Growth Performance and Methane Production of Thai Native Beef Cattle under Grazing and Cut-Carry Ruzi Grass with or without Concentrate Supplementation

Despite of concentrate supplements in ruminant diets have been recognized as an influence enteric methane abasement strategy, very few studies have investigated the effects of concentrate supplementation on enteric methane emission under grazing conditions of Thailand. This study aimed to measure growth performance and methane emission from Thai native beef cattle raising under grazing or cut and carry forage with or without concentrate supplementation. Thirty Thai native beef cattle heifers and steers were allocated to a randomized complete block design with six replications. Treatment is feeding systems were continuous grazing in natural pasture: control (T1), rotational grazing in Ruzi grass pasture (T2), cut and carry of Ruzi grass (T3), rotational grazing in Ruzi grass pasture + concentrate (1% of BW) (T4) and cut and carry of Ruzi grass + concentrate (1% of BW) (T5), respectively. Body weight was negative in continuous grazing natural grassland (T1), rotational grazing (T2) and cut-carry Ruzi grass without concentrate supplementation (T3). Continuous grazing natural grassland without concentrate (T1) gave 7.46 %Ym and was within a range of 6.5±1.0 %Ym (IPCC, 2006).  Thai native beef cattle assigned to confinement systems with cut and carry of Ruzi grass plus 1% body weight concentrate supplementation (T5) released methane of 3.05 %Ym.  Our results suggest that to improve the growth performance and mitigate methane emission of Thai native beef cattle, cut and carry of Ruzi grass with 1% body weight concentrate supplementation should be used.