Reducing the carbon footprint of Australian milk production by mitigation of enteric methane emissions

Abstract

Abstract. This review examines research aimed at reducing enteric methane emissions from the Australian dairy industry. Calorimeter measurements of 220 forage-fed cows indicate an average methane yield of 21.1 g methane (CH 4 )/kg dry matter intake. Adoption of this empirical methane yield, rather than the equation currently used in the Australian greenhouse gas inventory, would reduce the methane emissions attributed to the Australian dairy industry by~10%. Research also indicates that dietary lipid supplements and feeding high amounts of wheat substantially reduce methane emissions. It is estimated that, in 1980, the Australian dairy industry produced~185 000 t of enteric methane and total enteric methane intensity was 33.6 g CH 4 /kg milk. In 2010, the estimated production of enteric methane was 182 000 t, but total enteric methane intensity had declined~40% to 19.9 g CH 4 /kg milk. This remarkable decline in methane intensity and the resultant improvement in the carbon footprint of Australian milk production was mainly achieved by increased per-cow milk yield, brought about by the on-farm adoption of research findings related to the feeding and breeding of dairy cows. Options currently available to further reduce the carbon footprint of Australian milk production include the feeding of lipid-rich supplements such as cottonseed, brewers grains, cold-pressed canola, hominy meal and grape marc, as well as feeding of higher rates of wheat. Future technologies for further reducing methane emissions include genetic selection of cows for improved feed conversion to milk or low methane intensity, vaccines to reduce ruminal methanogens and chemical inhibitors of methanogenesis.

Tithonia diversifolia as a Supplementary Feed for Dairy Cows

“…The lack of statistical significance of methane production may be attributed to the poor sensitivity of this measurement technique. In the current experiment the rate of SF 6 released from the tracer was 2.63 ± 0.94 mg/d, which according to Moate et al [42] a minimum release rate of 3.0 mg/day is recommended. This variation in SF 6 release rate may also have resulted in the large variation of data as Deighton et al [43] recommends a uniform set of permutation tubes be used.…”

Estrategias de reducción de metano basadas en la genética y manipulación dietética de rumiantes: una revisión

“…The inclusion of wheat grain in the diet of dairy cows also results in a substantial reduction in methane yield (Moate et al 2015(Moate et al , pp. 1017.…”

“…121-40). According to Moate et al (2015Moate et al ( , pp. 1017, Australian dairy herds consume to 38 % of metabolisable energy intake as wheat.…”

The impact of genetic selection on greenhouse-gas emissions in Australian dairy cattle

“…Given the effect of GHG emission levels on climate change, mitigation of these gases has gained importance in recent years. While diet manipulation can alter the potential production of CH 4 (Moate et al 2016) and N 2 O emissions, selective breeding could offer a cost-effective means of abating emissions in the medium to long term, i.e. minimising the environmental impact and increasing the profitability of dairy systems at little to no extra cost.…”

“…Over 30 years (between 1980 and 2010), Moate et al (2016) estimated that production of enteric CH 4 has been almost static (185 000 t in 1980 versus 182 000 t in 2010); at the same time, milk production has increased, so that the intensity of CH 4 emissions (i.e. emissions per unit of product, in this case, milk) has declined considerably by 40% from~33.6 g CH 4 /kg milk to 19.9 g CH 4 /kg milk.…”