Impact of Co-Ensiling of Maize with <i>Moringa oleifera</i> on the Production of Greenhouse Gases and the Characteristics of Fermentation in Ruminants

The objective of this experiment was to evaluate the impact of maize co-ensiling with increasing percentages of MOL forage on the kinetics of biogas, methane (CH₄), carbon monoxide (CO) and hydrogen sulfide (H₂S) production, as well as the characteristics of ruminal fermentation and CH₄ conversion efficiency, using steers (STI) and sheep (SHI) as inoculum sources. With the STI, the inclusion of MOL reduced (linear: <i>p</i> ≤ 0.0199; quadratic: <i>p</i> ≤ 0.0267) biogas production (mL g⁻¹ DM incubated and degraded), CH₄ (mL g⁻¹ DM degraded), CO (mL g⁻¹ DM degraded), and H₂S (mL g⁻¹ DM incubated and degraded), without affecting (<i>p</i> > 0.05) the parameters (<i>b</i> = asymptotic gas, <i>c</i> = rate of gas production and <i>Lag</i> = initial delay time before gas production) of CH₄ and H₂S, and the proportion and production of CH₄ per kg of dry matter (DM). In addition, with this inoculum, pH, and dry matter degradation (DMD) increased (linear: <i>p</i> ≤ 0.0060), and although short-chain fatty acids (SCFA) and metabolizable energy (ME) decreased (linear: <i>p</i> < 0.0001; quadratic: <i>p</i> ≤ 0.0015), this did not affect (<i>p</i> > 0.05) the CH₄ conversion efficiency. Meanwhile, with the SHI, the inclusion of MOL only decreased (linear: <i>p</i> ≤ 0.0206; quadratic: <i>p</i> ≤ 0.0003) biogas per dry matter (DM) degraded and increased (linear: <i>p</i> ≤ 0.0293; quadratic: <i>p</i> ≤ 0.0325) biogas per DM incubated, as well as the production (mL g⁻¹ DM incubated and degraded and g⁻¹ kg DM) and proportion of CH₄, and CO per DM incubated and degraded. In addition, it did not impact (<i>p</i> > 0.05) on the CH₄ and H₂S parameters, and in the H₂S by DM incubated and degraded, and although it increased (linear: <i>p</i> ≤ 0.0292; quadratic: <i>p</i> ≤ 0.0325) the DMD, SCFA, and ME, it was inefficient (quadratic: <i>p</i> ≤ 0.0041) in CH₄ conversion. It is concluded that regardless of the percentage of MOL, the STI presented the highest values in the production of biogas, CH₄, H₂S, DMD, SCFA, and ME, and the lowest pH, so it turned out to be the most efficient in CH₄ conversion, while with the SHI only the highest production of CO and pH was obtained, and the lowest DMD, SCFA, and ME, so it was less efficient compared to STI.