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Unidentified Dietary Factors in Dairy Cattle Nutrition. II. Further Evidence of an Unidentified Factor(s) in Grain Needed to Balance Roughage for Milk Production1
UNIDENTIFIED DIETARY FACTORS IN DAIRY CATTLE NUTRITION. II. FURTHER EVIDENCE OF AN UNIDENTIFIED FACTOR(S) I N G R A I N N E E D E D TO B A L A N C E R O U G H A G E FOR MILK PRODUCTION 1 C. F. H U F F M A N , C. W. DUNCAN A~D C. 1~. CHANCE
Departments of Dairy and Agricultural Chemistry, Michigan Agricultural Experiment Station, East Lansing
I n the preceding p a p e r (12), digestion trial data were presented on f o u r milking cows receiving a ration of h a y alone and again a f t e r 15 lb. of the h a y h a d been replaced with 6 lb. of corn and 9 lb. of p e a n u t hulls. Three of f o u r cows increased in milk production against the tide of declining lactation on the hay-corn-peanut hulls ration, in spite of the f a c t t h a t there was a m a r k e d decrease in the consumption of T.D.N., calculated net-energy a n d starch equivalent and a significant increase in the a m o u n t of crude fiber in the d r y m a t t e r and in ballast. The work presented in this p a p e r is a continuation of the s t u d y on the effect of replacing p a r t of the h a y in an all-hay ration with grain and ballast in the f o r m of wheat straw, wood meal or p e a n u t hulls on milk production, with emphasis on the possibility of explaining the unidentified f a c t o r ( s ) in g r a i n on the basis of the calculated net-energy and starch equivalent concepts. EXPERIMENTAL
Seventeen Holstein cows were used in 25 trials to determine the effect on milk production when p a r t of the h a y was replaced with g r a i n plus either wheat straw, oakwood meal or p e a n u t hulls. T h e y had been depleted of their milk-stimulating f a c t o r ( s ) by the technique described previously (9, 10, 11). Six cows were used in seven trials with grain and wheat straw, three cows were used in three trials with wood meal and 11 cows were used in 15 trials with various amounts of corn a n d p e a n u t hulls. Some of the cows were used in two different trials at later stages of lactation. The cows varied f r o m 42 to 318 days in lactation at the s t a r t of the e x p e r i m e n t a l period and f r o m 0 to 146 days in gestation. Detailed data are presented f o r 10 representative cows, b u t complete d a t a are available u p o n request. The milk was handled as reported previously (12). The cows were weighed at the same hour every t h i r d day. The length of time t h a t the cows were on the basal ration varied f r o m 9 to 18 days and the s u p p l e m e n t e d periods r a n g e d f r o m 9 to 27 days. The description of the feeds, their chemical composition, coefficients of digestibility, digestible protein, T.D.N., calculated net-energy, starch equivalent a n d ballast values are shown in table 1. W h e n the cows were depleted on a m i x t u r e of alfalfa and brome hays, p a r t or all of the brome h a y was replaced with grain and ballast. The coefficients r e c o m m e n d e d by Morrison (20) were used for some of Received for publication July 19, 1951. Published with the approval of the Director of the l~[iehigan Agricultural Experiment Station as Journal article no. 1274. 41
TABLE I
1
2, 3, 6, 8
2, 3, 6, 8
4
5, 7
9--10
1-3
4
2
3
4
5
6
7
8
(~o.)
(no.)
I a, b
Used in trials
Feed
91.5
90.9
89.3
87.8
90.0
89.4
90.0
88.8
(%)
D.M.
88.7
77.9
69.9
66.4
75.8
67.0
77.3
67.2
(%)
CHO
0.61
5.56
5.66
5.93
4.53
5.91
4.72
6.59
(%)
Ash
1.6
5.1 8
12.6 72 6.8 51 14.2 72 8.6 51 14.0 70 12.1 66
(%)
Protein
29.5
34.6 70 39.4 64 38.3 71 43.0 64 38.7 69 39.6 64
Wood meal (oak) 0.60 59.2
46 30.3 53
27.6
32.5 43 36.9 59 28.7 43 32.8 59
(%)
N.F.E.
40.9 47
Hay
(%)
Crude fiber
W h e a t straw 2.35 37.9 41 52
2.47 31 2.15 39 2.32 34 1.09 39 ].55 40 1.60 29
(%)
Ether ext.
0.0
0.4
8.0
9.8
4.4
10.2
3.5
9.1
(%)
Dig. prof.
10.0
41.0
50.4
50.6
52.2
51.5
52.4
49.0
(%)
T.D.N.
- 111.5
19.1
38.3
38.8
41.7
40.3
41.9
35.7
(therms)
C.N.E.
- 24.3
19.5
32.8
34.6
33.2
34.9
31.0
30.1
(%)
S.E.
87.4
39.5
28.5
26.9
28.9
27.5
29.3
28.9
(%)
Ballast
The description, chemical composition, coefficients of digestibility, digestible protein, T.D.N., calculated net-energy (C.N.E.), starch equivalent (S.J~.) and undigested carbohydrates of feeds used in the various trials
~2
¢~
87.5
91.7
1
2, 3
1, 4
5-10
10
11
12
13
72.4
71.1
42.7
32.0
79.3
(%)
CHO
2.31
2.16
2.99
5.24
2.84
(%)
Ash
9.1 77 c 8.6 77 c
42.4 85c
46.4 84e
6.4 24
(%)
Protein
(%) 16.9 12 27.0 91 38.2 93 69.5 93 70.0 93
P e a n u t hulls 1.31 62.4 13 24 S o y b e a n oil m e a l 3.85 5.0 85 73 Corn g l u t e n m e a l 3.59 4.5 93 58 Corn (U. S. g r a d e 2) 4.66 2.6 90 57 3.78 2.4 90 57
N.F.E.
(%)
(%)
Crude fiber
Ether ext.
6.6
7.0
36.1
39.0
1.5
(%)
Dig. prot.
80.7
82.6
81.7
74.6
18.9
(%)
T.D.N.
82.0
83.9
83.0
74.7
- 52.6
(therms)
C.N.E.
80.7
82.6
81.7
74.6
- 16.8
(%)
S.E.
5.9
6.0
4.6
3.8
62.2
(%)
Ballast
a The first line in each t r i a l r e p r e s e n t s t h e chemical composition of t h e feed, whereas, t h e second line r e p r e s e n t s t h e coefficients of d i g e s t i b i l i t y o f t h e v a r i o u s f e e d f r a c t i o n s . All values were o b t a i n e d e x p e r i m e n t a l l y , except t h o s e lines m a r k e d w i t h a f o o t n o t e c which r e p r e s e n t calculated values. b D e s c r i p t i o n of f e e d s u s e d : 1. A l f a l f a , 1st cut. 2. B r o m e - t i m o t h y , 1st cut. 3. A l f a l f a , 2nd cut. 4. B r o m e - t i m o t h y - a l f a l f a ~ 1st cut. 5. A l f a l f a , 2 n d cut. 6. A l f a l f a - t i m o t h y - b r o m e , 1st cut.
87.1
88.0
89.8
(%)
5-10
(no.)
(no.)
