New CAST Issue Paper Addresses Applications of Biotechnology for Manure Nutrient Management

July 12, 2006

For Immediate Release

July 12, 2006…Ames, Iowa. The Council for Agricultural Science and Technology (CAST) is releasing a new Issue Paper, Biotechnological Approaches to Manure Nutrient Management, fourth in a nine-part series on “Animal Agriculture’s Future through Biotechnology.”

Food animals are fed and produced for the purpose of feeding humans, and the manure of these animals is a valuable source of fertilizer. But concentrations of manure nutrients such as phosphorus, nitrogen, and metals may exceed needs for plant growth and cause environmental pollution. Total collectable manure produced in the United States amounts to approximately 56 million dry metric tons per year, and the amount and composition of freshly excreted manure can vary considerably and is influenced primarily by the original composition of the diet, species, and feeding management.

“The term ‘biotechnology’ triggers an array of emotions,” says Dr. Xingen Lei, Department of Animal Science, Cornell University, and Task Force Chair. “Because of population growth and the increasing demand for animal foods, global livestock production will continue to evolve from smaller family support systems to larger, more market-oriented, integrated production systems. Through this progression, issues involving environmental contamination, air quality, and animal welfare will be more commonplace, resulting in more complex relationships among the animal industry, society, and governmental agencies. Because biotechnology potentially can provide important solutions to these problems, it is critical that we understand and address the associated issues.”

The agricultural industry constantly strives to lower the cost of animal production while minimizing the extent of environmental impact. Because manure production and excessive nutrient excretion largely result from indigestibility of nutrients in animal diets and imbalanced formulation of nutrients, enhancing the nutritional quality of feeds in diets becomes a key target for the biotechnological management of manure nutrients.

The manipulation of nutritional content, quality, and availability in plants has the potential to provide “designer feeds” for decreasing manure nutrient output. Managing nutrients by controlling animal diets is easier than intervening after release of these potential pollutants into the environment. Multifaceted mechanisms are implicated, and future research will target improved seed stock development and dietary enzyme use as economical and practical methods of treatment.

Written and evaluated by a Task Force of nine authors and three reviewers, this timely CAST Issue Paper brings together the expertise and experience of scientists and researchers “on the front lines” to evaluate these issues of worldwide concern. Specific areas addressed in Biotechnological Approaches to Manure Nutrient Management include:

Biotechnological Approaches to Manure Nutrient Management follows two previous related CAST Issue Papers (IP 21, Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution, and IP 23, Biotechnology in Animal Agriculture: An Overview)” says Dr. John M. Bonner, CAST Executive Vice President. “This new paper, however, provides a more comprehensive and updated review of developed technology—the advances in transgenic animals and microorganisms, in particular—and examines additional areas such as potential biotechnology derived by genomics approaches, integration of multiple technologies in production conditions, and industrial and societal issues related to biotechnology for manure nutrient management.”

The full text of Biotechnological Approaches to Manure Nutrient Management (Issue Paper No. 33) may be accessed on the CAST website at, along with many of CAST’s other scientific publications, and is available in hardcopy for $5.00 (includes shipping) by contacting the CAST office at 515-292-2125. CAST is an international consortium of 38 scientific and professional societies. It assembles, interprets, and communicates credible science-based information regionally, nationally, and internationally to legislators, regulators, policymakers, the media, the private sector, and the public.

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