Assessment of some browse tree leaves on gas production and sustainable mitigation of CH4 and CO2 emissions in dairy calves at different age

Abstract

The present context was aimed to determine the in vitro gas production (GP), mitigation of methane (CH4) and carbon dioxide (CO2) emission, and ruminal fermentation from nine different tree leaves as suitable alternatives for alfalfa hay. Tree leaves and alfalfa hay were incubated with rumen inoculum from calves at different ages (20, 40, and 60 d). The level of asymptomatic GP [mL/g dry matter (DM)] differed (P < 0.05) between different tree leaves compared with alfalfa hay. Most of the plant leaves showed differed (P < 0.05) asymptomatic CH4 production (mL/g DM), fractional rate of GP and lag time. The asymptomatic CO2 production and fractional rate of CO2 production decreased effectively (P < 0.01) with the different tree leaves. In vitro rumen CH4 and CO2 productions (mL/g incubated DM) by species incubated in the rumen liquor of calves collected at 60 d of age increased effectively. Fermentation pH (P < 0.001) was found to be significant parameter but DM degradability (P > 0.05) was not significant by dose and substrate × dose interaction. Tree leaves showed lower production of CH4 (mL/g incubated DM) and proportional CH4 emission when compared to alfalfa hay after the required period of incubation at significant level (P < 0.05). However, different tree leaves had no influence (P > 0.05) on CO2 production (mL/g incubated DM and mL/g degraded DM) and proportional CO2 production. The incorporation of tested tree leaves in diet would be a valuable alternative of alfalfa hay with sustainable reduction properties of CH4 and CO2 productions. These potent tree leaves can be used as valuable cleaner product and feeding stuffs for the environment and ruminants respectively due to their in vitro fermentative properties.