124 FEEDS AND FEEDING 



arises as to whether calves raised on skim milk or whey in place of whole 

 milk will secure enough of this vitamine, which is essential for growth. 

 Happily, calves begin to eat roughage when only a few days old, and 

 green-leaved forage is in general rich in the fat-soluble vitamine. There- 

 fore, calves fed skim milk or whey probably obtain sufficient of this 

 vitamine, even tho the concentrates fed are low in it. This is indicated 

 in a recent trial by Morrison, Humphrey and Hulce at the Wisconsin 

 Station 1 in which one lot of calves was fed whey, white corn, linseed meal, 

 and wheat middlings (all these feeds containing little or no fat-soluble 

 vitamine), with legume hay and corn silage for roughage. Another lot 

 was fed the same ration, except that it received yellow corn, which is 

 quite rich in fat-soluble vitamine. Both lots made satisfactory gains, 

 there being no appreciable difference in the rate of gain or in general 

 thrift. The fact that the calves fed yellow corn did no better than those 

 fed white corn shows that the latter received sufficient fat-soluble vita- 

 mine in the hay and silage. (202) 



In all probability most rations fed calves furnish plenty of the water- 

 soluble vitamine for normal development, since it is quite generally 

 distributed in ordinary feeding stuffs. (104) 



679. Protein requirements for growing cattle. Inasmuch as protein- 

 rich feeds are usually more expensive than those rich in carbohydrates, 

 it is a matter of great practical importance to determine how much 

 protein is required for normal growth, or in other words, how narrow the 

 nutritive ratio should be. For some time it has been generally believed 

 that the "Wolff-Lehmann feeding standards prescribed more protein than 

 needed for good growth. Therefore, thru the cooperation of the National 

 Research Council and several experiment stations, joint investigations 

 are being undertaken to study the effect upon the rate of growth of 

 supplying different amounts of protein in the rations of calves. Studies 

 of this character must extend over a considerable period of years before 

 definite conclusions are reached. In the trials thus far reported 2 calves 

 which were fed rations containing approximately the amounts of protein 

 now recommended in the Morrison feeding standards (Appendix Table 

 V) made materially more rapid gains than others which were fed 32 to 

 42 per ct. less protein up to 9 months of age and then 42 to 50 per ct. less 

 protein than the amount the first lot received. The calves gained only 

 87.2 per ct. as rapidly on the low-protein diet as on the ration higher in 

 protein, and stored only 56.6 per ct. as much protein in their bodies. It 

 was found that on the low-protein rations a marked depression of di- 

 gestibility occurred, due to the large amount of easily digested carbohy- 

 drates compared to the amount of protein. (84) This caused a less 

 complete utilization of the feed. 



1 Wis. Bui. 339, p. 128. 



Experiments by Beals and Lindsey at the Massachusetts Station, by Hold- 

 away, Ellett, and Harris at the Virginia Station, and by Plumb, Conklin, and 

 Lyman at Ohio State University. Summarized by Armsby, Bui. of National Re- 

 search Council No. 12, June 1921. 



