162 Sheep-Farming 



country and the conditions under which the flocks 

 must be maintained in the interests of practical 

 economy and profit. 



The farmer has seldom any need to cross breeds 

 for the above reasons. The practice requires the 

 purchase of other rams, and the flock must be 

 bred in two parts, one part being mated to rams of 

 their own breed to furnish fresh ewes to keep up the 

 breeding flock. If all the ewes produce cross-bred 

 lambs in any season, there is no opportunity to make 

 a change in the ewe flock that year. It is generally 

 considered that the crossing of breeds has the specific 

 effect of giving greater vigor and more rapid growth 

 than characterizes either of the parent breeds. The 

 extent of any such advantage over carefully raised 

 pure-bred sheep has not been determined by experi- 

 ment. The possible advantage from cross-breeding 

 in farm fiocks is seldom very great, and the practice 

 can be followed safely only when the main ewe flock 

 is kept pure. 



