671. The association between the fat percentage of cows' milk and the size and number of the fat globules

Milk samples were collected, between 17 April and 30 May 1956, from fifty-six Ayrshire and forty Friesian cows, which had been calved for between 45 and 165 days, when they were running out at grass day and night. The results showed that differences in the fat percentages of their milk were accompanied by corresponding variations in the average diameter of the globules in both breeds and in the numbers of globules per cu.mm. in the Friesian cows. These changes were not significant for either variant because there were some individuals in which changes in fat percentage appeared to be accounted for by either an increase in fat globule diameter or an increase in the number per cu.mm. with correspondingly low figures for the other variant.