884 VETEEINAEY HYGIENE 



mated with his own daughters, provided that they show the 

 desired type. 



This system has been much resorted to in the formation 

 of new breeds, and reduces the liabiUty to variation to a 

 minimum, as the blqod of both parents is almost the same. 



The offspring of such a union is usually exceptionally 

 good looking and full of quality, but there is always a strong 

 tendency to weakness of constitution, and if the system is 

 persisted in over a number of generations the stock will 

 become quite effete, and the females either refuse to breed or 

 produce a large proportion of weedy or malformed animals. 



When this system of inbreeding is resorted to, every 

 endeavour should be made to counteract its enervating 

 tendency by rearing the young stock under the healthiest 

 and most natural conditions possible. 



Among shorthorn breeders, who had recourse to this 

 system very largely in establishing the breed, attempts were 

 made to obtain exceptional vigour of constitution in the 

 sires by sending them away for a season or two to a totally 

 different climate to that in which they were reared. A well- 

 marked instance of the influence of inbreeding is seen in 

 the ' Snorer ' family of polo ponies, in which the type was 

 reproduced with remarkable fidelity. 



Unsoundness. — In nothing is the maxim that ' Like 

 produces like ' more certainly borne out than in the trans- 

 mission of the tendency to unsoundness, so that the breeder 

 should be most particular only to breed from absolutely 

 sound stock. By soundness we mean not only soundness 

 of wind and limb, but also of constitution. Among horses 

 there are certain well-accepted hereditary unsoundnesses 

 which are laid down as disqualifying a thoroughbred sire 

 from winning a Queen's Premium. They are as follows : 



Eoaring, whistling. Navicular disease. 



Eingbone. Spavin. 



Unsound feet. Cataract. 



An animal showing any of the above unsoundnesses 

 should be rigorously excluded for breeding purposes, how- 



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