Nitrogen Decreasing Methods Outlined in Paper

July 24, 2002

The Council for Agricultural Science and Technology (CAST) outlines the technologies and approaches that poultry and livestock producers can employ to decrease the amounts of nitrogen and phosphorus that enter the environment. By lowering the amounts of protein and phosphorus that are fed to poultry and livestock, 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 concentrated animal feeding operations," said CAST Task Force Chair Terry Klopfenstein of the Department of Animal Science at the University of Nebraska-Lincoln. "It is a guide to producers in the balancing act of offering an optimal diet for the animal while decreasing the impact on the environment."

In 1996, CAST published a report on Integrated Animal Waste Management. It recommended that producers change animal diets to decrease nutrient outputs. The new CAST issue paper, Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution, examines the 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 the important technologies and interrelated actions that are now available to help poultry, swine, beef and dairy producers fine-tune the protein and phosphorus content of animal diets.

Nitrogen (N) is a part of amino acids (AAs) that form proteins required by all animals and are then excreted in various forms of N. Phosphorus is a mineral nutrient required for bone growth and many important bodily functions. But these nutrients, if directly discharged into surface water in runoff or deposited in water from aerial emissions, can cause significant water pollution.

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

A full text of the paper Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution (Issue Paper No. 21) is available on the CAST website at www.cast-science.org along with many of CAST's other scientific publications.

CAST is an international consortium of 37 scientific and professional societies. It assembles, interprets and communicates science-based information regionally, nationally and internationally on food, fiber, agricultural, natural resource and related societal and environmental issues to its stakeholders-legislators, regulators, policymakers, the media, the private sector and the public.