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A toxic burp

Belching cows may be getting some relief.

Sulfur in a popular cattle feed — the ethanol byproduct, distiller’s dry grains — causes gas in cattle. If they eat too much, it could lead to brain damage and even death. But adding manganese oxide to the feed might neutralize sulfur’s harmful effects.


Although corn naturally contains sulfur, the ethanol production process adds and concentrates sulfur, which remains in distiller’s dry grains and solubles or DDGS. When cattle consume DDGS, sulfur reacts with hydrogen, creating hydrogen sulfide, a gas that cattle expel by belching. Prolonged inhalation of this gas can be toxic.

DDGS are used in cattle feed because they are high in protein and nutrients and cost less than whole corn. Because dairy cows are fed DDGS with hay and silage, the roughage helps process the feed and the sulfur is less toxic. But feedlot cattle require higher rations of grain-based feed.

AURI and the Minnesota Corn Growers are sponsoring research into manganese oxide’s potential to mitigate sulfur’s effects. Manganese is a hard element, typically used in fertilizer and alloys. Manganese may naturally oxidize hydrogen sulfide into sulfate, which cattle can easily pass without negative impact.

In the project’s first phase, University of Minnesota animal scientists studied whether manganese oxide could impact hydrogen sulfide’s release from distiller’s grains during digestion.

Laboratory results have been encouraging, and in the project’s second phase, researchers are determining the appropriate concentration of manganese oxide in cattle diets with 50 percent distiller’s grains.

If manganese oxide can negate hydrogen sulfide’s harmful effects, that would greatly benefit distiller’s grains suppliers since “the value of DDGS can approximate that of corn more closely when sulfur is not an issue,” says Jen Wagner-Lahr, AURI project director.

In 2006, about 85 percent of 13 million tons of DDGS produced in the United States went into beef and dairy cattle feed. “Given current corn prices, cattle feeders would like to use even more DDGS if possible, but the sulfur issue is a limiting factor,” Wagner-Lahr says.

Results of the manganese oxide DDGS study will be available this summer ¦