PART III ANIMAL BREEDING 



CHAPTER XXVII 

 THE GENERAL ASPECTS OF ANIMAL BREEDING 



From a scientific standpoint it would be practically useless in this 

 treatment of genetics in relation to animal breeding to develop exten- 

 sively the historical features of the subject; because they cannot be re- 

 lated effectively and satisfactorily to a growing knowledge and application 

 of the principles of variation and heredity, and because of the peculiar 

 nature of many of the problems of animal breeding. Accordingly this 

 chapter will be devoted for the most part to a discussion of the importance 

 and possibilities of the breeding industry, and of the opportunity for 

 service which genetics has therein. 



The History of Animal Breeding. The domestication of animals 

 occurred very early in the history of man ; so early that accurate historical 

 documents do not carry us back within sight of the time when man first 

 began to take wild animals under his care. The history of most of our 

 domesticated animals, in fact, is very incomplete, and in many cases we 

 can only conjecture as to the wild species which were probably subjected 

 to domestication, or from the hybridization of which our tame breeds 

 have had their origin. This difficulty of determining precisely what 

 wild species have been utilized by prehistoric man, or in finding among 

 wild species any which are obviously closely related to those under do- 

 mestication, is in itself proof conclusive that improvement in herds of live- 

 stock, kept at first perhaps in a state of semidomestication only, must 

 have been coincident with the beginnings of domestication. Through 

 long centuries of slow progress the level of excellence in early tribal herds 

 had gradually been raised, partly by the action of factors unknown to 

 and undirected by primitive herdsmen, partly under his conscious 

 direction. As a result man has established numerous races more defi- 

 nitely suited by far to his particular purposes than were their wild 

 ancestors which roamed the plains or inhabited the forests. Conse- 

 quently even at the dawn of history, domesticated animals had already 

 been developed to a high state of excellence, when measured by their 

 adaptability to particular local conditions of life and their suitability 

 for the purposes for which they had been bred. 



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