GESTATION AND LACTATION 73 



Merinos , * . . 150.3 days 



Southdowns . 144.2 days 



Half blood Merino and Southdown . . 146.3 days 



Three quarter blood Southdown . . . 145.5 days 



Seven eighths blood Southdown . . . 144.2 days 



Some doubt has been expressed as to the authenticity 

 of the maximum period of gestation in mares. The edi- 

 tor of the Breeder's Gazette eommenting on this fact says, 

 "Mares are usually credited with pregnancy lasting eleven 

 months. When they run twelve months we prefer to 

 believe that the date has not been properly kept. We 

 believe that forty-eight weeks, seven days to the week, or 

 326 days is about the average duration of pregnancy in 

 a mare." 1 Referring to this statement M. W. Johnson 2 

 of Illinois writes that he has been in the breeding business 

 for fourteen years and has complete records on the breed- 

 ing of 5000 mares. He reports one mare as having carried 

 her foal for twelve months and sixteen days and another 

 for twelve months and eighteen days. Both foals were 

 deformed. Another mare gave birth to a perfectly 

 healthy foal at the end of one year and eighteen days while 

 another carried her foal exactly thirteen months and 

 dropped a healthy foal. A Percheron mare belonging to 

 H. F. Sperry 3 dropped a mule colt twelve months and 

 two days after breeding. William Lokings of South 

 Dakota owned a pony mare which was twice bred and 

 gave birth to a foal twelve months and twenty-five days 

 after the last service. There is a popular belief that 

 male offspring are carried longer than female. Bement 4 

 found that the average length of gestation for male calves 



1 Breeder's Gazette, May 15, 1907. 



2 Ibid., June 19, 1907. 



3 Ibid., June 26, 1907. 



4 The Cultivator, 1845, p. 207. 



