1300 BREEDING 



stands, the felling yield of which remains below the mi ninunii amount, nmst 

 on the contrary be regarded as not yet workable. Consequently, all the 

 5'ouugest stand? will be entered in account not at their ordinary felling yield, 

 but in the form of a product obtained by nuiltiplying the total an'iual growth 

 of workable material by their respective ages. 



If the forest owner expects from his forest not only as high and valuable 

 as possible a yield of standing bulk, but also a maximum financial jdeld, it 

 is sufficient if management, instead of being based on the tables for yield 

 bv voHmie, is based on tables of monev return. 



LIVE STOCK AND BREEDING. 



989 - The Detection of the Prepotency of Sires. — hover j. m., in The journal of He- 

 redity, Vol. VII, Xo. 4, pp. 173-178. Washington, D. C, April, iyi6. 



The superiority of a parent or a breed in determining the characters 

 of its offspring is termed " pyepotencv " . This character only occurs in 

 very few animals of each breed, and was studied by the writer in the Guern- 

 sey cattle in the United States, making use of the herd- book instituted for 

 this breed by the American Guernsey Cattle Club. 



Sires having the power of producing improved offspring are generally 

 detected by an examination of the progeny, sometimes a long time after 

 the death or slaughter of the sires themselves. 



In order to determine the character of improvenient exhibited by a 

 sire, the number of his progeny admitted to registration in the herd-book 

 may be taken as a criterion. The writer rejects this method on various 

 grounds, especially in the case of the American Guernsey breed, owing to 

 the facility with which an animal may be registered, the conditions of ad- 

 mission not being sufficiently stringent (all that is required is the production 

 of 360 lb of butter-fat for a full grown cow, while the average production 

 is 312.771). He likewise rejects the method which consists in comparing 

 the daughters of different sires with their respective dams and noting the 

 amount of improvement. He therefore takes as the criterion of the pre- 

 potency of a bull the number of the latter's daughters which produce a 

 very high yield of fat, or, in the case of the (.kiernsey breed, 600 lbs per year 

 at the time of full growth, and he furthermore introduces the idea of the 

 " equivalent of 600 pounds ", that is to say of the young cow, which according 

 to its present production, will probably yield 600 pounds at the age of 5. 



In December 1915 there were only 32 bulls which had sired 3 or more 

 daughters with a production equivalent to 600 pounds of fat. This number 

 is very low-, representing only 0.092 % of the males registered in the herd- 

 book of the American Guernsey breed. The writer therefore concludes 

 that prepotency is very rare, being found in only i per 1000 of the Guernsey 

 breed of bulls. 



The writer next studied the ancestry of these 32 bulk which clearly ex- 

 hibited a prepotent character ; he found that with the exception of 3 they 

 all belonged to 7 families, which therefore clearly presented a prepotency. 



