SYMPOSIUM: NEW CONCEPTS AND DEVELOPMENTS
IN T R A C E E L E M E N T N U T R I T I O N
Variability in Mineral and Trace Element Content of
Dairy Cattle Feeds
R. S. ADAMS
Dairy Science Extension
The PennsylvaniaState University
University Park 16802
ABSTRACT
QUANTITIES IN FEEDS
Trace element content of feeds is
extremely variable compared to totat
digestible nutrients or protein. Differences are wide between low and high
values for many trace elements within a
given type of feed. Coefficients of variation for forages range from 42 to 100%.
Summary data are given for both major
and trace elements. Problems in supplementation are discussed. Amounts for
some d e m e n t s are skewed with relatively
few samples around the mean and over
60% below the mean. Suggested mineral
allowances for dairy cows are listed.
Under current supplementation, zinc is
the trace element most likely to be
limiting and manganese the least likely.
Iron, copper, cobalt, and iodine may be
limiting in some cases. Needs of research
and applied nutrition are presented.
The sharp contrast in variation among TDN,
protein, and several elements is pointed out in
Table 1. Even with allowances for extreme
values due to error, contamination, etc., variability for trace elements within a major category of feed is much greater than that for TDN
or protein. Also, the spread between low and
high values is greater for trace than major
elements, with the exception of calcium and
sodium, which were not listed. Certainly a 30
to 50-fold range in trace element content is not
unlikely within a given type of forage. Differences may be even greater among different
types of forage or feedstuffs. Extremely high
values, particularly for iron and aluminum, may
reflect soil or other contamination in some
cases.
INTRODUCTION
Nutritionists have been concerned for years
with the TDN (total digestible nutrients) or
energy and protein contents of items used in
feeding dairy cattle. To a lesser extent, there
has been concern for amounts of calcium and
phosphorus. However, too little attention has
been paid to other elements, particularly t r a c e
dements. Often trace mineral concerns stop
with the recommendation to use a commercial
product that has been trace mineralized. Due to
the extreme variability among feeds as well as
other factors, good trace element nutrition does
not come this easy. I hope this presentation will
demonstrate the great variation in trace element
content which may occur. In addition, summary data on mineral analysis for various feeds
will be provided and practical considerations in
trace mineral supplementation will be discussed.
Received December 13, 1974.
All mineral data, except for sulfur, taken
from Penn State summaries have been determined with an emission spectrometer. Essentially the procedures are those reported in (1).
This reference lists some of the important
precautions to avoid high values from contamination during processing and analysis. Sulfur
was determined with a Leco oxidizing unit. A
procedure must be modified to include elemental sulfur as well as that in sulfate form.
Another indication of large variability in
trace element content of feeds may be found in
Table 2. Here the mean coefficients of variation
have been listed as taken from a summary of
test data. Standard deviations as percents of
means are higher for trace than maior dements,
with the exception of sodium. Also, the coefficient of variation for calcium is relatively high
for corn grain. Aluminum has the highest
coefficient of variation among the trace elements. Both soil contamination and soil pH
greatly affect aluminum values.
Data in Tables 3 and 4 provide expectancies
on both trace and major elements for commonly used forages and corn. Most of the samples
1538
SYMPOSIUM: NEW TRACE ELEMENT NUTRITION
1539
TABLE 1. Range in nutritive content of legume-grass forage, a
Item
Range
TDN, %
Crude protein, %
Calcium, %
Phosphorus, %
Magnesium, %
Sulfur, %
Manganese, ppm
Iron, ppm
Copper, ppm
Zinc, ppm
51
6.6
.01
.07
.07
.04
6
10
2
8
Fold b
difference
-- 71
- 33.2
- 2.61
-- .74
-- .75
- .38
-- 265
1.4
5.0
261.0
10.6
10.7
9.5
44.2
-- 2599
259.9
-- 92
-- 300
46.0
37.5
aSummary of Penn State Forage Testing Service, 1969-73.
bMaximum - minimum.
s u m m a r i z e d in t h e s e tables originated in P e n n sylvania a n d N e w York. T h e d a t a s h o u l d b e
r e a s o n a b l y indicative of feeds p r o d u c e d in this
region or u n d e r similar soil a n d o t h e r conditions. Sulfur d a t a are available o n a m u c h
smaller p r o p o r t i o n o f t h e samples a n d are
s u m m a r i z e d in T a b l e 5.
S o m e w h a t similar d a t a for grains a n d byp r o d u c t i n g r e d i e n t s have b e e n p u b l i s h e d b y t h e
N a t i o n a l R e s e a r c h C o u n c i l (9, 10). T h e data in
Tables 6 and 7 for c o m m o n l y used c o n c e n t r a t e s
have b e e n a d a p t e d f r o m t h e s e sources. T h e s e
data were o b t a i n e d prior t o 1958. Also, few
samples are r e p r e s e n t e d in s o m e m e a n values.
