Benefit of including female genotypes in the Lacaune dairy sheep reference population

Breeding programs for Lacaune dairy sheep adopted genomic selection in 2015. Genomic predictions for young male candidates are based on a reference population of more than 10,000 artificial insemination rams born since the early 2000s. Because genomic accuracies for production traits remain lower than those achieved in main dairy cattle breeds, incorporating female genotypes into the reference population could be a profitable strategy. However, the gain in accuracy from female genotyping varies depending on the size of the reference population and the traits considered. Likewise, the costs associated with additional genotyping may decrease in the short or medium term. Using a deterministic gene flow model, this study evaluated the additional genetic gain and economic benefit of including female genotyping under different scenarios of increased genomic reliability and genotyping costs. Our results indicate that the profitability of female genotyping in the Lacaune dairy sheep population is possible but requires optimistic conditions. A significant increase in genomic reliability (+0.20) at current genotyping costs, or a very low genotyping cost (€4/sample) assuming no increase in reliability, would be necessary to make female genotyping beneficial over a 20-yr horizon. At current genotyping costs, genotyping ewe lambs does not appear to be a viable option unless it provides breeders with additional benefits, such as predictions for new traits or improved mating optimization.