770 



Breeding for Mile. 



[Dec. 



Mr. Paber adds an informing fact: " before the inauguration 

 of milk recording societies it had alreadj' become a general 

 practice to keep bulls for service for a number of years, and 

 . to judge the bulls by an examination of their offspring.*' 

 On this the natural reflection is : if this is the general practice 

 in Denmark, is there any reason why it should not become 

 general in the United Kingdom? Mr. Faber's paper contains 

 abundant evidence on the capacity of certain bull? to get 

 daughters showing a better performance than that of their 

 dams, and thereby raise the standard of the strain or breed. 

 On the other hand there is good evidence that, on occasion, 

 pedigree bulls get daughters whose performance is not so good 

 as that of their dams, and it is this fact which justifies the 

 progeny tests. A striking confirmation of this will be found 

 in a Bulletin* recently published by the Agricultural Experi- 

 ment Station, Maine, U.S.A. 



The Bulletin in question gives the result of a study of the 

 milk records contained in the Registry of Merit of J ersey Cows 

 published by the American Jersey Cattle Club. The object 

 in view was to place the pedigree bulls concerned in one of 

 two classes (a) bulls the performance of whose daughters was 

 better than that of their dams: and (b) bulls whose daughters' 

 performances were less than those of their dams. In order to 

 add to the reliability of the results, only those bulls ware 

 classified for which the records of two or more daughters (and 

 of their dams) were available. Tables containing the names 

 and numbers of 224 pedigree bulls are published showing the 

 performance cl daughters individually, as well as the records 

 of the dams of their daughters. This interesting and 

 important fact emerges. About one half (105) of these bulls 

 produced daughters which on the average gave a higher yield 

 of milk than their dams, while the remainder (119) had the 

 contrary effect: their daughters' performances fell short of 

 their dams. Two examples may be given. The bull named 

 " Hood Farm Torono " is the recorded sire of 34 daughters. 

 In the case of all but five of these daughters, the yields were 

 higher than those of the dams. On an average the net increase 

 on the daughters' yield over that of the dam was 2,620 lb. On 

 the other hand, the records for the bull " Jaeoba Emanon ,! 

 one of the 110 which affected their daughters' yield unfavour- 

 ably, show that his nine daughters on an average produced 

 2J00lb. less milk than the average of their dams. 



* Studies in Milk Secretion: Bull. 281. Main Experimental Station. 1920. 



