A bromochloromethane formulation reduces enteric methanogenesis in cattle fed grain-based diets

Abstract

Enteric fermentation has been estimated to be responsible for 64.2 Mt CO2-e, or ~16% of Australia’s greenhouse gas emissions (Australian Greenhouse Office 2007). A bromochloromethane (BCM) formulation, previously shown to inhibit methanogenesis, was included in the diet of Brahman (Bos indicus) cross steers, twice daily in three separate experiments, to determine the effect on methane production, daily feed intake, liveweight (LW) gain and accumulation of residues of BCM in edible tissue. In the first experiment, the BCM formulation was fed at rates of 0, 0.15, 0.30, or 0.60 g/100 kg LW, twice daily, for 28 days. Methane production (mean ± s.e.), measured over 11 h after feed was first consumed on day 28, was 0.3 ± 0.13 and 0.1 ± 0.03 L/h for animals treated at a rate of 0.30 and 0.60 g/100 kg LW, respectively. This was significantly less (P < 0.05) than for control animals (4.6 ± 0.46 L/h) and animals treated at a rate of 0.15 g/100 kg LW (2.1 ± 0.28 L/h). The dose rate of 0.30 g/100 kg LW was associated with a decrease in methanogenesis by ~93% compared with the control group and was used in subsequent experiments. The second experiment evaluated the efficacy of the BCM formulation fed at rates of 0 or 0.30 g/100 kg LW, twice daily, for 90 days. Methane production was measured over 24-h periods, on days 30, 60 and 90. For days 30 and 90, methane production was reduced by 60% (P < 0.05) to 4.2 ± 1.82 L/h and by 50% (P < 0.05) to 6.1 ± 0.63 L/h, respectively, for treated animals compared with the control group. The final experiment determined the effect on LW gain and detectable residues in edible tissue, with animals given the BCM formulation at rates of 0 or 0.30 g/100 kg LW, twice daily, for 85 days. Liver, kidney, depot fat and muscle samples collected 1 and 10 days after the last day of treatment had concentrations of BCM that did not exceed 0.015 mg/kg and were less than the temporary maximum residue limit (0.02 mg/kg BCM), which applies to bovine meat, fat and edible offal. There were no significant differences in LW gain (1.4 ± 0.10 v. 1.5 ± 0.07 kg/day), feed conversion ratio (5.7 ± 0.32 v. 5.4 ± 0.09), hot carcass weight (235 ± 5.0 v. 250 ± 6.5 kg) or P8 fat depth (6.4 ± 0.89 v. 8.1 ± 1.15 mm) between control and treated animals. The experiments reported here were completed in 2004 before the Australian Government prohibited the manufacture and use of BCM. It is unlikely that the BCM formulation will be available for commercial use to mitigate livestock methane emissions in Australia. Nevertheless, the study has demonstrated that methane emissions were substantially reduced over a 90-day feedlot finishing period. This indicates that alternative antimethanogens with a similar mechanism of action may have practical commercial relevance.

Effect of Tropical Algae as Additives on Rumen <i>in Vitro</i> Gas Production and Fermentation Characteristics

“…There seems potential that even at low levels of inclusion (<5% of dietary OM) some algae have strong effect on gas production and CH 4 emissions. In this in vitro study it was found that Cystoseria has potential for large CH 4 reductions when applied as an additive in ruminant diets as compared to the other algae tested.…”

“…In Table 3 it is shown that Cystoseira trinodis had a significant effect in promoting CH 4 reduction. The other selected algae, although showing a mild mitigation, did not reduce CH 4 significantly. There seems potential that even at low levels of inclusion (<5% of dietary OM) some algae have strong effect on gas production and CH 4 emissions.…”

“…However, when feed supplementation is incorporated to improve ruminant production then employing additives that have an effect on greenhouse gas production would be beneficial for individual producers and the industry. A number of feed additives such as halogenated analogues [4], monensin [5] and a range of plant compounds such as tannins [6], saponins [7], essential oils [8,9], and various secondary metabolites [10] have been demonstrated to have potential in reducing greenhouse gas emission from livestock production systems, but in most part it's difficult to administer across large herds which are managed in extensive environments.…”

Measurement and mitigation of methane emissions from beef cattle in tropical grazing systems: a perspective from Australia and Brazil

“…In a grazing environment, the use of these additives to achieve a sustainable reduction in enteric CH 4 production would be extremely challenging. Specific antimethanogenic activity (as % suppression) of several substances such as myristic acid (47%), nitroethane (26% to 69%), corrinoid inhibitors (15.5% to 97.1%), horse radish oil (90%) and a halogenated CH 4 analogue (93%) has been identified in ruminants Beef cattle CH 4 emissions in tropical pastures Anderson et al, 2004;Mohammed et al, 2004a and2004b;Tomkins et al, 2009). The use of many additives would require specific technological advances before they can be widely used in grazing systems.…”

“…A novel approach using micrometeorological methods has been tested and may offer a more appropriate method for extensive production systems . To date, most of the experimentation in Australia and Brazil that has either measured CH 4 emissions or investigated the effect of different mitigation strategies on CH 4 emissions have been conducted under well-defined and controlled conditions using the SF 6 tracer method (Johnson et al, 1994) or opencircuit respiration chambers (McCrabb and Hunter, 1999;Tomkins et al, 2009;Kennedy and Charmley, 2012). However, beef production dominates a large proportion of the grazing systems in both countries, and this introduces a dimension of scale for determining emissions and mitigation effects where the smallest unit of measure may be at the herd level.…”