Effect of supplementation of Moringa oleifera leaf slurry on performance, rumen metabolites and enteric methane emission of growing Yankasa rams

This study evaluated the anti-methanogenic and nutritional effects of Moringa oleifera leaf slurry (MLS) in growing Yankasa rams. Sixteen rams (16.6 ± 3.00 kg) were assigned to four treatments supplying 0, 4, 8, or 12 g MLS kg⁻¹ DM intake in a completely randomised design. All animals received the same total mixed ration at 5% of live weight for 85 days, followed by a 7‑day digestibility trial. Enteric methane was measured using a portable IRCD4 infrared gas analyser. MLS supplementation improved (p < 0.05) nutrient utilisation and growth performance, and reduced CH₄ per unit of feed intake and CH₄ per unit of NDF digested. Rams receiving 8 and 12 g MLS kg⁻¹ DM showed higher (p < 0.05) volatile fatty acid concentrations than the control. Principal component analysis revealed negative associations between MLS phytochemicals and CH₄/feed intake, CH₄/NDF digestibility, and feed conversion ratio. Overall, MLS inclusion up to 12 g kg⁻¹ DM increased feed intake (3.70–8.64%), weight gain (41.4–44.7%), feed efficiency (19.6–24.5%), nutrient utilisation, and volatile fatty acids, while lowering methane emission ratios. Although 4 g MLS kg⁻¹ DM appears effective for improving performance, further research should explore alternative feeding strategies and higher MLS levels in Yankasa rams and other ruminants.