te d
s ite
p la in s .
o f ro u g h f e s c u e
and
p in e
of
by
th e
th e
S o il
C o n s e r v a tio n
S e rv ic e
(1 9 7 6 )
F o re s t-G ra s s la n d
c o m p lex
in
D om inant v e g e t a t i o n on th e
s te e p e r
s lo p e s
(F e s t u c a s c a b r e l l a ) , Id a h o f e s c u e
b lu e b u n c h w h e a t g r a s s
( A g ro p y ro n
th e
s p ic a t u m ) w ith
(P in u s p o n d e r o s a ) o v e r s t o r y i n l o c a l i z e d a r e a s .
ty p ic a l
of
fo o th ill
b u n c h g ra ss
ra n g e la n d
in
a
w e s te rn
c o n s is ts
(F e s t u c a i d a h o e n s i s )
an op en p o n d e ro s a
The m ore g r a d u a l
s l o p e s w e re d o m in a te d by K e n tu c k y b l u e g r a s s ( Poa p r a t e n s i s ) .
is
as
M o n tan a.
The a r e a
The
s tu d y
21
a n im a ls w e re moved t o t h i s p a s t u r e J u l y 2 0 , and w e re moved t o a s i m i l a r ,
a d j a c e n t p a s t u r e on A u g u st 2 9 .
The s t o c k i n g r a t e d u r in g t h e s tu d y w as
1 .2 ha/AUM.
M ilk p r o d u c t i o n w as e s t i m a t e d on A u g u st 2 and A u g u st 21 u s in g t h e
w e ig h - s u c k le - w e ig h t e c h n i q u e d e s c r i b e d by W illia m s ( 1 9 7 9 ) .
and h i p
h e ig h ts
O c to b e r 1 .
( w t:h t)
o b ta in e d
a fte r
a
12 h s h r i n k
d u r i n g w e a n in g on
Body c o n d i t i o n s c o r e s w e re e s ti m a t e d b a s e d on w e i g h t : h e i g h t
ra tio s
.
b e tw e e n h t : w t
d iffe rin g
w ere
Cow w e i g h ts
K lo s te rm a n e t a l .
m e a s u re m e n ts and
b io lo g ic a l
ty p e s .
(1 9 6 8 ) r e p o r t e d a h ig h c o r r e l a t i o n
body
c o n d itio n
among m a tu re
cows o f
A d d i t i o n a l body w e ig h t m e a s u re m e n ts w e re
o b t a i n e d a t p r e - and p o s t b r e e d i n g , an d a t e a c h m ilk t e s t .
F o ra g e o r g a n i c m a t t e r i n t a k e
(OMI) was e s t i m a t e d
fro m b o th d a i l y
f e c a l o r g a n i c m a t t e r o u t p u t (FOMO) and f o r a g e IVOMD u s i n g t h e e q u a t i o n :
OMI = FOMO /
( I -IVOMD) .
D u rin g t h e
firs t
f e c a l o u t p u t w as e s t i m a t e d u s in g b o th t o t a l
3S1H cow s) and a C r2 Og d i l u t i o n
te c h n iq u e
and t h i r d
w eeks o f A u g u st
fe c a l c o lle c tio n s
(R a le ig h ,
1980;
(RH an d
a ll
c o w s).
T o t a l f e c a l c o l l e c t i o n s w e re e s t i m a t e d u s in g f e c a l c o l l e c t i o n b a g s and
u r i n e s e p a r a t i o n f l a p s ( K a r tc h n e r and C a m p b e ll, 1 9 7 9 )•
F iv e d a y s p r i o r
t o , and d u r in g t o t a l f e c a l c o l l e c t i o n s a l l cows w ere b o lu s e d w i t h 10 gm
o f pow dered C r2 Og i n a g e l a t i n c a p s u l e e a c h e v e n in g a t 1800 h .
fo u r days o f t o t a l
fec a l
c o lle c tio n s ,, c o lle c tio n
On t h e
b a g s w e re ch a n g ed a t
600 arid 1800 h . F e c e s c o l l e c t i o n s w e re w e ig h e d , sa m p le d a n d f r o z e n f o r
la te r
d e te rm in a tio n
(AOAC, I 9 6 0 ) .
to
1900
c o n te n t.
h
and
of
d ry
m a tte r,
o rg a n ic
m a tte r
and
C r 2 O3 c o n t e n t
R e c t a l g r a b s a m p le s from a l l cows w e re c o l l e c t e d a t 1800
w e re
a ls o
fro z e n
u n til
la b o ra to ry
a n a ly s is
fo r
C r 2 O3
Chromium c o n t e n t o f t h e g r a b s a m p le s w as e s t i m a t e d by u s e o f
22
a to m ic
a b s o rb tio n
W illia m s e t
le s s
a l.
s p e c tro m e try
(1 9 6 2 ).
th a n 2mm w ith
p re p a ra tio n
fo r
u s in g
th e
p ro ce d u re
S am p les w e re thaw ed a t 4 0 °C ,
a W iley m i l l
a to m ic
b e fo r e a c id
a b s o rb tio n
s p e c tro m e try .
d u r in g
each
fec a l
c o lle c tio n
w e re f r o z e n and l a t e r f r e e z e
d rie d
by
and g ro u n d t o
d ig e s tio n
c o l l e c t i o n s u s in g e i g h t e s o p h a g e a l I y f i s t u l a t e d
c o lle c te d
d e s c rib e d
of
s a m p le s i n
Two f o r a g e
e x tru s a
(RH and 3S1H) cows w ere
p e rio d .
E x tru s a
c o lle c tio n s
and g ro u n d th r o u g h a Imm s i e v e
fo r
IVOMD e s t i m a t i o n u s in g t h e B a r n e s m o d i f i c a t i o n o f t h e T i l l e y and T e r r y
te c h n iq u e
(H a rris ,
c a n n u la te d
v a lu e
of
1 9 7 0 ).
cow s f e d
Rumen
ad l i b i t u m
55% IVOMD was
used
flu id
was o b t a i n e d
g ra ss hay.
as
a
A g rass
s ta n d a rd
and
fro m
two
h ay w ith
a ll
rum en
a known
s a m p le s
w ere
s h ip p e d
to
r e p lic a te d th r e e tim e s .
D u rin g
th e
p a c k in g
p la n t
s p le e n ,
lu n g s,
firs t
in
week
B u tte ,
k id n e y s
in
Novem ber
M o n tan a,
and k id n e y
a ll
cows w e re
w h e re w e i g h ts
of
th e
f a t w e re o b t a i n e d .
liv e r,
a
h e a rt,
R e tic u lo r u m e n s
w e re rem o v e d , e m p tie d and s t o r e d i n w a t e r u n t i l t h e f o l l o w i n g day when
e x c e s s f a t w as rem oved fro m t h e s u r f a c e .
s e c u re ly
th e
s titc h e d
re tic u lo ru m e n .
w a t e r and f i l l e d
p ressu re
c lo s e d
and th e
The o p e n in g t o t h e omasum w as
eso p h ag u s t ie d
o ff
E ach r e t i c u l o r u m e n was e m e rse d i n
w i t h w a te r a t
a
c o n s ta n t
o f 4 cm o f w a t e r was a c h i e v e d .
p ressu re
R e tic u lo ru m e n
d r a i n e d fro m t h e t i s s u e .
w e ig h ts
w e re
m e a su re d
th e
th e
a fte r
c a rd ia
of
a ta n k o f warm
u n til
The p o t e n t i a l
volum e w as t h e n r e a d a s t h e c h a n g e o f t h e w a t e r i n
19 6 6 a ).
at
a in te rn a l
re tic u lo ru m e n
ta n k
th e
(T u llo h ,
w a te r
had
23
M e th o d o lg y Used I n 1986
S ix
ty p e s
p re g n a n t,
w ere
used
r a n d o m ly
la c ta tin g
as
s tu d y
s e le c te d
c ro ssb re d
fro m
h e rd .
S tra ig h tb re d
3 yr
a n im a ls
th e
cows e a c h
d u r in g
N o r th e r n
B io lo g ic a l
H e re fo rd
o ld
1986.
of
T h e se
A g ric u ltu ra l
ty p e s
in c lu d e d
(H H ), T a r e n t a i s e
fo u r
a n im a ls
R e s e a rc h
in
X H e re fo rd
b io lo g ic a l
th e
w e re
C e n te r’ s
s tu d y
w ere:
(T H ), T a r e n t a i s e
X
( S im m en tal X H e r e f o r d )
(T (S H )) and C h a r o l a i s X ( S im m e n ta l X H e r e f o r d )
(C (S H )).
T(SH)
W ith in
th e
g ro u p
th re e
w ere
50% T a r e n t a i s e
-
25%
S im m e n ta l - 25% H e r e f o r d w ith t h e r e m a in in g t h r e e b e in g 50% T a r e n t a i s e
- 37.5% S im m en tal -
12.5% H e r e f o r d .
The C(SH) g r o u p w as a l s o d i v i d e d
s i m i l a r l y w i t h t h r e e a n im a ls b e in g 50% C h a r o l a i s - 25% S im m e n ta l - 25%
H e re fo rd
and
H e re fo rd .
th re e
T h e se
b e in g
a d d itio n a l
50% C h a r o l a i s
s ire
b ree d s
-
37.5%
S im m en tal
re p re s e n te d
-
12.5%
b io lo g ic a l
ty p e s
w ith medium body s i z e , h ig h m ilk p r o d u c t i o n ( T a r e n t a i s e ) an d l a r g e body
s iz e
w i t h m o d e r a te m ilk
p ro d u c tio n
( C h a r o la i s ;
b r e d t o b u l l s o f t h e same b r e e d s a s i n 1 9 8 5 .
