Additions of Hay to Corn Silage to Maximize Feed Intake and Milk Production1

Additions of Hay to Corn Silage to Maximize Feed Intake and Milk Production1

A D D I T I O N S OF H A Y TO CORN S I L A G E TO M A X I M I Z E F E E D INTAKE AND MILK PRODUCTION 1 R. K. W A U G H , H. S. P O S T O N , -~ It. D...

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A D D I T I O N S OF H A Y TO CORN S I L A G E TO M A X I M I Z E F E E D INTAKE AND MILK PRODUCTION 1 R. K. W A U G H , H. S. P O S T O N , -~ It. D. M O C H R I E , W. It. M U I t L E Y , AND I~. L. L U C A S

.Yorth Carolina Agric~dtural Experiment Station, ttaleigh ~

E a r l y feeding trials have indicated t h a t a stimulation of milk production resulted when p a r t of the d r y roughage was replaced b y corn silage. P r a t t and White (7) reviewed the early literature and f o u n d general agreement for increased F C M production per unit of d r y m a t t e r with increasing amounts of silage in the ration of milking cows. Their own studies (7, 12) resulted in similar milk production and body weight changes for groups of cows fed a p p r o x i m a t e l y 18 and 36 lb. of corn silage per day in addition to h a y and grain. I t is well accepted t h a t silage as the only source of roughage will support r a t h e r high levels of milk production (3, 6). W i t h grass silage feeding, higher production has resulted f r o m including various amounts of hay in addition to silage (2, 5, 11). This p a p e r is a r e p o r t of a series of feeding trials carried out to determine the a m o u n t of h a y to be added to an ad libitum corn silage feeding regime which would result in m a x i m a for d r y m a t t e r intake and milk production. EXPERIMENTAL PROCEDURE

Animals. Sixty cows were used in six trials carried out during the 1951-52 a n d 1952-53 b a r n feeding periods at three locations, viz., the Mountain Test F a r m , Waynesville; the Coastal Plain Test F a r m , W i l l a r d ; and the Central Station, Raleigh, N o r t h Carolina. Since four t r e a t m e n t s were to be compared, four cows at a time at a given location were selected for being similar in breed, age, stage of lactation, and live weight to make up a replicate. B y breeds, the following n u m b e r of replicates were used: Ayrshire 1, Guernsey ], Holstein 2, and J e r s e y ]1. Rations and feeding procedure. The four cows in a replicate were simultaneously s t a r t e d on a 28-day standardizing period d u r i n g which each cow was offered daily corn silage ad libitum, 1 lb. of hay p e r 100 lb. of live weight and 1 lb. of grain per 4 lb. of F C M (1). I n five of the six trials the hay fed was alfalfa with an estimated mean T D N content (8, 9) of 54 to 59% (moisture-free basis) and a protein content r a n g i n g f r o m 13.6 to ]7.3%. A ] 5 . 1 ~ protein soybean hay with an estimated T D N content (8, 9) of 54% was fed to three replicates in the sixth trial. Among the trials the mean d r y m a t t e r content of the corn silage Received for publica¢ion January 17, 1955. 11)ublished with the approval of the Director of Research as Paper No. 610 in the Journal Series. A preliminary report of this work was presented at the 49th Ann. Meet. of A.D.S.A. (See J. Dairy Sci., 37: 657. 1954). -"Present address: Animal Husbandry Department, Iowa State College, Ames. 3Department of Animal Industry and Institute of Statistics. 688