This is true of t h o s e for trace e l e m e n t s ,
especially zinc a n d iodine. I n s u f f i c i e n t observations exist for s o m e i m p o r t a n t i n g r e d i e n t s such
as c o t t o n s e e d and s o y b e a n oil meals.
Many factors may influence the mineral
c o n t e n t of forages a n d o t h e r feeds. U n d e r w o o d
(14) has suggested t h a t the m o s t i m p o r t a n t
f a c t o r s are (a) genus, species, or s t r a i n of p l a n t ,
(b) t y p e of soil, (c) climatic or seasonal
c o n d i t i o n s d u r i n g g r o w t h , a n d (d) stage o f
m a t u r i t y of t h e p l a n t . D a t a on t h e s e a n d o t h e r
f a c t o r s have b e e n p u b l i s h e d m o r e r e c e n t l y (13).
T h e i n f l u e n c e of l o c a t i o n a n d soil via pH,
p a r e n t material, a n d f e r t i l i z a t i o n has b e e n
e s t a b l i s h e d in s o m e cases (2, 3, 4, 5, 7, 12, 13,
14). T h e s e are l a n d m a r k p u b l i c a t i o n s dealing
w i t h applied m i n e r a l n u t r i t i o n .
T h e e f f e c t of geographical origin o n t h e
m o l y b d e n u m a n d s e l e n i u m c o n t e n t of feeds is
well k n o w n . However, less d r a m a t i c b u t i m p o r -
TABLE 2. Mean coefficient of variation for elemental content, a
Element
Forages
Corn grain
Phosphorus
Potassium
Calcium
Magnesium
Sulfur
Sodium
Manganese
Iron
Boron
Copper
Zinc
Aluminum
25
32
28
33
29
128
75
68
42
57
63
100
22
33
196
17
24
318
116
83
58
62
39
172
Combined
(%)
25
32
73
30
28
170
84
71
46
58
57
116
aSummary of Penn State Forage Testing Service, 1969-73.
Journal of Dairy Science Vol. 58, No. 10
1540
ADAMS
TABLE 3. Trace element content of various feeds, ppm in dry matter, a
Item
Manganese
Legume forage (992) b
Mean
SD
Low
High
44.1
49.2
8.0
1080.0
Boron
Copper
Zinc
Aluminum
221.7
124.9
41.0
800.0
25.9
7.9
2.0
65.0
13.1
8.2
2.0
214.0
28.1
18.8
11.0
260.0
143.1
123.3
4.0
1000.0
48.1
21.3
6.0
265.0
222.0
142.7
10.0
2599.0
20.2
7.2
2.0
94.0
13.1
5.7
2.0
92.0
27.2
12.7
8.0
300.0
128.8
127.7
1.0
1500.0
57.3
40.0
7.0
1200.0
192.3
138.9
t9.0
2463.0
11.6
5.4
1.0
53.0
12.0
7.0
2.0
125.0
26.5
12.8
3.0
255.0
105.0
113.1
2.0
1271.0
Grass forage (352)
Mean
SD
Low
High
76.4
64.1
12.0
689.0
184.4
141.2
32.0
1200.0
8.3
3.8
.0
26.0
12.9
8.4
2.0
69.0
27.6
10.7
12.0
112.0
108.0
126.0
7.0
1200.0
Corn silage (7179)
Mean
SD
Low
High
38.1
20.8
1.0
267,0
200.1
131.1
5.0
1800.0
6.5
2.6
1.0
41.0
8.1
4.4
2.0
110.0
30.8
21.5
3.0
416.0
91.8
99.0
3.0
3500.0
Small grain forage (97)
Mean
SD
Low
High
62.6
41.0
9.0
276.0
298.8
155.9
40.0
900.0
8.0
4.3
1.0
27.0
11.9
7.7
2.0
36.0
33.2
25.5
14.0
212.0
181.8
166.5
1.0
1000.0
Sorghum-sudan forage (91)
Mean
SD
Low
High
69.1
65.2
9.0
571.0
320.5
278.2
67.0
2000.0
7.7
3.2
2.0
19.0
12.3
6.4
2.0
36.0
41.6
38.0
"15.0
315.0
173.6
157.8
23.0
691.0
Ear corn (324)
Mean
SD
Low
High
7.3
10.9
1.0
142,0
93.8
89.7
7.0
500,0
3.8
2.7
,0
36.0
4.7
2.7
1.0
19.0
26.8
14.4
11.0
200.0
21.7
43.6
.0
500.0
4.8
4.0
1.0
29.0
69.0
48.5
10.0
464.0
3.6
1.6
1.0
10.0
3.7
2.5
.0
23.0
24.7
5.9
13,0
58.0
10.7
15.3
1.0
85.0
Mixed mainly legume (4014)
Mean
SD
Low
High
Mixed mainly grass (4119)
Mean
SD
Low
High
Shelled corn (221)
Mean
SD
Low
High
Iron
aSummary of Penn State Forage Testing, 1969-73.
hNumber of samples.
