Location: Dale Bumpers Small Farms Research Center
Project Number: 6020-21500-001-008-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Jan 1, 2022
End Date: Nov 30, 2025
Objective:
1. Estimate genomic diversity metrics essential for the successful implementation of genomic selection in four main US sheep breeds (Katahdin, Polypay, Rambouillet, and Suffolk).
2. Leverage existing resources to build reference populations for key novel traits and understand their genomic background.
3. Develop the methods for genomic prediction of breeding values in four main US sheep breeds.
Approach:
Existing resources among collaborators will be integrated and new datasets and genomic tools developed to enhance sheep productivity and robustness. Key traits will be recorded in ARS flocks including reproductive and overall fitness, disease and flock health, sustainability and climatic resilience to further genetic progress. Traits include 1) survival (during gestation, within 1 or 2 days of birth, at weaning, and at adult stages) and ewe longevity; 2) health [gastrointestinal parasites (fecal egg count and FAMACHA scores), hoof health, and mastitis]; 3) climatic resilience (change in body condition scores across seasons, tolerance or resilience to environmental challenges, hair shedding); and, 4) reproductive performance [ram fertility (semen quality, volume, scrotal circumference), and ewe reproductive efficiency (including ultrasound-based reproductive success, out-of-season fertility, and adult body weight)]. To understand the genomic background of these traits, we will estimate genetic parameters (e.g., heritability, genetic correlations) and perform genome-wide association studies (GWAS) based on the single-step Genomic Best Linear Unbiased Prediction (SS-GBLUP) methodology. Subsequently, we will perform functional genomic analyses of all the important genomic regions to unravel candidate genes and metabolic pathways associated with these novel traits. Methodologies will generate more accurate breeding values. A strong partnership with US sheep producers and the National Sheep Improvement Program (responsible for the national genetic evaluation), USDA-ARS, and land-grant universities will contribute to the project design.
