Phenotypic differences and genetic parameters for methane concentration in BeefxDairy crossbred slaughter calves

Genetic selection for reduced methane emission and BeefxDairy crossbreeding are strategies to lower the climate impact of beef. Combined they require knowledge of phenotypes on methane production for BeefxDairy offspring. Slaughter calves sired by Belgian Blue, Charolaise and Angus sires to Holstein dams were compared to purebred Holstein calves. Heritability for methane concentration (CH4c) were estimated for Belgian blue crosses. Raw phenotypic means showed that CH4c was lower for calves born after Charolaise and Angussires compared to Belgian Blue. The heritability of log transformed CH4c for Belgian blue crosses was estimated to be 0.44 (±0.08), and for log transformed CH4c adjusted for background CH4 it was 0.33 (±0.06). This is in line with heritabilities found for log transformed CH4c in Holstein cows, and will be the basis for further analysis in genetic architecture of methane traits in crossbred slaughter calves.