Evaluating Selection Strategies Based on Inbreeding Load via Simulation

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Breeding Schemes

Background:

• Inbreeding load, the expression of recessive mutations in offspring, contributes to genetic heterogeneity.
• It can potentially serve as a selection criterion alongside estimated breeding values (EBVs).

Purpose of the Study:

• To evaluate the effectiveness of selection strategies incorporating inbreeding load in a dairy sheep breeding scheme.
• To compare genetic gain, inbreeding metrics, and selection accuracy across different strategies.

Main Methods:

• Stochastic simulation over 15 generations.
• Evaluation of seven selection strategies: EBVs only, inbreeding load only, combined, or random selection and mating.
• Comparison of genetic gain, inbreeding coefficients, rate of inbreeding, effective population size, inbreeding depression, and selection accuracy.

Main Results:

• No significant difference in genetic gain was observed between strategies based on EBVs and those incorporating inbreeding load.
• Selection solely on inbreeding load or random selection resulted in significantly lower genetic gain.
• The benefits of using inbreeding load in mate allocation were negligible.

Conclusions:

• Selecting animals using estimated inbreeding load is feasible but does not offer a clear practical advantage over EBVs alone.
• The accuracy and magnitude of inbreeding load effects did not demonstrate significant practical interest for improving dairy sheep breeding schemes.