Wilsdorf: German Zootechny 



111 



able strain of swine is prineipally due to 

 the blood of a single early boar Richard . ' ' 

 This means that the origin of most of 

 the valuable strains of live-stock in 

 Germany has been due to line-breeding 

 — and the same is true of any other part 

 of the world. The value of such breed- 

 ing was known to the Greeks and 

 Romans, but after their time it fell into 

 great disrepute, partly from theological 

 reasons, and until recently, the author 

 says, it was considered not only a 

 questionable, but a distinctly dangerous 

 procedure in Germany, while even today 

 many a breeder will pay a higher price 

 for an animal if he feels sure that it is 

 not related to any now in his herd. 

 "The modern science of breeding, how- 

 ever, stands firm in its belief that for the 

 production of definite types for special 

 purposes in-breeding is the quickest and 

 most certain method of procedure, and 

 all great breeders who work toward any 

 particular goal depend largely on in- 

 breeding, knowingly or unknowingly." 



REVERSION OR ATAVISM. 



A certain amount of inbreeding is 

 undoubtedly necessary to preserve the 

 type of any purebred strain of stock; 

 conversely, the quickest way to break 

 up the type is to mate with some widely 

 differing animal. Even if the mating be 

 between animals which look exactly 

 alike in respect to any given character, 

 that character will frequently disappear 

 altogether in the offspring and be 

 replaced by some character presumably 

 belonging to the breed or species very 

 early in its history : this is the phenome- 

 non of atavism, reversion or "throwing 

 back. ' ' It is parti ciilarly common in our 

 domestic animals because, as Dr. Wils- 

 dorf points out, most of them seem to be 

 the product of the union of several 

 different races or even species, at some 

 remote time in the past. The resiilt of 

 such mixture is seen in an interesting 

 case he cites, of the herd of white cattle 

 owned by the King of Wiirttemberg 

 and kept in Rosenstein Park near 

 vStuttgart. "Here a pure white herd 

 has been bred for many years, and new 

 pure white males of many breeds 

 (Schwyzer, Allgauer, Simmentaler, Lim- 

 purger, Swabian Haller, Hollander, 



East Friesian, Shorthorn, Alderney and 

 Zebu) introduced at intervals. But 

 although no animal which was not white 

 has been introduced, so far as is known, 

 since the herd was established, a number 

 of calves are born each year which are 

 not white, but some other color." 



Most existing breeds of live stock 

 probably have an origin not very much 

 less mixed than that of the King of 

 Wiirttemberg 's white cattle: the mix- 

 ture was made at a more remote period, 

 however, and its complexity is there- 

 fore not so vividly realized. 



With material of that sort to work 

 on, it is evident that the task of the 

 modern breeder is one of great delicacy. 

 His chief object is to produce animals 

 that are all of one type; and yet the 

 very make-up of his stock makes it in- 

 evitable that nature will constantly 

 strive to break away from that artifical 

 type and return to the more primitive 

 characteristics. How shall the breeder 

 thwart this effort of nature ? 



As suggested above, he does it by 

 line-breeding, that is, by breeding in 

 one blood-line as much as possible — • 

 "pure breeding." The so-called "pure- 

 bred" animal, then, has been produced 

 by line-breeding more than by any 

 other factor. 



"Strictly speaking, any introduction 

 of foreign blood would restdt in the 

 breed no longer being 'pure.' But 

 frequently it is to the interest of the 

 breed to introduce a new blood stream, 

 that is, new and valuable characteristics. 

 Speaking by and large, one cannot then 

 say that the breed is no longer pure; 

 the word 'purebred' is relative, not 

 absolute, in its meaning. Our producers 

 of purebred stock frequently speak of 

 'crossing' when they employ stock for 

 breeding which is not quite their ideal 

 in type. Here again the idea of 'pure- 

 bred' is pretty narrowly construed. 

 The practical breeder understands it 

 more broadly: for him the mating of 

 animals of the same type is pure breed- 

 ing." 



To sum up, the triumph of scientific 

 animal breeding has consisted in the 

 suppression of natural diversity and in 

 breeding animals true to a fixed type: 

 the study of pedigrees and the utiliza- 



