252 Qattle Prohlemg. 



taining capacity, if their contractility is to be inaintained, 

 and unless artery contractility be maintained, breeding 

 power must be impaired to the same extent that artery 

 contractility is weakened or suspended. 



Contractility in the udder-supply arteries is the power 

 by which cows dry themselves. It is, also, the power by 

 which they are enabled to breed, by controlling their 

 mammary blood-flow, and diverting it to the embryo, 

 which would be impossible, Avithout contractile power in 

 the udder-supply arteries, that enables cows to carry on 

 and to complete the process of embryonic breeding. 



When cows are advanced in age, as deep milkers usually 

 are when they can no longer breed — breeding power 

 being lost by chronic relaxation of their udder-supply 

 arteries — their recuperative power is so much reduced that 

 recovery of breeding power cannot be reasonably ex- 

 pected. And, perhaps, no better course can be pursued 

 than to dry them by reducing their supply of water, by 

 reducing the moisture in feed, or in any way, to a mini- 

 mum allowance, and fattening them after they become dry. 

 Such cases are not very numerous ; still it is desirable to 

 reduce their number, which will become less, when the 

 cause and origin of the trouble is better understood, lo 

 aid in which these explanations are made. 



