CHAPTER XI 

 IN-BREEDING 



THE breeder of domestic animals is frequently confronted 

 with the problem of in-breeding. If in-breeding is not 

 followed by injury, it would often be a convenient method 

 of improvement. The value of a proven and tested sire 

 is so great that if he could be safely mated with his own 

 offspring it would be of great economic advantage to 

 the breeder. If, on the other hand, positive advantages 

 follow the mating of closely related animals, the breeder 

 should know what these advantages are and how and when 

 they may be most certainly realized. 



203. Definitions. In-breeding has been variously 

 designated as close-breeding, consanguineous breeding, 

 in-and-in-breeding, inter-breeding and incestuous breed- 

 ing. The term in-breeding is used to indicate the mating 

 of animals which are near of kin or closely related. The 

 degree of relationship which it is proper to 'designate 

 as in-breeding is a matter of some disagreement. Stone- 

 henge, for example, has defined in-breeding as " The 

 pairing of relations within the degree of second cousins, 

 twice or more in succession." Randall would restrict 

 the application of the term to " animals of precisely the 

 same blood as own brother and sister." 



It would be very desirable if the term " in-breeding " 

 could be limited in its application as suggested by Mor- 



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