Estimation & Prediction

Impact of genomic information on breeding value accuracy and ranking of Rideau sheep

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Abstract

The aim of this study was to assess the impact of incorporating genomic information into genetic evaluation of sheep using the single-step genomic best linear unbiased prediction (ssGBLUP), compared to traditional genetic evaluation using the best linear unbiased prediction (BLUP). The analysis focused on evaluating the accuracy of estimated breeding values (EBVs) for growth and reproductive traits of Rideau breed, based on data from a herd located in Georgina (Ontario, Canada), which is currently participating in the national sheep genetic evaluation program. The growth-related traits analyzed included lamb survival, adjusted 50-day weight and gain from 50 to 100 days. The reproductive traits included age at first parity, number born and total weaning weight at first parity, lambing interval, number born and total weaning weight at later parities. In total, 471,631 and 187,196 records for growth and reproductive traits were available, respectively, including purebred and crossbred Rideau animals. Among them, 1,405 animals were genotyped with Illumina 50k SNP array panel. As in the Canadian national sheep evaluation, purebred and crossbred Rideau animals were combined in a single evaluation model using a genetic group strategy to adjust for breed effects. The EBVs and their accuracies were estimated by BLUP and ssGBLUP in the MiXBLUP software. Spearman rank correlation was also calculated to assess the degree of similarity between the classification ranking of the animals based on their traditional BLUP EBV and their GBLUP EBV. The inclusion of genomic data significantly increased the accuracy of genomic estimated breeding values (GEBVs) for all traits evaluated. For young genotyped animals, gains in accuracy reached up to 33% for growth-related traits and up to 149% for reproductive traits with average accuracies of GEBVs at 0.78 and 0.74, respectively. The highest average accuracies were observed for animals with both genotypic and phenotypic records at 0.84 for growth-related traits and 0.76 for reproductive traits, with genomic data improving accuracy by up to 13% and 54% over the traditional EBVs, respectively. The average rank correlation between the classifications of genotyped non-phenotyped young animals based on their traditional EBVs and GEBVs was 0.73 for growth-related traits and 0.84 for reproductive traits, indicating substantial changes in ranking of the young non-phenotyped animals when genomic information is incorporated. However, the number of genotyped individuals in the population remains relatively small, suggesting that there is still considerable potential to further improve in accuracy, especially for reproductive traits, as the genomic reference population expands to additional herds.

Keywords: 2026

How to Cite:

Lazaro, S., Cánovas, Á. & Schenkel, F., (2026) “Impact of genomic information on breeding value accuracy and ranking of Rideau sheep”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285848. doi: https://doi.org/10.31274/wcgalp.23807

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