72 Cattle Problems. 



maiicntly subject to the influences* which produce the 

 Yield ]\'[ark. 



Long continuance, of course, tends to fix forms or marks 

 that are acquired ; for tliis reason the Yield Mark be- 

 comes a fixed mark, co-extensively witli yield; as the same 

 force, in kind, which originates the mark, continues to 

 maintain this characteristic index of yield ; thus giving 

 the stronger power of transmission to the cow, as to 

 marks originating from milk yield. 



Furthermore, the "yield index, or mark," being derived 

 from a given cow, is not reproduced when transmitted by 

 male influence, until one or two generations later than 

 when transmitted by the cow directly ; or by cows of the 

 same age, to their calves of the first generation. And 

 this is true of other parts, such as large hind quarters, 

 that are favorable to yield, or a necessary condition of the 

 tendency to yield abundantly. 



Cows can only mark one calf in a season, while bulls 

 transmit such faint marks as they possess ; the male having 

 the advantage in giving his own markings as to numbers 

 of calves. So it is rapid propagation, as to numbers, not 

 superior power of transmission, which is the chief reason 

 why the marks of bulls have so much importance attached 

 to them by some writers on breeding. 



It also seems highly probable that cow calves are more 

 likely to inherit the growths and marks incident to 

 acquired milking capacity, from their milk-foi*ming struc- 

 ture being similar to that of the cow, and so being 

 naturally formed and adapted to receive impressions or 

 be affected by influences that contribute to establish milk- 

 ing capacity. 



The distinction betweeen marks or passive signs of yield 

 and active capacity itself should not be forgotten as 

 capacity depends upon food, exercise, digestion and secre- 



*See " Origin ol Yield Mark," &c. 



