SELECTION 589 



handicap as to fertility, and perhaps as to vigor, in which case 

 these two essential qualities must be borne in mind and the 

 deficiency remedied in future selections. The breeder is never 

 to forget that natural selection is at work side by side, or per- 

 haps over, his best endeavors. In nature the prevailing type is 

 a kind of resultant of the highest fertility and the best " fit." 

 It is not different in our herds. The type which naturally appears 

 in our herds will foe decided not only by our selections but by 

 the relative fertility and vigor of everything present. 



Examples are not wanting in which herds, and even whole 

 families, have gone down because of this unequal battle against 

 the persistent influence of natural selection. The most notable 

 instance is the " Duke and Duchess " family among Shorthorns, 

 most excellent individuals and true to type, but not sufficiently 

 prolific to maintain themselves. So they went down and out, 

 submerged under the inevitable decree of natural selection that 

 the unprolific shall die. The writer does not believe that this 

 most excellent family need have been lost to the breed had the 

 breeders of the day been sufficiently alive to the situation. 1 



This response to inequality in natural fertility of different 

 strains is technically known as " genetic selection," and it is 

 everywhere at work. It must be reckoned with in some form. 



Physiological selection. Certain individuals are sterile to each 

 other. It is a difficulty seldom encountered, but when it does 

 occur it constitutes an effective bar to those particular blood 

 combinations, however desirable. Because it is limited to pairs 

 of individuals, its interference is occasional rather than com- 

 mon ; yet, when encountered, it should be recognized, and time 

 and expense avoided in attempts to overcome it. 



Influence of age. Statistics show that a surprisingly large 

 proportion of sires are so young as to be clearly immature. The 

 effect of this has been much discussed, and the general opinion 

 seems to be that breeding from immature animals is bad. 



1 This family was always known to be " shy breeders." The writer well 

 remembers hearing breeders say, " How fortunate that this is so, else prices would 

 not be maintained.' 1 '' Happy would it have been could these same breeders have 

 read their doom in time to save their pockets ! They had ample warning, had they 

 known how to read the handwriting on the wall. 



