Breed differences and heterosis in triacylglycerol fatty acid composition of bovine adipose tissue

Subcutaneous adipose tissues were biopsied in purebred Jersey (n = 17), pur ebred Limousin (n = 17) and reciprocal F-1 Jersey x Limousin crossbred (n = 33) calves at the age of 9-10 months. Triacylglycerol fatty acids were ext racted and analysed for sex and breed differences. Heterosis, additive and maternal variances were estimated. All calves were pasture-fed in a single management group and biopsied from the same anatomical site. Heifer calves had significantly higher proportions of palmitoleate, total mono-unsaturate d fatty acids, desaturation index and lower stearate than steer calves. Sig nificant breed differences were observed in that Limousin calves had the hi ghest proportions of palmitate and total saturated fatty acids, whereas Jer sey calves had the most palmitoleate and desaturation index. Dominance effe cts were evident in the proportions of palmitate, stearate, desaturation an d elongation enzyme indices due to the observed highly significant heterosi s effect. Myristate, palmitate and total saturated fatty acids were conside red heritable due to the observed highly significant additive genetic effec t.