rant differences may exist within a state,
c o u n t y , c o m m u n i t y , or even o n a farm. F o r
example, zinc in Pennsylvania forages m a y vary
appreciably d e p e n d i n g u p o n location, as illusJournal of Dairy Science Vol. 58, No. 10
t r a t e d in Table 8. Forages g r o w n in Regions 2
and 5 t e n d to c o n t a i n m o r e zinc. T h e reasons
are n o t a p p a r e n t here, b u t o b s e r v a t i o n o f m a n y
tests over years suggests t h a t forages g r o w n
SYMPOSIUM: NEW TRACE ELEMENT NUTRITION
1541
TABLE 4. Major element content of various feeds, percent in dry matter, a
Item
Phosphorus
Potassium
Calcium
Magnesium
Sodium
Legume forage (992) b
Mean
SD
Low
High
.30
.05
.14
.56
2.55
.61
.21
4.93
1.18
.27
.03
2.23
.24
.07
.10
.58
.024
.017
.001
.100
Mixed mainly legume (4014)
Mean
SD
Low
High
.29
.06
.07
.74
2.26
.60
.42
9.63
1.02
.28
.01
2.61
.22
.07
.07
.75
.018
.015
.000
.110
Mixed mainly grass (4119)
Mean
SD
Low
High
.23
.06
.05
.81
1.79
.55
.30
4.70
.65
.28
.10
2.73
.18
.06
.03
.79
.013
.016
.000
.390
Grass forage (352)
Mean
SD
Low
High
.22
.07
.09
.56
1.68
.61
.24
4.04
.49
.20
.10
1.58
.16
.06
.04
.42
.014
.019
.000
.110
Corn silage (7179)
Mean
SD
Low
High
.23
.05
.01
.93
1.07
.27
.02
3.28
.27
.11
.01
1.88
.18
.05
.01
.55
.005
.014
.000
.350
Small grain forage (97)
Mean
SD
Low
High
.32
.09
.14
.76
2.29
.81
.49
5.30
.44
.20
.06
1.22
.16
.05
.07
.29
.030
.031
.001
.100
Sorghum-sudan forage (91)
Mean
SD
Low
High
.24
.06
.07
.44
1.73
.74
.12
4.00
.48
.23
.12
1.83
.28
.12
.06
.58
.008
.012
.001
.071
.28
.08
.14
1.14
.49
.18
.26
2.96
.05
.10
.01
1.15
.12
.02
.01
.25
.007
.020
.000
.100
.31
.05
.19
.59
.42
.13
.24
1.41
.03
.06
.01
.72
.12
.02
.06
.20
.003
.010
.000
.100
Ear corn (324)
Mean
SD
Low
High
Shelled corn (221)
Mean
SD
Low
High
aSummary of Penn State Forage Testing, 1969-73.
bNumber of samples.
closer to industrial centers may be higher in
some trace elements. Perhaps s o m e of this may
be due to air pollution, use of industrial
b y - p r o d u c t s o n soils, a n d r u n - o f f f r o m disposal
sites for industrial wastes. Forages grown in an
area w i t h slate m i n e s m a y s o m e t i m e s c o n t a i n
80 t o 2 2 0 p p m zinc. T h i s is 3 to 7 t i m e s h i g h e r
t h a n e x p e c t e d zinc. M o l y b d e n u m t o x i c i t y h a s
Journal of Dairy Science Vol. 58, No. 10
1542
ADAMS
T A B L E 5. Sulfur c o n t e n t of various feeds, dry m a t t e r basis, a
Item
No.
samples
Legume forage
Mixed mainly legume
Mixed mainly grass
Grass forage
Corn silage
Small grain forage
Sorghum-sudan
Ear corn
Shelled corn
39
121
71
4
249
1
3
18
8
Mean
Low
High
Standard
deviation
%
%
%
+-%
.26
•23
.20
.20
.14
.21
.10
.13
.14
.14
.04
.12
.14
.04
. .
.08
.08
.10
.43
.38
.35
•29
.22
. .
.14
.22
.19
.07
.06
.06
.07
.04
.
.
.
.
.
.03
.04
.03
a s u m m a r y of Penn State Forage Testing, 1969-73.
T A B L E 6. Zinc p p m in forages by major land resource areas in Pennsylvania. a
Corn silage
Legume-Grass hay
Grass-Legume hay
Region b
No. samples
ppm
No. samples
ppm
No. samples
ppm
1
2
3
4
5
879
278
295
1478
974
31
37
30
29
30
328
189
123
874
355
27
32
25
26
31
679
115
158
351
214
24
30
25
27
31
a c o n t e n t on a dry m a t t e r basis for samples tested from 1969 to 1973.
bRegions are described as follows: (1) Glaciated Allegheny Plateau and Catskill Mountains (Northwest and
Northeast), (2) Central Allegheny Plateau, (3) Eastern Allegheny Plateau and Mountains, (4) Northern Appalachian Ridge and Valleys (South Central), and (5) Northern P i e d m o n t (Southeast).