T a b le
2 ).
Cows w e re
H erd m anagem ent w as a l s o
s i m i l a r d u r in g 1986 t o t h a t em ployed i n . 1985.
The s tu d y
a n im a ls w e re p a s t u r e d
in
t h e p a s t u r e u s e d i n t h e 1985 s tu d y .
s iz e
•
th e
y e a rs.
• O c to b e r
to p o g ra p h y
F ifty -s ix
I,
M ilk
e s tim a te d
w ith
and v e g e t a t i o n
a 276 h a p a s t u r e a d j a c e n t t o
W ith t h e e x c e p t i o n o f t h e p a s t u r e
com plex w e re v e r y
cow s w ere p r e s e n t on th e
th e
s to c k in g r a t e
p ro d u c tio n
u s in g
30 d a y s p o s t
w e a n in g on S e p te m b e r 3 0 ,
th e
c a lv in g ,
1 9 86.
fo r
th e
s tu d y s i t e
p e rio d
fro m J u l y 22 t o
b e in g
w e ig h -s u c k le -w e ig h
J u ly
s i m i l a r b e tw e e n
1 .2
h a / AUM.
te c h n iq u e
w as
1 8 , A ugust 22 and j u s t p r i o r t o
Cow w e i g h ts a f t e r a
10 h s h r i n k w ere
24
o b ta in e d
d u r in g
th e
la s t
m ilk
p ro d u c tio n
te s t.
H ip
h e ig h ts
w e re
m e a su re d a t w e a n in g on O c to b e r I .
O rg a n ic m a t t e r i n t a k e
was e s t i m a t e d w ith
on a l l cows d u r in g t h e l a s t week i n J u l y ,
S e p te m b e r.
to ta l
fe c a l c o lle c tio n s
and d u r in g
t h e l a s t week i n
T h re e e s o p h a g e a l f i s t u l a c o l l e c t i o n s w e re made t h r e e t im e s
d u r in g e a c h f e c a l c o l l e c t i o n p e r i o d u s in g f o u r HH a n i m a l s .
to
In a d d itio n
IVOMD a n a l y s i s o f e x t r u s a , a n a l y s e s o f a c id d e t e r g e n t f i b e r ,
p ro te in
and
a c id
d e te rg e n t
lig n in
( AOAC,
1980)
w ere
c ru d e
c o m p l e te d
as
a d d itio n a l in d ic a to r s o f fo ra g e q u a li ty .
A ll a n im a ls w ere s h ip p e d t o B u t t e , M o n tan a, and v i t a l
d a ta
w e re
o b ta in e d
on
O c to b e r
r e t i c u l o r u m e n vo lu m e w as m e a s u re d .
9
and
10.
T he
o rg a n m ass
f o llo w in g
day
M easu rem en ts o f b a c k f a t a t t h e 1 2 ^
r i b i n t e r f a c e and m a r b lin g s c o r e s o f t h e l o n g is s im u s m u sc le u s in g USDA
(1 9 7 5 ) s t a n d a r d s w e re made t o f u r t h e r e s t i m a t e body f a t c o n t e n t .
S t a t i s t i c a l A n a l y s is
The d a t a
c o m p le te
c o n c e r n in g v i s c e r a l
b lo c k
d e s ig n .
m ass w ere a n a ly z e d
M e asu re d
tra its
at
a n a ly s is
te s t
ty p e s
w ith in
o f v a ria n c e
fo r
mean
S ta tis tic a l
p ro ce d u re .
a
year
w as
w ith a p r o t e c t e d
s e p a ra tio n .
A n a ly s is
R e g r e s s io n
S y s t e m 's . (S A S ,
a n a ly z e d
le a s t
a n a ly s e s
w ith in
D iffe re n c e s
u s in g
sq u a re s
1985)
a ra n d o m iz e d
s la u g h te r
b i o l o g i c a l ty p e w e re a n a ly z e d a s ra n d o m iz e d b l o c k .
b io lo g ic a l
as
le a s t
com puted
s te p w is e
among
sq u a re s
d iffe re n c e
w e re
a
(LSD)
u s in g
regression
25
L i n e a r r e g r e s s i o n m o d e ls w i t h m i l k p r o d u c t i o n a n d o r g a n i c m a t t e r
in ta k e
c lo se st
b io lo g ic a l
to
type
w e a n in g a s
as
a
m ain
dependent
effect
v a ria b le s
w e re
when one way a n a l y s i s
d e t e r m i n e d s i g n i f i c a n t d i f f e r e n c e s among b i o l o g i c a l
m o d els
u sin g
b io lo g ic a l
age
of
th e
same
dependent
v a ria b le s
t y p e a s a m ain e f f e c t .
c a lf,
c a lf
p re c e d in g w ean in g ,
w eig h t
at
w e re
c a lf
w ean in g ,
R e g ressio n
c a lc u la te d
average
w ith
o f v arian ce
ty p e s.
G o v a ria te s in c lu d e d :
w ean in g ,
cow w e i g h t a t
com puted
w ith o u t
sex of c a l f ,
d a ily
g a in
(ADG)
cow ADG p r e c e d i n g w e a n i n g ,
cow h e i g h t , cow c o n d i t i o n a t w e a n i n g , s p l e e n w e i g h t , h e a r t w e i g h t , l u n g
w e ig h t,
l i v e r w e ig h t,
w e ig h t,
to ta l
kidney w e ig h t,
organ w e ig h t,
k id n ey
f a t w e ig h t,
h o t c a rc a s s w e ig h t,
reticu lo ru m e n
r e t i c u l o r u m e n v o lu m e ,
m i l k p r o d u c t i o n and o r g a n i c m a t t e r i n t a k e a t w e a n in g .
To i d e n t i f y
th e
f a c t o r s in f l u e n c i n g fo ra g e in ta k e d u rin g a stu d y y e a r
d a t a w e re a l s o
a n a l y z e d w i t h a c o m p l e te r a n d o m iz e d b l o c k d e s i g n .
In d ep en d en t
v a ria b le s
m e a s u r e m e n t,
a
c a lf,
and
c a lf
in c lu d e d :
b io lo g ic a l
age.
type
E rror
b io lo g ic a l
X d a te
term
of
in clu d e d
ty p e ,
in ta k e
d a te
of
in te ra c tio n ,
cow w i t h i n
breed.
r e s u l t s a r e r e p o r t e d s e p a r a t e l y i n a p p e n d i x T a b l e s 24 and 2 5 .
in ta k e
sex
of
T h e se
26
RESULTS
1985
T h e r e w e re no d i f f e r e n c e s ( P X I O ) i n t h e s h r u n k body w e i g h t s among
th e fiv e
b io lo g ic a l
ty p es
(T a b le 2 ) .
How ever,
t h e r e w ere d i f f e r e n c e s
( P C .10) i n t h e h o t c a r c a s s w e i g h t s , w i t h t h e AH g r o u p h a v i n g a h e a v i e r
carcass.
The HH and 3S1H ha d t h e l o w e s t c a r c a s s w e i g h t s w i t h t h e 1S3H
an d SH cows b e i n g s i m i l a r t o e i t h e r e x t r e m e .
Hip h e i g h t s w e re a l s o s i m i l a r ( P X 1 0 ) a c r o s s a l l b i o l o g i c a l t y p e s .
Body c o n d i t i o n
w ith
th e
and k i d n e y
rem a in in g
fat
b io lo g ic a l
w e i g h t s w e re l o w e s t
ty p e s
h a v in g
for
e q u a b le
t h e 3S1H g r o u p
c o n d itio n
sco res.
K id n ey f a t w e i g h t was a l s o l o w e s t ( P C .05) f o r t h e 3S1H cows and h i g h e s t
f o r t h e AH, HH and I S 3 H .a n im a ls ( T a b l e 2 ) .
T ab le
2.
B io lo g ic a l
ty p e
Body w e i g h t , body c o n d i t i o n , h i p h e i g h t , k i d n e y f a t w e i g h t
an d h o t c a r c a s s w e i g h t o f f i v e d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1985a
Body
Weight
kfc
Body
C o n d itio n
w t:h t
Hip
H eight
cm
Kidney
F at
kg
Hot
C arcass
kg
588.24 + 17.6
5.75 + 0 .1 7 b 131.0 + 1 .73
CO
+1
O
HH
AH
605.93 + 14.5
6.3 3 + 0 .3 1 b 131.2 + 1 .28
3 .6 3 + 0 .5 2 d
1S3H
588.47 + 17-1
5.92 + 0 . l 6 b 132.5 + I .89
2 .44 + 0 .2 2 e f 2 8 0 .2 5 + 6 .1 7 b°
SH
615.91 + 14.2
5 .7 5 + 0 .1 7 b 134.7 + 1 .2 6
2.31 + 0 .1 5 e f 288.26 + 7 .5 3 bc
3S1H
597.39 + 14.7
5.0 8 + 0 .3 8 ° 134.8 + 0 .7 0
2.14 + 0 .2 9 f
0 .1 7 de 276.24 + 8 .07°
a L ea st sq u a re means +. SE.
bc Means w ith in ' a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (P < .1 0 ) .
d e f Means w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r ( P < .0 5 ) .
3 0 0 .4 3 + 8 .93b
2 69.14 + 8.37°
27
M ilk p r o d u c t i o n d i d n o t v a r y ( P X I O ) among b i o l o g i c a l t y p e s ( T a b l e
3).
th e
How ever, t h e r e t e n d e d t o
second
m ilk
p ro d u ctio n
be a i n c r e a s e i n m ilk p ro d u c tio n d u r in g
te st
over
th e
first
te st.
