26o MANAGEMENT AND BREEDING OF HORSES 



the known causes are: Confinement and lack of exer- 

 cise; irregular supply of food; food lacking the proper 

 nutrients; animals in too fat a condition; in-breeding; 

 excessive breeding; and the like. To lessen sterility, we 

 should avoid all causes likely to produce it. 



Sire and dam. — The relative influence of the parents 

 is a much-discussed question, and all kinds of statements 

 are made concerning the influence that each parent exerts 

 on the offspring. So far as is known, however, the 

 parents play an equal part in their control of the char- 

 acters of the offspring. This, of course, is aside from the 

 question of prepotency, discussed above, and in which 

 either parent is likely to dominate over the other. 



SYSTEMS OF BREEDING 



The system of breeding to be employed in raising 

 horses will depend on the purpose and circumstances of 

 the breeder. If the object is the production of pure-bred 

 animals the system employed may differ from that used 

 in raising horses for the market. The circumstance of 

 the breeder may modify the system, as he may be so situ- 

 ated as to make it practically essential for him to employ 

 a given method. 



, Grading. — The mating of unimproved animals with 

 those more highly improved is perhaps the most common 

 system of breeding. Usually the improved parent is the 

 sire and the unimproved one the dam. This is the safest 

 for beginners, as it is cheap. If a worthy pure-bred sire 

 is used improvement follows rapidly. The first genera- 

 tion of offspring is half pure, the second three-fourths 

 and the third seven-eighths, and so on. By continuing 

 this grading process, selecting the best mares as breed- 

 ers, it is entirely possible and by no means difficult, to 

 produce animals equal to pure breds in the production 

 of work. In view of the ease with which improvement 

 can be obtained by this method it is surprising that our 

 horse stock does not improve more rapidly. 



