44 THE PHYSIOLOGY OF REPRODUCTION 



the summer, but they do not, as a rule, breed more than once a 

 year. The Limestone sheep of Westmorland and Derbyshire, 

 and the Dorset Horn sheep of the South of England, are the only 

 British sheep which are ordinarily capable of breeding more 

 than once annually. With the former the general lambing 

 season is from the middle of February to the middle of March, 

 but lambs are often born earlier. The ewes sometimes receive 

 the ram very early when suckling the lambs, so that a second 

 crop of lambs is born in August. This increase in the sexual 

 capacity is especially noteworthy in view of the fact that Lime- 

 stone sheep are classed as a mountain breed which thrives best 

 on dry heaths or bare hill pastures. In Dorset Horn sheep 

 lambs are frequently produced twice a year, but the practice is 

 discouraged as it is said to deteriorate the ewes. With this 

 breed oestrus may continue to recur (in the absence of the ram) 

 from the autumn sexual season (when the sheep are ordinarily 

 tupped) onwards until the following spring. 



With many foreign breeds lambs are born twice yearly. 

 Thus Mr. Annandale informs me that the horned sheep which 

 run half wild in Patani, in the Malay Peninsula, normally have 

 lambs twice a year. It would appear also that among the 

 indigenous sheep of India, which are scarcely ever supplied 

 with any artificial or other food, green or dry, beyond what they 

 can pick up at the pasture ground, lambs may be born three 

 times in two years, and that there are no definite seasons for 

 lambing. 1 



Among the Merino sheep in Cape Colony the sexual season is 

 April (the autumn month, corresponding to October in this 

 country), but some sheep come " in season " earlier. At high 

 altitudes, however, where the sheep subsist entirely upon the 

 natural produce of the veldt, the sexual season is May, or a 

 month later than the usual time in Cape Colony. On the other 

 hand, in the low country below the second range of mountains, 

 there are two seasons for " tupping/' and lambs are produced 

 twice a year. Among the Merinos in Argentina there are also 

 two breeding seasons within the year. 



Probably the maximum amount of sexual activity experi- 



1 Shortt, A Manual of Indian Cattle and Sheep, 3rd Edition, Madras, 

 1889. 



