Feeding and Handling the Herd 17 



as good feeding. Without exercise the foundation of 

 good health is impossible. The most practical and de- 

 sirable method of supplying exercise is to give plenty of 

 range. Ordinarily, if the boar and sows are in the best 

 flesh for breeding purposes, they will take all the exercise 

 needed if given the opportunity. In the case of the boar 

 particularly, it too often happens that his range is limited 

 to a narrow pen where insanitary conditions and lack of 

 exercise combine in reducing his health and vigor. Ex- 

 ercise is sufficiently important for the breeding boar to 

 warrant the time and attention necessary to take him 

 out and drive him a half-hour twice in the day, if it cannot 

 be given by some other method. 



GENERAL CONSIDERATIONS 



The period of sexual excitement known as "heat" 

 should be understood. The significance of heat is that 

 the sow is secreting, or preparing to secrete, the ripened 

 eggs or ova. The appearance of heat is supposed to 

 precede by a day or two the production of these eggs or 

 germ-cells which, on fertilization by their union with the 

 male germ-cells, produce the embryo pigs. 1 The heat 

 period lasts about three days, and is the only time during 

 which a normal sow will accept service from the boar. 



A sow comes in heat every twenty or twenty-one days, 

 on the average, during the breeding season, if not bred. 

 The exceptions to this are sows which lack breeding con- 

 dition or thrift and those which are nursing pigs. It 

 frequently happens, however, that a sow will come in 

 heat a few days after farrowing, usually the third day, 



1 MacKenzie and Marshall: "Journal of Agricultural 

 Science," 1912. 

 c 



