PSII-32 Effects of feeding 60% dried distillers grains plus solubles or the equivalent sulfur as calcium sulfate on hydrogen sulfide gas production in the rumen

Abstract

Abstract Objective of this study was to evaluate the impact of feeding 60% dried distillers grains plus solubles (DDGS) or the equivalent sulfur from calcium sulfate (CaSO4) to yearling beef bulls on ruminal hydrogen sulfide (H2S). The hypothesis for this study was that bulls consuming elevated concentrations of sulfur in their diet will have an increase in H2S present in the rumen. Twenty-four crossbred beef bulls (10 months of age, BW=319.6 kg) were assigned one of three treatments 1) corn based diet containing 60% concentrate (CON, S=0.2%, n = 8); 2) diet containing 60% DDGS as a replacement for corn (DDGS, S=0.44% DM, n = 8); 3) CON diet+ equivalent sulfur of DDGS in diet added as CaSO4 (SULF, S=0.43%, n = 8). Bulls were individually fed in Calan gates at 2% of BW. Ruminal gas samples were taken via rumen puncture 4 to 6 hours post feeding on d0, 14 and 42. Concentrations of H2S were determined using hydrogen sulfide detector tubes which were connected to a volumetric gas pump (Gastec, Kanawaga, Japan). Data were analyzed as repeated measures using the MIXED procedures of SAS for effects of day, treatment, and a day × treatment interaction. A day × treatment interaction was present for ruminal H2S (P = 0.005). On d0, there was no effect of treatment (P = 0.97). Bulls fed DDGS or SULF had similar H2S concentration on d14 (P = 0.06), while animals fed CON had lower H2S concentration (P = 0.004). On d42, concentrations of H2S was greater in SULF than all other treatments (P£0.006), while DDGS was greater than CON (P£0.05). Elevated H2S in bulls fed the SULF treatment compared with the DDGS treatment may indicate that ruminal availability of sulfur (S) in CaSO4 was greater than that of the combination of sulfuric acid and S-containing amino acids present in DDGS.