228 THE CHEMISTRY OF THE FARM 



quantity it increases somewhat in richness. The milk 

 sent from the country to London, yielded for the most 

 part by cows calving in the spring, is poorest from 

 April to June, and richest in November, the total 

 variation amounting to 0'5 per cent, of fat. The 

 evening's milk is usually richer than the morning's 

 milk; the average difference in the milk sent to 

 London is 0"36 per cent, of fat, but in particular cases 

 the difference may exceed 1*0 per cent. This difference 

 is apparently connected with the times of supplying 

 food and water, it is greatest during winter feeding, 

 and may disappear altogether while a cow is on 

 pasture. The first milk leaving a cow's udder is very 

 poor in fat, sometimes but little superior to skim-milk ; 

 the last milk is extremely rich in fat. The whole of 

 the milk yielded by a cow must thus be thoroughly 

 mixed before its composition can be truly ascertained. 



Influence of Breed. — The richness of milk depends 

 much on the "race" of the cow, the fat being the 

 constituent most affected. The Jersey breed gives 

 the richest milk, the fat amounting to 6 — 6 per cent. 

 Next to this stands the Guernsey. The Kerry, 

 Welsh, and Ked-polled follow with over 4 per cent, 

 of fat. The milk of the Shorthorn and Ayrshire con- 

 tains nearly 4 per cent. The Holstein, and some 

 other Continental breeds, yield about 3*4 per cent. 

 The Holstein and Shorthorn are remarkable for the 

 large quantity of milk they yield. The difference 

 between individual cows of the same breed may be 

 very great. The milk of each cow in a dairy should 

 be separately tested if economic production is desired. 

 It is quite obvious that a different cow is required 



