656 PRACTICAL PROBLEMS 



and conditions generally in what ought to be one of the most 

 steadily conducted of all the industries. 



These, in brief, are some of the limitations of the animal 

 breeder. He cannot afford to close his eyes to their existence, 

 for they are realities. He will get on best to frankly confess their 

 existence and to meet them to the best of his ability. It remains 

 to examine a little more closely into some of these and other 

 detailed considerations that must engage the breeder's attention. 



SECTION II FEWER CHARACTERS FOR SELECTION 



The greatest single improvement possible in present-day 

 animal breeding in most lines would be to free the situation 

 from unimportant characters. At best the breeder must pay 

 regard to a large number of considerations in making selections. 

 Constitutional vigor, high productive powers, and utility for the 

 purpose in mind are fundamental considerations, and the last 

 (utility) is more than likely to cover many points. 



Now the difficulties of selection increase at a surprising rate 

 as requirements multiply. If a proper degree of constitutional 

 vigor is found in but one animal out of two, and it is not 

 higher than that, then the chances of a particular animal prov- 

 ing satisfactory in this respect are but one out of two, or, as we 

 say, his probability is J. If, again, but one animal out of three 

 is fully fertile, 1 and it is doubtful if the proportion is higher, 

 in certain lines at least, then the chances of a strong constitu- 

 tion and full fertility being found in the same animal are but 

 \ X J, or l. If, now, we add to this a third requirement found, 

 say, in but one animal out of ten, then our chances have been 

 reduced to \ X \ X -^ g\, which is equivalent to saying that 

 only one animal in 60 taken at random that is, but one animal 

 in 60 of all that are born into the breed will fully meet our 

 demands and satisfy our requirements, except in so far as the 

 characters in question may be related by causation and to that 

 extent overlap. 



1 By full fertility is not meant the power to reproduce as against absolute 

 barrenness, but rather full and maximum powers of reproduction, that is, regular 

 breeding throughout a reasonably long life. 



