Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
6/14/99
Contacts:
Wendy Powers, Iowa Pork Industry Center, (515) 294-4103
Sherry Hoyer, Iowa Pork Industry Center, (515) 294-4496
Reducing Manure Odor Takes Effort and Commitment
AMES, Iowa -- Reducing the amount of disagreeable odor from their swine operations is the goal of many of today's producers. Understanding the origin of the odor is important in determining how to decrease the potential of the unwanted smell.
Manure's malodor is the result of anaerobic decomposition of organic material fed to the animal that is unabsorbed and therefore excreted. Wendy Powers of the Iowa Pork Industry Center (IPIC) says decreasing odor involves planning based on the time and labor a producer is willing to commit, but the result is worth the effort. Powers, who also is also assistant professor of animal science at Iowa State University (ISU), says one key to less odor lies in reducing the amount of material that must be anaerobically degraded.
"By favorably changing the composition of manure, the potential exists to improve the odor of stored manure," she said. "There are currently five ways producers can help minimize the development of odor in their operations from a pre-excretion standpoint."
1. Feed a balanced diet. Proteins often are associated with increasing manure odor intensity, so using amino acids to offset some dietary protein may help. Another strategy is balancing dietary carbohydrate with protein.
2. Group animals according to nutrient requirements. This reduces the gap between different nutrient requirements and allows producers to formulate diets to more closely meet requirements.
3. Use of specific feed ingredients. Studies are underway to determine the effect of various feed additives on manure odors. Some work showed less malodor when peppermint oil was added to the diet. An ISU study considered the effect of adding bloodmeal to a nursery pig diet, and observed a trend of increasing odor intensity with increasing level of bloodmeal.
4. Consider mineral and water sources. Producers must consider mineral inputs and their impact on total dietary sulfur, which itself is odorous. Depending on the geographical location and source, water supplies might also contain a fair amount of sulfur, and producers should consider this.
5. Keep feed fresh. Offering a supply of fresh feed and promptly disposing of feed waste also helps in controlling odors. Wet feed will begin to ferment and produce odor similarly to stored manure. By keeping feeding areas clean, producers will help reduce odors from those areas as well as improve feed intake.
Powers says recommendations for feed and mineral selection to reduce unfavorable odors are likely to be available in the future. Also, there's the distinct possibility that byproduct processing techniques will be adequately refined to produce feeds with less potential for odor development.
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