16 The Horse Industry in New York State 



a mare. This practice may necessitate choosing an animal of 

 some age, bnt it is preferable, as we know for a certainty what 

 to expect of the offspring. 



PREPOTENCY 



There is a wide variation among horses in their power to stamp 

 their characteristics upon offspring. When the offspring resem- 

 bles one parent more than the other, the one transmitting it is 

 said to be prepotent over the other parent. Thus prepotency 

 becomes of importance in improvement, and tlie inflnences that 

 tend to produce it in the individual are worthy of careful con- 

 sideration. While many of the factors that influence prepotency 

 are little understood, tliose that do aid and are under the control 

 of man are: first, purity of breeding which favors stability; 

 second, strong constitutional development which strengthens the 

 characters; and third, limited inbreeding which aids prepotency 

 as it streng-thens dominant characters, both good and bad. 



In breeding horses the prepotency of the stallion is given more 

 consideration than that of the mare. This is due to the fact that 

 the sire is the parent of more individuals than the dam, and not 

 to individual resemblance. This is fortunate, as improvement 

 can be more cheaply secured through a good sire from the mere 

 fact that he is represented in more progeny. Furthermore, since 

 comparatively few males are needed for breeding purposes, they 

 are usually much more carefully selected than are the females, 

 practically all of which are bred. This also favors the prepotency 

 of the stallion. 



STERILITY 



Perhaps the horse breeder's greatest difficulty is the failure 

 of his animals to breed freely. The causes which lead to sterility 

 are many, some of which are understood and are more ot less under 

 control ; others — and by far the larger and more serious number 

 — are little known and beyond control. Some of the known and 

 preventable causes of sterility are: first, confinement and lack of 

 exercise ; second, irregular food supply ; third, food lacking proper 

 nutrients; fourth, animals too fat; fifth, close inbreeding; sixth, 

 excessive breeding, particularly with the stallion ; and like 

 causes. To lessen sterility, the breeder should make a careful 



