CAN INOCULATION OF SILAGE WITH A FERULIC ACID ESTERASE-PRODUCING INOCULANT REDUCE ENTERIC METHANE EMISSIONS IN GHANA?

Abstract

Methane (CH4) is a potent greenhouse gas accounting for 25 times the capacity of CO2 in causing global warming. Enteric CH4 emission from domestic ruminant production is greater in the tropics where more forage is fed than in temperate regions where concentrates can form more than 85% of the diet. Inoculation of silage with a fibrolytic inoculant improves fibre digestibility. Increased ruminal fibre digestion increases ruminal nutrient digestion, fermentable substrates and passage rate. This reduces the time available for methanogenesis to occur in the rumen. A glucogenic pattern of rumen fermentation associated with feeding silage inoculated with ferulic acid esterase-producing inoculant increases propionic acid in the rumen. Formation of ruminal propionic acid serves as a sink for H2 that would otherwise be used for methanogenesis. At a lower ruminal pH, methanogens also lose their ability to use H2. Efficient utilization of feed can therefore reduce enteric CH4 output. Other benefits of inoculating silage with fibrolytic silage inoculants include improvements in aerobic stability which also reduces emission of obnoxious gases such as nitric oxide, which reacts with atmospheric oxygen to form nitrogen dioxide. Abatement of CH4 emission by ensiling with ferulic acid esterase-producing inoculants may therefore represent a less expensive and most practical management strategy for reducing enteric CH4 emission in Ghana.