266 LIVE STOCK IMPROVEMENT 



deen Angus parents because years ago there were many- 

 red Angus cattle. This reversion is atavism. 



Mutants or Sports. — Frequently animals are born that 

 are direct deviations from their ancestors such as a poUed 

 animal from horned ancestors. These animals are called 

 " mutants " or " sports," and many breeds of animals 

 have been developed from these " sports." A good ex- 

 ample of this is seen in the case of the Double Standard 

 Polled Durham cattle. 



Crossbreeding. — Crossbreeding is the mating of animals 

 of the same species, but of different breeds. A calf pro?; 

 duced by mating a pure-bred Shorthorn with a purerbred 

 Hereford would be known as a Shorthorn-Hereford cross;; 

 bred calf. Introducing the blood of a different breed, for 

 only one generation is knowii as an " outcross." The 

 crossing of different breeds tends to break up the charac- 

 ters by which any particular breed is known, and is 

 unsatisfactory after the first cross. 



Hybrids. — The mating of animals from two different 

 species produces the hybrid. The mule is the commonest 

 and best-known hybrid among farm animals. Hybrids 

 are generally nonbreeders, but cases are on record where 

 they have reproduced. 



Inbreeding. — Inbreeding is the mating of closely re- 

 lated animals. It is resorted to by breeders in develop- 

 ing new breeds of animals, or in the fixing of certain 

 characters. 



Line Breeding. — Line breeding is allied to inbreeding, 

 except that the animals mated are not so closely related. 

 It generally applies to breeding of animals of the same 

 family that are more remotely related than in the case of 

 inbreeding. 



