Cross-validation of single-step genetic evaluation in U.S. Katahdin sheep

Authors: MCMILLAN, AARON - University Of New England; BROWN, DANIEL - University Of New England; Burke, Joan; MORGAN, JAMES - Round Mountain Consulting; LEWIS, RON - University Of Nebraska

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 2/23/2022
Publication Date: 2/1/2023
Citation: Mcmillan, A.J., Brown, D.J., Burke, J.M., Morgan, J.L., Lewis, R.M. 2023. Cross-validation of single-step genetic evaluation in U.S. Katahdin sheep. Meeting Abstract. https://doi.org/10.3920/978-90-8686-940-4_719.
DOI: https://doi.org/10.3920/978-90-8686-940-4_719

Interpretive Summary: Genomic information is used in genetic evaluation to improve prediction accuracy in most livestock species, but less so in sheep due to less genotyping, particularly in the U.S. Scientists from University of New England, Armidale, Australia, Agricultural Research Service - Booneville, AR, University of Nebraska-Lincoln, and Round Mountain Katahdin, AR, determined that genomic data was more accurate than pedigree information on body weight and fecal egg count data of Katahdin sheep in the U.S. National Sheep Improvement Program. The genomic estimated breeding values were implemented in 2021 to make targeted selections based on genetics to improve quality of flock traits. This information is important to sheep producers, geneticists, breeders, scientists, veterinarians, and extension specialists aiming to minimize parasite problems in sheep.

Technical Abstract: Genomic information is used in genetic evaluation to improve prediction accuracy in most livestock species. Such is less so in sheep, particularly in the U.S. In this study, the impact of implementing single-step genomic BLUP as compared to pedigree BLUP for weight and faecal egg count traits was evaluated in U.S. Katahdin sheep. Two methods of cross validation were utilised to compare the predictive ability and bias of estimated breeding values of these methods. Genomic information improved predictive ability for both traits, and reduced bias in the evaluation of faecal egg counts. Accuracies of estimated breeding values improved appreciably in genotyped animals. The benefit from including genomic information based on cross validation was minimal but is expected to improve as the reference population grows. Single-step genomic BLUP procedures developed will be used to update those applied in the routine genetic evaluation offered through the U.S. National Sheep Improvement Program.