Resumen:
The aim of the present study was to evaluate the potential of supplementing calves diets with exogenous enzymes (xylanase) and yeast (Saccharomyces cerevisiae) on the sustainable control of methane (CH4) and carbon dioxide (CO2) productions in agricultural calves farming. Three different levels of supplemented diets of xylanase (0, 3 and 6 mg/g of DM), S. cerevisiae (SC) (0, 2 and 4 mg/g of DM) and mixture of xylanase and SC (0, 2 μ xylanase + 2 mg S. cerevisiae, 6 μ xylanase + 4 mg yeast mg/g of DM) were tested. Asymptotic gas production consistently decreased by each of the additives with the lowest value at the high dose of xylanase + S. cerevisiae (P<0.05) compared with the control and the low dose of xylanase + S. cerevisiae. Methane production was reduced by additives inclusion (P<0.05) when compared with the control treatment with no additive. Xylanase + S. cerevisiae at all doses increased CO2 production (P<0.05) whereas the high dose had the most significant reduction in gas and methane productions compared with control, xylanase and S. cerevisiae additives at different doses. The findings of this study indicate that inclusion of xylanase or SC additives can improve rumen fermentation and reduce greenhouse gases production. The study also established that the mixture of xylanase and S. cerevisiae is more efficient in reducing gas and methane emissions for cleaner environmental production conditions in calves farming.