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Parameter estimation for carcass traits including growth information of Simmental beef cattle using restricted
B W Woodward1, E J Pollak, R L Quaas
1Department of Animal Science, Cornell University, Ithaca, NY 14853.
Journal of Animal Science
|April 1, 1992
Summary
Sire models incorporating growth traits improve predictions for beef retail cuts per day but offer minimal benefits for cutability and marbling score. This enhances genetic evaluations for specific carcass traits in Simmental cattle.
Area of Science:
- Animal Breeding and Genetics
- Quantitative Genetics
- Beef Cattle Production
Background:
- Accurate genetic evaluation of beef sires is crucial for improving carcass traits.
- Understanding the genetic correlations between growth and carcass traits informs breeding strategies.
- Simmental cattle producers collect extensive carcass and growth data for genetic analysis.
Purpose of the Study:
- To estimate (co)variance components for key carcass traits using a multiple-trait sire model.
- To assess the impact of including growth traits on the accuracy of carcass trait evaluations.
- To determine the heritability and genetic correlations between growth and carcass traits.
Main Methods:
- Utilized restricted maximum likelihood (REML) with an expectation-maximization algorithm.
- Analyzed carcass data from 8,265 Simmental progeny and growth data from 5,405 contemporaries.
- Compared three models: carcass traits with growth traits, carcass traits only, and single traits.
Main Results:
- Heritability estimates were 0.30 for retail cuts per day, 0.18 for cutability, and 0.23 for marbling score.
- Moderate positive correlations were observed between growth traits and retail cuts per day.
- Including growth traits significantly reduced prediction error variances for retail cuts per day but not for cutability or marbling score.
Conclusions:
- Growth traits are beneficial for improving sire evaluations of retail cuts per day.
- The inclusion of growth traits has limited impact on the genetic evaluation of cutability and marbling score.
- Future sire evaluations for carcass traits should consider incorporating growth data, particularly for predicting retail yield.
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