208 THE CHEMISTRY OF THE FARM 



COW is to yield her best return. Oilcakes, bean-meal, 

 bran, oats, and brewers' grains are recognised as 

 excellent foods for a milking cow; most of those foods 

 supply fat as well as albuminoids, and the cake and 

 bran are also rich in phosphates. In the winter feeding 

 of cows at Eothamsted, the general diet consisting of 

 hay, oat straw, and mangels, 2J lbs. of decorticated 

 cotton cake, and 2J lbs. of bran, were given daily to 

 every cow yielding one gallon of milk, and an additional 

 pound both of cotton cake and bran was given for 

 every additional gallon of milk produced. The milk 

 produced by each cow was registered, and the amount 

 of concentrated food supplied rose or fell with the milk 

 production. 



The quality of the milk may be influenced to some 

 extent by the character of the food. Thus a liberal 

 diet of fresh brewers' grains, or a diet of watery grass 

 (irrigated), will yield a moderate quantity of poor milk, 

 and the addition of oil-cake will increase both the yield 

 of milk and also its richness. The alteration in the 

 composition of the milk by poor or liberal feeding 

 is, however, often very small. The relative propor- 

 tions of casein and sugar are scarcely affected by the 

 character of the diet, the butter fat is somewhat more 

 variable. 



The quality of the butter may be a good deal 

 influenced by the character of the food. The white, 

 bard, tasteless character, which winter butter often 

 possesses, is chiefly due to the foods employed. 

 Pasture, whether grass or clover, yields butter of the 

 lowest melting point, containing the highest percent- 

 age of volatile fatty acids, and best flavour. Silage 

 appears to partake of the properties of green food, and 



