62 Dr. F. H. A. Marshall. Fertility in Scottish Sheep. 



over the secretory activity of the ovaries, while at the same time causing the 

 Graafian follicles to mature more rapidly and a larger number to discharge 

 during the earlier cestrous periods in the sexual season. 



Kegarding the effects of artificial feeding during one tupping season upon 

 the fertility of the sheep in after years, it has so far been difficult to obtain 

 precise information. The opinion usually expressed is that flushing is not 

 detrimental to subsequent fertility unless it is overdone ; but in a very few 

 of the returns the view is stated that the after-effect is adverse. It is also 

 said that if ewes are flushed one year the process must be repeated the next : 

 otherwise the ewes tend to be less fertile than if they had never been flushed 

 at all. 



On the other hand, several of the returns show that sheep which produce 

 twins one year very frequently bear twins also in the year following. This 

 seems to occur irrespectively of whether it was the practice to flush the ewes. 

 It would appear, therefore, that an increased degree of fertility is characteristic 

 of certain particular ewes. 



That fertility is a character which can be inherited admits of no doubt. It 

 is to be noted, however, that with the breeds considered in this paper, twins 

 are seldom if ever selected for purposes of tupping, since they generally are 

 not so well developed, owing to their having had less nourishment when they 

 were young lambs. It would seem, therefore, that the fertility of these 

 breeds is diminished owing to the fact that the rams which are probably 

 naturally the most fertile are the ones which are the least frequently employed 

 for breeding 



