Nov. 25, 2003
International Ag Researcher Speaks at UW-River Falls
By Sarah Matara
UW-RF News Bureau
A world-leading authority on cattle grazing systems recently addressed some 60 farmers, agriculture agency members and university researchers and professors at UW-River Falls.
Dr. Cameron Gourley, an expert from Australia on phosphorous losses in grazing systems, presented research findings concerning his work on commercial operations throughout his country.
Several key researchers from Minnesota and Wisconsin were also invited to discuss the implementation of nutrient management plans on grazing dairy farms and address solutions for water pollution.
UW-RF agronomy Professor Dennis Cosgrove said the conference allowed them to discuss ways to make sure grazing dairy farms are evaluated properly in regard to pollution regulations.
"This allowed us to start a dialogue to avoid inappropriate regulation of grazing dairy farms. We want to use good information based on grazing farms, not on confinement systems."
Feed intake and milk production for dairy cows that graze is often lower than for cows in confinement. Therefore, the amount of manure production by grazing cows is lower.
When cows graze, their manure and the nutrients going into the ground are more difficult to account for than for cows in confinement. Much less information exists concerning grazing systems than confinement systems.
One focus of the conference was point-source pollution versus non-point source pollution. Point-source pollution is when the specific source and location of the pollutant is known, such as a pipe pouring oil into a river.
Non-point source pollution occurs when the pollutant comes from an area too broad to determine the source. For example, when all the farmers in an area spread manure, herbicide or fertilizer on their fields, it is impossible to pinpoint the exact source of pollution.
Phosphorous and nitrogen are both present in manure. Too much phosphorous will pollute surface runoff water that goes into lakes and rivers, causing algae to bloom. If too much nitrogen is present, it can leak into the ground water and pollute it.
Phosphorous and nitrogen are also taken off a farm as nutrients present in milk, livestock and agricultural products.
Persons attending this conference hope to develop nutrient management plans for grazing farms that will account for all of the nutrients present in feed and manure. If they can determine how much manure is actually produced on dairy grazing farms, a nutrient management plan would help farmers avoid overapplication and prevent water pollution.
Nitrate levels in the ground water are safe, but they are higher than they should be. Cosgrove said this is not uncommon.
Cosgrove and UW-RF dairy science Professor Dennis Cooper received a grant last summer from the Sustainable Agriculture Research and Education program in the United States Department of Agriculture to conduct a three-year study and demonstration project on feed and nutrient intake on eight grazing dairy farms in Wisconsin.
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