Detection of genomic regions underlying milk production traits in Valle del Belice dairy sheep using regional heritability mapping

The aim of this study was to identify genomic regions underlying milk production traits in the Valle del Belice dairy sheep using regional heritability mapping (RHM). Repeated measurements for yield (MY), fat percentage and (F% FY) protein (P% PY), collected over a period 6 years (2006–2012) on 481 ewes, were used analysis. Animals genotyped with Illumina 50k SNP chip. Variance components, heritabilities repeatabilities within across lactations estimated, fitting parity, litter size, season lambing fortnights milk, as fixed; additive genetic, permanent environment lactations, flock by test-day interaction residual random effects. For RHM analysis, model included same fixed effects before, plus an additional effect (specific region being tested) random. While whole estimated relationship matrix (GRM) constructed from all SNPs, GRM SNPs each region. Heritability estimates ranged between 0.06 0.15, 0.14 0.24 0.23 0.39 lactation traits. A substantial flock-test-day also estimated. Significant at either genome-wide (p < .05) or suggestive (i.e., one false positive per genome scan) level identified chromosome (OAR) 2, 3 20 F% OAR3 P%, common two Our results confirmed role LALBA AQP genes, OAR3, candidate genes sheep.