TRANSACTIONS OF SECTION M. 



779 



Lot II. (With Phosphate.) 



5. The Significance of ilie Acl of Milking. 

 By Professor C. Ceowther, M.A., Ph.D. 



The operation of milking serves to remove pre-formed milk from the udder, 

 but it is possible that, in addition, the handling of the teats may iminirt a 

 stimulus to further vigorous secretion during the period of milking. Data 

 were adduced in support of the latter hypothesis. 



Further tests, in which the ' quarters ' were milked separately, and the 

 milk from each ' quarter ' collected in fractions, show that whereas in the case 

 of the first ' quarter ' milked there is a tendency for the percentage of fat in 

 the milk to rise steadily from the earliest-drawn to the last-drawn fractions, 

 this tendency is much less pronounced in the case of the other ' quarters,' and 

 indeed, in the case of the ' quarter ' milked last, the tendency for a consider- 

 able portion of the milking is for the percentage of fat to fall rather than 

 to rise. In all cases there is a very rapid rise in the percentage of fat towards 

 the close of milking. If the ' quarters ' be milked in jjairs, the records of the 

 first pair resemble those of a ' first quarter ' and those of the last pair resemble 

 the records of a 'last quarter.' If the four 'quarters' be milked simul- 

 taneously the records of each resemble those of a 'first quarter.' These con- 

 clusions are not affected by the order in which the ' quarters ' are milked. 



Taking the produce of each ' quarter ' as a whole, it was found almost 

 invariably that the milk from the ' quarter ' milked first was the richest in fat, 

 and that from the last ' quarter ' was poorest in fat. In thirty-seven com- 

 parisons of first and last ' quarters ' milked suigly the former gave the 

 richer milk on thirty-four occasions, the average percentages of fat being 

 4-26 (±"15) and 3-10 "(±'13) respectively. In ninety-five comparisons in which 

 the ' quarters ' were milked in pairs, the first pair milked gave the richer milk 

 on sixty-five occasions. 



The foregoing observations led to the conclusion that the time-factor must 

 be of considerable importance in millting. This was confirmed by a comparison 

 of very quick and very slow milking by ordinary methods, which showed a 

 difference of 10 per cent, of milk-yield and 40 per cent, of fat-yield in favour 

 of the quick milking. 



