Reduced Rumen Methane Eructation in Smallholder Cattle and Buffalo by Dietary Supplementation with a Plant Tannins and Citral Extract

Large ruminant production is associated with high greenhouse gas emissions (GHGe) intensity, with the highest in southeast Asia being Laos at 102.9 CO2eq/kg meat produced, compared with average global meat emissions intensity of 33 CO2eq/kg. As recent studies in Laos identified emissions control molasses blocks (ECBs) achieved abatement of 470kg CO2eq/20kg block consumed, a study was conducted with a supplement mix with reported methane reducing properties, containing plant tannins and citral extract, salt, molasses and water. Groups of housed dairy buffalo (n=7) and pasture-fed grazing beef cows (n=11) were randomly selected, body condition scores estimated (BCS:1-5) and baseline nasa-oral methane eructation measured daily for 2 weeks. All animals were offered 300-400g/day of the mix for a month, with buffalo accessing abundant fresh cut forages whereas the grazing cows accessing rice straw and pasture declining in quality and quantity due to severe drought. The buffalo consumed all of the mix and retained their BCS of 3, whereas the cattle consumed between 200-300g/day of the mix and their BCS declined from 1.5 to 1.0 during the trial. Analysis of data points (buffalo n=309; cattle n=378) found average methane concentration (AMP) per animal of both cohorts increased over the 2 week baseline period, then declined during the supplementation period by 36% in the buffalo and 18% in cattle cohorts.