MILK 



13 



variation than that of others. About 90 per cent, of the analyses showed 

 a variation of less than 0.2 per cent.; in certain cow's milk a variation 

 of 0.5 per cent, was not uncommon. The butterfat varied most, the 

 extreme being about 2 per cent, and only 56 per cent, of the samples 

 were within 0.3 per cent, of the average; 27.7 per cent, varied between 

 0.6 and 0.9 per cent, and 4.6 per cent, varied more than 0.9 per cent. 

 The investigators concluded that a sample taken from a single milking 

 gives little indication of the quality of milk produced by any cow. 



The variation in the fat content of individual cows was investigated 

 by Anderson also. His results are given in Table 8, wherein all those 

 animals that had a range of not more than 1 per cent, of butterfat are 

 grouped as one class; e.g., an animal testing as low as 3.2 per cent, and 

 as high as 4.1 per cent, would range 0.9 per cent, butterfat and would be 

 jisted in class 1; class 2 would have a range of 1.8 per cent, and so forth. 



TABLE 8. VARIATION IN BUTTERFAT CONTENT OF MILK OF INDIVIDUAL Cows 



(ANDERSON) 



(a) A few Jersey records included; the rest are Holstein. 



(6) 1,000 2-day semiofficial records of Jersey cows on register of merit tests and 

 1,000 2-day semiofficial records of Holstein-Friesian cows. 



The 7-day records in Table 8 indicate that about 50 per cent, of a 

 herd would, in 7 days, show a range of variation in butterfat of 1.1 to 2 

 per cent.; about 30 per cent, of them would show a range of to 1 per 

 cent.; about 14 per cent, would show a range between 2.1 to 3 per cent, 

 and the remaining 6 per cent, would show even greater variation. On 

 the basis of the 2-day test it would appear that about 66.66 per cent, of the 

 animals would show a range of variation of from to 1 per cent, of butter- 



