Animal breeding / by Laurence M. Winters.

  • Winter, Laurence Merriam, 1891-
Date:
1925
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Animal breeding / by Laurence M. Winters. Source: Wellcome Collection.

    249/328 (page 235)
    CHAPTER XVI FERTILITY 221. Importance of Fertility.—The function of breeding animals is to regularly perpetuate their kind; therefore, the degree of fertility within a herd, flock, or stud has a very direct bearing upon the profits from that herd, flock, or stud. No breeder, either of commercial or breeding stock, can afford to keep unproductive animals, except in the case of mares which can be used for work. In the case of dairy cattle there is an added loss, the lack of milk production. Not only are the more fertile females more profitable, since a given number of females will reproduce more off¬ spring which can be marketed, but in addition they enable the constructive breeder, and especially the пелу breeder, a chance to cull his breeding stock more closely. Assuming that three breeders start in the hog business with one sow each, the average litters of each sow and her descendants being 4, 6, and 8 pigs respectively—one-half of which are, in each case, males—and that the old sows are retained for five years, then the mmiber of females available for breed¬ ing purposes each year would be as in Table XXXII. None of the three would probably want all the females which would be available even before the sixth year was reached; but the owner of sow No. 2 would each year have been able to make a larger turnover in proportion to his capital investment and in proportion to his feed and housing costs than the owner of sow No. 1, while the owner of sow No. 3 would have exceeded either. In addition, the owner of sow No. 3 would each year have been able to cull much more severely than either of the others. 235