Effects of Different Ration Scenarios on Fecal-Greenhouse Gas Emissions from Awassi Ewes

This study investigated the effect of diets with different ratios of C4:C3 plant materials on CH4, CO2, and N2O emissions from manure produced by Awassi ewes. The trial compared the production of greenhouse gases from manures produced by sheep fed diets with low C4:C3 ratios (Group A–0.95:1) to those fed high C4:C3 plant ratios (Groups B–1:1; C–1.5:1; D–2:1). The trial was a randomized design with four groups and each group contained four sheep (total 16). The main feedstuffs were alfalfa and maize based combinations with similar nutrient contents. The body weight gain (BWG) and the feed conversion ratio (FCR) of the sheep were affected by C4:C3 ratio. They increased in the higher C4 plant-consuming groups, despite similar feed consumption. Manure components were not affected by the feed ratio, except for N, pH, and Neutral detergent fiber (NDF). Total diet digestibility of N increased cubically when maize silage was included (Groups B and D). The use of C3 plants as forage or grain sources led to increased manure and manure gas production (P = 0.04 and linear effect: 0.03). Regardless of the C4:C3 ratio, alfalfa increased N2O emissions from manures because more manure was produced by groups A and C. The temperature, humidity and mold of the manures were the main causes of the rise in the amount of manure based CO2 in the alfalfa and maize based groups