GESTATION AND LACTATION 



71 



287 to 419 days. Among 1131 cows the length of the 

 period varied from 240 to 321 days. The minimum gesta- 

 tion period among 912 sheep was 146 days and the maxi- 

 mum 161 days. It is of interest to note, however, that 

 among 676 ewes the period varied from 150 to 154 days 

 only. 



The Earl of Spencer 1 found the period to vary from 

 220 to 313 days in cows. The following table includes 

 the observations of a number of investigators and is useful 

 as indicating the somewhat wide variations which may 

 occur in the gestation period of the domestic animals : 



PERIOD OF GESTATION IN DOMESTIC ANIMALS 2 



1 Journal of the Royal Agricultural Society, vol. I, pp. 166, 167. 



2 See Tessier, Journal of the Royal Agricultural Society, vol. I, 

 pp. 166, 167. 



Franck-Albrecht-Goring, " Die Trachtigkeitsdauer," Thier- 

 artzliche Geburtshiilfe, vol. 4, 1901. 



Wing, Cornell Experiment Station, Bui. 162. 

 Smith, "Physiology of the Domestic Animals." 

 Allen, "American Cattle," p. 259. 

 Miles, "Stock Breeding," 1907, p. 400 et seq. 



