Influence of dietary sulfur level on growth performance and digestive function in feedlot cattle.

Abstract

Using ammonium sulfate, three levels of dietary S (.15, .20, and .25%, DM basis) were evaluated in a finishing trial with 108 yearling crossbred heifers (384 kg). The basal diet contained (DM basis) 4% alfalfa hay, 6% sudangrass hay, 74% steam-flaked corn, 4% yellow grease, 6% cane molasses, and 6% protein-mineral supplement. Increasing dietary S decreased ADG (quadratic effect, P < .10), DMI (linear effect, P < .10), feed efficiency (quadratic effect, P < .10), diet NE (quadratic effect, P < .10), and longissimus muscle area (linear effect, P < .05). Six Holstein steers (218 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of digestion. Treatment effects on ruminal and total tract digestion of OM and N were small (P > .10). However, ruminal digestion of ADF and starch was slightly lower (quadratic effect, P < .10), and postruminal digestion of ADF and starch was correspondingly greater (quadratic effect, P < .05) with supplemental S. Dietary S level did not influence (P > .10) ruminal synthesis of microbial N. Increasing dietary S did not influence (P > .10) ruminal pH or lactic acid. Increasing S decreased molar proportions of acetate (quadratic effect, P < .10) and increased molar proportions of propionate (linear effect, P < .10). We conclude that S in excess of .20% of dietary DM may have detrimental effects on growth performance and dietary NE. Excessive dietary S may also compromise carcass merit by decreasing longissimus muscle area.

High-sulfur in beef cattle diets: A review

“…No differences in marbling score were observed by Zinn et al (1997) or Spears et al (2011). Loneragan et al (2001) reported that increasing water sulfate concentration from 136 to 2,360 mg/L (equivalent to 0.18 to 0.40% S as a percent of the diet DM) decreased HCW, dressing percentage, and yield grade.…”

“…The effects of S on other carcass characteristics have been less consistent, likely due to difference in dietary composition, cattle type and age, and timing of harvest relative to control cattle. The inclusion of ammonium sulfate to both finishing heifer and steer diets to achieve concentrations of 0.25% (Zinn et al, 1997) and 0.46% S (Spears et al, 2011) resulted in decreased LM area when compared to control cattle consuming diets less than 0.20% S (Zinn et al, 1997) or less than 0.30% S (Spears et al, 2011).…”

“…These authors also reported a quadratic effect of sulfate on backfat, with greatest backfat noted in steers consuming 600 mg sulfate/L drinking water, and no difference in marbling scores. In most studies, when dietary S did not impact backfat, marbling 20 scores were not impacted either (Zinn et al, 1997;Uwituze et al, 2011a;Richter et al, 2012).…”

“…Numerous reports have noted the negative influence of high dietary S on finishing cattle performance (Loneragan et al, 2001;Zinn et al, 1997;Uwituze et al, 2011a;Richter et al, 2012;Drewnoski and Hansen, 2013). While not as obvious as S-PEM, S toxicosis as reflected by decreased DMI and ADG is economically detrimental.…”

“…Study and study × S concentration were designated as random and studies were weighted using the inverse of the variance associated with each measurement of interest (DMI, ADG, and HCW). Inclusion of the work by Zinn et al (1997) was carefully considered; however, this work includes a very small range of dietary S (0.15-0.25% S), making extrapolation beyond these concentrations highly uncertain, and some authors (NRC, 2005) have postulated that the depression in performance by cattle in this study may have been due to the addition of ammonium to a steam flaked corn diet, rather than purely an effect of added S. Additionally, the study utilized very low concentrations of dietary S, which are unlikely to be found in present diets containing even small amounts of DGS. Therefore, it was determined that the Zinn et al (1997) study represents a different population and it was excluded from the meta-analysis.…”