Abstract

Simple SummaryMethane is a potent greenhouse gas. It is 80-times more effective at heating the earth than carbon dioxide over the first 20 years following release into the atmosphere. Ruminant animals have diverse microbial populations in their stomachs that employ anaerobic fermentation to digest feed. Methane is belched into the atmosphere as a by-product of the digestive process. This gut, or enteric methane, primarily from cattle, but also sheep and goats, contributes 30% of the methane released into the earth’s atmosphere each day, and is more than any other single methane source. A major reduction in methane emissions from ruminants is crucial to preserve ecosystems on the planet. Various strategies to reduce enteric methane emissions in farm operations are reviewed to quantify their mitigation potential, determine their impact on animal productivity and likelihood of adoption. Two feed supplements, a commercial product, 3-NOP (Bovaer®), and the seaweed, Asparagopsis, can reduce methane emissions by 40+% and 90%, respectively, with associated increases in animal productivity and no adverse effects on animal health or product quality. The rumen microbial population can also be changed to provide long-term intergenerational reduction in methane emissions, if treated herds remain isolated from non-treated animals.Anthropomorphic greenhouse gases are raising the temperature of the earth and threatening ecosystems. Since 1950 atmospheric carbon dioxide has increased 28%, while methane has increased 70%. Methane, over the first 20 years after release, has 80-times more warming potential as a greenhouse gas than carbon dioxide. Enteric methane from microbial fermentation of plant material by ruminants contributes 30% of methane released into the atmosphere, which is more than any other single source. Numerous strategies were reviewed to quantify their methane mitigation potential, their impact on animal productivity and their likelihood of adoption. The supplements, 3-nitrooxypropanol and the seaweed, Asparagopsis, reduced methane emissions by 40+% and 90%, respectively, with increases in animal productivity and small effects on animal health or product quality. Manipulation of the rumen microbial population can potentially provide intergenerational reduction in methane emissions, if treated animals remain isolated. Genetic selection, vaccination, grape marc, nitrate or biochar reduced methane emissions by 10% or less. Best management practices and cattle browsing legumes, Desmanthus or Leucaena species, result in small levels of methane mitigation and improved animal productivity. Feeding large amounts daily of ground wheat reduced methane emissions by around 35% in dairy cows but was not sustained over time.

Highlights

  • Anthropomorphic production of greenhouse gases is raising the temperature of the earth to levels that are threatening the sustainability of ecosystems on the planet [1].Temperatures at regions on earth have risen since the 1960s by more than 1.2 ◦C and annual soil moisture is estimated to have declined by 20 to over 40% in the cropping regions of southern Australia [2]

  • There is an urgent need for managers of ruminant enterprises to adopt strategies that reduce enteric methane emissions to avoid further increases in anthropomorphic associated greenhouse gas emissions

  • In Australia, this will most likely happen when alternate income sources from carbon projects can be realized and in turn this requires a substantive increase in research investment that results in new Methods that can be employed in carbon projects under the Emissions Reduction Fund (ERF)

Read more

Summary

Introduction

Anthropomorphic production of greenhouse gases is raising the temperature of the earth to levels that are threatening the sustainability of ecosystems on the planet [1].Temperatures at regions on earth have risen since the 1960s by more than 1.2 ◦C and annual soil moisture is estimated to have declined by 20 to over 40% in the cropping regions of southern Australia [2]. Atmospheric concentrations of the major greenhouse gases, carbon dioxide and methane, have risen since 1950 from 350 to 410 ppm (28%) and 1100 to 1875 ppb (70%), respectively [3]. Ruminants produce a substantial amount of carbon dioxide (CO2), with a methane:CO2 ratio of approximately 4:1 [9], making a total contribution of ruminants to anthropogenic greenhouse emissions of 8%. There are demands from sections of the community for major reductions in the consumption of red meat to reduce the number of ruminants and amount of methane they release [10,11]. Rather than reducing red meat consumption or ruminant numbers, is to reduce methane emissions from ruminants

Methods
Findings
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call