ADDING HAY TO CORN SILAGE

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varied from 19.8 to 25.0% and had an estimated TDN content of the d r y matter (8, 9) of 64 to 67%. Conventional concentrate mixtures with a mean protein content of 14.3 to 22.2% were fed in these trials. Immediately after the standardizing period, the four cows in each replicate were randomly assigned to receive one of four levels of hay continuously for a 56-day comparison period. The four levels of hay offered were 1.00, 0.50, 0.25, and 0.00 lb. per 100 lb. of live weight daily. All feeds fed were those described above. In the first half of the comparison period concentrate was fed at 1 lb. per 4 lb. of F C M produced in the last week of the standardizing period. F o r the second half the amount was reduced by 5%. The corn silage was fed essentially ad libitum, being provided at least three times daily. Observations a~d analyses. The amounts of concentrate, hay and corn silage, fed and refused, were determined and recorded daily. All cows were milked twice daily; the weights were recorded, and aliquot samples were pooled for 1-week (in standardizing) or 2-week (in comparison) periods for fat test by the Babcock method (1). Cows were weighed on the first 3 days of the standardizing period and on the first and last 3 days of the comparison period. The 3-day averages were used for all calculations. All feeds were analyzed by official methods (1) except for the determination of d r y matter, for which 70 ° C. with vacuum was used. An analysis of covariance was carried out on the values obtained for the comparison period with the corresponding values for the last 14 days of the standardizing period used as the covariable (10). RESULTS

Feed consumption. The mean d r y matter intakes of grain, silage, and hay in the standardizing period and of grain in the comparison period were similar for the four treatment groups (Table 1). The intended levels of hay intake were not quite realized. The actual mean daily intakes for the groups in the standardizing period ranged from 0.81 to 0.86 lb. per 100 lb. of live weight. In the comparison period the intakes averaged 0.83, 0.47, 0.24, and 0.00 lb. of hay for the groups offered 1.00, 0.50, 0.25, and 0.00 lb. per 100 lb. of live weight, respectively. The decreased d r y matter intakes which resulted when the lower levels of hay were fed can be readily seen in Table 1. These differences were v e r y highly significant statistically ( P ~ 0.001). This response of d r y m a t t e r intake to level of hay in the diet was significantly quadratic (P ~ 0.05). This relationship was well described by the following equation: Y = 21.38 + 10.40X - 6.60X 2 where Y equals the d r y matter intake ill pounds per cow per day and X equals the daily pounds of hay consumed per 100 lb. live weight in addition to silage, ad libitum. Using the above relationship, maximum d r y m a t t e r intake was calcu-

R. K. WAUGHET AL

690

TABLE 1 Mean daily dry qnatter inta]~es and milk and f a t production for g.ro.~¢ps of cows offered the indicated level of hay to supplement corn silage

Lb. hay per 100 lb. live weight Standard error of 1.00 0.50 0.25 0.00 a mean Mean daily lb. dry matter intake Standardizing period Grain Hay Silage

8.5 6.9 9.6

8.7 6.8 9.1

8.4 7.0 9.4

8.0 6.9 9.5

Total

25.0

24.6

24.8

24.4

Comparison period Grain Hay Silage

7.6 6.9 11.2

8.0 3.9 13:2

7.4 1.9 13.5

7.5 0.0 14.1

Total

25.7

25.1

22.8

21.6

0.67

Comparison total adjusted for standardizing total

25.5

25.1

22.7

21.7

0.46

Standardizing period Comparison period Comparison adjusted for standardizing

Mean daily lb. milk production 30.85 3 1 . 9 4 2 9 . 5 7 28.81 27.75 2 8 . 9 9 2 6 . 0 1 24.73 27.22 2 7 . 4 3 2 6 . 6 9 26.13

0.77

1.36 1.34 0.36

Standardizing period Comparison period Comparison adjusted for standardizing

Mean daily lb. fat production 1.425 1 . 5 1 3 1 . 3 9 4 1 . 4 3 1 0.064 1.303 1 . 3 8 9 1 . 2 4 8 1 . 2 4 6 0.060 1.316 1 . 3 2 7 ].288 1 . 2 5 5 0.024

Standardizing period Comparison period Comparison adjusted for standardizillg

4.76 4.85 4.93

Standardizing period Comparison period Comparison adjusted for standardizing

% fat 4.84 4.81 4.92 4.93 4.93 4.98

5.02 5.14 5.00

0.12 0.11 0.04

Mean daily lb. FCM production 34.21 3 5 . 4 4 3 2 . 8 7 33.07 30.59 3 2 . 4 2 2 9 . 1 2 28.66 30.33 3 1 . 0 3 3 0 . 0 4 29.40

