FERTILITY 111 



lambs, four of which the mother nursed successfully. 

 The earless Shanghai breed of sheep exhibited in the 

 London Zoological Gardens in 1857 seem to have inherited 

 a remarkable fecundity. Bartlett 1 has described this 

 variety as breeding twice each year and often producing 

 four or five at a birth. In the spring of 1857 three ewes 

 of this breed gave birth to thirteen lambs. 



108. Unusual fertility among swine. There is more 

 difficulty in determining the normal number of young at 

 a birth among swine than among other domestic animals. 

 There is considerable variation among individuals belong- 

 ing to the same breed and between different breeds. 

 Some particular cases of high fertility are described 

 below : 



A three-year-old Chester White sow 2 farrowed ninety- 

 six pigs in six litters. There were fourteen in each of 

 the first three litters and eighteen in each of those last 

 farrowed. This tendency among highly fecund indi- 

 viduals to give birth to larger and larger numbers has 

 been observed in cattle, sheep and swine. 



A Poland China sow 3 produced thirty-four living pigs 

 in three litters during a single twelve months' period. 



A sow 4 gave birth to twenty-one pigs in a litter. Pre- 

 vious to this she had farrowed two litters of fifteen and 

 seventeen pigs each. A sow of uncertain breed 5 dropped 

 twenty-three pigs in one litter. All but two of these 

 were born alive. The same sow gave birth to eighty- 

 five pigs in five litters. Ray L. Zimmerman of Amazonia, 

 Andrew County, Missouri, reports to the author that a 



1 Bartlett, Proc. Zool. Soc., London, 1857, p. 105. 



2 Breeder's Gazette, 1897, p. 368. 



3 Ibid., 1894, p. 308. 



4 Country Gentleman, 1887, p. 281. 

 6 Ibid., 1894, p. 915. 



