Submitted to: Wisconsin Nutrient Management Curriculum
Publication Type: Monograph
Publication Acceptance Date: 5/30/2003
Publication Date: 5/30/2003
Citation: EBELING, A., BUNDY, L., POWELL, J.M., SATTER, L. DIETARY PHOSPHORUS CONSIDERATIONS IN DAIRY MANAGEMENT. WISCONSIN NUTRIENT MANAGEMENT CURRICULUM. 2003. 4p. Interpretive Summary:
Technical Abstract: Phosphorus (P) moving from dairy farms to surrounding water bodies has environmental implications. An overabundance of P in lakes and streams causes algae blooms, decreased oxygen supply, and death of fish. With environmental P concerns on the rise, dairy producers will want to be informed about dietary options involving P. This extension publication focuses on environmental consequences of overfeeding P, milk production and reproductive implications of lowering dietary P, and management options for the producer. A goal of dietary P management should be to avoid overfeeding P. Over-feeding P increases the amount of land required for manure application if P-based manure spreading restrictions are in place. It also accelerates the build-up of soil test P levels of fields and increases the amount of P in runoff. Many Wisconsin soils contain more P than is needed for crop production. When manure from dairy cows fed different concentrations of P are land-applied, the high P diet manure releases 4 to 10 more P in runoff than the low P diet manure. While it is important for producers to be concerned about the P content in the manure generated on their dairy farms, they also need to be assured that the dietary P content of the feed is adequate to keep milk production high and ensure reproductive efficiency. The benefits of feeding P at recommended levels must be weighted against the price, convenience, and availability of the feed supplements currently in use on a farm. Many common and affordable protein and mineral supplements contain high levels of P. It will be important for dairy farmers to be informed about the P content of feed in order to make decisions that are mindful of herd production, health, and are economically and environmentally sound.