For evaluating the effect of starch source in the diet on nutrient degradability and methane production, two in vitro experiments were conducted. In one experiment, four concentrate mixtures having similar proportion of various starch sources i.e. maize (CM1), barley (CM2), wheat (CM3) and pure starch (CM4) were evaluated for DM, starch degradability and methane production. In another experiment, 4 total mixed rations based on above mentioned concentrate mixtures and wheat straw (40:60) i.e. T1, T2, T3 and T4 were evaluated for IVDMD and methane production. Potential and effective DM degradability of all the concentrate mixtures were similar inspite of variation in the degradability pattern of their starch content, which resulted in similar production of methane, total gas and TVFA. Degradability of starch from barley and pure source based concentrate mixtures was higher than those based on wheat and maize during a period of 24 h. Methane production did not reveal any correlation with starch degradability although it had direct correlation with DM degradability. IVDMD of total mixed ration T2 was lower, while other rations had similar values. However, methane production as % of total gas per kg DM and per kg OM was significantly higher in wheat and barley based total mixed rations than those based on maize and pure starch, which did not differ from each other. It can be concluded that type of dietary starch had no significant correlation with methane production.
Starch, In vitro degradability, Methane production
