Effects of Feeding a Commercial Starch Binding Agent during Heat Stress on Enteric Methane Emission, Rumen Volatile Fatty Acid Contents, and Diet Digestibility of Merino Lambs

Abstract

Twenty-four Merino lambs were allocated to three dietary treatment groups to determine the effects of a dietary starch and protein binding agent and heat stress on methane (CH4) emissions and rumen parameters. The diets were a wheat-based diet (WD), a 2% Bioprotect™ (Bioprotect™, RealisticAgri, Rutland, UK) treated wheat-based diet (BD), and a maize-based diet (MD) for 3 periods of 1-week duration. During Period 1 (P1) the lambs were maintained under thermoneutral conditions and at a 1.7 × Maintenance (M) level. During P2 and P3, the lambs were maintained under cyclic heat stress conditions and fed at 1.7 × M and 2.0 × M, respectively. Total CH4 production was lower for the BD diet than the WD diet, which in turn was lower than the MD diet (p 4 production was lower during P2 than P1 with P3 intermediate (p = 0.04). Rumen total volatile fatty acid (TVFA) concentrations were higher for the WD diet than the MD diet with the BD diet intermediate (p = 0.01). Rumen TVFA concentrations were lower during heat stress than under thermoneutral conditions (p p 4 emissions without reducing starch digestibility.

Keywords

• temperature
• greenhouse gas
• feed additives
• sheep
• wheat
• maize