470 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



The same quantity of bean meal produced twice as much in- 

 crease in milk with cow No. i as with cow No. 2. 



Effect of Proteids. The effect of protein upon milk flow is 

 studied by replacing feeds poor in proteids by those richer in 

 proteids. For example, Fjard and Friis 1 replaced barely meal, 

 which is poor in proteids, by oil cake rich in proteids, in a number 

 of experiments on 8 farms and 1,152 cows, with the following 

 average results: 



Increase of proteids thus increased the quantity of milk. It 

 had, however, no effect upon the composition of the milk. From 

 these and other experiments, it is concluded that proteids exert 

 a great influence upon the quantity of milk secreted. The water 

 content of the milk, and the percentage composition of the dry 

 matter are affected only when proteids are fed for a long time in 

 quantities considerably exceeding the needs of the animal. In 

 such event, the water content increases and the fat decreases. 

 Ammonia salts can apparently be used for production of milk 

 when fed in a ration poor in nitrogen but rich in carbohydrates. 



Nitrogen-Free Nutrients. Since fat and carbohydrates may 

 promote flesh production indirectly or pass into body fat, it is 

 evident that they may influence the milk glands and milk pro- 

 duction. If the ration contains enough proteid but not enough 

 carbohydrates or fat to induce the highest production, the milk 

 production would not reach its highest limits, but a part of the 

 1 Jahresber, f. Agr. Chem., 1893, p. 394. 



