Essentials of Animal Breeding. 17 



THE ART OF BREEDING. 



SELECTION. 



Keeping in mind the principles laid down in the foregoing pages, 

 it is clear to every one that in order to make the best out of the 

 hereditary material represented in one's herd, and to use the laws 

 of nature to the best advantage, one must have clearly in mind a 

 standard which he sets for himself as the ideal toward which he 

 must work. This standard must be definite and should be as prac- 

 tical and simple as possible. The exercise of selection, wisely and 

 judiciously pursued, offers the breeder one of the two most effective 

 means of bending to his own purposes the operations of chance, 

 which otherwise nature will use to his confusion and undoing. 



We have made the statement already that the hereditary material 

 is passed down from generation to generation without change ex- 

 cept so far as the operation of the laws of chance may have affected 

 the process, beginning with the maturation of the germ cells. It is 

 plain, however, that constant selection of a good type will increas- 

 ingly intensify the properties of a given set of characteristics (in 

 other words, of a definite type), but that this selection must be pur- 

 sued constantly because the chromosomes which tend to produce the 

 less desirable types continue to be present, although in decreasing 

 numbers. If the force which has been selecting the desirable 

 chromosomes is removed, then the undesirable ones may once more 

 prevail. In other words, our modern breeds of farm animals are an 

 improvement over the stock from which they sprang. There is, 

 therefore, a constant pull backward and downward against which 

 the breeder must work by wise selection and skillful matings. If 

 this intelligent direction by human skill should be removed, our 

 animal stock would rapidly degenerate to the level of the types of 

 centuries ago. 



Selection should be -designed to correct faults in the parents, and, 

 as a rule, the male is depended on to do it. A few concrete cases will 

 illustrate. If the females have a tendency to be too leggy, select a 

 male that is compact and close to the ground. If the backs are not 

 ideal, select a male with an exceptionally strong back. If the sow's 

 feet are not the best, get a boar that is unusually strong in his feet 

 with strong, upright pasterns. We might multiply these illustra- 

 tions indefinitely. Therefore, a sire should be a better individual 

 than the females with which he is to be mated ; otherwise the stand- 

 ard of the herd or flock may decline. To some extent a breeder may 

 extend these principles to the grandparents, but for practical work 

 on a farm that is producing market stock it is commonly unnecessary 

 to go farther back than the sire to be selected. In other words, don't 

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