A new paper from the Council for Agricultural Science and Technology outlines technologies and approaches that poultry and livestock producers can employ to reduce nitrogen and phosphorus levels entering the environment. By cutting dietary protein and phosphorus levels, producers can limit the animals' excretions of nitrogen and phosphorus that may contribute to water and air pollution.

"This paper helps provide answers to the environmental concerns associated with livestock feeding operations," says CAST Task Force Chair Terry Klopfenstein, University of Nebraska animal scientist. "It is a guide to producers in the balancing act of offering an optimal diet for the animal while reducing the environmental impact."

In 1996, CAST published a report on Integrated Animal Waste Management. It recommended that producers change animal diets to reduce nutrient outputs. The new CAST paper, Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution, examines specific issues related to animal diets and the progress that has been made since 1996. The paper specifically addresses the volatilization of nitrogen in the form of ammonia. It also covers issues surrounding manure nutrient distribution.

CAST's paper identifies important technologies and interrelated actions that are now available to help pork, poultry, beef and dairy producers fine-tune the protein and phosphorus content of animal diets. Nitrogen is a part of amino acids that form proteins that all animals require, but that are then excreted in various forms. Phosphorus is a mineral nutrient required for bone growth and many important bodily functions. But if directly discharged into surface water via runoff or deposited in water from aerial emissions, phosphorus can cause water pollution.

Using new technologies, such as ideal protein, phytase as well as low-phytate corn and soybeans, potentially can decrease nitrogen and phosphorus excretion by pork and poultry by up to 40 percent and 60 percent, respectively. New metabolizable protein systems can potentially cut nitrogen excretion by up to 34 percent from beef and dairy cattle. In terms of phosphorus, more precise feeding cut that excretion in half.

The full text of Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution (Issue Paper No. 21) is available on the CAST Web site at www.cast-science.org. You also will find many of CAST's other scientific publications.