“SNP Assisted Breeding” for Sheep extensive systems: Utopia or Reality

A feasible SNP Assisted breeding program, adapted to extensive Uruguayan sheep system is under development. The focus is in Merino breed and their main selection criteria: clean fleece weight (CFW), fiber diameter (FD), yearling weight (YW) and parasite resistance (faecal egg count FEC). This program attempt to combine various commercial and custom designed panels in a cost-effective way.

In 2013, INIA together with Eureka Genomics® (now part of Affymetrix) developed a very low-density panel (507 SNP) including parentage, horn-poll and FEC-associated SNPs. This panel were validated in commercial stud-flocks. A moderate error of parentage assignment were found (6.1% Sire-lamb and 4.4% Dam-lamb in 539 and 161 pairs respectively). Its inclusion in a single-step evaluation (1015 genotyped animals) increased the EPD accuracy by 8.7, 17.0, 20.5 and 18.5% for FD, CFW, YW and FEC, respectively. The incremental cost for stud breeders for genotyping 40% of the top rams drop with LD and all rams with the HD panel and 30% of ewe lambs with 507SNP would be 2,330 USD per year. Between 2016 and 2018, needed genotyping for training population will be financed by research projects (n=3,000). In the near future, commercial stud breeders should decide if they continue with SNP program paying for the genotyping service.

The incremental cost of the SNP program for the stud breeders is similar to the price of four average rams (from approximately 100 rams), making it cost effective by providing a more accurate selection, higher genetic gain and some ram´s marketing advantages.