A series of experiments was conducted in New Zealand to evaluate the potential of forage brassicas for mitigation of enteric methane emissions. Experiments involved 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 a lower methane yield (g methane per kg of DM intake) than does ryegrass pasture. Pure forage rape fed as a winter crop resulted in 37% lower methane yields than did 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 yield than did feeding pasture. In conclusion, reductions in methane emission are achievable by feeding forage brassicas, especially winter forage rape, to sheep and cattle. Investigating other aspects of these crops is warranted to establish their value as a viable mitigation tool in pastoral farming.
Exploratory environmental assessment of large-scale cultivation of seaweed used to reduce enteric methane emissions
