Estimates of genetic parameters for triacylglycerol fatty acids in beef cattle at weaning and slaughter

Adipose tissues from the 12th-13th rib interface were sampled at weaning (3 24 cattle) and slaughter (310 cattle). The animals were progeny from Herefo rd dams sired by Angus, Belgian Blue, Hereford, Jersey, Limousin, South Dev on and Wagyu. Fatty acid composition of the triacylglycerol fraction at bot h stages was measured by gas-liquid chromatography. Estimates of heritabili ty and genetic and phenotypic correlations at weaning and slaughter were co mputed by restricted maximum likelihood using a sire model in both univaria te and multivariate analyses. Results indicated that generally, there were strong, positive genetic correlations between fatty acids at weaning and sl aughter (as high as 0.98). Phenotypic correlations were however, low and po or (0.04-0.44). Heritability (h(2)) estimates at weaning were low to modera te, ranging from 0-0.31. However, at slaughter, h(2) estimates were general ly higher than at weaning: Stearate, oleate and total monounsaturates had h (2) estimates of 0.43, 0.37 and 0.40, respectively. Other carcass traits su ch as marbling score and melting point of fat had h(2) estimates of 0.20 an d 0.52, respectively. Significant breed, sex and location differences in fa tty acid composition were also observed at weaning and slaughter.