1.43 1.39 0.54

l a t e d to occur a t a level of 0.79 lb. of h a y p e r ]00 lb. live weight. The 9 5 % confidence i n t e r v a l for this v a l u e was 0.42 to 1.16 lb., a r a n g e which b r a c k e t s the h i g h e s t level of h a y f e d i n t h i s s t u d y . The d r y m a t t e r i n t a k e s f r o m silage ( T a b l e 1) are of interest. The cows r e m a i n i n g on the 1.00 lb. level of h a y d u r i n g the c o m p a r i s o n i n c r e a s e d t h e i r silage c o n s u m p t i o n o n l y s l i g h t l y (1.6 lb.), whereas the t h r e e g r o u p s r e c e i v i n g the lesser a m o u n t s of h a y c o n s u m e d a p p r e c i a b l y m o r e d r y m a t t e r i n the f o r m of silage (4.1, 4.], a n d 4.6 lb., r e s p e c t i v e l y ) d u r i n g t h i s period. S o m e w h a t of a c r a v i n g for d r y r o u g h a g e was observed i n t h r e e of the 15 cows on the all-silage r a t i o n . This desire a p p a r e n t l y d i m i n i s h e d as the e x p e r i m e n t progressed. M i l k p r o d u c t i o n ( T a b l e 1). The same t r e n d was observed for milk, fat, a n d F C M , w i t h the lowest p r o d u c t i o n i n the zero h a y group, i n c r e a s i n g w i t h level of h a y to the 0.50 lb. g r o u p a n d d r o p p i n g off a g a i n i n the h i g h e s t h a y group.

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691

Although these over-all treatment differences for FCM and pounds fat were not statistically significant, those for pounds milk approached significance (P < 0.10). The trend in FCM response to level of hay was essentially quadratic (P --~ 0.10) and was described by the following equation : Y = 29.78 + 6.08X - 5.88X 2 where Y equals the FCM production in pounds per cow per day and X equals the pounds of hay consumed daily per 100 lb. live weight in addition to silage ad libitum. F r o m this relationship, maximum FCM production was calculated to result at an intake of 0.52 lb. of hay per 100 lb. live weight. The 95% confidence interval for this value was 0.30 to 0.74 lb. of hay. No influence of the experimental rations on the per cent fat in the milk was found. Live we~;ght. The mean initial live weights for the four treatment groups arranged by decreasing level of hay were 886, 883, 864, and 859 lb., with a standard error of 21 lb. The mean live weight changes during the comparison for these groups in the same order as above were +23.5, +24.8, +23.4, and +21.8 lb., with a standard error of 5.4 lb. These weight changes were not significantly different. DISCUSSION

These data confirm the belief that corn silage as the sole source of roughage will support rather high levels of milk production with moderate grain feeding. However, increases in d r y m a t t e r intake and milk production can be realized by feeding hay in addition to the silage. As might be expected, the response of both criteria to increasing the level of supplemental hay is curvilinear. The maximum for d r y m a t t e r intake occurred at a higher level of hay feeding than did that for FC1V[ production. The greater d r y m a t t e r intakes at the higher levels of hay did not result in as wide differences in milk or FCI~ production as might have been anticipated. This response is compatible with early observations (7) that d r y m a t t e r from silage is more valuable for milk production than that from hay. Since the cows in this s t u d y were.fed grain at 1 lb. to 4 lb. of FCM, it might be anticipated that wider differences in production would result from similar additions of hay at a lower level of concentrate feeding. This would be due, of course, to the necessity for the roughage to provide a greater portion of the total energy. SUM~CIARY

Sixty cows were used in a series of feeding trials conducted at three North Carolina experimental farms over two winter-feeding periods to determine the optimum amount of hay to be used to supplement an ad libitum corn silage feeding regime for milk production. The four hay levels consumed were 0.83, 0.47, 0.24, and 0.00 lb. per 100 lb. of live w e i g h t . A f t e r a 28-day standardizing period, in which cows were offered silage ad libitum and 1 lb. of hay per 100 lb. of live weight, each cow was carried for a 56-day comparison period on one of the four experimental rations.

