Synergistic effects of Albizzia lebbek, Moringa oleifera and Millettia thonningii leaves on weight gain and predicted enteric methane emission in sheep

Abstract

The digestive tract of ruminants though unique in the utilisation of low quality feed materials also emits methane, a potent greenhouse gas with a global warming potential of 25 times that of carbon-dioxide. Climate smart livestock production necessitated the use of browse leaves with the potential to inhibit methanogens and protozoa activity in the rumen and reduce methane emission. Thus, sixteen forest type ram lambs (13.94 ±1.02 ) were fed Albizzia lebbek (AL)+Moringa oleifera (MO)+Millettia thonningii (MT), AL+MO, AL+MT and MO+MT for twelve weeks. Data collected were feed intake, digestible energy, weight gain, energy loss, nitrogen loss and methane emission by sheep. Rumen methane production (MJ/d) was estimated using a model equation: Methane = 8.25 + 0.07 x Metabolisable Energy Intake. Sheep fed AL+MO had the highest (p<0.0001) average daily gain whilst those fed AL+MO+MT recorded the lowest (p<0.0001). Sheep fed AL+MO+MT emitted the lowest (p<0.0001) methane and those fed AL+MO emitted the highest (p<0.0001) methane. The dry matter intake, digestible energy, energy intake, faecal energy losses, average daily gain, feed conversion efficiency, faecal nitrogen losses, urinal nitrogen losses and methane production were in the range of 588.9-651.5g/d, 15.1-16.7 MJ/kg DM, 17.3-18 MJ/kg DM, 1.26-2.56 MJ/kg DM, 69.94-83.33 g/d, 8.66-11.10 g/d, 60.43-88.01g/animal/d, 11.22-16.99 g/animal/d and 3-5.34 MJ/d respectively. This study demonstrates the synergic action of browse leaves as a climate smart approach in reducing methane production and improving the productivity of sheep. Furthermore, this feeding strategy promotes uniform utilization of browse species leading to the sustainable use of preferred browse species as no one browse species will be heavily utilised.