Preliminary Research On Methane Emissions From Grazing Yaks On Winter Pasture Of The Qinghai-Tibetan Planteau

Agricultural operations play an important role in climate change. Farm animals and their manure are important sources of CH4, CO2 and N2O emissions. The magnitude of greenhouse gases emissions from animal production can vary with animal species, feeding schemes, manure handling practices and environmental conditions. Methane production in the rumen represents a loss of energy for the host animal; in addition, methane eructated by ruminants may contribute to a greenhouse effect or global warming. More and more scientists focus on methodologies of measurement methane emissions from ruminants recently.The present research was preliminary focus on methane emissions from grazing yaks on winter pasture of the Qinghai-Tibetan plateau by using in vitro gas production technique, and effect of increasing dietary level Coconut oil on methane output was also evaluated.. Three adult yak initially in average 170±10kg BW ) were grazing on winter pasture before the experiment, and in vitro fermentable substrate was Kentucky bluegrass (Poa pratensis),Qingzang Carex (Carex moorcroftii),nutans (Elymus nutans Griseb),Potentilla anserina (Potentilla anserine) and mixed sample. The main result are showed as follows:Difference among feed samples occurred for in vitro gas production and methane production. The cumulative gas production of Poa pratensis,Carex moorcroftii,Elymus nutans Griseb,Potentilla anserine and mixed sample were 118±2ml, 108±4ml, 83±2ml, 72±1ml and 70±1ml after 24 hours fermentation, respectively. The gas production of Kentucky bluegrass was significantly higher than the other treatments (P<0.05). methane production measured at 24 h of incubation were reached peak, and 30.4±1.05L/kg for the Kentucky bluegrass treatment, which was significantly higher than the other group(P<0.05). The methane production of Potentilla anserina was minimum that was 25.9±1.61L/kg, The methane production of mixed sample was 28.97±1.26L/kg. The result could be conclude that When the yak grazing on natural winter pasture, the corresponding methane emissions in in vivo range 25.9±1.61L/kg from 30.4±1.05L/kg.The addition of coconut oil was significantly (P<0.01) inhibited methane production in vitro. Compared with the control level, the methane production of inclusion of 3%, 6% ,9% coconut oil decreased by 37%, 56% and 67%, respectively.