Genomic selection strategies for the German Merino sheep breeding programme - A simulation study

Area of Science:

• Animal Breeding and Genetics
• Quantitative Genetics
• Sheep Production Systems

Background:

• Genomic selection is established in livestock breeding but underutilized in German Merino sheep due to genetic diversity.
• Traditional breeding value estimation relies on pedigree BLUP, which has limitations for diverse populations.

Purpose of the Study:

• To evaluate the effectiveness of different genomic selection strategies for the German Merino sheep breeding program.
• To compare genomic selection scenarios with a reference pedigree BLUP scenario.

Main Methods:

• Simulation study using the R package MoBPS with real genotype data.
• Comparison of reference scenario (pedigree BLUP) with single-step GBLUP (ssGBLUP) scenarios.
• Scenarios included varying genotyping strategies: all males, all males plus females, and preselected proportions (top 25%, 50%) of males.

Main Results:

• Genetic gain increased with the number of genotyped animals, but with diminishing marginal returns.
• Genotyping the top 25% of male lambs increased genetic gain by 13% for both health and production traits.
• Genotyping top 50% of males or all males resulted in 18% (17%) and 26% (21%) increases, respectively. Genotyping females showed limited additional benefit for male breeding value.

Conclusions:

• Genomic selection offers a valuable tool to enhance genetic gain in German Merino sheep.
• Genotyping a strategic proportion of male lambs can substantially improve upon pedigree-based breeding value estimation.
• Further economic evaluations are recommended before practical implementation of genomic selection in this population.