Impact of bovine somatotropin on ranking for genetic value of dairy sires for milk yield traits and somatic cell score
Genet. mol. res. (Online)
;
6(1): 79-93, 2007. tab, graf, ilus
Article
in English
| LILACS
| ID: lil-456753
ABSTRACT
Records of Holstein cows were used to examine how different models account for the effect of bovine somatotropin (bST) treatment on genetic evaluation of dairy sires for yield traits and somatic cell score. Data set 1 included 65,720 first-lactation records. Set 2 included 50,644 second-lactation records. Set 3 included 45,505 records for lactations three, four and five. Estimated breeding values (EBV) of sires were with three different animal models. With Model 1, bST administration was ignored. With Model 2, bST administration was used as a fixed effect. With Model 3, administration of bST was used to define the contemporary group (herd-year-month of calving-bST). Correlations for EBV of 1,366 sires with treated daughters between pairs of the three models were calculated for milk, fat and protein yields and somatic cell score for the three data sets. Correlations for EBV of sires between pairs of models for all traits ranged from 0.971 to 0.999. Fractions of sires with bST-treated progeny selected in common (top 10 to 15%) were 0.94 and usually greater for all pairs of models for all traits and parities. For this study, the method of statistical adjustment for bST treatment resulted in a negligible effect on genetic evaluations of sires when some daughters were treated with bST and suggests that selection of sires to produce the next generation of sires and cows might not be significantly affected by how the effect of bST is modeled for prediction of breeding values for milk, fat and protein yields and somatic cell score
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Lactation
/
Cattle
/
Growth Hormone
/
Quantitative Trait, Heritable
Type of study:
Diagnostic study
/
Prognostic study
Limits:
Animals
Language:
English
Journal:
Genet. mol. res. (Online)
Journal subject:
Molecular Biology
/
Genetics
Year:
2007
Type:
Article
Affiliation country:
United States
Institution/Affiliation country:
Roman L. Hruska U. S. Meat Animal Research Center/US
/
University of Nebraska/US
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