The r a t i o
of
h e i f e r s t o s t e e r c a l v e s was 1 : 1 , 2 : 1 , 2; I and 2:1
f o r HH, AH, 1S3H and
SH c o w s,
o n ly
re sp e c tiv e ly .
The
3S1H g r o u p
Mean c a l f a g e s a t w e a n in g w e re 16 8 ,
AH,
1S3H ,
SH a n d
3S1H cow s,
su c k le d
1 78, 1 8 6 , 177 and
re s p e c tiv e ly ..
B irth
h e ife r
c a lv e s.
177 d a y s f o r HH,
w e ig h ts
for
a ll
b i o l o g i c a l t y p e s a p p r o x i m a t e d 40 k g , and mean v a l u e s f o r 205 d w e a n in g
w e i g h t w e re s i m i l a r (2 6 0 k g ) f o r a l l b i o l o g i c a l t y p e s e x c e p t f o r t h e SH
g r o u p (317 k g ) .
4.
F a c to rs
C alf average d a il y g a in s
in c lu d in g
c a lf
sex,
c a lf
age,
(ADG) a r e r e p o r t e d
b irth
in T ab le
w e ig h t and c a l f
h a v e b e e n r e p o r t e d t o i n f l u e n c e m i l k p r o d u c t i o n ( C a s e b o l t , 1984)..
T able
3.
D a te
8 /2 /8 5
8 /2 9 /8 5
Mean
HH
8 .7 3 + 0 .7 6
8 .7 9 + 0 .8 6
8 .7 6 + 0 .2 7
AH
8 .7 1 +_ 1 . 16
1 0 .3 0 + 1 .0 2
9 .51 + o .96
1S3H
7 . 6 2 + 1 .3 8
1 0 .3 0 + 0 .7 5
8 .9 6 + 0 .8 2
SH
8.9 1
I+
O
VO
Cr.
B io lo g ic a l
ty p e
A v e ra g e d a i l y m i l k p r o d u c t i o n ( k g / d ) f o r f i v e b e e f
cow b i o l o g i c a l t y p e s , 1985ab
11.71 + 1 .3 7
10.21 + 0 . 1 8
3S1H
9 . 9 8 +_ 0 .7 1
1 1 .8 5 + 0 .8 6
1 0 .9 2 + 0 .5 7
a L e a s t s q u a r e m eans + SE.
bP > . 1 .
age
28
T able
4.
C a l f a v e r a g e d a i l y g a i n (k g ) from dams o f f i v e
d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s , I 985a
P e r i o d ___________________________
B io lo g ic a l
type
6 /3 - 7 /2 2
7/22 - 8/2
8 / 2 - 8 /2 9 . 8 /2 9 - 10/1
HH
.8 8 + .0 5
I .0 8 + .0 6 b
1.03
.02
1 .1 5 + .0 2
AH
. 9 8 + .0 4
1 .06 + .0 7 b
1 .1 5 + .0 5
1 .1 0 + .05
1S3H
.88
1 .17 + .0 4 bc 1 .1 2 + .04
1 .1 5 + .03
SH
.97 + . 0 5 v
I .2 8 + .0 7 °
1 .1 9 + .06
1 .2 9 + .1 0
3S1H
.8 6 + .0 4
1 .17 + .0 9 bc 1 .1 2 + .04
I .1 2 + .07
+
.11
+
a L e a s t s q u a r e m eans +. SE.
b c Means w i t h i n a colum n w i t h d i f f e r e n t s u p e r s c r i p t d i f f e r
(P < .1 0 ).
Of
th e
re g re ssio n
m o d els
fo r
m ilk
b i o l o g i c a l t y p e a s a m ain e f f e c t was n o t
p ro d u ctio n
sig n ific a n t
th e
model
(P > .1 0 ).
w ith
In th e
m odel w i t h o u t b i o l o g i c a l t y p e a s a m ain e f f e c t t h e w e i g h t o f t h e l u n g s ,
k i d n e y f a t and r e t i c u l o r u m e n a c c o u n t e d f o r 38% o f t h e v a r i a t i o n i n m i l k
p r o d u c t i o n a t w e a n in g ( T a b l e 5 ) .
A ve ra g e d a i l y
not d iffe re n t
g a i n s d u r i n g mid and l a t e
la c ta tio n
( T a b l e 6) w e re
( P > .1 0 ) among b i o l o g i c a l t y p e s w i t h i n a p e r i o d , y e t g a i n s
a c r o s s p e r i o d s w e re d i f f e r e n t .
D u r i n g J u n e and t h e f i r s t two t h i r d s o f
J u l y a l l cows g a i n e d a n a v e r a g e o f 0 . 6 6 k g a d a y .
days g a in in c re a s e d to
a n im a ls d e c re a s e d
to
In th e fo llo w in g
10
1 .0 5 k g a d a y . A verage d a i l y g a i n f o r t h e s t u d y
-0 .2 6 k g /d
d u r in g A ugust,
r e l a t i v e l y c o n s ta n t th ro u g h Sep tem b er.
w ith w eig h t
rem a in in g
29
T able
5.
S te p w ise r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p ro d u c tio n
p r i o r t o w e a n i n g , 1985
V a ria b le
Bo
K id n e y f a t w e i g h t
Lung w e i g h t
R e tic u lo ru m e n w e ig h t
B1
1 1 .2 1 4 5
1 1 .4 0 9 0
'1 2 . 7 3 0 9
- 1 .1521**
- 0 .9 5 7 6 *
0 .3 6 4 3
MSE
4 .4 5 6 9
R2
0 .3 8 0 5 “ ” *
* P C .10 .
â– * P C .05
* e ”PC.01
T able 6 .
B io lo g ic a l
type
A v e ra g e d a i l y g a i n (k g ) f o r f i v e d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1985ab
______________ ;___________ P e r i o d
6 /3 - 7 /22
7 /22
8/2
8 / 2 - 8 /2 9
8 /2 9 - 10/1
.6 9 ± 0 . 6 0
- . 2 7 + 0 .2 1
- . 0 7 + 0 .1 1
AH
.7 6 + 0 . 1 0
• 92 ± 0 .51
- .2 9 + 0 .1 2
—•01 + 0 . 1 9
1S3H
.8 5 + 0 . 2 2
1 .4 2 + 0 . 5 2
- . 0 5 + 0 .4 5
.0 8 + 0 .1 3
SH
.5 7 + 0 . 1 8
.91 + 1 .0 5
- . 2 4 + 0 .3 5
.26 + 0 .0 5
3S1H
.4 7 + 0 . 1 1
- .4 4 + 0 .1 2
- . 1 5 + 0 .2 3
a L e a s t s q u a r e s m eans + SE.
bP X I O .
CO
1 .2 9 +
.ro
.6 4 + 0 .1 1
O
HH
30
D a i l y OMI ( T a b l e 7) i n k g / d and a s a p e r c e n t o f body w e ig h t (%BW)
d id not d i f f e r
in
in ta k e
( P > .1 0 ) among cow t y p e s .
b e tw e e n
th e
two p e r i o d s
T h e re was a n i n c r e a s e
m e a s u re d
for
th e
BH,
cow s.
IVOMD w as e s t i m a t e d a t 43% f o r b o t h i n t a k e p e r i o d s .
T ab le
7.
( P < .1 0 )
AH and
1S3H
O r g a n ic m a t t e r i n t a k e p e r da y (01'11/d, k g ) , and OMI/d
a s p e r c e n t o f body w e i g h t (%BW) f o r f i v e b e e f cow
b i o l o g i c a l t y p e s , 1985ab
D a te
B io lo g ic a l
ty p e
8 /2 1 /8 5 - 8 /2 5 /8 5
OMI/d.*BW
OMI/d
8 /8 /8 5 - 8 /1 1 /8 5
OMI/d.%BW
OMI/d
HH
6 .4 0 + .1 3
1.07 + .0 4
7 . 5 8 + .2 2
1 .2 8 + .0 5
AH
7 . 1 9 + .2 2
1 .1 7 + .0 2
7 .7 1 + .35
1 .2 7 + .0 5
1S3H
6 .9 1 + .2 2
I .1 5 + .0 3
7 . 8 3 + .2 4
1 .3 4 + .0 5
SH
7 . 9 0 + .3 0
1 .2 7 + .0 4
8 . 0 2 + .4 8
1 .2 9 + .07
3S1H
7 . 3 9 + .6 0
I .21 + .1 2
7 . 4 5 + .1 8
1 .2 4 + .03
a L e a s t s q u a r e m eans +_ SE.
bP > .1 0 .
A m odel
w eaning,
in clu d in g
c a lf
g a in
sex o f
p rio r
to
c a lf,
age
of c a lf,
w e a n in g
and
sp le e n
m ilk p r o d u c tio n a t
w eig h t
as
co v a riate s
a c c o u n t e d f o r 54% o f t h e v a r i a t i o n i n OMI p r i o r t o w e a n in g ( T a b le 8 ) .
Of t h e v i t a l o r g a n s m e a s u re d o n l y t h e k i d n e y s and t h e l i v e r showed
d iffe re n c es
w ith
th e
( P < .1 0 j T a b l e 9) •
rem a in in g
b io lo g ic a l
The 3S1H g r o u p had t h e l a r g e s t k i d n e y s
ty p e s
B oth SH and 3S1H had l a r g e r l i v e r s
h a v in g
sim ila r
k id n ey
w e ig h ts.
