PRINCIPLES OF SWINE BREEDING 21 



greatest success has been the breeder's maxim, "Breed 

 the best to the best." While as a general rule this is a 

 good one to follow, and in most instances is the best, 

 there are instances where it will result in failure. If the 

 breed is pure as to origin the results may prove satisfac- 

 tory, but if the origin of the breed has been complex, and 

 especially if the breed is of recent origin, the practice of 

 breeding the best to the best may yield a high per cent 



Proper feeding must accompany breeding. Courtesy of E. J. 

 McCall of Louisiana. 



of failures. This is easily understood when we consider 

 that if a breed is pure there is a variation around one 

 mean only, while when the breed is complex as to origin 

 and is made up of several types, the variations tend to 

 cluster around several means, and marked reversions too 

 often accompany crossing of members of the breed that 

 appear similar. Therefore, while it is fraught with 

 danger in some instances, about the best we can do is to 

 breed the best to the best, unless we have good reasons 

 for doing otherwise. 



Pedigree. Our progress in swine breeding must be to 

 a large extent based upon proper utilization of pedigree 



