Dietary sulfur concentration affects rumen hydrogen sulfide concentrations in feedlot steers during transition and finishing

Abstract

Angus steers (n = 96; 321 ± 29 kg BW) were used to determine how previous exposure to increased dietary S would affect ruminal hydrogen sulfide concentrations ([H(2)S]) in the feedlot, to investigate the effects of dietary S on ruminal [H(2)S] during transition and finishing, and to determine if dietary S affects the glutathione status of finishing cattle. Steers were strip-grazed on smooth bromegrass (Bromus inermis L.) over a 35 d period and received a dry distillers grains plus solubles (DDGS) supplement at 1% of BW (DM basis) that contained either 0.50% S (LS; n = 4 plots) or the DDGS supplement with an additional 0.30% S from sodium sulfate (0.80% S in supplement; HS; n = 4 plots). On d 36 steers were moved from the pastures to feedlot pens with one-half of the steers on each treatment in the pasture period remaining on the same treatment during the feedlot period and half being switched to the other treatment (n = 6 pens). For the first 10 d in the feedlot, steers were fed hay ad libitum and 1% BW of the DDGS supplement representing their new treatment, followed by transition to finishing diets. Dietary S of transition and finishing diets were 0.2% to 0.3% S for LS and 0.5% to 0.6% S for HS. No interaction between pasture and feedlot treatment was observed (P ≥ 0.50), so data for the feedlot period were pooled by feedlot treatment (n = 12 pens). Rumen [H(2)S] were measured on d 35 of the pasture period and on d 46 while receiving ad libitum hay and supplement at 6 h after the feeding of the supplement and after 7 d on each of the 3 transition diets (d 53, 60, and 67) and on d 93, 126, and 155 of the study after receiving the finishing diet for 26, 59, and 88 d at 6 h after feeding. Ruminal [H(2)S] did not differ between treatment while steers were fed the supplement on forage-based diets. However, ruminal [H(2)S] of HS-fed steers was greater (P < 0.05) than LS-fed steers when transition diets and the finishing diets were fed. Relative to S intake, ruminal [H(2)S] increased disproportionally after 26 d on the finishing diet. This was followed by a decrease in [H(2)S] on d 59 of finishing, although S intake was increased (P < 0.05) compared with d 26 of finishing. It appears that factors other than S intake alone contribute to ruminal [H(2)S]. The amount of glutathione in the liver of steers did not differ (P = 0.47) because of dietary S, but the concentration of oxidized glutathione increased (P = 0.03) in HS-fed compared with LS-fed steers, suggesting that the potential for oxidative stress in cattle fed high-S diets may warrant further investigation.

High-sulfur in beef cattle diets: A review

“…Loneragan et al (2005) utilized three concentrations of sulfate in the drinking water (136, 583, 2,360 mg sulfate/L) of feedlot cattle and observed that ruminal H 2 S concentrations peaked on d 31 of the study, after which concentrations decreased and stabilized for the remainder of the trial. Drewnoski et al (2012b) found that cattle consuming a high S diet had concentrations of H 2 S that increased relative to their S intake during the first 30 d on a finishing diet, regardless of whether or not cattle were previously exposed to increased dietary S while on a high roughage diet. Delfiol et al (2013) recently reported that in sheep fed 0.9 or 1.2% S (in diets containing 31% oat hulls and 5% bermudagrass hay) rumen H 2 S concentrations reached a peak approximately 5 to 7 wk into the finishing period.…”

“…In this study, 3 or the 4 steers consuming a high S diet exhibited signs of PEM. However, many studies have observed concentrations of H 2 S two to three fold greater than 2,000 mg/L without observing clinical signs of PEM (Neville et al, 2010;Drewnoski et al, 2012b;Morine et al, 2012b;Drewnoski and Hansen, 2013a).…”

Determining the influence of dietary roughage concentration and source on ruminal parameters related to sulfur toxicity

“…Each fistula was equipped with a small polyvinyl chloride (PVC) fitting (1.27 cm LASCO PVC I; LASCO Fittings, Inc., Brownsville, TN) kept capped to minimize gas loss, as described by Drewnoski et al (2012a). To measure H 2 S concentration of the ruminal gas, a metal rod 45.72 cm long was inserted through the PVC fitting with a short piece of tubing connecting the rod to the gas detector tube and volumetric gas sampling pump (Matheson-Kitagawa 8014-400B; Matheson-Kitagawa, Kitigawa, Japan) according to the procedure described by Drewnoski et al (2012b).…”

Influence of sulfur on the fermentation characteristics of corn distiller's dried grains with solubles in in vitro culture

“…the effect would not appear until the product accumulates to a certain level. Drewnoski et al (2012) demonstrated that it took at least 29 days for the SRB to achieve peak rumen H 2 S production after abrupt exposure to diets containing a readily available sulfur source from Na 2 SO 4 . Maybe that is why it would present damage on animal performance when feeding high dietary sulfur for a long time in feeding practice.…”