Feed-intake and methane efficiency for weight and growth pre-slaughter of MLA resource flock lambs

Improving feed-use efficiency and reducing methane emissions in sheep are critical strategies for enhancing market access, profitability, and the long-term sustainability of the sheep industry. In this study, 758 lambs from Merino, Maternal and Shedding ewes mated artificially to Merino, Maternal, Terminal and Shedding sires were assessed for weight, growth, and methane production prior to slaughter across six kill groups (2 years x 3 ages). Weight and growth accounted for 72-89% of the observed variation in daily feed intake. No additional variation was explained by body composition or methane production, as measured in this study. Residual feed intake exhibited high variability across all breed types (sire means ranged from -0.17 to +0.18 kg/hd/day, SD=0.12), suggesting that genetic selection for feed efficiency and methane reduction is achievable for Terminal, Shedding, and Merino sheep. This research highlights the potential for genetic improvements in reducing methane emissions and enhancing feed efficiency in sheep, offering pathways to a more sustainable and profitable sheep industry.