Foaling number are highly affected by the genomic homozygosity in the Pura Raza Spanish mares

LASECA, N.; PERDOMO-GONZÁLEZ, D.I.; VALERA, M.; MOLINA, A.; SANCHEZ-GUERRERO, M.J.; AZCONA FLORENCIA; PIROSANTO YAMILA; DEMYRA-PEYRAS SEBASTIAN

Pisa

Congreso; International Symposium on Equine Embryo Transfer and Technologi; 2020

Breeding values of reproductive traits are scarcely evaluated in horses. Among them, foaling number (FN, number of foals produced per year of reproductive life), is highly considered character since it is influenced by both, fertility and longevity of the individuals. Additionally, molecular inbreeding (the actual degree of homozygosity molecular-values, FROH) it was also associated with fertility in livestock. In this study, we evaluated, in 243 PRE mares, the effect of FROH in the foaling number estimated breeding value (EBVFN). EBVFN ´s were estimated in base of all Pura Raza Española population (72,982 mares with foals), using a bivariate REML model including breeding stud size, owner stud size and country and birth year of the mother and the age of mare as a covariate. Molecular inbreeding was also estimated using 600,345 SNP markers (27,569 from ECAX) assessing ROH>1Mb (FROH) ROH>16Mb (FROH16) in order to evaluate ancient and recent inbreeding. EBVFN ranged from -1.72 to 2.78 depicting an ample genetic variability. FROH and FROHX varied from 0.005 to 0.3986 and 0 to 0.969 respectively also showing high variability in terms of homozygosity. Interestingly, we found a large negative correlation (r=-0.398; p