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Lactation curve models for estimating gene effects over a timeline.
E M Strucken1, D J de Koning, S A Rahmatalla
1Breeding Biology and Molecular Genetics, Department for Crop and Animal Sciences, Faculty of Agriculture and Horticulture, Humboldt-Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany.
Journal of Dairy Science
|December 25, 2010
Summary
This study integrates lactation curve models with gene effect estimation to reveal the dynamic impact of DGAT1 gene variants on dairy cattle production throughout lactation. The Wilmink model best predicted genotype effects, showing distinct gene actions post-day 40.
Area of Science:
- Animal Genetics
- Dairy Science
- Quantitative Genetics
Background:
- Traditional gene effect estimation relies on test-day data, providing only general genetic impacts.
- Lactation curve models offer a more nuanced approach, estimating biological, environmental effects, and predicting breeding values.
Purpose of the Study:
- To combine lactation curve models with gene effect estimation for a detailed understanding of genetic influences across lactation stages.
- To evaluate the efficacy of different lactation curve models (Wood, Wilmink, Ali and Schaeffer) in representing gene effects.
- To investigate the specific effects of DGAT1 gene polymorphisms (K232A, VNTR) on milk production traits in Holstein-Friesian cattle.
Main Methods:
- Applied Wood, Wilmink, and Ali and Schaeffer lactation curve models.
- Utilized a random regression test-day model for comparison.
- Analyzed K232A polymorphism and promoter VNTR of the DGAT1 gene in Holstein-Friesian cattle.
Main Results:
- All tested lactation curve models adequately predicted production curves.
- The Wilmink model demonstrated the best fit for predicting genotype-specific effects.
- Significant DGAT1 genotype effects on milk production traits were observed after lactation day 40.
- Allele K substitution effects revealed distinct patterns for milk, fat, and protein yield and content over lactation.
Conclusions:
- Integrating lactation curve models with gene effect estimation provides a temporal dimension to understanding genetic impacts.
- The Wilmink model is a suitable tool for predicting genotype effects on lactation curves.
- Findings offer improved insights for genetic and management strategies in livestock populations.
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