Estimation of genetic parameters for methane indicator traits based on milk fatty acids in dual purpose Belgian blue cattle

The genetic parameters of CH4 indicators were estimated by single trait test-day models from 16,825 records collected on Walloon Dual Purpose Belgium Blue cows in their first 3 lactations. Fatty acid based CH4 indicators published in the literature were predicted from milk mid-infrared spectra using 597 calibration samples. For the indicator showing the highest link (R2 =0.88) with SF6 CH4 data, the average daily heritability was 0.21, 0.20 and 0.10 for each lactation, respectively. The sire genetic variability was on average 2.82 kg2 of CH4 per lactation. The genetic difference between the sires having cows eructing higher and lower CH4 was 10 kg of CH4 averaged per lactation. In conclusion, CH4 indicators can be predicted by MIR and the genetic variability of these traits seems to exist.