CHAPTER XXXI. 



INVESTIGATIONS WITH SWINE. 



I. Miscellaneous Studies. 



809. Period of gestation. — According to Coburn/ young sows 

 carry their pigs from 100 to 108 days and old sows from 112 to 115, 

 the average for all being 112 days. Spencer,^ writing of English 

 pigs, says : ' ' The variations in the time which a sow will carry her 

 pigs are very slight, and these are pretty well regulated by the age 

 and condition of the sow; thus, old and weakly sows and yelts 

 (young sows) will most frequently bring forth a day or two before 

 the expiration of the 16 weeks. Sows in fair condition will generally 

 farrow on the 112tli day, while strong and vigorous sows will fre- 

 quently go a feAV days over time." 



810. Birth weight. — In a study by the author at the Wisconsin 

 Station,^ each pig as soon as farrowed was marked and its weight 

 and condition recorded. The weights of the pigs of 3 litters are 

 presented in the table which follows: 



Weight of pigs, when farrowed, in the order of their hirfh. 



*Farrowed dead. 



It is shown that the individual pigs when farrowed weighed from 

 1.3 to 3.1 lbs., the litter aggregating from 18.7 to 22.5 lbs. The first- 

 farrowed pig was neither heavier nor stronger, and the last was 

 neither lighter nor weaker than the others. The so-called "titman, " 

 or weakling, found in a litter, is probably such thru lack of food or 

 other extraneous cause, for if given good food and care it not infre- 

 quently outgrows its mates. 



Carlyle* found that 4- and 5-year-old sows bore 9 pigs to the litter 

 on the averasre, the litter weighing 26 lbs., while 1-year-old sows aver- 



Swine in America. 

 ' Pigs, Breeds and Management. 



"" Ept. 1897 

 ' Bui. 104. 



