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Abstract

There has been increasing concern regarding methane emissions from cattle and sheep in the UK. The aim of this project is to examine the effects of home grown forages and supplements on methane production in dairy cattle.

Description

Methane is a potent greenhouse gas with a Global Warming Potential (GWP) 25 times that of carbon dioxide. The Climate Change Act 2008 commits the UK to reduce greenhouse gas emissions by at least 80% by 2050, and by at least 34% by 2020, against a 1990 baseline. While there is no agriculture sector target for reduction in GHG emissions, any reduction from agriculture will contribute to the overall national target.  Due to its high GWP and relatively short atmospheric lifetime, methane makes a good target for GHG emission reductions.

The majority of methane emissions from cattle are a result of fermentation in the rumen which is released through eructation. Enteric methane production in cattle was estimated to be 24% of UK methane emissions in 2007, of which dairy cattle were responsible for 37%.

Grass and grass silage are the traditional forages fed to cattle and sheep in the UK, but are high in fibre which is associated with the generation of methane in the rumen. In contrast, ruminal digestion of starch is associated with a reduction in methane production. Starch content is naturally high in home grown forages such as whole-crop cereals, legumes and maize silage, but there is a lack of experimental data on the effects of these forages on mitigating ruminal methane production in UK production systems. Additionally, other naturally occurring compounds in forages such as polyunsaturated fatty acids and tannins may also reduce methane production.

There will be 2 phases to this project. 

Phase 1 will examine the effect of different home-grown forage sources and plant compounds on methane production in vitro.

Phase 2 will examine the effects of the most promising home-grown forages or supplements from phase 1 on methane production in dairy cattle using SF6 as a marker, and examine their effects on intake and milk yield and composition.