D.lVL
9
U s e d in trials
Feed
1--Concluded
TABLE
.~
44
C. F . H U F F M A N
ET AL
the feeds, but actual coefficients of digestibility were used f o r the m a j o r i t y of the feed stuffs. The requirements suggested b y the National Research Council (15) were used for T.D.N. and the u p p e r limits suggested b y Morrison (20) were used for calculating net-energy. Moore's method (19) also was used to determine the calculated net-energy values. The wood meal was made by grinding oakwood shavings. The T.D.N. content of the meal was assumed to be 10 per cent on the basis of the work of Kirsch and J a n t z o n (13), who determined the T.D.N. content of birch and pine sawdust silage. RESULTS
The p e r t i n e n t data showing the representative results obtained b y replacing p a r t of the h a y in an all-hay ration with an equivalent a m o u n t of g r a i n and either wheat straw, oakwood meal or p e a n u t hulls are presented in table 2. The data given f o r the three cows are representative of the seven trials in t h a t they include the m i n i m u m and m a x i m u m increases in milk yield when straw and grain were fed. The cow used in trial 1 produced 2.2 lb. more of 4 per cent F.C.M. per day on the h a y - s t r a w - g r a i n ration with the same a m o u n t of T.D.N., calculated netenergy and ballast, t h a n t h a t p r o d u c e d on h a y alone. W h e n corn gluten meal a n d s t r a w replaced p a r t of the h a y in trials two a n d three, the amounts of F.C.M. increased slightly, although there was decline in T.D.N. and calculated net-energy a n d an increase in the ballast content. The n u m b e r of pounds of F.C.M. per 100 lb. of T.D.N. increased in all seven trials following the change f r o m h a y alone to the hay-straw-grain ration. W h e n 10 lb. of h a y were replaced with 5 lb. of a grain m i x t u r e and 5.5 lb. of wood meal, in trial 4, the a m o u n t of milk increased on the same a m o u n t of T.D.N., less calculated net-energy, more ballast and the same amount of starch equivalent a n d crude fiber in the d r y matter. Milk production increased still f u r t h e r , however, when the wood meal was removed f r o m the ration. This increase was associated with an increase in calculated net-energy a n d starch equivalent intake and a decrease in the per cent of crude fiber on the d r y basis and in ballast. The results presented for this cow are typical of those obtained f r o m the other two cows. The n u m b e r of pounds of F.C.M. increased in all three trials on the hay-grainwood meal ration, but an additional increase was obtained when the wood meal was w i t h d r a w n f r o m the ration. P e a n u t hulls are an excellent source of ballast because of their high crude fiber a n d low T.D.N. content, but wheat straw is not a satisfactory source of ballast, because the s p r e a d between some of the hays and wheat s t r a w is not wide enough to accentuate the effect of ballast. Also, the per cent of crude fiber in some of the hays a n d wheat straws does not v a r y enough to p r o p e r l y evaluate the role of the level of crude fiber in the ration. Corn a n d p e a n u t hulls replaced p a r t of the basal h a y in 15 trials. I n trials 5 to 8, inclusive, 15 lb. of h a y were replaced by 6.5 lb. of corn and 8 lb. of peanut hulls. All of the cows showed an increase in the production of F.C.M. on this ration c o m p a r e d to the periods on h a y alone. The increases in milk production occurred even though the amounts of calculated net-energy and starch equivalent
12 12 15 12 12 18 12 12 12 9 12 15 12 12 27
5
1319 1305 1257 1130 1112 1082 1097 1100 1092 1093 1036 1048 1096 1134 1146
937 937 913
3.5 3.3 3.2 3.6 3.3 3.1 3.4 3.1 3.1 3.1 3.6 3.6 3.3 3.5 3.3
17.6 20.1 20.4 19.6 19.7 19.7 15.0 18.3 22.9 28.3 11.7 12.2 17.6 19.8 20.1
17.1 19.3 20.1
6.9 9.1 8.3 9.5 25.0 25.2
(tb.)
F.C.M. yield
40.0 25.0 25.0 34.0g 19.0 19.0 35.8 20.3 34.0g ]9.0 34.0 26.5 38.0 30.5 23.0
35.0 25.0 25.0
35.8 10.0 29.5b 10.0: 39.7 e 10.0 c
(Zb.)
ttay
............... 6.5 8.0 6.5 ......... ............... 6.5 8.0 6.5 ......... ............... 6.5 8.0 ............... 6.5 8.0 ......... 3i0 4.5 ......... 310 4.5 6.0 9.0
Peanut hulls 20.3 19.4 17.6 17.1 16.3 14.7 18.2 17.1 17.0 16.4 17.1 16.6 19.2 18.6 18.1
18.3 18.5 18.0
5~0f 5.0:
Wood meal ......... 5.5 .........
(lb.) 17.5 17.6 15.5 14.9 20.7 15.0
(Zb.)
Ballast
T.D.l~. rec.
Wheat straw ............... 6.0a 17.3 ......... 4"i0d 15.7 ............... 4.0 d 16.0
(Zb.)
Corn
Feed1 (b)
15.5 10.8 15.0 12.9 7.7 12.4 13.9 9.0 13.0 8.5 13.0 10.3 14.6 11.8 9.0
14.6 9.3 15.4
12.8 12.6 12.4 10.4 16.8 10.4
15.5 15.0 15.0 12.9 12.4 12.4 13.9 13.2 13.0 12.7 13.0 12.6 14.6 14.1 13.7
......... ......... .........
......... ......... ......... ......... ......... .........
(therms)
(a)
C.N.E. received~
13.9 12.5 13.8 11.5 10.0 11.5 12.4 10.9 11.7 10.5 11.2 10.3 12.5 11.6 10.8
11.7 11.9 13.2
10.8 12.0 9.5 9.7 12.7 9.8
(Zb.)
S.E.
31.4 34.6 25.6 33.0 38.3 26.8 31.4 35.1 31.4 35.2 34.0 36.0 33.9 35.8 37.6
36.4 35.4 30.1
36.6 32.0 37.7 33.0 38.8 33.0
(%)
in D.M.
Crude fiber
40.6 43.8 33.5 41.4 46.8 33.4 40.6 44.2 40.6 44.3 41.0 43.6 41.0 43.3 45.6
38.2 42.1 31.9
43.0 44.0 39.2 44.0 39.0 44.2
(%)
Ballast
85 104 116 115 121 134 93 107 135 173 68 73 92 106 111
93 104 112
39 52 54 64 121 168
(Zb.)
T.D.N.
F.C.M./ 100 lb.
1 Components of the r a t i o n : ( a ) . 1 lb. of soybean oil meal and 5 lb. of corn. ( b ) . 19.5 lb. h a y no. 2 and 10 lb. of hay no. 3. (c). H a y no. 3. ( d ) . Corn gluten meat. ( e ) . 29.7 lb. hay no. 2 and 10 lb. hay no. 3. ( f ) . 4 lb. o f corn and 1 lb. of corn gluten meal. ( g ) . 10 lb. of h a y no. 2 and 23 lb. of hay no. 3. ( a ) C.N.E. values determined b y l~Ioore's method, ( b ) C.N.E. values when p e a n u t hulls equal zero.
10
9
8
7
6
15 15 15
2.9 3.1 3.0
4.0 4.0 3.4 3.4 3.3 3.3
1203 942 934 1002 1045
1175
18 15 15 12 9 12
(%)
(Zb.)
(d.)
Fat test
Body wt.
Exptl. period
4
3
2
1
Trial no.
