NOTES ON BREEDING FOR INCREASE OF MILK 

 IN DAIRY CATTLE. 



By ELIZABETH ROBERTSON. 



(With Eight Pedigree Charts.) 



The following paper deals with the breeding of Dairy Cattle. The 

 subject is one of great complexity, and the methods suggested are, I am 

 aware, open to statistical criticism. Much more work is required before 

 the principles urged can be considered as fully established, but the 

 results are sufficiently striking to justify this statement in the hojje that 

 other breeders may be induced to try to improve their stock along similar 

 lines. The breed used is the Kerry, one of the remnants of the Celtic 

 cattle that are supposed in pre-Roman times to have covered the Conti- 

 nent of Europe and to have been gradually replaced by breeds from 

 elsewhere brought by the Romans. They are longer and narrower in the 

 skull and face as well as smaller than the Long Horns, Shorthorns and 

 Herefords. For size they stand midway between the Jersey and the 

 Ayrshire and obviously have far more affinities with the former than 

 with the latter. When used for cross breeding they are strongly pre- 

 potent. Being comparatively few in numbers they are apt to be inbred, 

 and being for the most part in uneducated hands the inbreeding has 

 been casual. 



The contents of the paper may be briefly summarized as follows : 



1. Inbreeding to a male relationship tends to increase both the 

 quantity and the quality of the milk produced. 



2. Inbreeding to a female relationship tends to decrease both the 

 quantity and the quality of the milk produced, especially the quantity. 



In Table I, the three tables of male inbreeding include 26 cases 

 of which five were failures in respect of quantity. One of these cows 

 (No. 109) failed to retain the milk in the udder ("ran out") but not 

 taking this into account she is included as though she had been a normal 

 cow. The results are (discarding the decimals) 80 /^ of cases in which 

 the cows showed an increase of milk when compared with the record of 



