Forage brassica: a feed to mitigate enteric methane emissions?

A series of experiments have been conducted in New Zealand to evaluate the potential of forage brassicas for mitigation of enteric methane emissions. Experiments included sheep and cattle fed winter and summer varieties of brassica forage crops. In the sheep feeding trials, it was demonstrated that several species of forage brassicas can result, to a varying degree, in lower methane yield (g methane per kg of dry matter intake) than ryegrass pasture. Pure forage rape fed as a winter crop resulted in 37% lower methane yields than pasture. Increasing the proportion of forage rape in the diet of sheep fed pasture linearly decreased methane yield. Feeding forage rape to cattle also resulted in 44% lower methane yields than feeding pasture. In conclusion, reductions in methane emissions are achievable by feeding forage brassicas, especially winter forage rape fed to sheep and cattle. Investigating other aspects of these crops is warranted to establish their value as a viable mitigation tool in pastoral farming.