588 PRACTICAL PROBLEMS 



Size in the dam ; quality in the sire. In many lines of breed- 

 ing, size in the sire is considered by many breeders as of first 

 importance. This is against reason and biological principles. 

 We need in the sire all the desirable characters possible, and 

 these are most readily found in animals of medium, not extreme, 

 size. It is comparatively easy to get size alone, and this can be 

 gotten on the side of the dam. The herd must depend for uni- 

 formity largely upon the sire, and he should be freed as much 

 as possible from the requirement of size. 1 



Natural selection always at work. Natural selection is always 

 at work in field and flock and herd. Of this we may be well 

 assured. No matter what we desire to accomplish, our success 

 or our failure will turn, in the last analysis, upon the fitness of 

 the product to live and to reproduce amid the conditions by 

 which it must be surrounded. 



Some of the best things among both plants and animals are 

 weak or comparatively unprolific. Natural selection is decidedly 

 against their survival, no matter how valuable they may be to 

 us. Lack of constitution or vigor is easily seen, but lack of 

 breeding powers is not so easily detected, and here is where 

 the greatest amount of trouble arises. 



We have already seen that in nature the population that is 

 born into the world is proportioned according to relative fertility, 

 while the population that is permitted to remain is conditioned 

 upon relative powers to resist adverse conditions and to fit into 

 the conditions of life. 



This same relation obtains in our herds, with this difference, 

 that we, with our selection, decide arbitrarily what shall live. 

 That is right and according to economic necessity, only in 

 doing so we must not assume that all individuals and types are 

 equally fertile and equally able to propagate themselves. 



It may be in certain instances that in order to secure what 

 we desire we shall of necessity proceed temporarily with some 



1 A manifest exception to this general principle is in the breeding of draft 

 horses from farm mares. Here size is an objection on the dam's side, besides 

 being difficult to get. Weight is the chief desideratum just now (it will not always 

 be so) in draft-horse breeding, and \a\\Aev present circumstances it must be sought 

 especially in the sire. 



