728 Diseases of the Genital Organs 



ing the non-breeding season. During the breeding season 

 the number of ewes assigned to a ram should be carefully 

 limited. Ordinarily when the ram is placed with the flock, 

 all ewes are sexually ready for breeding and will be in es- 

 trum within three weeks, so that it may be assumed that the 

 male will copulate at least once with each ewe within that 

 time and will at first probably copulate several times with 

 each ewe. According to such observations as I have been 

 able to make, small flocks constantly show higher reproduc- 

 tive efficiency and more vigorous offspring than large 

 ones. Many elements doubtless enter into the problem, 

 but I believe the most important factor, assuming that the 

 general care is good, is the proper limitation of the sex 

 strain upon the ram. The large breeds of sheep are essen- 

 tially twin breeders and if properly handled may, and some- 

 times do, average throughout the flock two lambs each. Thus 

 in one flock twenty-six ewes produced fifty-two vigorous 

 lambs, there having been enough triplets to counterbalance 

 singles. It is probable that such a number of ewes is near 

 to or quite the maximum for one ram, if the highest effi- 

 ciency is to be maintained. Admittedly instances may be 

 cited where rams have withstood a far greater sexual strain 

 with apparent impunity, but it is doubtful policy to assume 

 that any breeding animal is wholly and technically free 

 from genital infections. Knowing these to be essentially 

 universal, and knowing that under prudent sex or physical 

 strain the infections are generally harmless, it appears to 

 me best to assume the existence of infection and guard 

 against its intensification. The cost of the maintenance of 

 additional rams, beyond the value of the fleece, is not highly 

 important and does not require many additional lambs to 

 render the plan economically profitable. Such care in breed- 

 ing is not merely for the immediate influence upon the next 

 lamb crop. The progressive breeder must always contem- 

 plate future generations. Health lines are as important as 

 blood lines, and it requires as great patience and intelligence 

 to establish that physical vigor upon which high productive 

 efficiency depends as it does to build up a satisfactory pedi- 