TABLE 2
2'he effect on milk yield when part of the T.D.N. in hay was replaced with an equivalent amount of grain and ballast
o
Q
46
C. F. I ~ I U F F ~ A N E T A L
were reduced and the p e r cent of crude fiber in the d r y m a t t e r and ballast were increased. The cow used in trial 5 increased 2.5 lb. of F.C.M. per d a y on the h a y - g r a i n - p e a n u t hulls ration over that produced on the all-hay ration and milk p r o d u c t i o n increased an additional 0.3 lb. when the p e a n u t hulls were removed, whereas, the F.C.M. produced b y the cow used in trial 6 was u n c h a n g e d on the same ration. There was no significant difference between the calculated netenergy and starch vMues a f t e r the 8 lb. of p e a n u t hulls h a d been discontinued a n d the values on the all-hay ration, but an increase was obtained in the n u m b e r of pounds of F.C.M. p e r 100 lb. of T.D.N. consumed. I n trials 9 and 10, 3 lb. of corn a n d 4.5 lb. of p e a n u t hulls replaced about 7.5 lb. of hay. This ration produced an increase in F.C.M. in all of the trials, although the T.D.N., calculated net-energy and starch equivalent vah:es were reduced and the amount of ballast and crude fiber in the d r y m a t t e r were increased. The supplements were doubled in the last p a r t of trial 10 and the basal h a y was decreased by 7.5 lb. per day for a 27-day period. This change resulted in a f u r t h e r increase of 0.3 lb. of F.C.M. per d a y a n d an additional drop in the T.D.N., calculated net-energy a n d starch equivalent intakes and a m a r k e d increase in the crude fiber and ballast intakes. The results presented for the six cows are typical of the results obtained from the other nine trials. I n all trials, the a m o u n t of 4 per cent F.C.M. increased against the tide of a d v a n c i n g lactation when p a r t of the basal h a y was replaced with corn a n d wheat straw, wood meal or p e a n u t hulls, even when a zero value was used for the nete n e r g y content of the p e a n u t hulls. The efficiency of caloric conversion of T.D.N. to milk is strikingly illustrated in table 2 when the n u m b e r of pounds of F.C.M. p e r 100 lb. of T.D.N. consumed is examined. The p e r cent of f a t in the milk remained unchanged a f t e r the ration was changed f r o m h a y alone to the hay-grain-wheat s t r a w ration and to the hay-grainwood meal ration, but when corn and p e a n u t hulls replaced p a r t of the hay, there was a decline in the f a t content of the milk in six trials, no change in seven trials a n d an increase in two trials. The differences in body weights recorded in table 2 for the cows on the various rations do not a p p e a r to be significant. DISCUSSION
The seven trials with wheat straw indicate t h a t the unidentified f a c t o r ( s ) present in grain improves the balance of the ration. These findings are in agreem e n t with the results reported by B u r r o u g h s et al. (2), who f o u n d t h a t corncobs f e d with good hays and grain were alraost as productive per pound of T.D.N. for body gains in steers as that in corn grain. The increased ballast intake when oakwood meal was fed failed to suppress the milk p r o d u c i n g f a c t o r ( s ) in the grain, as was shown b y an increase in the amount of F.C.M. in each trial. The wood meal exerted some inhibitory effect, however, because milk production increased in all trials following w i t h d r a w a l of the meal f r o m the ration. Although the a m o u n t of ballast decreased f r o m 42 to 32 per cent f r o m the periods on the hay, g r a i n and wood meal to the hay-grain ration, it a p p e a r s unlikely t h a t ballast
UNIDENTIFIED
D I E T A R Y F A C T O R . II
47
was a f a c t o r in view of the higher ballast values in all of the trials with p e a n u t hulls. The increased production of F.C.lV[. can not be explained on the basis of calculated net-energy, even when a zero value is used f o r p e a n u t hulls, since the a m o u n t of F.C.M. increased in all trials which contained the same or less calculated net-energy. These results are not in agreement with Moore (18), S a a r i n e n et al. (22) or Shaw et al. (23), who have postulated that the unidentified lactation factor (s) in grain is due to an increase in calculated net-energy, b u t they do confirm previous findings (9, 10, 11, 12), which indicated t h a t concentrates s u p p l y an unidentified f a c t o r ( s ) needed to balance the n u t r i e n t s in some hays f o r efficient milk production. These results also are in agreement with those of Smith et al. (24), who showed t h a t the r e p l a c e m e n t of 13 to 25 per cent of the T.D.N. in an all-alfalfa h a y ration with various con~eentrates, on an equal T.D.N. basis, resulted in an increase in m i l k p r o d u c t i o n . Davis and K e m m e r e r (5) f o u n d t h a t milk p r o d u c t i o n was increased When dried g r a p e f r u i t peel was added to an a l f a l f a ration. Loosli (14) r e p o r t e d t h a t an increase in F.C.M. occurred when h a y was replaced with an equal amount of T.D.N. in either corn distillers grains or corn distillers solubles. The increases obtained in F.C.M. when the cows were changed f r o m an all-hay ration to a hay-corn-peanut hulls ration were assocmted with an increase in the per cent crude fiber in the d r y m a t t e r and in the p e r cent of ballast. These results are in agreement with those of Graves et al. (8), who showed t h a t high levels of crude fiber do not depress milk p r o d u c t i o n when the total ration is reasonably well-balanced. The work of Graves et al. also indicated t h a t some h a y s m a y contain a sufficient a m o u n t of the unidentified lactation f a c t o r ( s ) f o r efficient milk production when fed as the only feed. The results, however, are not in accord with N o r d f e l d t et al. (21) who r e p o r t e d an o p t i m u m crude fiber content of 16 per cent on the d r y basis f o r liberally milking cows, or with Axelsson (1) who stated t h a t the o p t i m u m crude fiber content of the d r y m a t t e r of the ration f o r cattle was 18 to 23 per cent. The highest values (about 38 p e r cent on the d r y basis) observed in this work m a y have been close to the m a x i m u m u n d e r the conditions of this experiment, since one cow went off-feed when 22.5 lb. of h a y were replaced b y 9 lb. of corn a n d 13.5 lb. of p e a n u t hulls. The T.D.N. supplied b y p e a n u t hulls m a y be as poorly balanced as t h a t in the h a y which was replaced. The efficiency of the conversion of T.D.N. to milk is a better index of the balance of a ration t h a n either calculated net~energy, starch equivalent or a n y system of feed evaluation based on the s u m m a t i o n of empirical values assigned to individual feed stuffs when t h e y are fed in combination. The increase in milk production which resulted when p a r t of the h a y was replaced with g r a i n also m a y a p p l y to gains in body weight b y beef cattle. Forbes et al. (7) studied the metabolism of steers fed alfalfa h a y alone, corn alone a n d a m i x t u r e of h a y and corn a n d concluded t h a t the net-energy (actual, not calculated) of corn in the mixed ration was g r e a t e r t h a n when the components were fed alone. The results of B u r r o u g h s et al. (2) also showed t h a t the T.D.N. of corncobs exerted about the same production in steers as the T.D.N. in corn. The unidentified lactation factor (s) present in concentrates m a y be r e q u i r e d
