SEX-DETERMINATION IN SHEEP 



Effect of Special Feeding on Ratio of Males to Females and on Fecundity of 



Ewes — First Result Nullified by Addition of Data from Following Years — 



Method of Handling the Multi-Nippled Sheep at Beinn Bhreagh. 



Compiled by the Editor from the Records of Alexander Graham Bell, 



Washington, D. C. 



SINCE 1889, Alexander Graham 

 Bell has been engaged in sheep- 

 raising on his farm of Beinn 

 Bhreagh, near Baddeck, Nova 

 Scotia, in order to fix a breed possessing 

 supernumerary mammae, and exceeding 

 the ordinary breeds in fecundity. In 

 the course of this experiment (which, it 

 may be mentioned, has been a complete 

 success) he has had an exceptionally 

 good opportunity to test the theory that 

 the sex of offspring is dependent, in 

 part at least, on the nourishment of the 

 mother, and also to test another hypo- 

 thesis suggested in the course of his 

 experience — namely, that the degree of 

 nourishment had an effect in favoring 

 the production of twins — one of the 

 objects for which he was working. 



On April 17, 1901, Dr. Bell read a 

 paper on "Conditions affecting the 

 Fertility of Sheep and the Sex of their 

 Offspring," before the National Academy 

 of Sciences at Washington, in which he 

 explained the circumstances which 

 favored his investigation of this problem 

 of the influence of nutrition on the sex 

 of offspring, as follows: 



"Foi some years past my shepherd, 

 Mr. John McKillop, has attempted to 

 record periodically the weights of the 

 sheep entrusted to his care, for the reason 

 that weight has been found to give a 

 valuable indication of the general physi- 

 cal condition and health. Sheep, when 

 suffering from serious illness, nearly 

 always lose in weight — indeed loss of 

 weight is commonly the first indication 

 that anything is wrong. This fact has 

 been utilized to guard the Beinn 

 Bhreagh flock from infectious disease. 

 When a sheep is found to be losing un- 

 duly in weight, it is separated from the 

 others and given special attention. 



"In some cases these sheep have been 

 found to be suffering from unsuspected 

 diseases; in others unknown accidents 

 had induced abscesses requiring surgical 

 treatment. A decline in weight affecting 

 a number of young lambs turned out 

 to be due to the presence of tapeworm, 

 and the lambs undoubtedly owed their 

 lives to the timely discovery of the 

 cause. 



FLOCK WEIGHED FREQUENTLY. 



"Experience having demonstrated 

 that variations in weight are sometimes 

 of great significance, the attempt was 

 made to weigh the whole flock at least 

 once a month. 



"Unfortunately the summer and au- 

 tumn records are imperfect, for it is 

 not always easy or practicable to induce 

 sheep to come and be weighed — especi- 

 ally when they are roaming about on 

 a large pasture with plenty of cover. 

 Still, a large enough number of records 

 exist to enable us to ascertain the average 

 weight of a Beinn Bhreagh ewe at the 

 end of September, October, November, 

 and December — thus covering the breed- 

 ing season. Data were collected for 

 this purpose in the summer of 1899 

 and the results show that the average 

 weight increased rapidly up to the end 

 of October. Beyond this point there 

 was very little increase; and after the 

 end of November there was an actual 

 decline (which continued all winter 

 under ordinary conditions of feeding). 



"Thus, in Cape Breton Island, when 

 mating occurs in October, the average 

 ewe is improving rapidly in condition at 

 the time of mating: When it occurs in 

 November the weight is about the max- 

 imum, but increasing slowly: And when 

 mating occurs in December the average 



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