Abortion in Cows. 209 



fed liberally from their calf-hood up, and if put upon the 

 scant feed that many cows on grain farms receive, such 

 dairy cows would certainly shrink their yield, or flesh, 

 probably both. On the contrary, the " new cows" from 

 the mixed farming country, outside the dairy districts, are 

 subject to very great changes. The quantity of feed the 

 stranger cows receive on coming into dairy herds, par- 

 ticularly into cheese-dairy herds, is a very great increase 

 over the quantity of feed they are previously accustomed 

 to. Besides which, the new feed of those new stranger 

 cows is much of it richer in quality, consisting of corn- 

 meal, shorts, bran, etc. — than such as they have previously 

 received. The consequence is, the new cows eat with 

 great avidity, making a rapid increase in blood, and in 

 yield, as the fact that many of these new cows double 

 their yield in fourteen months* clearly shows. Some of 

 this new cow class are believed to double their yield in 

 eight to twelve weeks, though as a class they are 7!of large 

 milkers. 



But large yield is not here the question. When cows of 

 only small or moderate yield, that have been previously 

 only scantily fed, double their yield in only a few weeks, 

 or months, as many of the stranger cow class are known 

 to do, their udder-supply arteries are meanwhile en- 

 gorged, and the artery walls thinned down with as much 

 rapidity as their yield is increased. And the udder-sup- 

 ply arteries' walls in many of them are relaxed in degrees 

 varying in different cows, according to the extent of en- 

 gorgement from over-rapid increase of feed, mammary 

 blood, and yield in excess of their previous quantity of 

 feed, mammary blood, and yield. It is the excess of in- 

 crease above their previous yield, whether the latter be 

 small or moderate, which engorges their udder-supply ar- 

 teries, and the danger of their engorgement increases with 



* Sec Table. 



