Cattle, climate and complexity: food security, quality and sustainability of the Australian cattle industries

Abstract

Background Marked increases in atmospheric CO2 concentrations are largely associated with the release of sequestered carbon in fossil fuels. While emissions of green‐house gasses (GHG) from cattle have significant global warming potential, these are biogenic sources and substantially involve carbon in natural cycles, rather than fossil fuel. Cattle use human inedible feeds and by‐products of human food production to produce nutrient‐dense foods of great value to humans. Interventions to reduce GHG production Reductions in land clearing and burning of grasslands and increased carbon sequestration in soils and trees have potential to substantially reduce GHG emissions. Increased efficiencies of production through intensified feeding and enteric modification have markedly reduced intensity of GHG emissions for cattle in Australia. Genetic selection for lower emissions has modest, but cumulative potential to reduce GHG (mostly CH4) emissions and intensity. Improved reproductive performance can reduce intensity of GHG emissions, especially in beef production. Feeds and technologies that reduce GHG production and intensity include improved pastures, grain feeding, dietary lipids, nitrates, ionophores, seaweed, 3‐NOP, hormonal growth promotants in beef, and improved diets for peri‐parturient dairy cattle. There is considerable potential to further reduce emissions from cattle using the technologies reviewed. Interventions to reduce heat stress Cattle are susceptible to heat stress and ameliorating interventions include tree and shelter belts, shade, housing, cooling with fans and water and dietary manipulations. Conclusions Numerous interventions can reduce GHG emissions and intensity from cattle. There are opportunities to increase carbon capture and maintain biodiversity in Australia's extensive rangelands, but these require quantification and application. We can reduce the intensity of CH4 emissions for cattle in Australia and simultaneously improve their well‐being.

Meta-Analysis and Ranking of the Most Effective Methane Reduction Strategies for Australia’s Beef and Dairy Sector

“…This report also confirms the lifetime of CH 4 is 11.8 years in the atmosphere, making the potency much closer to 84 times as potent as carbon dioxide over the relevant approximately 20-year lifespan [63]. The argument for GWP* is supported in the literature, where the "*" represents the lifespan of the GHG in question [18,20].…”

“…Parra et al [51] assessed a range of additives to reduce CH 4 in grazing cattle and found the addition of biochar and nitrate, biochar and Asparagopsis, and citral extract to significantly reduce CH 4 emissions by 22.83%, 19.82%, and 41%, respectively. Lean and Moate [20] reviewed CH 4 reduction strategies in Australia and found that nitrate supplementation reduced emissions by 10% and feed supplemented with 3-nitro-oxypropanol (3-NOP) reduced CH 4 by 22% in beef cattle and 39% in dairy cattle. Australian research has inspired researchers in the United States to study a locally produced seaweed grown in the waters of California to reduce CH 4 in cattle.…”

“…Almeida et al [17] argue for increased efficiency and production by triggering early puberty in breeding cows and reducing the post-weaning phase and associated feeding and emissions generated during non-productive times. Lean and Moate [20] found that providing ozonated water to cattle could reduce CH 4 by 20%.…”

“…The Australian beef and dairy sector predominately rely on pasture-based cattle, with feedlot finishing accounting for 4% of Australia's herd consisting of 1 million beef cattle [19]. About 60% of the beef supply comes from extensive grazing [19] and 62% of the national herd grown in northern Australia primarily relies on native grasses with less than 5% of pastures sown with grass and legumes [13,20]. In the dairy industry, milk production has surged by 116% in the last 40 years resulting in a decrease in CH 4 intensity.…”

The societal role of meat: the Dublin Declaration with an Australian perspective

“…This change has significant effects on GHG emissions intensity as the proportion of methane ascribed to maintenance is reduced. Over this time, the industry has changed from being seasonal and pasture-based (Lean 1987) to less seasonal and with greater reliance on a wide range of fodder crops, feed supplements and concentrate inputs (Rugoho et al 2017). Victorian farms evaluated for the Dairy Farm Monitor fed 61% of the metabolisable energy consumed as homegrown forages (Anonymous 2021).…”