Food by-products and methane-inhibiting feeds for ruminants

Abstract

Recently, ruminant production has been criticized due to feed-food competition and methane emission produced by enteric ruminal fermentation. Solving the problems is indispensable for sustainable ruminant production in the future. The review provides the descriptions of food by-products and methane-inhibiting feeds which have attracted a lot of attention as a strategy to solve the problems. Food by-products, including vegetable, fruits, and seasoning by-products, were useful as feeds for ruminants due to the nutritive values. Moreover, utilization of the by-products leads to decrease their disposal costs as well as reducing environmental impacts. Fats have the potential to reduce methane production from ruminants although those may have an adverse effect on ruminal microbes and fermentation. To avoid the adverse effects, it is important to carefully determine the dose and the type of fats.