Comparison of feed intake, body weight gain, enteric methane emission and relative abundance of rumen microbes in steers fed sainfoin and lucerne silages under western C anadian conditions

Beef cattle are major contributors of enteric methane (CH4) emissions in Canada. Feeding forages containing condensed tannins (CT) has been suggested as a means of reducing enteric CH4 emissions and improving production efficiency. Sainfoin (Onobrychis viciifolia) is one of the CT‐containing legumes, which has also been recognized to have several additional beneficial properties. This study compared sainfoin silage (SS) and lucerne (Medicago sativa) silage (LS) with respect to animal performance, enteric CH4 production, abundance of selected rumen microbes and selected serum parameters in yearling steers during a Canadian winter. Sainfoin silage in our study contained approximately 12 g CT kg−1 dry matter (DM), a level which did not adversely affect silage palatability as steers fed SS experienced higher DM intake. However, animals fed LS and SS had similar body weight gain over the course of the trial. Feeding SS resulted in lower blood urea nitrogen concentrations and relative abundance of methanogenic archaea in rumen fluid. Yet, microbial population shifts fell short of exerting significant influence on enteric CH4 emissions. This study suggests that under western Canadian growing and animal‐rearing conditions, sainfoin is not yet competitive with lucerne forage with respect to enteric CH4 emissions or animal productivity warranting further research and development.