48
C. F. HUFF1VI/kl~I ET AT,
by the rumen bacteria to improve the balance of the ration. Burroughs et al. (3) found that the digestibility of the dry matter of corncobs was depressed by the addition of starch, but when the same amount of starch was added to alfalfa hay, the depression in the digestibility of dry matter did not occur. These workers (4) showed later that alfalfa hay ash contained essential nutrients for the growth of rumen microorganisms. It is difficult to determine whether the factor(s) is needed by the rumen microflora or by the host or by both. The results reported herein support the modern concept of a balanced ration which was first expressed by Forbes (6) and officially defined by Mitchell (16) in 1935. They also are in agreement with Maynard (17) who stated: " S i n c e individual feeds are seldom if ever balanced rations, it is evident that the summation of the net-energy values of the feeds making up a ration is not an accurate measure of the energy value of the ration as a whole and that the values for certain individual feeds may be highly misleading as to their effects as constituents of completely balanced rations. Herein lies another practical limitation of the netenergy system." These results suggest that an objective in forage crop research should be to produce hays high in milk-stimulating factors in order to reduce the amount of grain-feeding. SUmmARY AND CONCLUSIONS Seventeen depleted cows were used in 25 trials to determine the effect of replacing p ar t of the hay in an all-hay ration with grain and either wheat straw, oakwood meal or peanut hulls. In all but one trial, the replacement of part of the hay with these feed stuffs resulted in an increase in 4 per cent F.C.M., even though the intakes of T.D.N., calculated net-energy and starch equivalent decreased and the crude fiber in the dry matter and ballast increased. Crude fiber values up to 38 per cent of the dry matter did not depress milk production when the cows were changed from hay alone to a ration of hay, corn and peanut hulls. The results of this investigation indicate that calculated net-energy and starch equivalent values of individual feeds are not additive, but that they support the modern concept of a balanced ration. F u r t h e r evidence is presented to show that the unidentified lactation factor (s) in grain is needed to improve the balance of roughages. i~ EFERENCES
(1) AXELSSON, J. Die wissenschaftliche Grundlage des St~rkewertes. Biedermanns Zentr. B. Tierern~hr., 11: 176-205. 1939. (2) BURROUGHS, W., GERLAUGtt, P., SCltALK, A. F., SILVER, ~E. A., AND KUI~KLE, L . E . The Nutritive Value of Corncobs in Beef Cattle Rations. J. Animal Sei., 4: 373-386. 1945. (3) BURROUGHS, W., GERLAUGtt, :P., :EDGINGTON, B. H., AND BETHKE, R . M . The Influence of Corn Starch upon Roughage Digestion in Cattle. J. Animal Sci., 8: 271-278. 1949. (4) BURROUGHS, W., GERLAUGH, P., AND BETHKE, R. i~. The Influence of A l f a l f a Hay and
UNIDENTIFIED DIETARY FACTOR. II
(5) (6)
(7)
(8) (9)
(10)
(11)
(12)
(13)
(14) (15)
(16)
(17) (18)
(19)
(20) (21)
(22)
49
Fractions of A l f a l f a I t a y upon the Digestion of Ground Corncobs. J. Animal Sci., 9: 207-213. 1950. DAvis, R. N., AND KE~/[MERER,A . R . Lactation Factors for Dairy Cows in Dried Grapef r u i t Peel. J . Dairy Sei., 31: 973-975. 1948. FORBES, E . B . Net Energy of Completely Ba)~aneed N u t r i m e n t as a Measure of Nutritive Value of Rations and of Nutritive Requirement of Animals. Proc. Am. Soc. Animal Prod., 1932: 32-40. 1933. FORBES, E. B., BRAI~AN, W. W., KRISS, M., SWIFT, R. W., 1VIIbLER, R. C., FRENCH, R. B., LETONO~'r, T. V., AND SHARPLESS, G . R . The Metabolizable Energy and Net Energy Yalues of Corn Meal when Fed Exclusively and in Combination with A l f a l f a Hay. J . Agr. Research, 43: 1015-1026. 1931. GRAVES, R. R., DAWSON, J . R., KOPLAND, D. V., WATT, A. L., AND VAN HORN, A. G. Feeding Dairy Cows on A l f a l f a Hay Alone. U . S . D . A . Tech. Bull. 610. 1938. HUFF~AN, C. F., AND DUNCAN, C.W. The Nutritive Value of A l f a l f a Hay. I. Cystine as a Supplement to an All-alfalfa Hay Ration for Milk Production. J. Dairy Sci., 25: 507-515. 1942. HUEF~AN, C. F., AND DUNCAN, C . W . The Nutritive Value of A l f a l f a Hay. II. Starch and Glucose as Supplements to an All-alfalfa Hay Ration. J . Dairy Sci., 27: 821-833. 1944. HUFF~AN, C. F., AND DUNCAS, C . W . The Nutritive Value of A l f a l f a ttay. I I I . Corn as a Supplement to an All-alfalfa Hay Ration for Milk Production. J. Dairy Sci., 32: 465-474. 1949. HUFF~AN, C. F., AND DUNCAN, C . W . Unidentified Dietary Factors in Dairy Cattle Nutrition. I. Digestibility of P e a n u t Hulls and their Use in ~' B a l l a s t ' ' Studies with Milking Cows Depleted on H a y Alone. 5. Dairy Sci., 35: 29-40. 1952. KIRSCH, W., AND JANTZON, H. Untersuchungen tiber den Einfluss ether Yergarung yon Buchenholz- und Fichtenholzsagemehlen u n t c r Umsatz eines Molke-PhosphorsKuremi~ches sowie von Zucker a u f die Verdaulichkeit der N~hrstoffe durch den WiederkKuer. Z. Tierernfihr. Futtermittelk., 5: 244--259. 1941. Loose1, J . K . Influence of Distillers' Feeds on Milk Production. Proc. Sixth Distillers' Feed Conference, Cincinnati, Ohio, 30-36. 195l. LOOSLI, ,]-. K., HUFFI~IAN, C. F., PETERSEN, W. E.~ AND PHILLIPS, e . H. Recommended N u t r i e n t Allowances for Domestic Animals. I I I . Recommended N u t r i e n t Allowances for Dairy Cattle. National Research Council. 1950. I~[ITCHELL, 1=t. H. Some Problems in the Study of Energy Metabolism. Report of the Conference on Energy Metabolism. The Committee on Animal Nutrition, N a t i o n a l Research Council, 66-93. 1935. MAYNARD, L . A . Animal Nutrition. 2rid ed. McGraw-Hill Book Co., Inc., New York. 1947. p. 301. MOORE, L. A. A Relationship between Total Digestible N u t r i e n t s (T.D.N.) and Estimated Net Energy Values (E.N.E.) and a Possible Method for Estimation of Net Energy Values with Producing Dairy Cows. J. Animal Sci., 9: 663. 1950. MOORE, L. A. _A. Relationship between Total Digestible N u t r i e n t s (T.D.N.) and Estimated Net Energy Values (E.N.E.) and a Possible Method of E s t i m a t i n g Net Energy Values with Producing Dairy Cows. U. S, D. A., Bur. Dairy Ind., B D I - I n f - l l 4 . Nov., 1950. MORRISON, F . B . Feeds and Feeding. 21st ed. The lt{orrison Publishing Co., Ithaca, N . Y . 1948. NORDFELDT, S., IWANAGA, I., MORITA, K., HENKE, a . A., AND TO1V~, A. I~. S. Influence of Crude Fiber in the Ration on Efficiency of Feed Utilization by Dairy Cows. J. Dairy Sci., 33: 473-485. 1950. SAARINEN, P., SA~I, M. A., SHAW, J: C., AND MOORE, L . A . The Adequacy of an Alla l f a l f a H a y Ration for Milk Secretion. J . Dairy Sci., 34: 287-294. 1951.