( P < . 1 0) t h a n t h e HH and 1S3H,
t h e AH g r o u p e x h i b i t e d i n t e r m e d i a t e l i v e r w e i g h t s .
and
.When o r g a n w e i g h t s
31
w ere e x p r e s s e d a s a p e r c e n t o f body w e i g h t ( T a b l e 10) t h e 3S1H cows had
a h i g h e r p e r c e n t a g e o f t h e i r body w e i g h t a s k i d n e y w e i g h t t h a n o t h e r
b i o lo g i c a l ty p e s (P < .1 0 ).
The 3S1H g r o u p a l s o ha d t h e h i g h e s t l i v e r t o
body w e i g h t p e r c e n t a g e , BH, AH, and 1S3H g r o u p s t h e l o w e s t , and t h e SH
g r o u p was i n t e r m e d i a t e .
R e t i c u l o r u m e n volum e d i d
not
d iffe r
among b i o l o g i c a l t y p e s ( T a b l e 1 1 ) .
T ab le
8.
S tep w ise r e g r e s s i o n c o e f f i c i e n t s f o r o rg a n ic m a tte r
i n t a k e p r i o r t o w e a n i n g , 1985
V a ria b le
Bo
Sex o f c a l f
Age o f c a l f
M ilk p r o d u c t i o n p r i o r
t o w e a n in g
C a l f ADG p r i o r t o w e a n in g
S p le en w eig h t
B1
7 .8 1 7 6
7 .3 3 8 4
0 .4 5 1 9 a "
-0 .0 2 7 3 "* *
7 .2 6 2 5
9 .4 1 7 9
8 .9 1 0 0
-0 .1 0 3 2 °«
2 .0 5 2 2 «
1 .5 4 4 3 "
MSE
0 .3 0 9 1
R2
0 .5 3 5 6 " » *
a
The c l a s s v a r i a b l e Sex i s s c o r e d :
c a lf.
*
P C .1 0 .
P C .0 5 .
trteiiP C .0 1 .
I= H e ife r c a l f , P = S teer
(P X lO )
32
T ab le
9.
O rgan m ass o f f i v e d i f f e r e n t b e e f cow b i o l o g i c a l t y p e s ,
1985*
B io lo g ic a l
H eart
Kidney
Lung
L iv e r
ty p e
Ycr
S p leen
R eticulorum en
.
2.2 0 + .07
1.11 + .04b
5 .0 5 ± .IO b
4.31 + .66
0.71 + .05
12.95 + .74
AH
2 .2 0 ± .12
1.0 8 + .02b
5 .2 5 ± .08bc 3 .5 5 + .11
0.71 + .02
12.83 + .44
1S3H
2 .1 4
+
.10
1.13
+
.04b
5.11
±
.22°
3 .6 0 + .17
0.71
+
.04
13-53
SH
2 .2 9
+
.05
1.12
+
.04b
5.56
+
.16°
4 .0 3
+
.25
0.8 6
+
.08
14.90 + .82
3S1H
CM
+
.08
1.3 0
+
. 10°
5 .5 2
+
.0 9 °
3 .7 7
+
.27
0.86 + .09
CM
CO
HH
15.08
+
+
.86
.73
a L e a st sq u a re means + .S E .
bcMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r ( P < .1 0 ) .
T ab le 10.
B io lo g ic a l
ty p e
Organ m ass a s a p e r c e n t o f body w e i g h t , o f f i v e d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1985*
H eart
Kidney
L iv e r
Lung
S p leen
R eticulorum en
HH
0.3 7 + .002
0 .1 9 + .008d 0.86 + .0 l6 b
0 .7 3
+
.110
0 .1 2 +
.004
2.21 + .122
AH
0.3 6 + .016
0 .1 8 + .OOltd 0.87 + .024b
0 .5 9
+
.020
0 .1 2 +
.004
2 .1 3 + .102
1S3H
0.36 + .012
0 .1 9 + .004d 0.87 + .0 l6 b
0.61 + .024
0 .1 2 +
.004
2 .2 9 + .102
SH
0 .3 7 + i004
0 .1 8 + .OOltd 0.90 + .016bc 0 .6 6 + .045
0 .14 +
.012
2 .4 2 + .139
3S1H
0 .3 9 + .008
0 .2 2 + .012® 0.93 + .016°
0 .6 3 + .040
0 .1 5 +
.016
2 .53 + .110
a L e a st sq u a re means +_ SE.
bcMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (P C .1 0 ).
deMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r ( P < .0 5 ) .
33
T a b l e 11.
P o t e n t i a l r e t i c u l o r u m e n volum e o f f i v e d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1985ab
R e tic u lo ru m e n
Volume
---------- I — --------
B io lo g ic a l
type
HH
5 8 .5 4 +
2 .3 0
AH
6 2 .2 9 +
7 .6 2
1S3H
6 3 .7 8 +
7 .2 2
SH
8 0 .3 2 + 1 0 .6 0
3S1H
6 8 .0 1 +
7 -1 3
a L e a s t s q u a r e m eans + SE.
bP>.10.
1986
Body w e i g h t s f o r t h e RH, TH and T(SH) d i d n o t d i f f e r ( P X 1 0 ; T a b l e
1 2 ) , y e t t h e mean w e i g h t o f t h e C(SH) g r o u p was 9% l a r g e r
t h e n e x t l a r g e s t g r o u p (HH).
Hip h e i g h t s w e re a l s o t a l l e r ( P C .10) f o r
t h e C(SH) g r o u p , w i t h t h e HH g r o u p b e i n g
hot
c a rc a s s w e ig h ts
th e
stu d y .
( P C .10) t h a n
d id n o t d i f f e r
M easurem ent o f : body f a t
th e
(P X 10)
s h o rte st.
In
c o n tra st,
among b i o l o g i c a l
and body c o n d i t i o n
d id
ty p e s
in
not y ield
a n y d i f f e r e n c e s ( P X 1 0 ) among b i o l o g i c a l t y p e s ( T a b l e 13) •
M ilk
group
p ro d u ctio n
d u rin g
th e
(T ab le
firs t
14)
th irty
was
days
g rea test
of
( P C .10)
la c ta tio n .
for
The
th e
T (S H )
HH a n i m a l s
e x h i b i t e d t h e l o w e s t v a l u e s ( P C . 10) f o r t h e s e c o n d m i l k p r o d u c t i o n t e s t
on J u l y 18 .
D i f f e r e n c e s i n m i l k p r o d u c t i o n w e re d i m i n i s h e d ( P X 1 0 )
34
T a b l e 12.
B io lo g ic a l
type
Body w e i g h t , body c o n d i t i o n , h i p h e i g h t and h o t
c a r c a s s w e i g h t o f f o u r d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1986a
Hot
C arcass
kg
Hip
H eight
cm
Body
C o n d itio n
w t:h t
Body
Weight
kg
HH
516.95 +
3 .6 b
4 .0 5 + 0 .0 3
127.3 + 0 .8 8 d
233.25 +
2 .84
TH
515.51 + 1 7 .6b
3.90 + 0.0 9
132.0 + I .9 0 °
244.04 +
9.46
T(SH)
507.58 +
4 .8 b
3.83 + 0.04
132.7 + 1 .14°
230.88 +
5 .2 9
C(SH)
561.18 + 2 3 .8 °
4.07 + 0.1 3
137.5 + 1 .6 7 f
255.30 + 10.63
a L e a st sq u a re means and SE.
bc Means w ith in a column w ith d i f f e r e n t 's u p e r s c r i p t d i f f e r (P < .1 0 ).
d e tMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (PC .0 5 ) .
T a b l e 13.
K id n ey f a t w e i g h t , back f a t t h i c k n e s s and
M a r b l in g s c o r e o f f o u r d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1986ab
M a r b l in g
sco re
K id n ey
Fat
kg
Back
Fat
mm
HH
2 .2 3 . + 0 . 2 4
1 .5 0 + 0 .4
1 .8 + 0 . 1 8
TH
2 .5 7 + 0 . 4 2
1 .7 5 + 0 . 5
1 .5 + 0 . 2 2
T(SH)
1.71 + 0 . 1 6
0 .6 7 + 0 . 2
1 .3 + 0 . 5 2
C(SH)
2 .1 8 + 0 .2 5
I .0 0 + 0 . 2
1 .5 + 0 . 2 2
B io lo g ic a l
ty p e
a L e a s t s q u a r e m eans +. SE.
bP > . 1 0 .
35
f o r th e t e s t
h ig h er
d u r in g A ugust 22.
( P < .1 0 )
for
T(SH)
and
M ilk p r o d u c t i o n
lo w est
( P < . 1 0)
h e i f e r c a l v e s t o s t e e r c a l v e s w ere 2 : 1 ,
T(SH) and C(SH) g r o u p s r e s p e c t i v e l y .
a ll
b io lo g ic a l
group
ty p e
ty p es
(35 k g ) .
w ere
190,
174
of
th e
R a tio s
and 2:1
of
f o r HE, TH,
w ith
th e
e x c e p tio n
o f th e
TH
c a l v e s a t w e a n in g by b i o l o g i c a l
days
for
HH,
TH,
T(SH)
and
C(SH )
I n a d d i t i o n , 205 day w e a n in g w e i g h t s w e re 2 0 5 , 2 2 4 , 252
and 241 k g f o r BH, TH, T(SH)
g a in
183
C (S H ).
1 :1 , 0 .5 :1
n e a r 40 k g ,
and
for
w e a n in g was a g a i n
B ir th w e ig h ts o f th e c a lv e s f o r
The a v e r a g e age o f ' t h e
1 74,
re sp e c tiv e ly .
w ere
at
c a lv e s
are
and C (S H ), r e s p e c t i v e l y .
liste d
on
T ab le
15
for
four
A verage d a i l y
p e rio d s
from
p a r t u r i t i o n t o w e a n in g .
