168 Relation of Food to Milk Production, [june, 



sufficient food to maintain their weight while in milk. A cow 

 that normally produces 3 per cent, of fat cannot be made to 

 give milk containing 4 per cent, of fat by any special system 

 of feeding known, nor can the proportion of fat in the milk to 

 the other milk solids be changed at will by the food. The 

 quality of the milk produced by a cow is determined by her in- 

 bred characteristics, and cannot be changed to any extent by 

 feeding special foods or by changing the system of feeding. At 

 the same time, it is considered that there is evidence to show 

 that feeding-stuffs of a nitrogenous character, like oil-cake, 

 &c, have a beneficial influence on the quality of the milk 

 produced, and that, in general, the best quality and also the 

 largest quantity of milk which a cow is capable of producing 

 will be obtained by feeding rations fairly rich in protein. A 

 comparison between the yields of fourteen cows in the University 

 in 1903-4 and the previous year is mentioned as supporting this 

 view, and similar results are stated to have been obtained else- 

 where. In the case referred to, an increase in the nitrogenous 

 food fed during the winter to the same cows gave an increase of 

 nearly one-third per cent, of fat, though the influence of differences 

 in the age and live weights and the uneven milking periods make 

 anything like exact comparison difficult of attainment. It is 

 said, however, that in all the experiments made, at least four- 

 fifths of the cows have responded to a heavier nitrogenous 

 feeding by producing milk of a somewhat better quality and 

 increased quantity. The improvement obtained in the quality 

 has generally been less than one-half per cent., and on the 

 average not more than two or three-tenths of 1 per cent. The 

 beneficial effect of albuminoids on the milk secretion should, 

 therefore, be borne in mind, and where larger quantities of nitro- 

 genous foods can be given, somewhat better results, both as 

 regards the quality and the amount of milk produced by the 

 cows, may be expected. 