T A B L E 7. Trace mineral c o n t e n t of various concentrates, dry m a t t e r basis, a
Item
Manganese
Iron
Copper
Zinc
Cobalt
Iodine
(ppm)
Barley
No. samples
Mean
Low
High
Beet pulp, dried
No. samples
Mean
Low
High
Brewers' grains, dried
No• samples
Mean
Low
High
Citrus pulp, dried
No. samples
Mean
Low
High
(73)
18.2
2.4
29.9
(41)
60.0
40,0
100.0
(33)
8.6
1.3
20.0
(3)
17.1
11.9
20.9
(27)
.117
.000
.321
(39)
38.5
12.1
77.9
(27)
331.0
85.0
600.0
(31)
13.9
8.4
22.7
(1)
7.0
. . . .
. . . .
(26)
.112
023
116
(29)
40.7
21.1
56.1
(22)
271.6
100.0
410.0
(16)
23.1
5.5
45.3
.
.
.
.
..
. . .
. . .
. . .
(15)
067
044
110
(16)
7.5
1.1
19.4
(14)
183.1
94.0
303.0
(8)
6.3
2.0
14.5
(1)
16.0
. . . .
. . . .
(4)
.236
066
704
Journal of Dairy Science Vol. 58, No. 10
•
o .
SYMPOSIUM: NEW TRACE ELEMENT NUTRITION
1543
T A B L E 7. ( C o n t i n u e d ) T r a c e m i n e r a l c o n t e n t o f v a r i o u s c o n c e n t r a t e s , d r y m a t t e r basis, a
Item
Manganese
Iron
Copper
Zinc
Cobalt
Iodine
(2)
19.6
12.1
26.8
(460)
•022
.002
.299
(16)
•344
.064
•7 0 4
(ppm)
Corn, dent
No. samples
Mean
Low
High
C o r n distillers w sol.
No. samples
Mean
Low
High
Corn gluten feed
No. samples
Mean
Low
High
C o t t o n s e e d m e a l , solv.
No. samples
Mean
Low
High
H o m i n y f e e d , yel.
No. samples
Mean
Low
High
Oats
No. samples
Mean
Low
High
Molasses, c a n e
No. samples
Mean
Low
High
Sorghum
No. samples
Mean
Low
High
S o y b e a n m e a l , solv.
No. samples
Mean
Low
High
Steamed bone meal
No. samples
Mean
Low
High
Wheat bran
No. samples
Mean
Low
High
Wheat std. raids
No. samples
Mean
Low
High
(568)
5.7
.7
53.9
(518)
20.0
10.0
100.0
(463)
2.4
.9
9.0
(10)
30.9
15.6
67.3
(8)
334.1
200.0
600.0
(2)
67.1
56.1
78.5
.
.
.
.
..
(2)
. . .
120
. . . . .
. . . . .
(45)
26.3
8.8
42.2
(32)
514.0
260.0
955.0
(33)
52.7
13.0
89.3
.
.
.
.
. .
. . .
. . .
. . .
(26)
097
022
286
(5)
21.8
16•2
30.1
(3)
167.0
110.0
246.0
(3)
23.3
16.3
32.6
.
.
.
.
..
. . .
. . .
. . .
(3)
086
033
176
(17)
17.8
11.4
30.6
(12)
109.0
10.0
260.0
(5)
10.7
7.9
13.9
.
.
.
.
..
. . .
. . .
. . .
(3)
061
048
066
(199)
42.9
20.0
203.5
(88)
80.0
20.0
300.0
(73)
6.6
2.4
25.7
.
.
.
.
..
. . .
. . .
. . .
(19)
064
000
321
(9)
56.6
12.8
83.8
(9)
251.0
130.0
429.0
(8)
80.0
33.4
137.1
•..
. . .
. . . .
...
(4)
1.213
224
3.485
(42)
16.2
.0
27.3
(44)
50.0
.0
180.0
(38)
10.8
2.0
19.1
(2)
15.4
11.8
18.9
(22)
.304
.040
.737
(7)
30.8
24.9
33.9
(9)
147.0
110.0
240.0
(8)
16.0
13.6
18.3
.
.
.
.
(6)
103
031
176
(57)
31.9
2.0
92.4
(63)
882.4
159.0
2829.0
(56)
17.1
.9
33.4
(36)
446.0
51.3
1835.9
(44)
129.9
90.0
164.3
(29)
193.0
88.0
270.0
(30)
13.8
4.4
(20)
132.0
103.4
157.7
(13)
115.9
83.0
192.0
(10)
11.1
22.2
28.2
29.9
. .
. . .
. . .
. . .
.
(24)
108
031
178
...
. . . .
. . . .
. . . .
(10)
094
079
130
.
. °
, . .
° . .
(17)
.065
.044
.110
. ..
. . . .
. . . .
.
,
.
aAdapted from National Academy of Science, National Research Council Publications No. 449 and 585.