T ab le
14.
B io lo g ic a l
ty p e
A v e ra g e d a i l y m il k p r o d u c t i o n
b i o l o g i c a l t y p e s , 1986a
(k g /d )
f o r f o u r b e e f cow
__ _____________________________D a te
30 d p o s t
c a lv in g
7/18
HH
6 .6 1 + 0 .7 3 ^
6 .1 0 + 0 .3 6 b
7 .9 8 + 0 . 3 6
5 .6 3 + 0 .4 0 b
TH
7 .7 3 + 0 . 8 l b
9.09 + I . O l c
8 .5 3 + 0 .7 1
7 . 8 0 + 0 . 7 1 cd
T(SH)
1 2 .5 3 + 2 . 1 4 c
8 .7 4 + 0 .7 8 °
7 .6 2 + 1 .1 6
8 .1 6 + 0 . 4 7 d
C(SH)
8 . 4 9 + I .1 3 b
8.41 + 0 . 9 7 °
8 .8 9 + I .06
6 . 3 5 + 0 . 9 5 bc
8 /2 2
9 /3 0
a L e a s t s q u a r e m eans ±_ SE.
b c d Means w i t h i n a colum n w i t h d i f f e r e n t s u p e r s c r i p t d i f f e r
( P t . 10).
36
T a b l e 15.
C a l f a v e r a g e d a i l y g a i n (k g ) from dams o f f o u r d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1986a
B i o l o g i c a l . _____________________________ P e r i o d
30 d
type
p o st c a lv in g
B i r t h - 30 d
7 /1 8 - 8 /2 2
- 7/18
D ost c a l v i n g
8/2 2 -
0 .8 5 + .0 5 °
O
cr
0 .6 8 + .07
TH
0 .8 6 + .06
0 .9 9 + . 0 4 c
0 .9 8 + .0 7 c
0 .7 4 ± .0 4
T(SH)
0 .9 2 + .01
1 .0 5 + .0 3 °
1+ .
UO
O
0 .8 9 + .0 4
C(SH)
0 .8 2 + .0 9
1 .0 0 + .0 6 °
+1
Zf
O
O
CU
O
0 .8 8 + .06
_
O
1+
CO
O
Ul
0 . 7 2 + .03
oo
HH
O
9/3 0
a L e a s t s q u a r e m eans +_SE.
bcMeans w i t h i n a colum n w i t h d i f f e r e n t s u p e r s c r i p t d i f f e r
(P < .0 5 ).
A lo n g
w ith
b io lo g ic a l - ty p e ,
sex
of
c a lf
and
sp le e n
w e ig h t
a c c o u n t e d f o r 65% o f t h e v a r i a t i o n i n m i l k p r o d u c t i o n ( T a b l e 1 6 ) .
When
b i o l o g i c a l t y p e was n o t i n c l u d e d a s a m ain e f f e c t s e x o f c a l f , cow ADG,
body
c o n d itio n
and
hot
carcass
w e ig h t
a cco u n ted
fo r
52%
of
th e
v a r i a t i o n i n m ilk p r o d u c tio n (T ab le 1 7 ).
A ve ra g e d a i l y g a i n f o r t h e cows ( T a b l e 18) s t e a d i l y i n c r e a s e d fro m
th irty
d a y s p o s t c a l v i n g t o A ugust 2 2 , y e t an a v e r a g e d e c r e a s e i n body
w e i g h t o f .9 5 k g / d o c c u r r e d d u r i n g l a t e r A u g u st and i n S e p te m b e r.
O rg a n ic
m a tte r
in ta k e
d id
not
( P > .1 0 ; T a b l e 19) i n e i t h e r p e r i o d .
d iffe r
IVOMD f o r t h e f i r s t p e r i o d was
e s t i m a t e d a t 42%, and 35% f o r t h e s e c o n d p e r i o d .
was 6.1% d u r i n g A u g u s t ,
ty p es
T h i s was a l s o t r u e when i n t a k e was
e x p r e s s e d a s a p e r c e n t o f body w e i g h t .
forage
among b i o l o g i c a l
Crude p r o t e i n o f t h e
and 7% i n S e p t e m b e r .
A cid d e t e r g e n t
f i b e r was 39% and 45% i n A u g u s t and S e p te m b e r r e s p e c t i v e l y .
A cid
37
T a b l e 16.
S te p w ise r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p ro d u c tio n
a t w e a n i n g , 1986
V a ria b le
B0
B1
13-6956
1 6 .0 3 8 0
1 7 .4 9 1 3
1 4 .8 6 3 6
13-3189
7 .0 3 0 0
-1 .8 2 5 0 eeie
0 .5 1 7 4
1 .9 7 0 6 * “ *
-0 .6 6 3 0
- 2 . 2 0 1 8a “ *“
-8 .4907«*
HH
TH
T(SH)
C(SH)
Sex o f c a l f
S p leen w eig h t
MSB
1 .7 0 6 3
R2
0 .6 5 4 6 * “ *
a
The c l a s s v a r i a b l e Sex i s s c o r e d :
I= H e ife r c a l f , P = S teer
c a lf.
* PC.10.
«" P C .0 5 .
eiettPC .01 .
T ab le 17.
S tep w ise r e g r e s s i o n c o e f f i c i e n t s f o r m ilk p r o d u c tio n
a t w e a n i n g , 1986
V a ria b le
Bo
Sex o f c a l f
Cow ADG
C o n d itio n s c o re
Hot c a r c a s s w e i g h t
3 0 .3 8 7 6
3 4 .6 8 0 5
2 5 .1 2 0 4
3 5 .0 8 1 3
B1
-1 .7766*
2 .5 1 2 2 *
_ 9 .8944“ “
0 .0 6 6 5 ”
MSB
2 .2 2 5 8
R2
0 .5 2 3 0 “ *
a The c l a s s v a r i a b l e Sex i s s c o r e d :
c a lf.
*» P C .0 5 .
e e P C .0 1 .
I= H e ife r c a l f , P = S teer
38
T able 18.
A v e ra g e d a i l y g a i n ( k g ) o f f o u r d i f f e r e n t b e e f cow
b i o l o g i c a l t y p e s , 1986ab
P e rio d
B io lo g ic a l
type '
30 d
post c a lv in g
- 7 /1 8
7 / 1 8 - 8 /2 2
HH
0 . 7 0 + .1 8
0 . 7 0 + .06
TH
0 .7 1 + .11
0 .6 7 + .17
- 0 . 8 7 + .0 9
T(SH)
0 .5 7 + -13
0 .4 7 + .13
- 0 . 9 6 + -11
C(SH)
0 .6 3 + .2 4
0 . 9 8 + .15
- 1 .21 + -11
VD
I
♦'
O
8 /2 2 - 9 / 3 0
+ .1 8
a L e a s t s q u a r e m eans +. SE.
bP > .1 0 .
T ab le 19.
O r g a n ic m a t t e r i n t a k e ( k g ) p e r day ( O M l / d ) , and OMI/d a s
p e r c e n t o f body w e i g h t (%BW) f o r f o u r b e e f cow b i o l o g i c a l
t y p e s , 1986ab
-i
D a te
B io lo g ic a l
ty p e
7 / 2 4 - 7 /3 1
OMI/d.%BW
OMI/d
9/21 - 9 /2 9
O M I / d BW
OMI/d
HH
7 . 7 9 + 0 .6 6
1 .43 + 0 . 1 3
6 .8 0 + 0 .4 4
1 .3 2 + 0 .0 9
TH
7 .6 8 + 0 . 8 6
1 .4 0 + 0 . 1 6
7 .7 3 + 0 .4 8
1 .5 0 + 0 . 0 8
T(SH)
7 .1 4 + 0 . 7 1
1.31 + 0 - 1 4
6 . 7 0 + 0 .5 6
1 .3 2 ,+ 0 .1 2
C(SH)
6 .9 3 + 0 . 7 2
1 .1 8 + 0 . 1 7
8 ,3 0 + 0 . 6 0
I .53 + 0 . 1 0
a L e a s t s q u a r e m eans +_SE.
bP > . 1 0 .
39
d e t e r g e n t l i g n i n was 5.2% i n
b o t h A u g u s t and S e p t e m b e r .
Sex o f c a l f ,
c a l f a g e , cow ADG p r i o r t o w e a n in g and k i d n e y w e i g h t a c c o u n t e d f o r 62%
o f t h e v a r i a t i o n f o r OMl ( T a b le 2 0 ) .
T ab le 2 0 .
S tep w ise r e g r e s s i o n c o e f f i c i e n t s f o r o r g a n ic m a t te r
i n t a k e a t w e a n i n g , 1986
V a ria b le
Bd
.
5 .2 0 5 2
6 .1 0 0 2
7 .6 7 5 7
-2 .2 5 3 5
Sex o f c a l f
Age o f c a l f
Cow ADG p r i o r t o w e a n in g
K id n ey w e i g h t
B1
- 0 . 9 4 9 1 aett
- 0 .0 4 9 9 « = * *
1 .5 2 5 6 = "
8 .4036*= *
MSE
0 .8 5 7 8
R2
0 .6 1 9 9 * « *
a
The c l a s s v a r i a b l e Sex i s s c o r e d : I = H e i f e r c a l f , 2 = S t e e r
c a lf.
* P < .1 0 .
»* P< . 0 5 .
* * * P < .0 1 .
