360 FEEDS AND FEEDING 



It has previously been pointed out that protein is a cell stimulant 

 and that a supply somewhat above the minimum promotes the well-being 

 of the animal. Perhaps for these reasons, it is the general practice 

 in feeding cows on official test to give much larger amounts of protein 

 than is required to meet the recommendations of any of the feeding 

 standards. 



From trials at the Massachusetts Station 53 Lindsey concludes that 

 feeding an excess of protein over the actual amount required for body 

 maintenance and milk production tends to stimulate the cow to a greater 

 yield of milk. In one test, supplying twice the minimum amount of 

 protein required increased the milk flow 15 per ct. While the yield of 

 milk may be thus increased by feeding an excess of protein, Lindsey con- 

 cludes from 8 trials that varying amounts of protein do not seem to in- 

 fluence the percentage composition of the milk, making it richer or poorer 

 in fat, for example. On the other hand, the experiments of the Copen- 

 hagen Station, 54 covering observations with about 2,000 Danish cows and 

 extending over ten years, indicate that the fat percentage was possibly 

 raised as much as 0.1 per ct. thru the feeding of highly nitrogenous ra- 

 tions. Michels of the North Carolina Station 55 found the fat content of 

 the milk slightly higher when a ration having a nutritive ratio of 1 :4.0 

 was fed than when the nutritive ratio was 1 :5.7. 



To produce the large amount of protein in her milk efficiently, the 

 dairy cow must receive proteins furnishing a well-balanced supply of 

 amino acids. Therefore, it was found in trials by Hart and Humphrey 

 at the Wisconsin Station, which are mentioned in Chapter VI, that gluten 

 feed (a corn grain by-product) was a much less efficient protein-rich 

 supplement than linseed meal when added to a ration of corn grain and 

 corn stover. (148) However, when fed with alfalfa hay, corn silage, 

 and corn grain, there was little difference in the efficiency of gluten feed 

 compared with linseed meal, cottonseed meal, and dried distiller 's grains, 

 due to the fact that the proteins in the alfalfa hay balanced the de- 

 ficiencies of the proteins in the corn grain and gluten feed. In a trial at 

 the South Dakota Station 558 by Larsen and colleagues the protein of 

 gluten feed was even superior in efficiency to that of linseed meal in 

 supplementing prairie hay and corn silage. 



From these trials we may conclude that in the common mixed rations 

 usually recommended for dairy cows, in which silage and hay (preferably 

 from the legumes) are combined with grains, there is little difference in 

 the efficiency of the proteins furnished by the various protein-rich supple- 

 ments. In other words, when fed in such rations, a pound of digestible 

 crude protein in one supplement will have about the same value as a 

 pound of digestible crude protein in the other available supplements. 



Many experienced dairymen prefer concentrate mixtures made up of a 

 reasonable variety of feeds to using only two concentrates in the ration. 



53 Mass. Rpt. 1911, I, pp. 86-121. 55 N. C. Rpt. 1911, pp. 90-97. 



"Copenhagen Sta Rpt. 45; Woll, Wis. Bui. 116. W S. D. Bui. 188. 



