ASSESSING THE CONTRIBUTION ON METHANE PRODUCTION OF THREE FODDERS DURING THE MAHA SEASON IN SRI LANKA

Abstract

The present study was conducted to evaluate CH4 emission and in-vitro rumen characteristics of two hybrid Napier (Pennisetum perpureum x P. americanum) varieties (CO-3 and CO-4) and a fodder sorghum variety (Sorghum bicolor var. Sugargraze). Fodder samples were collected at three harvesting intervals as 4, 6 and 8 weeks during Maha season in low country wet zone, Sri Lanka. They were analyzed for Metabolizable energy (ME), Organic matter digestibility (OMD) and CH4 production by in-vitro gas production technique. The data were analyzed using General Linear Model procedure. ME content and OMD gradually declined (p<0.05) while methane production increased (p<0.05) with increasing harvesting interval for all three varieties. Compared with Hybrid Napier varieties, sugargraze recorded the greatest ME content (9.13, 8.65, 8.08 MJ/kg DM) and OMD (62.58, 59.05, 54.88 %) and lowest (p<0.05) methane production (10.05, 12.13, 14.33 mg/g digested DM) at 4, 6 and 8 weeks harvesting interval, respectively. Sugargraze is superior to CO-3 and CO-4 in terms of higher ME content and OMD and lower CH4 production.