The k i d n e y s p r o v e d t o be l a r g e r ( P < .0 5 ) i n th e - C(SH) g r o u p t h a n i n
t h e e i t h e r t h e HH o r TH a n i m a l s , w h e r e a s t h e T(SH) g r o u p was s i m i l a r t o
bo th e x tre m e s (T ab le 2 1 ) .
for
s p le e n w eig h t
k idney
was
no
as w e ll.
lo n g er
T h i s p a t t e r n was r e p e a t e d a t t h e P < .1 0 l e v e l
When e x p r e s s e d
d iffe re n t
(P > .1 0 ),
d i f f e r e n t w ith o u t a change in ra n k .
as
a %BW ( T a b le
how ever
D ifferen ces
th e
sp le e n
( P > .1 0 )
o r g a n w e i g h t s among b i o l o g i c a l t y p e s w e re n o t d e t e c t e d .
2,2)
th e
r e m a in e d
in th e o th e r
R e t ic u l o r u m e n
volum e a l s o d i d n o t v a r y ( P > .1 0 ) among b i o l o g i c a l t y p e s ( T a b l e 2 3 ) .
40
T able 21.
Organ m ass o f f o u r d i f f e r e n t b e e f b i o l o g i c a l cow t y p e s ,
1986a
H eart
B io lo g ic a l
type
S p leen
Lung
L iv e r
Kidney
-
R eticulorum en
0CVi
3-17 + .18
0 .60
TH
I .85 + .05
I .02
5.8 0 + .18
3 .0 2 + -15
0 .5 8 + .0 2 d
T(SH)
1.92 + .04
I .08 + .04bc 5 .6 8 + .17
3-55 + -37
0.67 + .0 4 Ce 15.35 ± 0.71
C(SH)
2.07 + •' .05
1.21
6.00 + *27
3 .24 +. • 16
0.76 + .0 5 e
+1
VO
1+
O
5.40 + .11.
+I
0.97 + .02b
O
I .92 + .07
in
15.27 + 0 .6 9
HH
14.70 ± 1.04
16.71 + 0 .7 6
a L e a st sq u a re means +_ SE.
bcMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (P < .1 0 ) .
c e Means w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (P < .0 5 ) .
T ab le 2 2 .
O rgan m ass a s a p e r c e n t o f body w e i g h t o f f o u r d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1986a
B io lo g ic a l
type
H eart
Kidney
L iv e r
. ---------------------- _________---- ------------
Lung
S p leen
R eticulorum en
JtBW ______---- -—__—------------- ------------------O
0 .12 + .004bc 2.95 + .131
1 .04 + .016
0.61
TH
0.36 + .008
0.2 0 t .004
1.13 + .024
0 .5 8 + .020
0.11 + .004b ' 2.84 + .138
+ .002
0.21 + .008
1 .12 + .033
0.70 + .069
0.13 + .008°
3-02 + .131
0.37 + .012
0.2 2 + .016
1.07 + .041
6.5 8 + .016
0.13 + .004?
2.99 + .131
T(SH)
C(SH)
+1
0.1 9 t .004
- CO
m
0.37 + .012
O
HH
a L ea st sq u a re means +_ SE.
bcMeans w ith in a column w ith d i f f e r e n t s u p e r s c r i p t d i f f e r (P< .0 5 ) .
41
T ab le 23.
P o t e n t i a l r e t i c u l o r u m e n volum e o f f o u r d i f f e r e n t
b e e f cow b i o l o g i c a l t y p e s , 1986a
B io lo g ic a l
ty p e
R e t ic u l o r u m e n
Volume
------------I ---------- -
HH
6 3 .3 4 +
TH
6 8 .3 7 + 13-57
T(SH)
7 0 .3 7 +
4 .5 2
C(SH)
8 0 .6 3 +
3 .0 9
4 .6 7
a L e a s t s q u a r e m eans +_SE.
bP X I O .
J
42
DISCUSSION
Forage In ta k e
Forage i n ta k e f o r a l l
low er th an
b io lo g ic a l
ty p es in
v a l u e s r e p o r t e d by Wagner e t a l .
Wagner u s i n g t h e
same l a c t a t i n g
1985 was s u b s t a n t i a l l y
(1 9 8 6 )
f o r 1983 and 1984.
b i o l o g i c a l t y p e s and p a s t u r e
rep o rted
OMI t o be c l o s e r t o 2.3% body w e i g h t i n A u g u s t , 1 9 8 3 , and 2.0% o f body
w e i g h t i n A u g u s t , 1984.
57% i n
1984.
1982 u s i n g
F o r a g e IVOMD was e s t i m a t e d a t 59% i n 1983, and
K ronberg e t .
la c ta tin g
a l.
HH and
(1 9 8 6 )
3S1H on
fo und somewhat l o w e r OMl d u r i n g
th e
same
p a stu re
used
in
1985.
They r e p o r t e d OMI a t 1.7% o f body w e i g h t f o r HH co w s, and 1.9% f o r 3S1H
cow s.
Forage
The i n c r e a s e
d ig e stib ility
in
forage
for
q u a lity
K ronberg's
in
stu d y
was
41% i n
1983 and 1984 seem s t o
A u g u st.
account fo r
t h e d i f f e r e n c e s i n i n t a k e o v e r 1982, y e t d o e s n o t a c c o u n t f o r t h e much
lo w er
in ta k e
in
1 985.
Work by F u n s t o n
e x p l a n a t i o n f o r t h e low 1985 i n t a k e s
(1987)
found.
may o f f e r
Fu n sto n
a p o ssib le
(1 9 8 7 )
u sin g
an
a d j a c e n t p a s t u r e and t h e same b i o l o g i c a l t y p e s i n 1985 r e c o r d e d g r a z i n g
tim es
th a t
exceeded
fatig u e
lim its
fo u n d
by
S c a rn e c c h ia
a p p r o a c h e d f a t i g u e l i m i t s fo u n d by S t o b b s ( 1 9 7 5 ) .
of
1 1 .9
lim ite d
hours
per
in ta k e .
day
su g g ests
th a t
fatig u e
(1985),
and
O v e ra ll g ra z in g tim e
rath e r
th an
rumen
fill
F u n sto n f e l t t h a t in a d e q u a te fo ra g e a v a i l a b i l i t y
(d u e
t o s u c c e s s i v e d r o u g h t y e a r s ) was a m a j o r c a u s e o f t h e e x t e n d e d g r a z i n g
tim e s.
P r e c i p i t a t i o n i n 1985 was 2 8 .7 4 cm, o r 57% o f n o r m a l , w i t h l e s s
t h a n 30% o f t h e r a i n f a l l b e i n g r e c e i v e d p r i o r t o o r d u r i n g t h e g r o w in g
season.
L athrop
(1985),
i n a c o m panion s t u d y t o W agner e t a l .
(1 9 8 6 )
\
43
reco rd ed g ra z in g
o f 9 .4 h /d .
tim e s in
1984 and r e p o r t e d o v e r a l l mean g r a z i n g t i m e
L a t h r o p ' s r e s u l t s s u g g e s t t h a t f a t i g u e was n o t a l i m i t i n g
f a c t o r t o t h e i n t a k e v a l u e s fo u n d by W agner e t a l .
O r g a n ic m a t t e r
in ta k e
a lth o u g h h ig h e r th a n
was h i g h ,
w ith
for
th e
b io lo g ic a l
1985, was a l s o
g razin g
tim e
lo w .
e stim a te s
s t u d y b e i n g 1 1 .3 h / d ( F u n s t o n , 1 9 8 7 ) .
a p p ro x im a te ly
1 ,2 0 0 k g
DM/ha,
lim itin g in ta k e
(F u n sto n ,
1 9 8 7 )•
was s i m i l a r t o K r o n b e rg e t a l .
(1 9 8 6 ) i n 1984.
types, s tu d ie d
O v e ra ll
of
th e
d a ily
same
1986,
g razin g
tim e
cows w i t h i n
th is
H ow ever, f o r a g e a v a i l a b i l i t y was
w hich
su g g e sts
th at
fatig u e
Forage d i g e s t i b i l i t y
(1 9 8 6 )
in
was
not
i n J u l y o f 1986
i n A u g u st o f 1 9 8 2 , t h i s may mean
f o r a g e r e a c h e d m a t u r i t y e a r l i e r i n t h e y e a r and c o n t i n u e d t o d r o p s i n c e
IVOMD e s t i m a t e s i n S e p t e m b e r , 1986 w ere 35%.
p ro te in ,
a c id
d e t e r g e n t f i b e r and p e r c e n t l i g n i n
m a t u r e f o r a g e s low i n d i g e s t i b i l i t y
W ith
th e se
in h ib ito ry
(H o d g so n ,
a n im a l
lo w
fo rag e
p h y sic a l
1985).
sw ard
sa tie ty
McClymont
g e n e tic p o te n tia l.
(1 9 6 7 )
w h ic h
suggest
th a t
S e le c tiv ity
for
fe lt.th a t
demands
due
in
d e c lin in g r a te of in ta k e .
cows may e x p l a i n
due
s im ila r to
o th er
a l . , 1985; W h it e , 19 8 3 ) •
v a lu e s
response
are
it
to
seem s
rum en
lik e ly
fill
an
o ccu rred
two m ec h a n ism s l i m i t
im posed upon t h e
a n im a l
th e
by
its
A l i m i t a t i o n o f d i g e s t i v e c a p a c i t y f o r low q u a l i t y
And l i m i t a t i o n s
c o n d itio n s,
(Jung, e t.
d ig e s tib ility
from m e e t i n g n u t r i e n t
fo rag es.
