688 CYCLOPEDIA OP lilTB STOCK AND COMPLETE STOCK DOCTOR, 



cannot ascertain their presence in any but very good cows. Of all the 

 iiiarks of abundant milk secretion, the best, and in fact the only infallible 

 marks, are furnished by the veins of the twist and of the udder. To 

 estimate them correctly it is necessary to take into account the state of 

 the cow in respect to flesh, the thickness of skin, food, ability to stand 

 fatigue, heat; all the circumstances, in fact, which cause variations in the 

 general state of the circulation, and in the dilation of the veins. It is nec- 

 essary, moreover, to recollect that in both sexes all the veins are larger in 

 the old than in the young ; that the veins which encircle the udder are 

 those which, if the cows are in milk, vary most according to the age of 



GREAT MILK MIRROR ON HOLSTEIN COW. 



the animal. Small when the animal is young, they continue to increase 

 in size until after the cow has had several calves, when they come to their 

 full development. 



"This proportion between the size of the veins and the milk secreted, 

 /s observed in all females without exception. The size of the veins and 

 their varicose state being due to the blood attracted by the increased 

 activity of the milk-glands, is not only the sign, but also the measure, 

 of this activity — this connection. In fact, this connection is so close that, 

 if the glands do not give an equal quantity of milk, the larger veins are 

 on the side of the udder which gives the largest quantity. 



