Line 1 Hereford cattle: conserved and transformative€¦ · Line 1 Hereford Cattle Line 1 breeding program more than 75 years old. Unique in the contribution to science and industry

LINE 1 HEREFORD CATTLE: CONSERVED AND TRANSFORMATIVE

Harvey Blackburn Mike MacNeil Vicki Leesburg

Line 1 Hereford Cattle

Line 1 breeding program more than 75 years old.

Unique in the contribution to science and industry

Line 1 Developmental Objectives

1930’s no systematic effort to develop, isolate, perpetuate, or catalog superior livestock germplasm.

Objective: Develop true breeding lines of Hereford cattle adapted to western range areas, having high fertility & superior quality

Line 1 Development

50 cows used to form line (Montana).

2 bulls were paternal ½ sibs (Colorado).

Daughters of one bull bred to the paternal 1/2 sib.

Selection based upon: Progeny testing Rate & efficiency of BW gain

to 1 yr of age

Advance Domino 20

Advance Domino 54

Early Contributions

Correction factors for analyzing (Knapp et al., 1940; Koch and Clark, 1955)

Sex of calf Season of birth Age of dam

1st estimates of heritability and genetic correlations for beef cattle traits (Knapp & Nordskog, 1946; Knapp & Clark, 1947, 1950)

Later Contributions

Genetic x environmental interactions (Florida-Montana)

Breeding value estimation

Crossbreeding systems

Industry Linkages

Dissemination of Line 1 germplasm began 1940’s.

Scientist Woodward convinced brother-in-law (J. Cooper & L. Holden) merits of line breeding and selection based upon performance

By 2008 1,303 Lines 1 bulls transferred from Miles City to registered and commercial breeders

Industry Trends and Issues

Short compressed cattle & emergence of dwarfism, late 1950’s

Industry Trends and Issues

Industry Issue Line 1 Contribution

Dwarfism

Importation of continental breeds from Europe in late 60’s & 70’s

Late 20 century Deleterious recessive – idiopathic epilepsy

Line 1 free of dwarfism gene

Line 1 selected for growth gave Hereford breeders a resource to compete

Line 1 used

By 1984 57% of bulls listed in Am Hereford Assoc sire summary were predominantly Line 1

0

0.05

0.1

0.15

1 7 13

19

25

31

37

43

49

55

61

67

73

79

85

91

97

103

Axi

s Tit

le

Fmean

Fmean

Genetic Trend in 365-d Weight of Line 1 (MacNeil, 2009)

Cryopreserved Collection

Samples from 1948 to the present are in the gene bank.

Deviation from the Mean Post-thaw Motility for Hereford Bulls (* denotes bulls with deviations significantly different from zero)

How Prevalent Are Line 1 Cattle?

Density of Herefords & Presence of Highly Related Line 1

Density of Herefords & Presence of Highly Related Line 1

Density of Hereford cattle in Canada with relationship to Line 1 Hereford

Global Relationships (Leesburg, 2012)

Country # Sires evaluated % with Line 1 relationship

Ave Relationship L1

United Kingdom 1,498 22% .106

Australia 1,769 30% .116

Uruguay 318 23% .106

Canada 317,478 dataset 8% 0.037

South Africa* entire pop

4,491 14% .24 .38 microsat

United States Entire population 81% 0.026

Use in Genomic Research

L1 Dominette 01449 Provided DNA for bovine genome sequence Genetic relationship of sire and daughter 93%

L1 Domino 99375 Provided DNA bacterial artificial chromosome BAC library - discovery of causal mutations affecting economically important traits

Conclusions Line 1 is a globally important Hereford population

Success of US Herefords can be largely attributed to:

the population and

breeders willingness to further use and manipulate Line 1 genetics

Potential to make further contributions

Some big questions: How is it that an inbred population can be so robust in a

broad array of environments, including different countries? During the inbreeding process were deleterious alleles

deleted from the population?