ABSTRACT
Ruminant production carries with it a significant environmental cost; locally this is mainly associated with nitrogenous compounds and phosphorus released from intensive operations. However, the global effect is predominantly due to the emissions of greenhouse gases (GHG), which occur in both intensive and extensive systems. Agricultural production accounts for 10-12% of global annual GHG emissions (Smith et al., 2014), with livestock production being the most important contributing factor within this sector. The largest single contributor to agricultural GHG emissions is methane produced during enteric fermentation, which represents between 32 and 40% of the total GHG emitted from the sector (Smith et al., 2014). If the sheep sector is to remain a significant component of the agricultural industry, then strategies which allow the industry to grow must be implemented, whilst at the same time reducing the environmental impact of this sector.