50
C. F. tIUFFMAN ET AL
(23) SHAW, J. C., IRWIN, H. M., SAARINEN, P., SAMI, M. A., CAIRNS, G. M., A N D MOORE,L. A. The :Effect upon Milk Production of A l f a l f a Hay when Fed Alone and with Concentrates, ft. Animal Sci., 9: 675-676. 1950. (24) S~IT~, ¥ . 1% JONES, I. ]~., AND HAAG, J. t~. A l f a l f a with and without Concentrates for Milk Production. J. Dairy Sci., 28: 343-354. 1945.
Departments of Dairy and Agricultural Chemistry, Michigan Agricultural Experiment Station, East Lansing
I n the preceding p a p e r (12), digestion trial data were presented on f o u r milking cows receiving a ration of h a y alone and again a f t e r 15 lb. of the h a y h a d been replaced with 6 lb. of corn and 9 lb. of p e a n u t hulls. Three of f o u r cows increased in milk production against the tide of declining lactation on the hay-corn-peanut hulls ration, in spite of the f a c t t h a t there was a m a r k e d decrease in the consumption of T.D.N., calculated net-energy a n d starch equivalent and a significant increase in the a m o u n t of crude fiber in the d r y m a t t e r and in ballast. The work presented in this p a p e r is a continuation of the s t u d y on the effect of replacing p a r t of the h a y in an all-hay ration with grain and ballast in the f o r m of wheat straw, wood meal or p e a n u t hulls on milk production, with emphasis on the possibility of explaining the unidentified f a c t o r ( s ) in g r a i n on the basis of the calculated net-energy and starch equivalent concepts. EXPERIMENTAL
Seventeen Holstein cows were used in 25 trials to determine the effect on milk production when p a r t of the h a y was replaced with g r a i n plus either wheat straw, oakwood meal or p e a n u t hulls. T h e y had been depleted of their milk-stimulating f a c t o r ( s ) by the technique described previously (9, 10, 11). Six cows were used in seven trials with grain and wheat straw, three cows were used in three trials with wood meal and 11 cows were used in 15 trials with various amounts of corn a n d p e a n u t hulls. Some of the cows were used in two different trials at later stages of lactation. The cows varied f r o m 42 to 318 days in lactation at the s t a r t of the e x p e r i m e n t a l period and f r o m 0 to 146 days in gestation. Detailed data are presented f o r 10 representative cows, b u t complete d a t a are available u p o n request. The milk was handled as reported previously (12). The cows were weighed at the same hour every t h i r d day. The length of time t h a t the cows were on the basal ration varied f r o m 9 to 18 days and the s u p p l e m e n t e d periods r a n g e d f r o m 9 to 27 days. The description of the feeds, their chemical composition, coefficients of digestibility, digestible protein, T.D.N., calculated net-energy, starch equivalent a n d ballast values are shown in table 1. W h e n the cows were depleted on a m i x t u r e of alfalfa and brome hays, p a r t or all of the brome h a y was replaced with grain and ballast. The coefficients r e c o m m e n d e d by Morrison (20) were used for some of Received for publication July 19, 1951. Published with the approval of the Director of the l~[iehigan Agricultural Experiment Station as Journal article no. 1274. 41
TABLE I
1
2, 3, 6, 8
2, 3, 6, 8
4
5, 7
9--10
1-3
4
2
3
4
5
6
7
8
(~o.)
(no.)
I a, b
Used in trials
Feed
91.5
90.9
89.3
87.8
90.0
89.4
90.0
88.8
(%)
D.M.
88.7
77.9
69.9
66.4
75.8
67.0
77.3
67.2
(%)
CHO
0.61
5.56
5.66
5.93
4.53
5.91
4.72
6.59
(%)
Ash
1.6
5.1 8
12.6 72 6.8 51 14.2 72 8.6 51 14.0 70 12.1 66
(%)
Protein
29.5
34.6 70 39.4 64 38.3 71 43.0 64 38.7 69 39.6 64
Wood meal (oak) 0.60 59.2
46 30.3 53
27.6
32.5 43 36.9 59 28.7 43 32.8 59
(%)
N.F.E.
40.9 47
Hay
(%)
Crude fiber
W h e a t straw 2.35 37.9 41 52
2.47 31 2.15 39 2.32 34 1.09 39 ].55 40 1.60 29
(%)
Ether ext.
0.0
0.4
8.0
9.8
4.4
10.2
3.5
9.1
(%)
Dig. prof.
10.0
41.0
50.4
50.6
52.2
51.5
52.4
49.0
(%)
T.D.N.
- 111.5
19.1
38.3
38.8
41.7
40.3
41.9
35.7
(therms)
C.N.E.
- 24.3
19.5
32.8
34.6
33.2
34.9
31.0
30.1
(%)
S.E.
87.4
39.5
28.5
26.9
28.9
27.5
29.3
28.9
(%)
Ballast
The description, chemical composition, coefficients of digestibility, digestible protein, T.D.N., calculated net-energy (C.N.E.), starch equivalent (S.J~.) and undigested carbohydrates of feeds used in the various trials
~2
¢~
87.5
91.7
1
2, 3
1, 4
5-10
10
11
12
13
72.4
71.1
42.7
32.0
79.3
(%)
CHO
2.31
2.16
2.99
5.24
2.84
(%)
Ash
9.1 77 c 8.6 77 c
42.4 85c
46.4 84e
6.4 24
(%)
Protein
(%) 16.9 12 27.0 91 38.2 93 69.5 93 70.0 93
P e a n u t hulls 1.31 62.4 13 24 S o y b e a n oil m e a l 3.85 5.0 85 73 Corn g l u t e n m e a l 3.59 4.5 93 58 Corn (U. S. g r a d e 2) 4.66 2.6 90 57 3.78 2.4 90 57
N.F.E.
(%)
(%)
Crude fiber
Ether ext.
6.6
7.0
36.1
39.0
1.5
(%)
Dig. prot.
80.7
82.6
81.7
74.6
18.9
(%)
T.D.N.
82.0
83.9
83.0
74.7
- 52.6
(therms)
C.N.E.
80.7
82.6
81.7
74.6
- 16.8
(%)
S.E.
5.9
6.0
4.6
3.8
62.2
(%)
Ballast
a The first line in each t r i a l r e p r e s e n t s t h e chemical composition of t h e feed, whereas, t h e second line r e p r e s e n t s t h e coefficients of d i g e s t i b i l i t y o f t h e v a r i o u s f e e d f r a c t i o n s . All values were o b t a i n e d e x p e r i m e n t a l l y , except t h o s e lines m a r k e d w i t h a f o o t n o t e c which r e p r e s e n t calculated values. b D e s c r i p t i o n of f e e d s u s e d : 1. A l f a l f a , 1st cut. 2. B r o m e - t i m o t h y , 1st cut. 3. A l f a l f a , 2nd cut. 4. B r o m e - t i m o t h y - a l f a l f a ~ 1st cut. 5. A l f a l f a , 2 n d cut. 6. A l f a l f a - t i m o t h y - b r o m e , 1st cut.
87.1
88.0
89.8
(%)
5-10
(no.)
(no.)
