464 MANAGEMENT AND FEEDING OF SHEEP 



viously. The outcross in such instances is to efifect a pur- 

 pose, and when that purpose is attained, as it usually 

 is in a single outcross, such crossing for the time being 

 should cease. Action in the second instance aims to in- 

 sure renovation and improved stamina when indications 

 of deterioration may have appeared. These outcrosses, 

 however, should be introduced with great caution. They 

 should only be made in the flock generally after their 

 potency has been proved in the progeny resulting from 

 the use of the sires thus brought in on a few females of 

 the flock. 



Breeding for single or twin lambs — That the breed- 

 ing may influence the proportion of the lambs that shall 

 be of single or plural birth, must be conceded. As to this 

 there cannot be any room for a difference in opinion, but 

 opinions may differ with reference to some of the influ- 

 ences which bear upon this question and the part which 

 these play respectively. It would seem to be true that 

 the difference in the prolificacy of breeds has been 

 brought about by breeding, accompanied by selection and 

 food. 



Opinions differ as to the desirability of having ewes 

 produce but one or two lambs at a birth. In some in- 

 stances they produce three, and in rare instances even 

 more, but a larger number than three is not desirable. 

 The ewe furnishes milk from but two teats, hence the 

 lambs do not share equally in the milk produced, nor is 

 one ewe capable of furnishing all the milk that is neces- 

 sary to grow three lambs at their best. 



The following are chief among the arguments in 

 favor of the production of single lambs: (i) They forge 

 ahead more rapidly when young, and in consequence may 

 be marketed at an earlier age ; (2) that a ewe is not so 

 capable of feeding two lambs properly as of feeding but 

 one ; hence (3) it is easier to maintain a high standard 

 of development in flocks in which single lambs are the 

 rule. There is considerable force in the first argument 