692

~. K. W/kUGtt ET AL

D r y m a t t e r i n t a k e w a s h i g h e s t i n t h e g r o u p w h i c h c o n s u m e d 0.83 lb. o f h a y p e r 1 0 0 l b . o f l i v e w e i g h t w i t h t h e c a l c u l a t e d m a x i m u m i n t a k e b e i n g a t 0.79 ___ 0.37 lb. o f h a y . M i l k , f a t , a n d F C M p r o d u . c t i o n w a s h i g h e s t f o r t h e g r o u p c o n s u m i n g t h e 0.47 lb. l e v e l of h a y w i t h t h e c a l c u l a t e d m a x i m u m f o r FC1V[ b e i n g a t 0.52 ___ 0.22 lb. o f h a y . M e a n c h a n g e s i n l i v e w e i g h t w e r e e s s e n t i a l l y t h e s a m e for the four treatment groups. ACKNOWLEDGMENTS The authors wish to acknowledge the assistance of ]3. F. Hollon, H. R. Sink, J. W. Stunner, and M. R. Whisenhunt in the collection of these data. The analytical work of F. H. Smith and the statistical computations by J. L. Cason are greatly appreciated. REFERENCES (1) ASSOCIATIOI~OF OFFICIAL AGEICULTUEAL C~E~ISTS. O~eial Methods of Analysis. 7th ed. Washington, D. C. 1950. (2) BLOSSER, T. H., POI~TER, G. W., LINTOTT, R. E., SHAW, A. 0., AND ASHWORTH, U. S. Milk Production and Body Weight Changes of Dairy Cows Receiving All of Their Roughage in the Form of Silage. Proc. 32nd Ann. Meet., West. Div.,.A.D.S.A.p. 121. 1951. (3) CONVE~SB, H. T., AND WISE~AN, H. G. Corn Silage as the Sole Roughage for Dairy Cattle. USDA Tech. Bull. 1057. 1952. (4) GAINES, W. L., AND DAVIDSONi F. A. Relation Between Percentage F a t Content and Yield of Milk. IlI. Agr. Expt. Sta., Bull. 245. 1923. (5) HENDERSON, ]3. W., JI¢., AND N01~TON, C. L. Grass Silage for Dairy Cattle. R. I. Agr. Expt. Sta., Bull. 311. 1950. (6) P01~TER, A. R. How Much Silage in the Dairy Ration. Iowa Farm Sci., 5: 32. 1950. (7) Pm~TT, A. D., AND WHITE, G. C. Optimum Amount of Silage in the Dairy Ration for Most Economical Production. J. Dairy Sci., 13: 291. 1930. (8) SCttNEIDER, B. H. Feeds of the World, Their Digestibility and Composition. J a r r e t t P r i n t i n g Co., Charleston, W. Va. 1947. (9) SCHNEIDER, ]3. H., LUCAS, H. L., PAVLECH, HELEN M., AND CIPOLLONI, MAI~Y A. Estimation of the Digestibility of Feeds from Their Proximate Composition. J. Animal Sci., 10: 706. 1951. (10) SNBDEC0E, G. W. Statistical Methods, 4th ed. The Iowa State College Press, Ames. 1946. (11) STE-MARIE, J. A., AND GEaVAIS, P. Silage Feeding. ]Prog. Rept. Dom. Expt. Sta. (Lennoxville, Canada) 1946. (12) WHITE, G. C., AND PRATT, A. D. Optimum Amount of Silage in the Dairy Ration for Economical Production. Storrs (Conn.) Agr. Expt. Sta., Bull. 169. 1930.

AUTHORS ' CORRECTIONS " L i p a s e Activity in Fresh Milk as Related to Portions of Milk Drawn and F a t Globule S i z e , " Vol. 38 (March, 1955), by W. R. Thomas, W. J. Harper, and I. A. Gould. 1. Page 316, Table 1, the column heading " F a t c o n t e n t " should read " A c i d d e g r e e . " ~' On the Mechanism of Activation of Lipolysis and the Stability of Lipase Systems of Normal M i l k , " Vol. 38 (April, 1955), by N. P. Tarassuk and E. N. Frankel. 1. Page 438. Table 1, Experiment 2, line 3: " F o a m e d 2 minutes without a n t i f o a m i n g a g e n t " should read ~'Foamed 12 minutes without antifoaming a g e n t . " 2. Page 439, line 3-b: ~'Lipase is a surface r e a c t i o n " should read ~'Lipolysis is a surface reaction. ' '