UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1372 
Washington, D. C. ▼ March, 1926 
TRANSMITTING ABILITY OF TWENTY-THREE HOLSTEIN-FRIESIAN SIRES 
By R. R. Graves, 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 blending-inheritance theory 13 
What is a great sire of production?. 14 
Page 
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 wdth outbreeding, 
also of close inbreeding with outbreeding. Another project w^as 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 1 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 (I). 1 Such studies, how r ever, 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 their dams, of each Holstein-Friesian sire 
having six or more 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. 2 
1 Figures in italics in parentheses refer to " Literature Cited," p. 32. 
5 The writer desires to give credit to T. W. Gullickson, formerly with this bureau, for compilations in 
connection with the studies presented in this bulletin. 
— 25f 1 
