Genetic progress in multistage dairy cattle breeding schemes using genetic markers

Area of Science:

• Animal Breeding and Genetics
• Genomics
• Quantitative Genetics

Background:

• Multistage breeding schemes are complex, and their efficiency can be influenced by selection intensity and accuracy across stages.
• Integrating quantitative trait loci (QTL) information into breeding programs offers potential for enhanced genetic progress.

Purpose of the Study:

• To explore general characteristics of multistage breeding schemes.
• To evaluate dairy cattle breeding schemes incorporating QTL information for improved genetic response or reduced progeny testing.
• To assess the impact of QTL on genetic gain and the number of progeny-tested bulls.

Main Methods:

• Evaluation of multistage breeding schemes using deterministic simulation.
• Comparison of schemes with and without QTL information.
• Simulation of an additional index trait incorporating QTL information.

Main Results:

• Multistage schemes' response reduction depends on selection intensity and accuracy ratios between stages.
• QTL information increased genetic response in progeny test schemes by 4.5% to 21.2%.
• A QTL explaining 5% of genetic variance allowed a 35% reduction in progeny-tested bulls while maintaining response.

Conclusions:

• Multistage breeding schemes can be optimized by balancing selection intensity and accuracy across stages.
• QTL information significantly enhances genetic gain and can reduce the need for progeny-tested bulls in dairy cattle breeding.
• Finding the optimal balance between genetic progress and cost is crucial for breeding organizations.