50 Cattle Frobhms. 



pose, also begins. With the storage of milk in the udder, 

 milk-weight in the bottom of the udder begins to extend 

 its strain higher and wider, in this way reversing the 

 hair and enlarging the size of the Vield Mark, during 

 the heifer's first season of storing her milk in the udder. 

 The size of the Yield Mark is, of course, increased in 

 this way as long as the quantity of milk and its weight- 

 strain increase ; the maximum yield of a season being 

 reached, generally, before the first of August ; after this 

 time, yield gradually declines, but the Yield Mark re- 

 tains its size undiminished. During the several succeed- 

 ing seasons, the yield increases till the heifers reach 

 mature or full size, at five or six years of age ; yield gen- 

 erally increasing, if feed be increased, enlarging the udder, 

 the yield, and the size of the Yield Mark correspond- 

 ingly, as shown in Plates I. and II., and the size of this 

 Index Mark is according to the weight and quantity of 

 maximum yield, without regard to size or breed of cows. 



The Practical Value of the Yield Mark 



consists in its known relation to yield. It is established 

 that the milk-weight originates the Yield Mark, tlic 

 yield thus establishing its own maximun Index by thestrain 

 or tension of its own weight or Gravitation. There is 

 no myth about it, for it is so clearly evident that it cannot 

 be disputed, nor reasonably denied. 



The Yield Mark indicates the maximum yield, which 

 is an advantage, as, if the yield be small compared with 

 the size of the INIark, it must have diminished, and meas- 

 ures c?n be taken to restore the yield to the full capacity 

 of the cow, as shown by the Yield ]\1ark, which may in- 

 dicate capacity for larger yield. The udder must have 

 size according to its contents at any time, but its con- 

 tents and size may be increased by stanking, or storing 

 a days yield, or more — instead of only a twelve-hour sup- 



