MILK PRODUCTION 425 



the percentage of the fat. It is true, nevertheless, that if a 

 cow has been fed so long on innutritions food that her 

 condition as to flesh and bodily vigor have been greatly 

 reduced, and if such food is supplanted by a ration, rich 

 in character, there will in time be some increase up to a 

 certain limit in the fat in the milk. Under normal con- 

 ditions there may be slight variations in the percentage 

 of butter fat following a change of food, but these are 

 more or less temporary in character. It is also true that 

 food may in the course of generations exercise some in- 

 fluence on the normal quality of milk as to butter fat, as 

 witnessed in the essential difference in this respect with 

 reference to the milk of cows maintained on the bulky and 

 watery foods of moist lands of the Netherlands, and those 

 maintained on foods less bulky and watery as grown in the 

 Channel islands. But selection also with the cows in the 

 two countries has had its influence. How much is to be 

 attributed to each can never be known. Food also in- 

 fluences the mechanical condition of the butter fat and to 

 some extent its chemical condition, as shown in its keep- 

 ing qualities. Some foods, as cottonseed for instance, ren- 

 der butter more firm, and others as oil cake when fed in 

 very large quantities, render it less so. 



The influence of food also extends to taste, flavor and 

 color. - Taste and flavor are so closely allied, that usually 

 if not indeed always, what influences one also influences 

 the other. Among the foods that influence both favorably 

 are fresh succulent grasses, nutritious in character. Among 

 those that influence both unfavorably, when eaten in large 

 quantities are rye and rape among pastures ; turnips, ruta- 

 bagas and the tops of these, and to less extent potatoes 

 among roots and tubers; and leeks (Allium trie oc cum) and 

 penny cress (Thalsapi arvense) among weeds. The taint 

 thus imparted to the milk extends also to the butter. Color 

 in milk is more influenced by breed than by feed as shown 

 below, but it is true also that foods which furnish the 

 most palatable milk also furnish it of good color. 