D.lVL
9
U s e d in trials
Feed
1--Concluded
TABLE
.~
44
C. F . H U F F M A N
ET AL
the feeds, but actual coefficients of digestibility were used f o r the m a j o r i t y of the feed stuffs. The requirements suggested b y the National Research Council (15) were used for T.D.N. and the u p p e r limits suggested b y Morrison (20) were used for calculating net-energy. Moore's method (19) also was used to determine the calculated net-energy values. The wood meal was made by grinding oakwood shavings. The T.D.N. content of the meal was assumed to be 10 per cent on the basis of the work of Kirsch and J a n t z o n (13), who determined the T.D.N. content of birch and pine sawdust silage. RESULTS
The p e r t i n e n t data showing the representative results obtained b y replacing p a r t of the h a y in an all-hay ration with an equivalent a m o u n t of g r a i n and either wheat straw, oakwood meal or p e a n u t hulls are presented in table 2. The data given f o r the three cows are representative of the seven trials in t h a t they include the m i n i m u m and m a x i m u m increases in milk yield when straw and grain were fed. The cow used in trial 1 produced 2.2 lb. more of 4 per cent F.C.M. per day on the h a y - s t r a w - g r a i n ration with the same a m o u n t of T.D.N., calculated netenergy and ballast, t h a n t h a t p r o d u c e d on h a y alone. W h e n corn gluten meal a n d s t r a w replaced p a r t of the h a y in trials two a n d three, the amounts of F.C.M. increased slightly, although there was decline in T.D.N. and calculated net-energy a n d an increase in the ballast content. The n u m b e r of pounds of F.C.M. per 100 lb. of T.D.N. increased in all seven trials following the change f r o m h a y alone to the hay-straw-grain ration. W h e n 10 lb. of h a y were replaced with 5 lb. of a grain m i x t u r e and 5.5 lb. of wood meal, in trial 4, the a m o u n t of milk increased on the same a m o u n t of T.D.N., less calculated net-energy, more ballast and the same amount of starch equivalent a n d crude fiber in the d r y matter. Milk production increased still f u r t h e r , however, when the wood meal was removed f r o m the ration. This increase was associated with an increase in calculated net-energy a n d starch equivalent intake and a decrease in the per cent of crude fiber on the d r y basis and in ballast. The results presented for this cow are typical of those obtained f r o m the other two cows. The n u m b e r of pounds of F.C.M. increased in all three trials on the hay-grainwood meal ration, but an additional increase was obtained when the wood meal was w i t h d r a w n f r o m the ration. P e a n u t hulls are an excellent source of ballast because of their high crude fiber a n d low T.D.N. content, but wheat straw is not a satisfactory source of ballast, because the s p r e a d between some of the hays and wheat s t r a w is not wide enough to accentuate the effect of ballast. Also, the per cent of crude fiber in some of the hays a n d wheat straws does not v a r y enough to p r o p e r l y evaluate the role of the level of crude fiber in the ration. Corn a n d p e a n u t hulls replaced p a r t of the basal h a y in 15 trials. I n trials 5 to 8, inclusive, 15 lb. of h a y were replaced by 6.5 lb. of corn and 8 lb. of peanut hulls. All of the cows showed an increase in the production of F.C.M. on this ration c o m p a r e d to the periods on h a y alone. The increases in milk production occurred even though the amounts of calculated net-energy and starch equivalent
12 12 15 12 12 18 12 12 12 9 12 15 12 12 27
5
1319 1305 1257 1130 1112 1082 1097 1100 1092 1093 1036 1048 1096 1134 1146
937 937 913
3.5 3.3 3.2 3.6 3.3 3.1 3.4 3.1 3.1 3.1 3.6 3.6 3.3 3.5 3.3
17.6 20.1 20.4 19.6 19.7 19.7 15.0 18.3 22.9 28.3 11.7 12.2 17.6 19.8 20.1
17.1 19.3 20.1
6.9 9.1 8.3 9.5 25.0 25.2
(tb.)
F.C.M. yield
40.0 25.0 25.0 34.0g 19.0 19.0 35.8 20.3 34.0g ]9.0 34.0 26.5 38.0 30.5 23.0
35.0 25.0 25.0
35.8 10.0 29.5b 10.0: 39.7 e 10.0 c
(Zb.)
ttay
............... 6.5 8.0 6.5 ......... ............... 6.5 8.0 6.5 ......... ............... 6.5 8.0 ............... 6.5 8.0 ......... 3i0 4.5 ......... 310 4.5 6.0 9.0
Peanut hulls 20.3 19.4 17.6 17.1 16.3 14.7 18.2 17.1 17.0 16.4 17.1 16.6 19.2 18.6 18.1
18.3 18.5 18.0
5~0f 5.0:
Wood meal ......... 5.5 .........
(lb.) 17.5 17.6 15.5 14.9 20.7 15.0
(Zb.)
Ballast
T.D.l~. rec.
Wheat straw ............... 6.0a 17.3 ......... 4"i0d 15.7 ............... 4.0 d 16.0
(Zb.)
Corn
Feed1 (b)
15.5 10.8 15.0 12.9 7.7 12.4 13.9 9.0 13.0 8.5 13.0 10.3 14.6 11.8 9.0
14.6 9.3 15.4
12.8 12.6 12.4 10.4 16.8 10.4
15.5 15.0 15.0 12.9 12.4 12.4 13.9 13.2 13.0 12.7 13.0 12.6 14.6 14.1 13.7
......... ......... .........
......... ......... ......... ......... ......... .........
(therms)
(a)
C.N.E. received~
13.9 12.5 13.8 11.5 10.0 11.5 12.4 10.9 11.7 10.5 11.2 10.3 12.5 11.6 10.8
11.7 11.9 13.2
10.8 12.0 9.5 9.7 12.7 9.8
(Zb.)
S.E.
31.4 34.6 25.6 33.0 38.3 26.8 31.4 35.1 31.4 35.2 34.0 36.0 33.9 35.8 37.6
36.4 35.4 30.1
36.6 32.0 37.7 33.0 38.8 33.0
(%)
in D.M.
Crude fiber
40.6 43.8 33.5 41.4 46.8 33.4 40.6 44.2 40.6 44.3 41.0 43.6 41.0 43.3 45.6
38.2 42.1 31.9
43.0 44.0 39.2 44.0 39.0 44.2
(%)
Ballast
85 104 116 115 121 134 93 107 135 173 68 73 92 106 111
93 104 112
39 52 54 64 121 168
(Zb.)
T.D.N.
F.C.M./ 100 lb.
1 Components of the r a t i o n : ( a ) . 1 lb. of soybean oil meal and 5 lb. of corn. ( b ) . 19.5 lb. h a y no. 2 and 10 lb. of hay no. 3. (c). H a y no. 3. ( d ) . Corn gluten meat. ( e ) . 29.7 lb. hay no. 2 and 10 lb. hay no. 3. ( f ) . 4 lb. o f corn and 1 lb. of corn gluten meal. ( g ) . 10 lb. of h a y no. 2 and 23 lb. of hay no. 3. ( a ) C.N.E. values determined b y l~Ioore's method, ( b ) C.N.E. values when p e a n u t hulls equal zero.
10
9
8
7
6
15 15 15
2.9 3.1 3.0
4.0 4.0 3.4 3.4 3.3 3.3
1203 942 934 1002 1045
1175
18 15 15 12 9 12
(%)
(Zb.)
(d.)
Fat test
Body wt.
Exptl. period
4
3
2
1
Trial no.
