CHAPTER V 



SIZE OF LITTERS; BIRTH WEIGHT OF PIGS; 

 MILK-FLOW OF SOWS 



IN the following pages some figures are given showing 

 the influence of certain factors on the size of litters, birth 

 weight of pigs, and the milk-flow of sows. Since the 

 usefulness and value of a sow are largely determined by 

 her performance in these particulars, it is thought the 

 statistics will be of interest and value. 



SIZE OF LITTERS 



The ability of the sow regularly to produce large litters 

 is the most fundamental and valuable of those traits 

 which determine her usefulness in the breeding herd. In 

 view of this, it is of considerable importance to learn what 

 factors are responsible for its wide variation and the 

 extent to which these factors are under the control of the 

 breeder or feeder. The following have each been re- 

 garded by hog-men as important : age, feeding and condi- 

 tion at breeding time, cross-breeding, the boar to which 

 the sow is mated, type, breed, and individuality. 



Age of sow. 



It is a matter of observation that the number of pigs 

 produced by a sow varies from year to year throughout 

 her breeding life. Her age is usually considered the most 



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