Excess nutrients in livestock feed all end up in manure because animals cannot utilize them. What you feed your livestock makes a big difference in the composition of the manure output. Feed management practices that not only meet animal requirements but minimize the amount of excess nutrients in manure help reduce risk of water contamination problems. Knowing the requirements of the animal you are feeding can improve your ability to feed the animal the correct amount of nutrients.
Phosphorus is often the limiting nutrient in manure management:
- Less phosphorus in manure produces less chance for an excessive phosphorus buildup in the soil.
- Lower soil phosphorus reduces the risk of phosphorus transport with erosion and runoff and lower phosphorus loading in surface water.
- Excess phosphorus in our surface water leads to algae blooms.
- Feeding excess phosphorus may not be avoidable when feeding distillers grains plus solubles which are high in phosphorus; but other feed additives can be used to increase absorption of phosphorus by animals.
- Use of phytase rather than phosphorus supplements in swine rations reduces excreted phosphorus
- Other feed additives can be used to increase absorption of phosphorus by animals.
- Feeding excess salt is another concern as it can result in salt build-up where manure is repeatedly applied.
- Altering feed composition can also alter the amount of manure odor. For more information on this issue within this Web site, see Air Quality.
For information on feed management as it relates to animal manure, we recommend the following links to webcasts and regional and national Web sites that provide factual science-based information:
Livestock and Poultry Environmental Learning Center on national e-Xtension site. "Best of the Best" educational and research resources from land grant universities including the University of NE; US EPA, and USDA.
- Extensive Feed Management section.
- LPES curriculum also contains 4 lessons on animal dietary strategies for reducing manure nutrient excretion.
Webcast presentations on feed management: Ethanol Co-Products and Their Effects on Manure Management, from LPELC archives.
- 05 CORN-030 Beef Products Circular (.pdf)
- Distillers Grains Use (.ppt slides)
- WDGS Storage Report Plus News Release (.doc)
- ASABE Standard: Typical Excretion Values (.doc)
- Excretion: Hand Estimator Tool (.doc)
- ASABE Standard (.ppt slides)
- Feed Nutrient Management Planner- Economics Estimator
Information presented within the livestock manure management section of this Water Web site has been authored and/or reviewed by University of Nebraska-Lincoln Manure Management Team members Leslie Johnson, Rick Koelsch, Charles Shapiro and Charles Wortmann.