CHAPTER XV. 

 THE BREEDING SEASON. 



Nature apparently has determined that animals be born 

 in the spring of the year, because this is the most favor- 

 able season. Since there is considerable difference in the 

 length of the period of gestation, the period from the time 

 the dam is bred until the offspring is born of different 

 animals, they are bred at different times of the year. Do- 

 mesticated swine, however, come in heat at any time and 

 may be bred to suit the wishes of the breeder. 



NUMBER OF LITTERS PER YEAR. 



In former times most of the swine of the country were 

 produced by having the sows farrow only one litter of 

 pigs per year, and these were usually farrowed at the nat- 

 ural time, namely, the spring. During later years some 

 breeders have adopted the policy of raising two litters a 

 year, one in the spring and one in the fall. This has occa- 

 sioned considerable discussion in regard to the policy of 

 having a sow produce two litters a year as compared to 

 one. It is sometimes argued that the sow cannot produce 

 more than one good litter per year, and that if she is re- 

 quired to produce two, it is such a drain upon her and will 

 reduce her to such an extent in condition and vitality that 

 she will neither produce good pigs nor remain prolific as 

 long as she should. From a study of the facts, this does 

 not seem to be necessarily true. 



In the production of beef cattle the cow is usually re- 

 quired to produce one calf per year. The period of ges- 



