66 Oattle Prollems. 



with breeding power, it is not desirable, as a rule, after 

 about the middle of pregnancy. It seemed necessary, how- 

 ever, to explain the reason of cows drying, and of the dif- 

 ference in duration of yield, in different cows. The "ir- 

 repressible conflict" between art and commerce, as against 

 natural breeding power, will probably continue, the fear 

 being that nature in the cow will be worsted in the strug- 

 gle to survive, the too prevalent tendency being to feed 

 and milk cows without regard to the conditions or limits 

 of their digestive power. 



The size of the udder is naturally changeable, and if it 

 were not, it would be difficult to estimate its contents, as it 

 is quite variable and irregular in form. 



The Yield Mark varies in form in different cows, with 

 the outline of the breech figure, and underlying muscle 

 growth of the parts it is formed upon, but its total size or 

 area, regardless of difference in form, is generally propor- 

 tioned to yield, because the mark is formed by the strain of 

 the milk-weight itself, and must therefore be an index of 

 the weight of the milk. So the relation between yield and 

 the Yield Mark is that of cause and effect, the Yield 

 Mark being the evident consequence of yield. 



The Yield Mark is, therefore, the certain and natural 

 sign of maximum yield, and as the continuance of yield is 

 according to quantity, duration of yield is generally accord- 

 ing to the size of the Yield Mark. The larger the yield, 

 the longer the period of drying, by contraction of the ud- 

 der supply arteries, and diversion of blood to supply the 

 embryo demand. 



It seldom happens that cows having a large Yield Mark 

 dry up rapidly or early. Hence a large Yield Mark sig- 

 nifies duration as well as gua?itity of yield in proportion to 

 the area of the index mark. A cow may inherit faint out- 

 lines of her dam's Yield Mark. This would show only 

 inherited capacity in her structure. But a clear, full Yield 



