1906.] BREEDING ANIMALS ON THE FARM. 165 



tionate to the excellence of the individuality in the sire. The 

 importance, therefore, of possessing good and prepotent sires 

 cannot easily be overestimated. The truth that the sire is half 

 the herd is only a half truth. He is as much more than half 

 the herd as his prepotency exceeds that of each female parent 

 in the same. 



But how may it be known that a sire is prepotent before his 

 prepotency has been actually proved, as evidenced in the off- 

 spring. The answer to this question is of all absorbing in- 

 terest to the breeder, for sires are usually chosen before they 

 have begotten progeny. This raises the question as to the 

 probable guarantee of prepotency. These include purity of 

 breeding ; line breeding in degree and individual vigor. 



Other things being equal, a sire is prepotent in proportion 

 to the duration of the time that he has been bred pure. This 

 result follows from the continuous increase in the dominant 

 blood elements wdth increase in duration in breeding without 

 the introduction of alien blood. Whether there is a time limit 

 to this increase is as ^-et an unsettled question. In other words, 

 it is not yet certain that an animal from an ancestry bred pure 

 for a thousand years will be appreciably more prepotent than 

 an animal bred from an ancestry kept equally pure for five 

 hundred years. These dominant blood elements having be- 

 come thus fixed and stable, are transmitted with at least reas- 

 onable certainty to the progeny. 



Other things being equal, a sire is visually prepotent in pro- 

 portion as he is line bred or otherwise. Line bred means bred 

 within the limits of one family for at least several generations. 

 The closer the relationship at the outset of the line breeding 

 and the longer the duration of such breeding, the more prepo- 

 tent the sire is likely to be. For instance, suppose a Shorthorn 

 sire is chosen from the Missie family of Cruikshank Shorthorns. 

 If the said sire is chosen amid progeny bred for generations 

 from Missie sires and dams, no other Shorthorn blood mean- 

 while having been introduced, the line is likely to be more pre- 

 potent than if drawn from progeny whose ancestry included 

 members of various families of Chuikshank Shorthorns. 



Other things being equal, prepotency is strong in propor- 

 tion as the sire is possessed of inherent vigor. This is in keep- 

 ing with that other observed fact, that usually prepotency is 

 stronger in an animal when at that age in which bodily vigor 