TABLE 2
2'he effect on milk yield when part of the T.D.N. in hay was replaced with an equivalent amount of grain and ballast
o
Q
46
C. F. I ~ I U F F ~ A N E T A L
were reduced and the p e r cent of crude fiber in the d r y m a t t e r and ballast were increased. The cow used in trial 5 increased 2.5 lb. of F.C.M. per d a y on the h a y - g r a i n - p e a n u t hulls ration over that produced on the all-hay ration and milk p r o d u c t i o n increased an additional 0.3 lb. when the p e a n u t hulls were removed, whereas, the F.C.M. produced b y the cow used in trial 6 was u n c h a n g e d on the same ration. There was no significant difference between the calculated netenergy and starch vMues a f t e r the 8 lb. of p e a n u t hulls h a d been discontinued a n d the values on the all-hay ration, but an increase was obtained in the n u m b e r of pounds of F.C.M. p e r 100 lb. of T.D.N. consumed. I n trials 9 and 10, 3 lb. of corn a n d 4.5 lb. of p e a n u t hulls replaced about 7.5 lb. of hay. This ration produced an increase in F.C.M. in all of the trials, although the T.D.N., calculated net-energy and starch equivalent vah:es were reduced and the amount of ballast and crude fiber in the d r y m a t t e r were increased. The supplements were doubled in the last p a r t of trial 10 and the basal h a y was decreased by 7.5 lb. per day for a 27-day period. This change resulted in a f u r t h e r increase of 0.3 lb. of F.C.M. per d a y a n d an additional drop in the T.D.N., calculated net-energy a n d starch equivalent intakes and a m a r k e d increase in the crude fiber and ballast intakes. The results presented for the six cows are typical of the results obtained from the other nine trials. I n all trials, the a m o u n t of 4 per cent F.C.M. increased against the tide of a d v a n c i n g lactation when p a r t of the basal h a y was replaced with corn a n d wheat straw, wood meal or p e a n u t hulls, even when a zero value was used for the nete n e r g y content of the p e a n u t hulls. The efficiency of caloric conversion of T.D.N. to milk is strikingly illustrated in table 2 when the n u m b e r of pounds of F.C.M. p e r 100 lb. of T.D.N. consumed is examined. The p e r cent of f a t in the milk remained unchanged a f t e r the ration was changed f r o m h a y alone to the hay-grain-wheat s t r a w ration and to the hay-grainwood meal ration, but when corn and p e a n u t hulls replaced p a r t of the hay, there was a decline in the f a t content of the milk in six trials, no change in seven trials a n d an increase in two trials. The differences in body weights recorded in table 2 for the cows on the various rations do not a p p e a r to be significant. DISCUSSION
The seven trials with wheat straw indicate t h a t the unidentified f a c t o r ( s ) present in grain improves the balance of the ration. These findings are in agreem e n t with the results reported by B u r r o u g h s et al. (2), who f o u n d t h a t corncobs f e d with good hays and grain were alraost as productive per pound of T.D.N. for body gains in steers as that in corn grain. The increased ballast intake when oakwood meal was fed failed to suppress the milk p r o d u c i n g f a c t o r ( s ) in the grain, as was shown b y an increase in the amount of F.C.M. in each trial. The wood meal exerted some inhibitory effect, however, because milk production increased in all trials following w i t h d r a w a l of the meal f r o m the ration. Although the a m o u n t of ballast decreased f r o m 42 to 32 per cent f r o m the periods on the hay, g r a i n and wood meal to the hay-grain ration, it a p p e a r s unlikely t h a t ballast
UNIDENTIFIED
D I E T A R Y F A C T O R . II
47
was a f a c t o r in view of the higher ballast values in all of the trials with p e a n u t hulls. The increased production of F.C.lV[. can not be explained on the basis of calculated net-energy, even when a zero value is used f o r p e a n u t hulls, since the a m o u n t of F.C.M. increased in all trials which contained the same or less calculated net-energy. These results are not in agreement with Moore (18), S a a r i n e n et al. (22) or Shaw et al. (23), who have postulated that the unidentified lactation factor (s) in grain is due to an increase in calculated net-energy, b u t they do confirm previous findings (9, 10, 11, 12), which indicated t h a t concentrates s u p p l y an unidentified f a c t o r ( s ) needed to balance the n u t r i e n t s in some hays f o r efficient milk production. These results also are in agreement with those of Smith et al. (24), who showed t h a t the r e p l a c e m e n t of 13 to 25 per cent of the T.D.N. in an all-alfalfa h a y ration with various con~eentrates, on an equal T.D.N. basis, resulted in an increase in m i l k p r o d u c t i o n . Davis and K e m m e r e r (5) f o u n d t h a t milk p r o d u c t i o n was increased When dried g r a p e f r u i t peel was added to an a l f a l f a ration. Loosli (14) r e p o r t e d t h a t an increase in F.C.M. occurred when h a y was replaced with an equal amount of T.D.N. in either corn distillers grains or corn distillers solubles. The increases obtained in F.C.M. when the cows were changed f r o m an all-hay ration to a hay-corn-peanut hulls ration were assocmted with an increase in the per cent crude fiber in the d r y m a t t e r and in the p e r cent of ballast. These results are in agreement with those of Graves et al. (8), who showed t h a t high levels of crude fiber do not depress milk p r o d u c t i o n when the total ration is reasonably well-balanced. The work of Graves et al. also indicated t h a t some h a y s m a y contain a sufficient a m o u n t of the unidentified lactation f a c t o r ( s ) f o r efficient milk production when fed as the only feed. The results, however, are not in accord with N o r d f e l d t et al. (21) who r e p o r t e d an o p t i m u m crude fiber content of 16 per cent on the d r y basis f o r liberally milking cows, or with Axelsson (1) who stated t h a t the o p t i m u m crude fiber content of the d r y m a t t e r of the ration f o r cattle was 18 to 23 per cent. The highest values (about 38 p e r cent on the d r y basis) observed in this work m a y have been close to the m a x i m u m u n d e r the conditions of this experiment, since one cow went off-feed when 22.5 lb. of h a y were replaced b y 9 lb. of corn a n d 13.5 lb. of p e a n u t hulls. The T.D.N. supplied b y p e a n u t hulls m a y be as poorly balanced as t h a t in the h a y which was replaced. The efficiency of the conversion of T.D.N. to milk is a better index of the balance of a ration t h a n either calculated net~energy, starch equivalent or a n y system of feed evaluation based on the s u m m a t i o n of empirical values assigned to individual feed stuffs when t h e y are fed in combination. The increase in milk production which resulted when p a r t of the h a y was replaced with g r a i n also m a y a p p l y to gains in body weight b y beef cattle. Forbes et al. (7) studied the metabolism of steers fed alfalfa h a y alone, corn alone a n d a m i x t u r e of h a y and corn a n d concluded t h a t the net-energy (actual, not calculated) of corn in the mixed ration was g r e a t e r t h a n when the components were fed alone. The results of B u r r o u g h s et al. (2) also showed t h a t the T.D.N. of corncobs exerted about the same production in steers as the T.D.N. in corn. The unidentified lactation factor (s) present in concentrates m a y be r e q u i r e d