J o u r n a l o f D a i r y S c i e n c e Vol. 5 8 , N o . 10
1544
ADAMS
TABLE 8. Major mineral content of various concentrates, dry matter basis, a
Item
Phosphorus
Potassium
Calcium
Magnesium
Sulfur
Sodium
Chlorine
(234)
.14
.01
.23
(213)
.19
.10
.35
(10)
.02
.01
.06
(14)
.13
.09
.17
(%)
Barley
No. samples
Mean
Low
High
Beet pulp, dried
No. samples
Mean
Low
High
Brewers' grains, dried
No. samples
Mean
Low
High
Citrus pulp, dried
No. samples
Mean
Low
High
Corn, dent
No. samples
Mean
Low
High
Corn distillers w sol.
No. samples
Mean
Low
(331)
.47
.28
.92
(233)
.63
.33
.99
(57)
.11
.05
.17
(8)
.23
.15
.39
(56)
.75
.36
1.03
(14)
.30
.06
.43
(4)
.22
.13
.31
(6)
.19
.11
.23
(1)
.04
...
...
(37)
.54
.36
.68
(5)
.09
.04
.18
(37)
.29
.14
.65
(7)
.15
.03
.31
(4)
.34
.05
.51
(1)
.28
. . . .
. . . .
(4)
.20
06
26
(38)
.13
.09
.24
(4)
.69
.10
1.41
(38)
2.18
1.24
3.55
(20)
.18
.02
.50
.
.
.
.
"(571)
.03
.00
.35
(88)
.14
.08
.90
(38)
.14
.10
.19
(53)
.01
.00
.O6
(72)
.06
.02
.O9
(8)
.71
.22
1.13
(22)
.19
.I1
.28
(13)
.27
.09
.38
(5)
.33
.24
.40
(3)
.39
.18
.79
(3)
.19
.17
.19
(29)
.66
.62
1.33
(59)
.51
.03
1.08
(31)
.32
.29
.87
(26)
.24
.06
1.40
(3)
1.05
1.03
1.10
(7)
1.24
.06
1.04
(3)
1.61
1.03
2.20
(14)
.16
.07
.26
(4)
.64
.37
.82
(3)
.06
01
11
(2)
.04
.04
.05
(586)
.31
.09
.24
(22)
.74
.43
1.02
High
Corn gluten feed
No. samples
(82)
Mean
.85
Low
.38
High
1.20
Cottonseed meal, solv.
No. samples
(16)
Mean
1.20
Low
.65
High
1.70
(88)
.33
.20
.73
(325)
.09
.03
.41
b e e n f o u n d in plants and animals l o c a t e d in t h e
vicinity o f zinc and m o l y b d e n u m smelters.
S o m e o f the e x t r e m e l y high trace e l e m e n t s in
Table 3 were o b t a i n e d in forages f r o m farms
with animal health p r o b l e m s w h i c h a p p a r e n t l y
resulted f r o m intake o f industrially c o n t a m i n a t e d forages.
S U P P L E M E N T A T I O N PROBLEMS
Neither universal p r o d u c t s nor general reco m m e n d a t i o n s can insure t h a t all cows on all
farms will receive p r o p e r a m o u n t s o f mineral
e l e m e n t s at all times. Yet, this is w h a t s o m e
Journal of Dairy Science Vol. 58, No. l0
.
.
.
.
.
.
.
.
(1)
.23
. . . .
. . . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
d a i r y m e n are led t o believe for various reasons.
F u r t h e r , s o m e f a r m e r s believe t h a t h o m e - p r o d u c e d feeds will c o n t a i n a d e q u a t e a m o u n t s o f
m o s t e l e m e n t s , if t h e y fertilize according to soil
tests or get good yields. U n f o r t u n a t e l y , s o m e
mineral n u t r i t i o n p r o b l e m s result f r o m a differential r e q u i r e m e n t o f the animal over t h a t o f
plants or f r o m low availability of .an e l e m e n t t o
the animal (7).
P r o p e r use o f forage and feed testing with
mineral analyses c o m b i n e d with c u s t o m f e e d
p r o g r a m m i n g offers t h e b e s t a p p r o a c h t o reas o n a b l y g o o d mineral n u t r i t i o n . T h e use of
SYMPOSIUM: NEW T R A C E ELEMENT N U T R I T I O N
1545
T A B L E 8. (Continued) Major mineral c o n t e n t o f various concentrates, dry matter basis, a
Item
Phosphorus
Potassium
Calcium
Magnesium
Sulfur
Sodium
Chlorine
(%)
Hominy feed, yel.
No. samples
Mean
Low
High
0 ats
No. samples
Mean
Low
High
Molasses, cane
No. samples
Mean
Low
High
Sorghum
No. samples
Mean
Low
High
Soybean meal, solv.
No. samples
Mean
Low
High
Steamed bone meal
No. samples
Mean
Low
High
Wheat bran
No. samples
Mean
Low
High
Wheat std. mids
No. samples
Mean
Low
High
(22)
.57
.30
.87
(273)
.39
.05
1.02
(32)
,11
.01
.25
(235)
.35
.10
.52
(34)
.75
.50
1.09
(1)
.57
. . .
