THE FEEDING OF MILCH CATTLE 309 



ditions. It may be said, though, that in general the 

 Dutch, Oldenburg, East Friesland, etc. cattle give 

 a greater quantity of milk poorer in fat and solids 

 than such breeds as the Simmental, Shorthorn, 

 Jersey, Guernsey, Alderney, etc. 



The individual animals of the various breeds also 

 behave very differently : for example, eighteen Dutch 

 cows which had been bred in East Prussia were kept 

 under observation during the whole period of lacta- 

 tion, and between the best and worst yields the 

 following differences were noticed : — 



Total milk yield . . 2230 — 4702 kg. . Proportion, 100 : 202 



„ amount of fat. 74-4 — U9'3 » • » IO ° : 201 



Percentage of solids 10-56— 12-86 % . „ 100 : 122 



„ fat . 2-63- 3.81 „ . „ 100 : 145 



In addition to the differences which are observed 

 between cows, there are also the variations in the 

 daily yield which are often observed with the same 

 cow, and which in some cases may be as much as 

 3-4 kg. milk, as well as differences in the percentage 

 of fat. The same cow may one day give milk 

 with 2-8% of fat, and the next day 3-9% without 

 any explanation, except the peculiarity of the 

 animal, being possible. 



The individual relations also show themselves in 

 the alterations which a change of food makes in 

 the quantity and contents of the milk. In one series 

 of experiments with fifteen cows, where some of the 

 carbohydrate portion of the ration was replaced by 



