276 DOMESTIC ANIMALS, DAIRYING, ETC. 



the mating of related animals in a single instance, or at intervals 

 among the generations, without much regard for the closeness of the 

 relationship. (3) Close breeding merely implies that closeness of re- 

 lationship existed between the animals mated. (4) Line breeding 

 implies the breeding of animals within the members of one family, 

 or one or more related families. It is virtually a continuation of 

 in-and-in breeding, the relationships being less close. 



It is astonishing the extent to which in-and-in breeding and in- 

 breeding are allowed among the common stocks of the country, and 

 this too, by some persons who realize fully the seriousness of the 

 practice. It arises, of course, from the selection of sires from among 

 the offspring of the herd; in some cases, it may be due to a lack of 

 means to make a suitable purchase, but in general, it is due to care- 

 lessness or indifference. When in-and-in 'breeding is carried too 

 far the following evils are likely to result, viz. : loss of size, delicacy 

 of constitution, impaired reproductice powers, and in fact general 

 deterioration. 



The practice of in-and-in breeding, and in-breeding, should not 

 be denounced entirely, for they may become useful factors when em- 

 ployed by those skilled in the art of breeding ; they must almost nec- 

 essarily be used in the formation of new breeds, where it is the aim 

 to fix new characters in animals, and secure uniformity and perma- 

 nence in the transmission of the same. But, on the other hand, the 

 improver of common stocks has no occasion to resort to close breed- 

 ing. He is not going to become a former of new breeds or types but 

 is going to improve his common stocks through up-grading, in which 

 he will rely solely on the prepotency of the sires chosen to work the 

 transformations by w r hich each succeeding generation will be brought 

 more near to his own standard of excellence. 



Prepotency. What is prepotency? Strictly speaking, prepo- 

 tency is the superior power which one parent has over the other in 

 determining the character of the off-spring. But the term is more 

 commonly used to indicate that power which an animal has to trans- 

 mit its own qualities. If a pure male were to beget progeny from fe- 

 males of the same breed, which bear a close resemblance to the male 

 parent, this result would be a stronger evidence of prepotency in the 

 male, than a similar result produced by mating him with females of 

 mixed breeding, since the resistance to modification in the progeny 

 of the females in the first instance, would be stronger than resistance 

 to the same in females in the second instance. This quality in a sire 

 is one of the most important factors stimulating rapid improvement 

 in any process of upgrading. It is more important in the sire than 

 the dam, as the effect on the sire's side is more far reaching. Prob- 

 ably one of the most difficult things in animal breeding is to deter- 

 mine whether a sire is possessed of prepotency or not. It is conceded 

 by some, that prepotency is the result of certain lines of breeding, 

 and that certain visible characteristics must accompany it. The fol- 

 lowing are some influences tending to produce prepotency, viz. : (1) 

 duration of purity of breeding without admixture of alien blood; 

 (2) uniformity of type and results from animals in pedigree; (3) 



