CHAPTER FIFTEEN. 



INBREEDING, LINE BREEDING AND CROSS 

 BREEDING. 



Inbreeding is one of the surest ways known to establish, 

 permanent type in animals, and has been from the time of 

 the early history of improved herds of swine, as well as all 

 other domestic animals. It might be said it is nature's 

 way of reproduction among animals and all living things, 

 except the human family, but it must be carried on with 

 great caution when handled by man. Of course in the 

 matter of wild animals, birds, etc., it is simply a matter 

 of the survival of the fittest, so that weaklings would never 

 probably be reproducers of their kind. For instance, take 

 game birds ; there seems to be no degeneration of 

 their species, as there would be in animals of the 

 domestic kind if they were allowed to take nature's course 

 unlimited, but a man of wise judgment can inbreed even to 

 a great degree by being extremely careful in his matings 

 and always seeing that no female with a marked weak point 

 in her make-up is ever mated with a sire, with the same 

 weakness. In other words, the mating should be of two 

 animals of similar blood lines, both strong and well devel- 

 oped in their general make-up. In this latter case the 

 produce should be an improvement on either sire or dam, 

 and yet there will occasionally crop out an inferior animal 

 or two in the offspring which should immediately be dis- 

 carded as a future reproducer of its kind. Herds would be 

 improved to a great degree if this rule was practiced intel- 

 ligently, but woe be unto the practice of indiscriminate in- 

 breeding. 



Line breeding is somewhat similar to inbreeding, but not 

 carried to as great an extent. It is the mating of animals 

 along similar blood lines on the part of both sire and dam 

 with occasional out-crosses, that is, a cross of different 

 blood lines, but of the same type, a little further back in 