. . .
(83)
.42
.22
.89
(9)
3.20
2.16
3.64
(16)
.38
.28
.50
.
.
(22)
.06
02
12
(2)
.04
.02
.06
.
.
.
.
(227)
.11
.04
.48
(77)
.19
.03
.29
(15)
.23
.15
.31
(18)
.07
.01
.16
(19)
.47
.16
.87
(15)
.46
.10
.97
(5)
.23
.10
.53
(4)
3.69
2,60
4.35
(227)
.05
.01
.53
(23)
.19
.02
.25
(6)
.18
.15
.21
(9)
.05
.01
.09
(7)
.10
.07
.14
(35)
.36
.23
.96
(8)
_30
.00
,45
(1)
.48
. . . .
. . . .
(6)
.38
04
62
(1)
,00
, ••
•..
(109)
30.44
22.75
36.65
(45)
,64
.11
1.19
(40)
.23
.07
.91
(18)
.48
.40
.55
...
...
...
...
(9)
.07
.01
A1
(7)
.05
.02
.10
(35)
1.20
.32
2.20
(6)
2,20
2.00
2.30
..
(1)
. . .
14
. . . . . . . .
. . . . . . . .
(109)
14.28
8.34
18.35
118
...
...
(86)
1.31
.10
1.91
(11)
1.39
.93
1.77
(84)
.16
.07
.56
(10)
.62
.50
.80
(9)
.25
.19
.36
(53)
1.01
.73
1.35
(33)
1.09
1.06
1.37
(30)
.17
.07
.50
(34)
.41
.40
.56
(32)
(1)
.06
.25
. . . . . . .
. . . . . . .
. ••
.••
(19)
.11
.05
.19
(3)
.03
03
04
aAdapted f r o m National A c a d e m y of Science, National Research Council Publications No. 449 and 585.
multiple product
lines designed to provide
f l e x i b i l i t y in m i n e r a l c o n t e n t o f f i n i s h e d f e e d s
affords a satisfactory means of improving mineral n u t r i t i o n . T h e u s e o f m a n u f a c t u r e d p r o t e i n
concentrates without added minerals, at least
t h e m a j o r o n e s , p r o v i d e s still a n o t h e r a l t e r n a tive.
T r a c e m i n e r a l t e s t s m u s t be u s e d w i t h
c a u t i o n in f e e d p r o g r a m m i n g . E x t r e m e v a l u e s
m a y o c c u r d u e t o c o n t a m i n a t i o n b e f o r e or a f t e r
sampling, faulty procedures, and improperly
o p e r a t e d or m a l f u n c t i o n i n g e q u i p m e n t . T h u s , it
is b e s t t o u s e v a l u e s t h a t a r e c o n s i s t e n t w i t h
past test reports from a farm when unreasonable values are encountered.
It is e x t r e m e l y i m p o r t a n t
to use sound
assumptions, good expectancy data, and reasonable allowances for developing either general
recommendations
or universal formulas for
supplements, Should one base supplementation
on average values for forage and concentrates?
Or should values be used that range from
Journal of Dairy Science Vol. 58, No. 10
1546
ADAMS
one-half to more than one standard deviation
below average? In regard t o trace e l e m e n t s , it
a p p e a r s best to use a value t h a t at least
a p p r o a c h e s o n e s t a n d a r d deviation b e l o w m e a n
values. This t h e o r e t i c a l l y w o u l d m a k e t h e reco m m e n d a t i o n s a d e q u a t e a b o u t 84% of t h e
time. As i l l u s t r a t e d in T a b l e 9, values for a
given e l e m e n t m a y n o t fit a n o r m a l d i s t r i b u t i o n
curve. T h e y m a y be s k e w e d w i t h relatively few
samples close t o t h e m e a n a n d c o n s i d e r a b l y
m o r e values falling b e l o w t h e m e a n t h a n a b o v e
it.
T h e m i n i m u m allowances w h i c h we p r e f e r to
use in general feed p r o g r a m m i n g are in T a b l e
10. P h o s p h o r u s allowances a p p r o x i m a t e t h o s e
of t h e 1971 N R C p u b l i c a t i o n (11). M o s t t r a c e
mineral a l l o w a n c e s agree w i t h t h o s e of J a c o b son et al. (8).
