SWINE MANAGEMENT 167 



ceptionally valuable sow, when other expedients may be 

 resorted to. 



Age and time to breed pure-bred sows. — A great many 

 of our best breeders make a practice of having their gilts 

 bred to drop pigs at one year of age, and, if they have 

 been properly pushed along, this is not too young. 

 Others seem to prefer to wait until later. In farrowing 

 at from one year to fifteen months of age gilts from one 

 spring may farrow the first litter the next spring. Fall 

 pigs are usually a little slower growing than spring pigs 

 and fall-farrowed gilts may frequently be bred to farrow 

 in the winter or early spring after they are a year of age. 

 While most breeders prefer spring litters on account of 

 the food supply for the several months to come, fall 

 litters or litters at any other season are all right and can 

 be made successful. Throughout the southern states the 

 market for pure-bred pigs is best in the late winter 

 months and pigs farrowed in the early fall can often be 

 sold early to good advantage. 



Period of gestation. — After the ova or germ cells of the 

 sow have been fertilized, gestation or pregnancy starts, 

 vi'hich ends with the expulsion of the pigs from the 

 uterus. The length of the period of gestation is fairly 

 constant and will vary but little either way from 112 

 days. Heavy feeding tends to hasten and light feeding to 

 retard the farrowing date. Early-maturing types also 

 require slightly less time. A sudden cold spell, nervous 

 excitement, the sight of another sow farrowing, the sight 

 or taste of fresh meat or blood, and certain drugs, as 

 ergot, cotton root extract and digitalis, may cause pre- 

 mature termination of gestation. 