E s tim a te s o f fo ra g e crude
p lan t
tu rn
b e h a v io ra l
m o d ifie s
a d a p tio n
g razin g
to
tim e
lim itin g
a
o ffset
a
to
I n c r e a s e d s e l e c t i v i t y by young i n e x p e r i e n c e d
e x te n siv e
g raz in g
to
g razin g
b e h a v io r
p a rts,
tim e s
lim ite d
fo u n d
in ta k e
sp e c ific a lly
le a f
in
1986,
rath e r
over
w hich
th an
ste m
GI
and
a lso
fill.
green
m a t e r i a l o v e r d e a d h a s b e e n fo u n d t o i n c r e a s e g r a z i n g t i m e and d e p r e s s
44
in ta k e
( M in s o n ,
1 986 s u p p o r t s
sta n d in g
areas
th at
C asual
had
near
c o n d itio n s
been
th e
in
o b se rv a tio n s
a h ig h d eg ree o f
bio m ass a p p e a re d
th a t
tille rs
1981).
base
1985
of
a n im a ls
grazed,
b u n chgrass
w here
sta n d in g
th e
stu d y
a n im a ls
se le c tio n o ccu rred .
su ffic ie n t
p re v io u sly
of
or
spent
m ore
se le c te d
sp e cie s.
bio m ass
was
Even t h o u g h
tim e
green
T h is
is
g raz in g
v e g e ta tiv e
opposed
u n ifo rm ly
g r o u n d , and was composed o f v e g e t a t i v e t i l l e r s .
in
low
to
to
S e l e c t io n d u rin g
th e
1985
appeared m in im a l.
M ilk P r o d u c t i o n
M ilk p r o d u c t i o n f o r a l l b i o l o g i c a l , t y p e s was g r e a t e r i n 1985 t h a n
fro m t h e
In
A ugust
same b i o l o g i c a l
198 4 ,
from 2 k g / d
h ig h er
for
fo rag e
t y p e s u s e d by Wagner e t .
Wagner e t .
a l.
1S3H cows t o
q u a lity
la rg e r re s p o n sib ility
in
1984
(1 9 8 6 )
a h ig h
it
is
fo u n d m i l k
o f 8 .2 k g /d
p o ssib le
A n so teg u i
(1 9 8 6 )
(1 9 8 6 )
in 1984.
p ro d u ctio n
for
th a t
f o r n u t r i e n t in ta k e th an in
f o r a g e q u a l i t y was lo w .
a l.
SH cow s.
c a lv e s
ran g in g
W ith
assum ed
a
1985 o r i n 1986 when
fo u n d t h a t
f o r a g e i n t a k e t o c o m p e n s a te f o r r e d u c e d m i l k i n t a k e .
c a lv e s in creased
The o p p o s i t e may
a l s o be t r u e i n t h a t c a l v e s may i n c r e a s e o r m a i n t a i n h i g h e r m i l k i n t a k e
l e v e l s when f o r a g e s l i m i t m e t a b o l i z a b l e e n e r g y i n t a k e
because of poor
forage q u a lity .
M ilk p r o d u c t i o n r e m a in e d h i g h d e s p i t e lo w , o r i n
forage
q u a lity .
Forage i n ta k e
d a ily
g a in s
th e
m ain ta in
m ilk
of
cows
p ro d u ctio n .
in creased
in d ic a te ,th a t
L a c ta tio n
to
some e x t e n t ,
body
ta k e s
1986, d e c re a s in g
c o n d itio n
p recedence
yet
average
d ecreased
over
to
o th e r
45
m e ta b o lic f u n c t i o n s even t o th e p o in t o f m e ta b o lic d y s fu n c tio n
I 98O ) .
and C u r r i e ,
T h is i s
in d ic a te d
by t h e l o w e r c a r c a s s w e i g h t s o f
t h e s t u d y a n i m a l s w i t h c a l v e s o f h i g h e r w e a n in g w e i g h t s .
th a t
th e
carcass
is
a m ajo r
p ro d u ctio n .
K id n e y
p ro d u ctio n
p o te n tia l
fat
was
in
a lso
1985.
p r e v i o u s l y (H am m ond,'1947;,
in
so u rce
of n u trie n ts
reduced
T hese
in
T his s u g g e s ts
f o r m a in ta in in g m ilk
cows w i t h
o b se rv a tio n s
B o tts e t a l .
c o n d itio n i s ex p ected d u rin g l a t e
(Bauman
1979).
h ig h er
m ilk
been
n o ted
have
G e n e r a l ly , an i n c r e a s e
l a c t a t i o n and d u r i n g n o n l a c t a t i n g
p e r i o d s i f n u t r i t i o n a l and e n v i r o n m e n t a l c o n d i t i o n s a r e a d e q u a t e
(NRC,
1984).
Sex
of
p ro d u ctio n
M e lto n
c a lf
for
e t.
w as
b o th
a l.
(1 9 6 7 )
d u rin g th e
im p o rta n t
reg ressio n
r e a r i n g m ale c a l v e s was
c a lv e s
an
fo und
R u tled g e
et
a l.
m o d e ls
th at
th e
.5 8 k g a b o v e
77 da y p o s t p a r t u m
t h i s d i f f e r e n c e d im in ish e d t o
(1 9 7 1 )
v a ria b le
o f m ilk
d a ily
th a t
of th e
p e rio d .
th at
m ilk
in
p ro d u ctio n
cows r e a r i n g
As l a c t a t i o n
1986.
of
cows
h e ife r
progressed
C o n trary t o t h i s r e p o r t ,
dams n u r s i n g
s i g n i f i c a n t l y m ore m i l k t h a n dams n u r s i n g b u l l
e x p la in in g
p ro d u ctio n
m ilk
.1 0 k g p e r d a y .
n o ted
in
h e ife r
c a lv e s.
c a lv e s
gave
Over a 205 d
l a c t a t i o n p e r i o d H e r e f o r d dams n u r s i n g h e i f e r c a l v e s g a v e a p p r o x i m a t e l y
56 k g m ore m i l k .
R e s u l t s o f t h i s s t u d y w ould s u p p o r t t h e i d e a o f dams
w i t h h e i f e r s g i v i n g m ore m i l k ( s e e T a b l e 4 ) .
Organ m ass
D i f f e r e n c e s i n o r g a n m ass among b i o l o g i c a l t y p e s a p p e a r t o r e f l e c t
d i f f e r e n c e s i n m ilk p r o d u c tio n p o t e n t i a l
i n 1985,
w i t h b o t h body s i z e
46
and m i l k p r o d u c t i o n i n f l u e n c i n g o r g a n m ass i n
th e
k id n ey s
p ro d u ctio n
and
th e
liv e rs
p o te n tia l.
The
w ere
larg e r
re la tiv e
siz e
1986.
in
of
D u r in g 1985 b o t h
cows w i t h
th e se
h ig h er
organs
m ilk
rem a in e d
s i g n i f i c a n t when s c a l e d t o b o t h body w e i g h t and m e t a b o l i c body w e i g h t .
T h i s was a s e x p e c t e d
s i n c e b o t h o r g a n s a r e known t o i n c r e a s e
d u rin g l a c t a t i o n a s opposed t o a n o n l a c t a t i n g s t a t e
1974),
im p ly in g
p o te n tia ls.
observed
b e in g
d iffe re n c es
may
e x ist
w ith
in
siz e
(S m ith and B a ld w in ,
d iffe re n t
la c ta tio n
D u r i n g 1986 d i f f e r e n c e s i n body s i z e seem ed t o a c c o u n t f o r
d iffe re n c e s
d iffe re n t
in
th e
k idney
among b i o l o g i c a l
w e ig h ts,
ty p es.
The
w ith
liv e r
w e ig h ts
sig n ific a n c e
of
not
sp le e n
w e i g h t on m i l k p r o d u c t i o n (1 9 8 6 ) and OMI (1 9 8 5 ) i s n o t u n d e r s t o o d .
L iv e r w e ig h ts
rep o rted
by S m ith and B a ld w in
(1 9 7 4 )
f o r a 700 kg
l a c t a t i n g cow w e re 1 1 .4 k g , n e a r l y t w i c e t h e s i z e o f t h e l i v e r w e i g h t s
r e p o r t e d i n t a b l e s 8 and 2 0 .
t i s s u e " " I x d""^ i s
assum ed
I f an e n e r g y v a l u e o f 3 7 0 . 2 k c a l x k g o f
( S m ith
and B a l d w i n ,
1974),
th en th e l a r g e r
l i v e r o f t h e SH r e p r e s e n t s a 9% i n c r e a s e i n l i v e r m a i n t e n a n c e o v e r t h e
s m a l l e s t mean l i v e r w e i g h t (HH).
A a d d i t i v e e f f e c t may o c c u r i f o t h e r
sm a lle r d i f f e r e n c e s are c o n sid e re d .
D u r in g
1985
re tic u lo ru m e n w eig h t d id n o t d i f f e r
( P > .1 0 )
be e x p e c t e d fro m p r e v i o u s s t u d i e s ( S m i t h and B a l d w i n , 1 9 7 4 ) .
a s m ig h t
W eight o f
t h e r e t i c u l o r u m e n a p p e a r s t o be c l o s e l y a s s o c i a t e d w i t h t h e i n c r e a s e i n
feed
in ta k e
d u rin g
la c ta tio n
demand w i t h l a c t a t i o n
d id not d i f f e r
rath e r
th an
(C a m p b e ll and F e l l ,
among b i o l o g i c a l
th e
in cre ase
1964).
e n e rg e tic
S in ce fo ra g e i n ta k e
ty p es in e i t h e r y e a r,
r e t i c u l o r u m e n w e i g h t was n o t e x p e c t e d .
in
a d ifferen ce
in
47
S in ce
organ
t h e y may n o t
w e ig h ts
be s i m i l a r
w e re
to
observed d u rin g l a c t a t i o n .
not
th e
o b tain ed
d u rin g
la c ta tio n
d i f f e r e n c e s w h ic h m ig h t
of
in
1985
have
been
Due t o h i g h e r e n e r g y demands f o r l a c t a t i o n
(NRC, 1984) o r g a n w e i g h t s may h a v e b e e n g r e a t e r i f m e a s u r e d e a r l i e r .