Q u a n t i t i e s of t r a c e m i n e r a l s n e e d e d in t h e
grain m i x t u r e to b a l a n c e a c o m m o n l y used
r a t i o n are in T a b l e 11. Likewise, a m o u n t s of
m i n o r e l e m e n t s n e e d e d in a trace m i n e r a l salt to
be used in s u p p l e m e n t i n g a c o r n a n d s o y b e a n
oil meal m i x t u r e are given. A s s u m p t i o n s include
feeding a c o w weighing 545.5 kg a n d p r o d u c i n g
22.7 kg of m i l k t e s t i n g 4% fat. In a d d i t i o n , 65%
of the t o t a l dry m a t t e r was f u r n i s h e d b y a
TABLE 9. Distribution of iron in mixed mainly
legume forages, a
ppm
30
60
90
120
150
180
210
240
270
- 60
-- 90
-- 120
- 150
-- 180
-- 210
- 240
- 270
- 300
3OO - 330
330 -- 36O
360 - 390
39O -- 42O
420 - 45O
450 -- 480
480 -- 510
Percent
of samples
1.5
5.9
5.2
19.3
14.8
11.1
2.2
3.0
1.5
5.9
.7
2.2
4.4
1.5
1.5
19.3
a135 samples randomly selected from 1973-74
testing year at Penn State. Mean 255.9 + 150.1 ppm;
range 38 to 500 ppm. Skewed positively with 61.5%
of the samples below the mean and 38.5% above the
mean.
Journal of Dairy Science Vol. 58, No. 10
TABLE 10. Mineral allowances for dairy cows. a
Element
Amount
Calcium, %
Phosphorus, %
Potassium, %
Magnesium, %
Sulfur, %
Manganese, ppm
Iron, ppm
Copper, ppm
Zinc, ppm
Cobalt, ppm
Iodine, ppm
.68 -- .76
.38
.70
.22
.20
44
150
11
70
1
2
aLevels expressed on a dry matter basis.
forage r a t i o n consisting of 50% c o r n silage a n d
50% m i x e d m a i n l y l e g u m e forage o n a d r y
m a t t e r basis. If m e a n e x p e c t a n c i e s are used, o n e
c o u l d feed r e a s o n a b l y c e r t a i n t h a t needs were
b e i n g m e t o n l y 50% of t h e t i m e or less. W h e n
an e x p e c t a n c y of o n e s t a n d a r d d e v i a t i o n b e l o w
m e a n is used, one m a y be m e e t i n g needs a b o u t
84% of the time.
F o r c o m p a r i s o n , trace m i n e r a l s in a p o p u l a r
m a n u f a c t u r e d dairy feed a n d a widely used
trace m i n e r a l salt are s h o w n in p a r e n t h e s e s .
M a n g a n e s e usually a p p r o a c h e s or exceeds needs
in p r o d u c t s used for s u p p l e m e n t a t i o n . T h i s
p r o b a b l y is a carry-over f r o m p o u l t r y n u t r i t i o n ,
r a t h e r t h a n t h e r e s u l t of g o o d f o r m u l a t i o n f o r
dairy p u r p o s e s . Zinc s u p p l e m e n t a t i o n is m o s t
likely i n a d e q u a t e . Iron m a y be lacking in s o m e
fortifications. Copper, cobalt, a n d i o d i n e m a y
be i n s u f f i c i e n t in s o m e cases. Classical c o b a l t ,
c o p p e r , and, to a lesser e x t e n t , i o d i n e deficiencies have b e e n f o u n d in P e n n s y l v a n i a d e s p i t e
usual s u p p l e m e n t a t i o n w i t h t h e s e e l e m e n t s .
This is n o t surprising in view of t h e i n f o r m a t i o n
in T a b l e 11 a n d elsewhere in this paper.
Supplementation may be inadequate to meet
m i n i m u m needs. Also, various factors or imbalances m a y increase r e q u i r e m e n t s for c e r t a i n
elements. F o r e x a m p l e , goitrogens m a y increase
iodine r e q u i r e m e n t . Availability of m i n e r a l s in
forages m a y also vary f r o m t i m e t o t i m e , as in
the case of m a g n e s i u m .
While s o m e dairy h e r d s m a y suffer f r o m a
lack of minerals, o t h e r s m a y be over-supplemented with major and trace elements to the
p o i n t of decreased p r o f i t s a n d r e d u c e d p e r f o r m ance, It is n o t u n c o m m o n to find d a i r y m e n
w h o provide trace m i n e r a l s u p p l e m e n t a t i o n via
SYMPOSIUM: NEW TRACE ELEMENT NUTRITION
1547
TABLE 11. Possible elemental quantities for supplementary feeding.
Basis:
Mean
One standard deviation below mean
Element
Concentrate
mixa
Trace mineral
salt b
Concentrate
mixa
Trace mineral
salt b
Manganese
Iron
Copper
Zinc
Cobalt
Iodine
(ppm)
39
31
10
123
2.3
3.1
(%)
.310
.000
.044
.934
.023
.028
(ppm)
78 (76) c
245 (363).
19 (10)
143 (105)
2.3 ( ...)
4.0 (...)
(%)
.690
1.800
.130
1.112
.023
.037
(.600) d
(.200)
(.060)
(.010)
(.015)
(.016)
aTotal of the element (natural + supplemental) necessary to balance the forage ration using the grain mixture
or complete dairy feed as the vehicle.
bElement necessary in a trace mineral salt to provide needed supplementation when used at 1% in a cornsoybean oil meal mixture.
