MILK PRODUCTION 427 



for producing milk equal in quantity or quality to the milk 

 gland of the other. But the primary cause must trace 

 back to the variations which accompany inheritance. 



As the time of calving is receded from, the quantity of 

 the milk produced decreases more or less gradually. With 

 such decrease comes an increase in the proportion of casein 

 and to some extent decrease in the proportion of fat. The 

 fat also contains a larger proportion of volatile fatty acids 

 during the earlier periods of lactation, hence the butter 

 made from it is more highly flavored. 



The variations found in the percentage of fat in the 

 same animal from whatever source they may arise are 

 slight, compared with those found in milk as it is drawn 

 from the udder. That first drawn is lowest in butter fat 

 and the increase in the per cent of the fat is continuously 

 progressive, the richest milk being taken last. The differ- 

 ence is in some instances considerably more than 100 per 

 cent. 



Quantity in the milk flow influences the proportion 

 of solids in the milk. It may be affirmed that as a rule: 

 (i) Large yields of milk from cows are more watery than 

 small ones; (2) that milk is less watery as the lactation 

 period advances and (3) that the longer the intervals 

 between the milkings the more watery is the milk. 



Breeds and milk production. Breed influences: (i) 

 Quantity in production; (2) quality in the same and (3) 

 adaptation for production with reference to environment. 

 It is by no means the only influence bearing upon any 

 one of the phases of production just mentioned, but it does 

 bear upon each of them sufficiently to entitle it to careful 

 consideration when deciding upon the breed or high 

 grade of the same that shall be chosen for dairying. 



That breed influences quantity in milk production is 

 well brought out in the considerably higher averages ob- 

 tained from Holstein-Friesian cows as compared with the 

 Jersey. The same is true of high grades of these respec- 

 tive breeds. The difference in this respect cannot j^e. 



