598 THE PHYSIOLOGY OF REPRODUCTION 



In the report which has since been issued,^ and which contains 

 the lambing statistics for various flocks of Scottish sheep for 

 the years 1905, 1906, and 1907, it is shown that the percentage 

 of lambs born was, as a general rule, highest among sheep 

 which had been subjected to a process of artificial stimulation. 

 The method adopted was to feed the ewes upon turnips, oats, 

 maize, dried grains, or other additional food at the tupping 

 time and for about three weeks previously, while maintaining 

 them upon grass only during the greater part of the year. Some 

 flocks, however, received a hmited supply of extra food 

 (generally turnips) during gestation, and especially during the 

 later part of this period. The additional supply of turnips, 

 which are specially rich in carbohydrate material, was found 

 to be in no way detrimental to fertihty, but rather the reverse, 

 when accompanied by other food (pasture), and so not taken in 

 excess. The statistics show that in the flocks treated in the 

 way described, the percentage of lambs per ewes ^ was almost 

 invariably in excess of the average percentage for flocks which 

 received no special treatment, while the percentage of barren 

 ewes was usually also less in the specially fed flocks. In some 

 cases the number of lambs per ewes in the flushed flocks was 

 nearly 200 per cent. Among flocks belonging to the same 

 breeds (Border Leicester or half-bred Border Leicester) which 

 received no sort of special treatment, the average proportion 

 of lambs per ewes was between 150 and 160 per cent., while 

 flocks which were run upon superior pasture at the approach 

 of the sexual season, without being otherwise specially fed, 

 generally produced a shghtly larger percentage of lambs. The 

 t^vins appear almost invariably to have been born early during 

 lambing, thus showing that the generative activity of the ewes 

 tends to be greatest at the commencement of the sexual season. 



It has proved more difiicult to obtain definite information 

 concerning the effects of flushing in one year upon the fertility 

 of the ewes in subsequent seasons. The more usual experience 

 of flockmasters seems to be that flushing is not in any way 

 prejudicial to breeding stock unless it is overdone, the object 



^ Marshall, "Fertility in Scottish Sheep," Trans. Highland and Agric. 

 Soc, vol. XX., 1908. See also Proc. Roy. Soc, B., vol. Ixxvii., 1905. 

 ^ That is to say, the number of lambs per 100 ewes. 



