Nutritional and host effects on methanogenesis in the grazing ruminant

Abstract

Concentrations of methane (CH 4 ) in the atmosphere have almost doubled since the mid 1700s, and it is estimated that ,30% of the global warming experienced by the planet in the last century and a half can be attributed to CH 4 . Between 25% and 40% of anthropogenic CH 4 , emissions are estimated to arise from livestock farming. Mitigating absolute emissions from livestock is extremely challenging technically and is made more difficult because of the need to increase food production to meet the demands of a burgeoning world population. Opportunities for manipulating the diet of intensively managed ruminant to reduce absolute CH 4 exist, but in grazing livestock the opportunities are constrained practically and economically. Mitigating emissions per unit of product is more tractable, especially in the short term. Although the formation of CH 4 is an anaerobic microbiological process, the host animal does seem to exert an influence, as animals differ in the quantity of CH 4 they emit when fed the same diet. The reasons for this are not yet clear, but evidence is accumulating that these differences are consistent and have a genetic basis. Exploiting these between animal differences by animal breeding is an attractive mitigation option as it is potentially applicable to all animals and is open to continuous improvement. However, identifying the desired phenotype poses severe practical constraints. Vaccinating the host animal to produce antibodies that can modulate the activities of the organisms responsible for CH 4 formation also presents a novel mitigation option.

Methane emissions from beef cattle grazing on semi-natural upland and improved lowland grasslands

“…However, over the entire grazing season, NDF and ADF concentrations were lower in E1 than in E2 or E3. Several studies have suggested that level of intake rather than digestibility is the main determinant of absolute CH 4 emissions (DeRamus et al, 2003;Beauchemin and McGinn, 2006;Pinares-Patino et al, 2007;Hart et al, 2009;Pelve et al, 2012;Boland et al, 2013;Clark, 2013).However, the difference in absolute CH 4 emissions between experimental periods in the current work cannot be explained solely by differences in DMI. McCaughey et al (1999) found significant differences in DMI among cattle grazing swards of contrasting quality, but not between sampling periods, while corresponding absolute CH 4 emissions (L/day) differed significantly between sampling periods.…”

“…However, over the entire grazing season, NDF and ADF concentrations were lower in E1 than in E2 or E3. Several studies have suggested that level of intake rather than digestibility is the main determinant of absolute CH 4 emissions (DeRamus et al, 2003;Beauchemin and McGinn, 2006;Pinares-Patino et al, 2007;Hart et al, 2009;Pelve et al, 2012;Boland et al, 2013;Clark, 2013).…”

“…Methane (CH 4 ) emissions represent important losses of ingested dietary energy in ruminant livestock and have been studied in considerable detail for well over 50 years, commencing with a decade of technically challenging and pioneering work at the Rowett Institute as summarised by Blaxter and Clapperton (1965), and added to by other research groups (Johnson and Johnson, 1995;Beauchemin and McGinn, 2006;Hart et al, 2009;Clark, 2013 animal 130 losses account for between 2% and 12% of the gross energy (GE) intake of cattle, as dictated by the type, quality and quantity of feed consumed (Johnson et al, 1994;Yan et al, 2000;Yan et al, 2009). More recently, the focus of interest in CH 4 has shifted towards its contribution to global greenhouse gas (GHG) emissions and, thence, to climate change (Clark, 2013).…”

“…More recently, the focus of interest in CH 4 has shifted towards its contribution to global greenhouse gas (GHG) emissions and, thence, to climate change (Clark, 2013). Agricultural systems (particularly those for milk and red meat production) produce ∼17% of overall global anthropogenic GHG emissions with cattle, alone, accounting for 15% of the CH 4 emissions (FAO, 2006).…”

Progress in the development of vaccines against rumen methanogens

“…A range of different strategies are being investigated to reduce methane emissions from farmed ruminants (reviewed by Martin et al, 2010;Buddle et al, 2011;Clark, 2013). Vaccination of ruminants against rumen methanogens has the potential to reduce methane emissions by decreasing the number or activity of methanogens in the rumen.…”