| One of the challenges with using ethanol co-products is the potential for increased dietary S concentration. Dietary S concentration has been implicated as a cause of polioencephalomalacia (PEM) in ruminants. The focus of this research was to evaluate PEM in ruminants fed distillers dried grains plus solubles (DDGS) based finishing rations. Two separate hypotheses were formed: 1) Providing increased dietary thiamin will decrease the incidence of PEM in lambs fed increased S diets without affecting animal performance; and 2) Feeding DDGS would increase concentrations of H2S gas and incidence of PEM compared to diets based on dry-rolled corn. Two studies were conducted utilizing lambs to evaluate either 1) the influence of increasing supply of dietary thiamin (0, 50, 100, or 150 mg/d) on performance and incidence of PEM when fed diets containing 60% DDGS or 2) the influence of DDGS inclustion (0, 20, 40, or 60% DM basis) on sulfur balance. A third study was conducted using beef steers to examine the influence method of corn processing (high-moisture vs. dry-rolled corn) and concentration DDGS (20, 40, or 60% DM basis) on animal performance, H2S concentrations and incidence of PEM. No differences in lamb performance were noted ( P ≥ 0.17) when diets containing increasing concentrations of thiamin were fed. Lambs fed elevated concentrations of DDGS had a 3 fold increase in water intake and a 4.8 fold increase. Lambs fed 150 mg of thiamin per day and steers fed 60% DDGS had the greatest concentrations of H2S (1.07 g H2S/m³; P ≤ 0.009; 1.38 g H 2S/m³, P ≤ 0.01, respectively). Ruminal pH was not affected by a day x treatment interaction (P = 0.65) or by treatment (P = 0.32), but decreased (P < 0.001) across the adaptation phase from 5.82 (d -7) to 5.33 (d 35) in lambs fed increasing concentrations of DDGS. The role dietary S from DDGS plays in incidence of PEM is questionable as no cases of PEM were observed with dietary S concentrations exceeding 2--3 times the maximum tolerable level. Additional research may be needed to clarify species specific observations and responses to dietary S levels. |
