146 Effect of External Influences. 



milking. The principal cause lies probably in the fact that the separation of the fat 

 represents a greater expenditure of energy than the secretion of the plasma. If the cell 

 is exhausted by previous milking it then secretes milk during the period of rest which 

 is especially rich in plasma and poor in fat. Through this period the alveoli and milk 

 ducts are dilated, and the gland cell becomes flat and is at rest. In this position of 

 rest it recovers and is ready for renewed action when, through renewed milking 

 operations, the fluid is withdrawn and stimulation of the secretion is applied through 

 the teat. 



If the milk is removed without this stimulation of secretion, with the aid of a 

 milking tube, only milk poor in fat flows from the cistern and the larger milk ducts, and 

 the flow ceases as soon as pressure is no longer exerted on the secretion. 



If, however, through milking (or other stimulation) new secretion takes place, the 

 rested gland cell engorges with nutritive material, and converts it into fat, which is 

 separated during the milking in increased quantities until the secretion of plasma and 

 the separation of fat cease, which marks the height of these two processes in the 

 secretion of milk. Through an increased stimulation by additional milkings the cell 

 may be further stimulated to a special production, which consists in an increased fat 

 formation (Hegelund). Henkel succeeded by this procedure, in increasing the quantity 

 of milk by 2.4%, and the fat content by 6.2%. 



As already mentioned Hegelund 's method requires additional 

 work, which may possibly lead to the hiring of additional help 

 and must be considered (Kirchner), when estimating profit and 

 expense. The principal factor in the various methods of milking 

 lies in the thorough milking out of the udder, which will retain 

 its maximum of production only by such practice. Henkel suc- 

 ceeded in demonstrating the extent to which the milk production de- 

 pends on the thoroughness of the milker. The production of a cow 

 when milked by a thorough milker amounted to 8.1 kg. (17.8 Ibs.) 

 of milk, with 4.2% of fat; by a less satisfactory employee to only 

 5.6 kg. (12.31bs) with 2.7% of fat. 



At the same time it is immaterial what method of milking is 

 pursued, that is, whether the teats are milked crosswise, or those 

 on one side, or those of opposite quarters, simultaneously. Milk- 

 ing of a single teat at a time, which of course is not customary, 

 yields less milk, and the last milked quarter is the poorest in fat 

 (Lepoutre and Babcock). The influence of special methods of milk- 

 ing has been more fully discussed in the chapter on the procuring 

 of milk. According to Klinkmiiller the milk yield of the right half 

 of the udder is 3. 97 kg. (8.7 Ibs.), the left 3.65 kg. (8.03 Ibs.), with 

 fat contents of 3.65 and 3.31% respectively. The cause of this 

 increased production of the right half of the udder is, according 

 to Klinkmiiller, the result of the practice of milking the right half 

 first, and therefore it is advisable to practice alternation in milking, 

 from right and left. 



If milking stools are used care should be taken that the 

 milkers do not take hold of the seat with their hands. The most 

 recommendable stools have only a single foot, and are secured 

 around the body by a strap. Switching~of the animal's tail must 

 be prevented during milking by tying it up, or by other effective 

 contrivances. 



Conditions which prevail in the handling of milk after it has 

 been procured are of special importance in providing milk of Hie 

 best quality. The changes which milk undergoes have been dis- 



