6 MILK AND DAIRY PRODUCTS PART 



amount of fat in separate milkings may vary from 1 to 8 per 

 cent. When, however, the mixed milk from several animals is 

 examined, it is found that the fluctuations are much smaller, 

 being then from 2*5 to 4'5 per cent., with an average, for 

 Germany, of 3'4 per cent. 



The variations in the fat content of milk are partly constant 

 and partly accidental. In the case of a single cow, breed, 

 individuality, and the stage of the period of lactation are the 

 chief factors which influence the amount of milk fat. 



As regards the breed, it is found that Jersey cattle give the 

 richest milk, whilst that from Low Country breeds, such as East 

 Friesland, is poorest in fat. The milk of Jersey cows contains 

 on an average 5 per cent, of fat, whilst that of East Friesland or 

 Dutch cows only contains 3'l-3'2 per cent. When, however, 

 the quantity of milk is considered, it is seen that the Low 

 Country cattle give an average of 670-780 gals, per annum, 

 whilst the yield of a Jersey cow is only some 510-560 gals. 

 All other breeds have a milk yield somewhere between that of 

 Jersey and Low Country cattle. 



The individuality of the animal also plays a very important 

 part, for there are cows which, in all circumstances, give 

 milk with a remarkably high or low percentage of fat, and often 

 this peculiarity is transmitted to their offspring. This fact is 

 of great importance when a good milking herd is being built up. 



The amount of fat in the milk is at its lowest after calving, 

 and rises without interruption almost to the next time of 

 calving. Here, too, the quantity of fat stands in inverse 

 proportion to the milk yield, for the latter is largest (as regards 

 one day) immediately after calving, and then gradually decreases 

 until the cow becomes " dry." 



The percentage of fat varies very much in the different 

 portions of one milking, for the first are found to contain only 

 small quantities of fat, whereas the succeeding fractions become 

 richer and richer until the last drops are very rich indeed. 



Accidental factors which may influence the fat content of the 

 milk are, for instance, sudden changes in the food, unskilful 

 treatment of the cows by their attendant, or anything that 

 disturbs or frightens them. 



On the other hand, it is impossible, except for a short period, 

 to raise the* amount of fat in the milk by the aid of specific 



