Abstract:

Post-slaughter alimentary tract measures were collected from eight-month-old ram lambs during routine culling of sheep divergently selected for methane yield. Measures from 142 and 132 lambs from the high and low methane lines respectively were collected over five years. Low CH₄ animals had lighter reticulo-rumen full, empty and contents weights (P<0.05), but tended to have longer rumen papillae (P=0.06). Preliminary heritability estimates for reticulo-rumen components and papillae traits were significantly different from zero, ranging from 0.09 to 0.25. Results validate earlier findings that differences in the anatomical characteristics of the alimentary tract are associated with methane emissions and suggest that there is a significant host genetic component, warranting further investigation.