1916] ANIMAL PRODUCTION. 563 



corn grain and corn by-products, or wheat grain and by-products (much of the 

 protein of which is unbalanced in composition), or milli protein, supplied in the 

 form of sliim-millj powder and casein (furnishing proteins which are well bal- 

 anced in composition). 



The percentage of the digestible protein of these rations which was used by 

 the cows for milk production and the formation of body protein was 40 per 

 cent with the corn ration, 34 per cent with the wheat ration, and 58 per cent 

 with the milk protein ration. Such complete proteins as are furnished by milk 

 are thus apparently of high efficiency for milk production. 



Commonly tinappreciated factors in food, by E. V. McCollum. — Previous 

 experiments (E. S. R., 31, p. 864) have demonstrated that certain fat-soluble 

 substances found in milk fat, fats from egg yolk, corn grain, and wheat embryo, 

 and the soft portion of beef fats are necessary in the diet for continued growth. 

 It appears that there is also required another class of substances which are 

 soluble in water, the nature of which has not been discovered. These sub- 

 stances have been found thus far in egg yolk and wheat embryo, and are prob- 

 ably present in corn. Growing rats fed a ration of highly purified casein, egg 

 albumin, dextrin, mineral matter, and milk fat failed to grow. However, nor- 

 mal growth took place when the water extract of wheat embryo was added, 

 which evidently supplied the necessary accessory to the diet. It has been 

 found that neither the fat-soluble nor the water-soluble accessor i; a are injured 

 by heating above the boiling point of water. 



Influence of strictly vegetable diets on growth and reproduction, by E. B. 

 Hart and E. V. McCollum. — It is thought that strictly vegetable foods might be 

 found insufficient for normal growth. To study this problem experiments were 

 carried on with growing pigs kept in pens away from the soil and supplied in 

 some cases with distilled and in others with natural water. On a well-balanced 

 concentrate mixture of oats, corn, wheat, and oil meal, pigs failed to grow after 

 about three months, even when sugar beets and alfalfa hay were supplied two 

 or three times a week. Where but 1 per cent of meat scrap was added to the 

 ration the pigs grew normally, reaching a weight of 250 lbs. by the time those 

 on the strictly vegetable diet had reached 100 lbs. 



Other experiments, however, showed that the missing essential constituents 

 could be supplied in vegetable feed. In the earlier experiments uncut alfalfa 

 hay was offered the pigs, but they consumed very little. Fifteen per cent of 

 finely ground alfalfa meal was then mixed with the ration, so that the pigs 

 would be forced to consume larger amounts of alfalfa. On this vegetable ration 

 good growth occurred. These experiments indicate that the meat supplied a 

 better-balanced protein mixture than the ba.sal ration of grains and oil meal, 

 and also more of the diet accessories needed for rapid growth. These acces- 

 sories are also apparently present in alfalfa. 



Corn silage for beef cattle, by J. L. Tormey. — In six trials, each of which 

 lasted 90 days, a total of 63 2-year-old steers were fed. In these trials the 

 addition of silage to rations of concentrates and either alfalfa or clover hay 

 decreased the amounts of concentrates required per pound gain, but increasad 

 the roughage requirement. In all cases the addition of the silage lessened the 

 feed cost per pound of gain and reduced the necessary margin, although a heavy 

 concentrate allowance with less silage produced more rapid gains. For fatten- 

 ing 2-year-old steers an average daily ration throughout the feeding period of 

 20 lbs. of corn silage, 5 lbs. of clover, alfalfa, or mixed hay, 12 lbs. of shelled 

 corn, and 2 lbs. of cotton-seed meal, or amounts of other protein-rich concen- 

 trates furnishing an equal amount of digestible protein, is recommended. 



In one of the trials steers fed an average ration of 37.6 lbs. silage, 3.1 lbs. 

 clover hay, and only 7 lbs. concentrates (3.1 lbs. corn, 2.7 lbs. cotton-seed meal 



