Female Inclusive MACE for Improved Genetic Evaluations in Small Populations

A Special Case for Ayrshire Dairy Herds

Abstract

Abstract

Small reference populations hinder prediction accuracy in minor breeds, thereby limiting genetic progress. In response, the World Ayrshire Federation (WAF) initiated an international collaboration through the Interbull Centre (IBC) to enhance genomic evaluations for Ayrshire-based populations across countries. This initiative is primarily to ensure breed sustainability by addressing the challenge of limited reference population sizes in individual countries, which affects the reliability of national genomic evaluations. The aim of this study is to adapt IBC’s Multiple Across-Country Evaluation (MACE) to include female estimated breeding values (EBVs) alongside male data while leveraging the Interbull Data Exchange Area (IDEA) and GenoEx-GDE platforms for data management.

The participating countries initially include Australia, Canada, Colombia, the United Kingdom, New Zealand, South Africa, and the United States. A total of 22,383 genotyped Ayrshire animals (4,403 males and 18,880 females) have been identified, with Canada contributing 46% of the genotypes. Adding cow data is envisioned to accelerate reference population growth, boost genotyping returns and improve the reliability of both national and international genetic and genomic evaluations over time. The first phase of implementation involves integrating cow EBVs into MACE while sharing genotypes among participating countries using the GenoEx-GDE platform. The second phase envisions extending these evaluations through InterGenomics for interested countries and those that cannot perform their own national genomic evaluations. This collaboration paves the way to faster growth of reference population sizes and improves genetic and genomic prediction accuracy for not only Ayrshire sustainability, but also the opportunity exists for other small breed populations like Guernsey, among others.

Key words: Ayrshire, genomic evaluation, MACE, small populations, international evaluation