12 



Farmers' Bulletin 1167. 



and daughters, we say that the stock " breeds on." In rare instances 

 an animal, usually a male, is found, which has such power as a breeder 

 that it leaves an indelible impress, even to the extent of becoming the 

 fountain head of a new breed, such as the stallions Justin Morgan, 

 Hambletonian 10, and Denmark. 



Most of the cases of prepotency which the breeder usually meets 

 with are probably instances of the operation of what is called 

 Mendel's law. A clear explanation of this great law of heredity can 

 not be made within the scope of this short article, and the interested 

 reader, if he cares to go into the subject in detail, is referred to Dr. 

 Wright's bulletin. 5 



How Good Blood " Breeds on." 



FIG. 3. Cannon, Standardbred stallion at head of United States Government stud, 

 Buffalo, Wyo., a horse which has been remarkably successful in stamping his 

 characteristics on his offspring. Photograph taken when Carmon was 20 years old. 



It must be pointed out, however, that most operations of heredity 

 are not simple; on the contrary, they are highly complex and often 

 extremely difficult to understand. The chief use which the practical 

 breeder of domestic animals can make of Mendel's law at this time 

 is to find in it an explanation of occurrences that otherwise have no 

 rational explanation. 



One of the most interesting applications of Mendel's law in cattle 

 breeding is the inheritance of the polled characteristic. If we breed 

 a horned cow to a Red Polled, Galloway, Angus, or other true polled 

 bull, the chances are 9 to 1 or better that we shall get a polled calf. 

 The white face of the Hereford appears to be a similar instance. 



5 TJ. S. Department of Agriculture Bulletin 905, "Principles of Livestock Breeding." 



