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Estimation of genetic parameters for feed efficiency traits using random regression models in dairy cattle
K Houlahan1, F S Schenkel1, F Miglior2
1Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, N1G 2W1.
Journal of Dairy Science
|September 10, 2023
Summary
Improving dairy cow feed efficiency is crucial due to rising costs and environmental concerns. This study analyzed genetic parameters for feed efficiency, finding heritability estimates vary across lactation stages, informing breeding program strategies.
Area of Science:
- Animal Science
- Genetics
- Dairy Production
Background:
- Rising feed costs and environmental concerns necessitate improved feed efficiency in dairy cows.
- Accurate measurement of feed intake is challenging for large populations, hindering its inclusion in breeding programs.
- Understanding genetic parameters of feed efficiency throughout lactation is key to improving dairy cattle breeding.
Purpose of the Study:
- To investigate the genetic parameters of feed efficiency and related traits across the first lactation in Holstein cows.
- To develop a genetically corrected measure of feed efficiency (genomic residual feed intake - gRFI).
- To provide insights into genetic variation and potential selection strategies for feed efficiency.
Main Methods:
- Utilized a large dataset (121,226 dry matter intake, 120,500 energy-corrected milk, 98,975 metabolic body weight records) from 7,440 first-lactation Holstein cows across 6 countries.
- Employed a multiple-trait random regression model with a fourth-order Legendre polynomial to estimate genetic parameters.
- Derived genomic residual feed intake (gRFI) by re-parameterizing dry matter intake (DMI) to be genetically corrected for energy-corrected milk (ECM) and metabolic body weight (MBW).
Main Results:
- Heritability estimates for DMI ranged from 0.15 to 0.29, ECM from 0.24 to 0.29, MBW from 0.55 to 0.83, and gRFI from 0.12 to 0.22.
- Heritability estimates were generally lower in early lactation compared to later stages.
- Additive genetic correlations between weekly lactation traits varied, showing stronger associations between adjacent weeks.
Conclusions:
- Genetic parameters for feed efficiency traits change throughout the first lactation.
- The developed gRFI provides a valuable tool for genetic selection of feed efficiency in dairy cattle.
- Findings support the integration of feed efficiency into dairy breeding programs for enhanced sustainability and productivity.
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