﻿UNITED STATES DEPARTMENT OF AGR 



DEPARTMENT BULLETIN No. 1372 



Washington, D. C. T March, 1926 



TRANSMITTING ABILITY OF TWENTY-THREE HOLSTEIN-FRIESIAN SIRES 



By R. R. Gbaves, Specialist in Dairy Cattle Breeding, Bureau of Dairying 



CONTENTS 



Page 



Breeding studies on dairy cattle 1 



Scope of the study 2 



How the sires were selected 2 



Production records of daughters and their 



dams 3 



Method of inheritance 11 



The biending-inheritance theory 13 



What is a great sire of production?.. 14 



Prepotency of the sire 18 



Method of breeding and record of dam as in- 

 dication of sire's breeding ability 19 



Which parent has greater influence on milk 

 yield, butterfat percentage, and butterfat 

 yield? 21 



Summary 31 



Literature cited 32 



BREEDING STUDIES ON DAIRY CATTLE 



Dairy-cattle breeding experiments were initiated by the Bureau of 

 Dairying in 1918 with the object of determining what method of 

 mating would give the most uniformly good results in the transmis- 

 sion of large milk and butterfat producing ability. These experi- 

 ments included the comparison of line breeding with outbreeding, 

 also of close inbreeding with outbreeding. Another project was the 

 use, for generation after generation, of sires which have shown by the 

 producing ability of their daughters that they are prepotent in trans- 

 mitting the capacity for uniformly high milk and butterfat produc- 

 tion. In addition to these experiments, studies are being made of 

 the inheritance, for milk and butterfat production, of the animals in 

 the advanced registry and register of merit of the dairy breeds. 



The last-mentioned research has included a genealogical study to 

 determine what families are most likely to transmit large milk and 

 butterfat production (1).^ Such studies, however, give very little 

 information on the laws governing the transmission of milk and 

 butterfat producing ability, in the following pages a study is made 

 of the comparative milk and butterfat producing ability of the 

 daughters, compared with then- dams, of each Holstcin-Fricsian sire 

 having six or moi(! daughters with yearly records, all out of dams also 

 having yearly records. This includes all sires on record up to and 

 including volume 29 of the Advanced Register Yearbook.^ 



' Klgures In Italics In parentheses refer to " Lit<:r:il iire Cited," p. 32. 



'The writer dcslrfyt to give credit to 'i'. W. Onllickson, formerly with this bureau, for compilations in 

 conncxition with the studl(« presented In this bulletin. 



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