CIn a popular manufactured dairy feed.
din a popular trace mineral salt.
as many as 6 to 8 sources. To illustrate, some
dairymen using a grains plus supplement mixture may furnish supplementary trace minerals
via each of the following means: (a) manufactured dairy concentrate, (b) trace mineral salt
in mix, (c) trace mineralized phosphorus supplement in mix, (d) liquid protein supplement
free-choice, (e) trace mineral salt free-choice,
(f) commercial mineral supplement free-choice,
and (g) nonprotein nitrogen (NPN) corn silage
made with a commercial additive.
This kind of supplementation should be
discouraged for numerous reasons. Trace mineral supplementation via one or two sources in
forced feeding and one in free-choice feeding
should be adequate in most cases, if well-formulated products are used. We have encountered
herds with appetite and other problems where
5 to 7% of the grain mixture consisted of
supplementary mineral compounds and premixes, as recommended by some computer
programs.
NEEDS
Additional information is necessary in several areas, as follows:
(a) More research is needed to develop
improved allowances for use in feed programming and formulation of commercial products.
(b) Further studies are necessary on the use
of chelated minerals from both the basic and
applied standpoints,
(c) Guarantees or specification sheets for
manufactured feeds and concentrates should be
expanded to include mineral content in all
cases, not just for pre-mixes, super-concentrates, or feeds tagged under the feed control
laws of certain states.
(d) Improved compilations of the content of
mineral and other nutrients in feeds are vital to
aid in improving the nutrition of farm animals.
Further elaboration on the fourth point is
justified. Compilations which provide as full
information as possible on well-described feeds
should be published on a more regular basis.
The format preferably should include standard
deviations and coefficients of variation. The
efforts of the National Research Council in the
past (9, 10) are to be commended. The current
effort being made by the International Feedstuffs Institute at Utah State University (6) also
is commendable. It provides the basis upon
which a more satisfactory job of compilation
and publication could be accomplished. To
date, however, funding and voluntary efforts
appear inadequate to serve the needs of the
animal industry in today's world.
A more deliberate effort may be needed to
make certain that the number of samples
included in a meaningful compilation approach
a minimum of 100 to 150 for any particular
analysis of an important feed. Further compilations probably should be published at least
every 5 yr to keep values abreast of changing
technology in production and processing. Preferably, only data within such a limited period
Journal of Dairy Science Vol. 58, No. 10
1548
ADAMS
should be included. Additional regionalization
of data based on k n o w n differences in mineral
c o n t e n t of feeds or special environmental conditions is necessary. While a large, highly
specific as well as detailed compilation is
necessary for certain situations, the greater
need is for one that covers in detail only the
i m p o r t a n t forages and concentrates in somewhat broader categories. Such a version is badly
needed by applied nutritionists and essential to
improvements in feeding.
More a t t e n t i o n m u s t be paid to mineral
nutrition, especially trace elements, in feeding
dairy cattle. T o o m a n y people in feed trade and
educational circles have not put sufficient
emphasis on mineral nutrition. This has encouraged m a n y entrepreneurs, well meaning and
otherwise, to market minerals directly to dairymen and livestock farmers. Because of the
inherent inefficiencies of this approach, the
costs of these minerals to farmers has b e e n
considerably higher than necessary. Nevertheless, s o m e good has been done in m o r e closely
meeting nutritional needs and in encouraging
greater efforts on the part of researchers and
the feed trade.
There is no substitute for a ration t h a t is
well balanced f r o m the chemical and physical
standpoints. A balanced ration is essential to
good p e r f o r m a n c e under b o t h farm and research conditions. Whenever possible, experimental rations should be isomineralized as well
as isocaloric, isonitrogenous, and otherwise
nutritionally adequate. Poorly f o r m u l a t e d rations can result in faulty conclusions or severely
limit the usefulness of the research in practical
feeding.
SUMMARY
The trace element c o n t e n t of feeds is extremely variable. Differences b e t w e e n high and
low values for a given t y p e of feed are wide for
m a n y elements. There is a lack o f data for
certain elements in some widely used feeds.
Zinc is the element m o s t likely to be inadequate under current s u p p l e m e n t a t i o n practices.
Manganese is the least likely to be limiting.
Cobalt, copper, iodine, and iron are apt to be
provided in insufficient a m o u n t s with current
practices.
ACKNOWLEDGMENTS
The a u t h o r wishes to acknowledge the technical assistance of Barrie Moser and William
Journal of Dairy Science Vol. 58, No. 10
Stout, as well as the cooperation of the
dedicated staff of the Penn State Forage Testing Service. In addition, partial financial support for s u m m a r y w o r k by Agway, Inc., of
Syracuse, NY and the Animal F e e d Supplements group of Borden Chemical of Norfolk,
V A is appreciated greatly.
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Technique for rapid analyses of corn leaves for
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2 Becker, R. B., P. T. Dix Arnold, W. G. Kirk,
George K. Davis, and R. W. Kidder. 1953.
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Adams, and M. E. Ensminger. 1961. Influence of
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