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Department of Animal Sciences

cows in stalls

Environmental Impacts

Reducing the Environmental Impact of Livestock

One of the major contributors to greenhouse gases is the production of ammonia. Dr. Jeffrey Firkins studies interactions among rumen microbes to assess the effects of dietary components and feed additives and the role of ruminal protozoa in the production of ammonia in the rumen. His team also has examined this from the standpoint of a farm system. The full benefits have not yet been assessed. In addition, Dr. Zhongtang Yu is working on feed additive combinations that effectively reduce methane production by the rumen microbiome while not adversely affecting feed digestion, fermentation, or other aspects of rumen functions. These combinations have a potential to be practical and effective in reducing methane emission from cattle.

Dr. Bill Weiss has conducted numerous studies showing that diet formulation (type of forage, concentrations of starch and fiber, and source of protein) can have a substantial effect on the amount of ammonia produced from dairy manure. They also have shown that total manure output by cows can be greatly reduced by diet composition without negatively reducing milk yield.

Dr. Chanhee Lee has found diet modification effectively manipulated feed digestion and also manure characteristics, resulting in methane mitigation from animals and manure. Diet manipulation had a large impact on nitrogen and phosphorus excretion in manure, potentially decreasing ammonia emissions during manure storage and phosphorus runoff from manure when applied to fields. Manure treatment was also an effective strategy to lower ammonia emissions from manure. The manure treatment he examined decreased ammonia emissions up to 25% when compared with non-treated manure, which improved the nutritional value of manure as fertilizer. Diet manipulation strategies that were successful in lowering environmental impacts have been under process for commercialization.