48
C. F. HUFF1VI/kl~I ET AT,
by the rumen bacteria to improve the balance of the ration. Burroughs et al. (3) found that the digestibility of the dry matter of corncobs was depressed by the addition of starch, but when the same amount of starch was added to alfalfa hay, the depression in the digestibility of dry matter did not occur. These workers (4) showed later that alfalfa hay ash contained essential nutrients for the growth of rumen microorganisms. It is difficult to determine whether the factor(s) is needed by the rumen microflora or by the host or by both. The results reported herein support the modern concept of a balanced ration which was first expressed by Forbes (6) and officially defined by Mitchell (16) in 1935. They also are in agreement with Maynard (17) who stated: " S i n c e individual feeds are seldom if ever balanced rations, it is evident that the summation of the net-energy values of the feeds making up a ration is not an accurate measure of the energy value of the ration as a whole and that the values for certain individual feeds may be highly misleading as to their effects as constituents of completely balanced rations. Herein lies another practical limitation of the netenergy system." These results suggest that an objective in forage crop research should be to produce hays high in milk-stimulating factors in order to reduce the amount of grain-feeding. SUmmARY AND CONCLUSIONS Seventeen depleted cows were used in 25 trials to determine the effect of replacing p ar t of the hay in an all-hay ration with grain and either wheat straw, oakwood meal or peanut hulls. In all but one trial, the replacement of part of the hay with these feed stuffs resulted in an increase in 4 per cent F.C.M., even though the intakes of T.D.N., calculated net-energy and starch equivalent decreased and the crude fiber in the dry matter and ballast increased. Crude fiber values up to 38 per cent of the dry matter did not depress milk production when the cows were changed from hay alone to a ration of hay, corn and peanut hulls. The results of this investigation indicate that calculated net-energy and starch equivalent values of individual feeds are not additive, but that they support the modern concept of a balanced ration. F u r t h e r evidence is presented to show that the unidentified lactation factor (s) in grain is needed to improve the balance of roughages. i~ EFERENCES
(1) AXELSSON, J. Die wissenschaftliche Grundlage des St~rkewertes. Biedermanns Zentr. B. Tierern~hr., 11: 176-205. 1939. (2) BURROUGHS, W., GERLAUGtt, P., SCltALK, A. F., SILVER, ~E. A., AND KUI~KLE, L . E . The Nutritive Value of Corncobs in Beef Cattle Rations. J. Animal Sei., 4: 373-386. 1945. (3) BURROUGHS, W., GERLAUGtt, :P., :EDGINGTON, B. H., AND BETHKE, R . M . The Influence of Corn Starch upon Roughage Digestion in Cattle. J. Animal Sci., 8: 271-278. 1949. (4) BURROUGHS, W., GERLAUGH, P., AND BETHKE, R. i~. The Influence of A l f a l f a Hay and
UNIDENTIFIED DIETARY FACTOR. II
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49
Fractions of A l f a l f a I t a y upon the Digestion of Ground Corncobs. J. Animal Sci., 9: 207-213. 1950. DAvis, R. N., AND KE~/[MERER,A . R . Lactation Factors for Dairy Cows in Dried Grapef r u i t Peel. J . Dairy Sei., 31: 973-975. 1948. FORBES, E . B . Net Energy of Completely Ba)~aneed N u t r i m e n t as a Measure of Nutritive Value of Rations and of Nutritive Requirement of Animals. Proc. Am. Soc. Animal Prod., 1932: 32-40. 1933. FORBES, E. B., BRAI~AN, W. W., KRISS, M., SWIFT, R. W., 1VIIbLER, R. C., FRENCH, R. B., LETONO~'r, T. V., AND SHARPLESS, G . R . The Metabolizable Energy and Net Energy Yalues of Corn Meal when Fed Exclusively and in Combination with A l f a l f a Hay. J . Agr. Research, 43: 1015-1026. 1931. GRAVES, R. R., DAWSON, J . R., KOPLAND, D. V., WATT, A. L., AND VAN HORN, A. G. Feeding Dairy Cows on A l f a l f a Hay Alone. U . S . D . A . Tech. Bull. 610. 1938. HUFF~AN, C. F., AND DUNCAN, C.W. The Nutritive Value of A l f a l f a Hay. I. Cystine as a Supplement to an All-alfalfa Hay Ration for Milk Production. J. Dairy Sci., 25: 507-515. 1942. HUEF~AN, C. F., AND DUNCAN, C . W . The Nutritive Value of A l f a l f a Hay. II. Starch and Glucose as Supplements to an All-alfalfa Hay Ration. J . Dairy Sci., 27: 821-833. 1944. HUFF~AN, C. F., AND DUNCAS, C . W . The Nutritive Value of A l f a l f a ttay. I I I . Corn as a Supplement to an All-alfalfa Hay Ration for Milk Production. J. Dairy Sci., 32: 465-474. 1949. HUFF~AN, C. F., AND DUNCAN, C . W . Unidentified Dietary Factors in Dairy Cattle Nutrition. I. Digestibility of P e a n u t Hulls and their Use in ~' B a l l a s t ' ' Studies with Milking Cows Depleted on H a y Alone. 5. Dairy Sci., 35: 29-40. 1952. KIRSCH, W., AND JANTZON, H. Untersuchungen tiber den Einfluss ether Yergarung yon Buchenholz- und Fichtenholzsagemehlen u n t c r Umsatz eines Molke-PhosphorsKuremi~ches sowie von Zucker a u f die Verdaulichkeit der N~hrstoffe durch den WiederkKuer. Z. Tierernfihr. Futtermittelk., 5: 244--259. 1941. Loose1, J . K . Influence of Distillers' Feeds on Milk Production. Proc. Sixth Distillers' Feed Conference, Cincinnati, Ohio, 30-36. 195l. LOOSLI, ,]-. K., HUFFI~IAN, C. F., PETERSEN, W. E.~ AND PHILLIPS, e . H. Recommended N u t r i e n t Allowances for Domestic Animals. I I I . Recommended N u t r i e n t Allowances for Dairy Cattle. National Research Council. 1950. I~[ITCHELL, 1=t. H. Some Problems in the Study of Energy Metabolism. Report of the Conference on Energy Metabolism. The Committee on Animal Nutrition, N a t i o n a l Research Council, 66-93. 1935. MAYNARD, L . A . Animal Nutrition. 2rid ed. McGraw-Hill Book Co., Inc., New York. 1947. p. 301. MOORE, L. A. A Relationship between Total Digestible N u t r i e n t s (T.D.N.) and Estimated Net Energy Values (E.N.E.) and a Possible Method for Estimation of Net Energy Values with Producing Dairy Cows. J. Animal Sci., 9: 663. 1950. MOORE, L. A. _A. Relationship between Total Digestible N u t r i e n t s (T.D.N.) and Estimated Net Energy Values (E.N.E.) and a Possible Method of E s t i m a t i n g Net Energy Values with Producing Dairy Cows. U. S, D. A., Bur. Dairy Ind., B D I - I n f - l l 4 . Nov., 1950. MORRISON, F . B . Feeds and Feeding. 21st ed. The lt{orrison Publishing Co., Ithaca, N . Y . 1948. NORDFELDT, S., IWANAGA, I., MORITA, K., HENKE, a . A., AND TO1V~, A. I~. S. Influence of Crude Fiber in the Ration on Efficiency of Feed Utilization by Dairy Cows. J. Dairy Sci., 33: 473-485. 1950. SAARINEN, P., SA~I, M. A., SHAW, J: C., AND MOORE, L . A . The Adequacy of an Alla l f a l f a H a y Ration for Milk Secretion. J . Dairy Sci., 34: 287-294. 1951.
50
C. F. tIUFFMAN ET AL
(23) SHAW, J. C., IRWIN, H. M., SAARINEN, P., SAMI, M. A., CAIRNS, G. M., A N D MOORE,L. A. The :Effect upon Milk Production of A l f a l f a Hay when Fed Alone and with Concentrates, ft. Animal Sci., 9: 675-676. 1950. (24) S~IT~, ¥ . 1% JONES, I. ]~., AND HAAG, J. t~. A l f a l f a with and without Concentrates for Milk Production. J. Dairy Sci., 28: 343-354. 1945.