Restructuring breeding programs 2: Assortative mating for improved commercial genetic gain when using optimum...

Area of Science:

• Animal Breeding and Genetics
• Quantitative Genetics
• Genomic Selection

Background:

• Commercial breeding programs aim for genetic gain and competitive products.
• Managing genetic diversity is crucial but can reduce short-term genetic gain.
• Assortative mating strategies were investigated to increase genetic variance in next-generation animals.

Purpose of the Study:

• To investigate assortative mating for increasing genetic variance in livestock breeding.
• To compare 'maximum' and 'tuned' assortative mating strategies.
• To assess the impact of assortative mating on genetic diversity and genomic prediction accuracy.

Main Methods:

• Two assortative mating strategies: 'maximum' and 'tuned'.
• Comparison with random mating and optimum contribution selection (OCS).
• Evaluation of genetic diversity, breeding value variance, and prediction accuracy.

Main Results:

• 'Maximum' assortative mating outperformed the 'tuned' strategy.
• Assortative mating accelerated genetic diversity loss under truncation selection.
• Assortative mating with OCS maintained comparable inbreeding rates and increased breeding value variance.

Conclusions:

• Assortative mating improves the genetic level of breeding program outputs.
• The benefits of assortative mating may not outweigh competitiveness losses from diversity introduction.
• Assortative mating should be used with diversity-aware selection methods like OCS to mitigate diversity loss.