Effect of thiamine concentration on animal health, feedlot performance, carcass characteristics, and ruminal hydrogen sulfide concentrations in lambs fed diets based on 60% distillers dried grains plus solubles1

Abstract

Limited data are available regarding the influence of thiamine supplementation on the incidence of polioencephalomalacia (PEM) in lambs fed diets containing increased concentrations of S in the diet (>0.7%). Therefore, our objective was to evaluate the influence of thiamine supplementation on feedlot performance, carcass quality, ruminal hydrogen sulfide gas concentrations, and incidence of PEM in lambs fed a finishing diet containing 60% distillers dried grains with solubles (DDGS; DM basis). Two studies were conducted using completely randomized designs to evaluate the influence of concentration of thiamine supplementation. Study 1 used 240 lambs fed in 16 pens, whereas study 2 used 55 individually fed lambs. Lamb finishing diets contained 60% DDGS, which resulted in a dietary S concentration of 0.73% (DM basis). Treatments diets were based on the amount of supplemental thiamine provided: 1) no supplemental thiamine (CON), 2) 50 mg/animal per day (LO), 3) 100 mg/animal per day (MED), or 4) 150 mg/animal per day (HI). Additionally, in study 2, a fifth treatment was included, which contained 0.87% S (DM basis; increased S provided by addition of dilute sulfuric acid) and provided 150 mg of thiamine/animal per day (HI+S). In study 1, ADG decreased quadratically (P = 0.04), with lambs fed the CON, LO, and MED diets gaining BW at a greater rate than lambs fed the HI diet. In study 1, DMI responded quadratically (P < 0.01), whereas G:F tended to differ linearly (P = 0.08) to concentration of thiamine supplementation, with MED lambs having greater DMI and decreased G:F. No differences (P > or = 0.17) in lamb performance were observed in study 2. In both studies, most carcass characteristics were unaffected, with the exception of a tendency for decreased carcass conformation (study 1; P = 0.09) and greater flank streaking (study 2; P = 0.03). No differences in ruminal hydrogen sulfide concentration (P > 0.05) among treatments were apparent until d 10, at which point lambs fed the LO diet had less hydrogen sulfide concentrations than all other treatments. Lambs fed HI had the greatest concentrations of hydrogen sulfide on d 31 (1.07 g of hydrogen sulfide /m(3); P < 0.009). Ruminal pH did not differ (P = 0.13) and averaged 5.6 +/- 0.06. No clinical cases of PEM were observed during the course of either study. The use of thiamine as a dietary additive to aid in the prevention of PEM in finishing lambs does not appear to be necessary under the conditions of this study.

High-sulfur in beef cattle diets: A review

“…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).…”

Polioencephalomalacia in ruminants caused by excessive amount of sulphur - a review

“…In lambs given feed supplemented with sulphur and vitamin B 1 , the clinical signs were not seen, but microscopic lesions were observed in the brain, however, no changes in B 1 concentrations in plasma and tissues were noted (32). Neville et al (28), imposing a diet high in sulphur (0.73%-0.87% of dry matter) and simultaneously vitamin B 12 supplements (50, 100, and 150 mg/animal/d) did not observe the disease, but the concentration of H 2 S in the rumen increased to 1.07g/m 3 . However, the results of most studies both experimental and field do not confirm the direct influence of vitamin B 1 deficiency or supplement on PEMES development or on the course of the disease's clinical symptoms.…”

“…Various factors probably influence the reductive activity of the bacteria; among them the amount and kind of sulphur compound in the diet, diet composition, and the pH of rumen contents (4,28). The reduction process is not fully understood yet.…”

A review of polioencephalomalacia in ruminants: is the development of malacic lesions associated with excess sulfur intake independent of thiamine deficiency?

“…Gould [46] observation) up to 25000 ppm [47]. Neville et al, [48] reported that ruminants exposed to elevated dietary S (0.65% or 0.83% DM) exhibited relatively high H 2 S gas ranging from 2000 to 8000 ppm, but did not show clinical signs of PEM. Similarly, Amat et al, [11] did not observe any clinical or histopathological changes associated with PEM in beef heifers fed high dietary S (0.62% S, DM), despite the elevated ruminal H 2 S level (2296 ppm).…”