Our o b s e r v a t i o n s do i n d i p a t e t h a t d i f f e r e n c e s i n o r g a n m ass e x i s t among
b i o l o g i c a l t y p e s when i n a n o n l a c t a t i n g s t a t e .
G r e a t e r d i f f e r e n c e s may
h a v e a l s o b e e n o b s e r v e d d u r i n g p e a k l a c t a t i o n when d i f f e r e n c e s i n m i l k
p r o d u c tio n a r e found to o c c u r .
R e t i c u l o r u m e n Volume
A lth o u g h p o s s i b l e
fill
l i m i t a t i o n s may h a v e l i m i t e d i n t a k e d u r i n g
1986 f o r a g e i n t a k e d i d n o t v a r y ( P > .1 0 ) among b i o l o g i c a l t y p e s .
sam e
resp ect
reticu lo ru m en
volum e
a lso
su g g ests a p o ssib le r e la tio n s h ip e x is te d .
th is
h y p o th e sis
needs
to
be
d id
not
v ary
In th e
(P X IO )
w hich
How ever, f u r t h e r t e s t i n g
a c c o m p lish e d
b efo re
any
of
d e fin itiv e
c o n c l u s i o n s c a n b e m ade.
G eneral D is c u ss io n
T h e s e r e s u l t s s u g g e s t t h a t a s s e s s i n g d i f f e r e n c e s i n v i s c e r a l m ass
may
lea d
la c ta tin g
to
a
beef
b e tte r
cow
u n d e rsta n d in g
and
a ssist
b i o l o g i c a l t y p e s o f b e e f cow s.
in
of
th e
to ta l
q u a n tify in g
of
d iffe re n c e s
th e
am ong
S e v e r a l im p ro v e m e n ts i n f u t u r e r e s e a r c h
a re su g g ested to b e t t e r d e fin e th e s e r e l a t i o n s h i p s .
several
e n e rg e tic s
D u rin g t h i s
c o n f o u n d i n g f a c t o r s may h a v e i n f l u e n c e d o u r r e s u l t s .
stu d y
R e su lts
48
c o n c e r n i n g t h e w e i g h t o f t h e l i v e r w e re l i k e l y t o be i n f l u e n c e d by t h e
fa stin g
to
s ta te
tim e i n
w e re
o f t h e a n im a l b e f o r e e x s a n g u i n a t i o n .
tra n sit
o b tain e d
and t o
w e re
lik e ly
(1 9 7 2 ) f o u n d t h e t o t a l
purchased
fro m
dry l o t
to
c o n d itio n s
affect
sh rin k ag e in
a rancher
liv e r
T issu e
b efo re
s h r i n k due
v i s c e r a l w e ig h ts
w e ig h t.
S e lf
and N e ls o n
s t e e r s was a p p r o x i m a t e l y 7 .2 $ when
and t r a n s p o r t e d
fro m 150 t o
1133 m i l e s .
A
l a r g e p o r t i o n o f t h i s s h r i n k can be a t t r i b u t e d t o e x c r e t o r y S h r in k , y e t
any t i s s u e
sh rin k th a t
occurred i s
lik e ly
to have i t s
on t h e w e i g h t o f t h e l i v e r b e f o r e a f f e c t i n g
and G e r o k , 1 9 8 6 ) .
and
its
rap id
g re a te st e ffe c t
o th er tis s u e s
( H a u ssin g e r
B e c a u se o f t h e r o l e o f t h e l i v e r a s a s t o r a g e o r g a n
lo ss
of
glycogen
and
p ro te in
(B ietz
and
A llen ,
1983;
V ernon and P e a k e r , 1983) t h e f a s t i n g and s t r e s s c o n d i t i o n s im posed may
have
caused
a
to ta l
red u c tio n
in
liv e r
w e ig h t
up
to
48%.
F u rth e r
s t u d i e s s h o u l d c o n s i d e r i n s i t u m e a s u r e m e n ts t o e l i m i n a t e t h i s e r r o r .
S tre s s as a r e s u l t o f in ta k e
in
m e a su re m e n ts
of
v isc e ra l
e s t i m a t e s may p r o v i d e f u r t h e r e r r o r
organ
m ass.
T his
s tre s s
may
cause
a
n e g a t i v e e n e r g y b a l a n c e i n t h e a n im a l t o o c c u r t h e r e b y a f f e c t i n g o r g a n
w e ig h ts.
n o rm a l
In
a d d itio n
g razin g
tim e
to
is
th e
added
d isru p ted ,
e ffe c ts
h a v in g
of
stre ss,
p o ssib le
th e
a n im a l's
consequences
of
e x a c e r b a tin g th e a n im a ls n e g a tiv e energy b a la n c e .
The e f f e c t s o f t o t a l
fecal
subsequent
c o l l e c t i o n s on t h e
g razin g
a n im a l
and
the
e stim a te s
n e e d t o b e e x a m in ed f u r t h e r and a l t e r n a t i v e m eth o d s t e s t e d .
A d d i t i o n a l m e a s u r e m e n ts t h a t i n d i c a t e e x t e n t a n d t y p e o f m e t a b o l i c
a c tiv ity
p e r u n i t o f t i s s u e w e i g h t may be h e l p f u l .
Dry m a t t e r w e i g h t s
sh o u ld i n c r e a s e
t h e a c c u r a c y o f m e a s u r e m e n ts by l i m i t i n g
v a ria tio n
tissu e
lev e ls.
c o u p le d w i t h
m o istu re
P ro te in
c o n te n t
of th e v is c e r a
in
49
o t h e r m e a s u r e s o f m e t a b o l i c a c t i v i t y may p r o v e t o be a b e t t e r i n d i c a t o r
of
an a n i m a l ’ s
e n e rg e tic
su g g ested t h a t t o t a l
to
th e
energy
M e a s u re m e n ts
am ino a c i d s
for
c o rre la tio n s
m ain te n a n c e
RNA c o n t e n t
acro ss
if
e x ist.
Tess
(1 9 8 4 )
p r o t e i n w e i g h t o f t h e v i s c e r a m ig h t be a r e l a t e d
req u ired
of
sta tu s
th e
o r enzym es
of
d iffe re n t
re sp o n sib le
p la s m a membrane may be
sto c k s
for
usefu l
of
p ig s.
tra n sp o rt
in
of
d ete rm in in g
d i f f e r e n c e s i n m a i n t e n a n c e due t o p r o t e i n m e t a b o l i s m .
B a ld w in a n d S m ith (1 9 8 3 ) e s t i m a t e d t h e e f f e c t s o f l a c t a t i o n on t h e
a c tiv itie s
o f l i v e r enzym es i n
th e ru m in a n t.
T h e se e n z y m a t i c c h a n g e s
a s s o c i a t e d w i t h g l u c o n e o g e n e s i s may v a r y among b i o l o g i c a l t y p e s and may
be a f a c t o r
enzym es
i n w hole
sh o u ld
be
c h a ra c te ristic s
p art
en erg y
(B a ld w in
and
of
m e ta b o lism
S m ith ,
1983),
d iffe re n c e s
a rea c o n tin u e s.
energy
p a rtitio n in g .
fu tu re
among b i o l o g i c a l
v isc e ra l
u n d e rsta n d in g
a
body
of
but
stu d ie s
ty p e s.
among b i o l o g i c a l
c o m p a r in g
R e g u la to ry
ru m in a n ts
p ro m ise
A ssays
are
to
ty p es
of
p e rtin e n t
th e
v isc e ra l
m ec h a n ism s
c u rre n tly
fu rth e r
if
not
known
a ssist
research
in
in
in
th is
50
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60
APPENDIX
61
T able 24.
L east sq u ares a n a ly s is o f v a ria n c e o f o rg an ic m a tte r
i n t a k e (OM I), 1985
Source
df
B io lo g ic a l ty p e
OMI p e r i o d
B io lo g ic a l type x
OMI p e r i o d
C a lf sex
4
I
4
I
R eg ressio n
Age o f c a l f
Body w e i g h t
I
I
MSE
Mean S q u a r e s
OMI
(% BW/d)
1 .0 9 2 4
4 .6 9 3 4 * ” *
0 .7 1 1 0
2 .6 4 2 3 " *
.
4 .0 6 4 0 " » *
0 .5 3 1 1
47
0 .5 4 8 3
R2
0 .4 3 9 1 ” **
*
P < .1 0 .
P < .0 5 .
01 .
T ab le 2 5 .
Least squares a n a ly s is o f v a ria n ce of o rg an ic m a tte r
i n t a k e (O M I), 1986
Source
df
C a lf sex
i
R eg ressio n
Age o f c a l f
i
MSE
43
R2
Mean S q u a r e s
OMI
'(% BW/d)
'
7 .5 7 6 2 *
9 .6 8 0 2 » «
2 .1 1 5 4
0 .1 4 6 7 ” »
*
P C . 10.
P C .0 5 .
'I
MONTANA STATE UNIVERSITY LIBRARIES
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