Use of Metabolic Modifiers in Animal Production Subject of New Issue Paper

July 27, 2005

For Immediate Release

New CAST Issue Paper Examines Use of Metabolic Modifiers in Animal Production

July 27, 2005…Cincinnati, OH. The Council for Agricultural Science and Technology (CAST) is releasing a new Issue Paper, Metabolic Modifiers for Use in Animal Production, an in-depth review of the classification, characteristics, and effects of metabolic modifiers approved for use in animal production. The rollout will take place at the 2005 Joint Annual Meeting of the American Dairy Science Association, the American Society of Animal Science, and the Canadian Society of Animal Science.

Written and reviewed by U.S. and international experts, this new Issue Paper specifically evaluates anabolic implants for finishing beef cattle, beta-adrenergic agonist feed additives for finishing swine and beef cattle, and somatotropin growth hormones administered to lactating dairy cattle and swine.

Metabolic modifiers are compounds that alter the biochemical pathways regulating nutrient use for growth and lactation. “Certain metabolic modifiers alter the relative rates of muscle and adipose tissue growth to improve carcass composition when animals are harvested for meat, and others are used only to improve lactation performance,” says Don Beermann, Task Force Coauthor, University of Nebraska, Lincoln. “Most metabolic modifiers decrease the proportion of nutrients that are excreted relative to that retained in the body.”

Specific topics addressed in Issue Paper 30 include

“The ultimate benefit of currently approved metabolic modifiers and successful development efforts under investigation or review is enhanced sustainability and profitability in livestock,” adds Frank Dunshea, Task Force Coauthor, Department of Primary Industries, Werribee, Victoria, Australia. “And these benefits are shared by producers, processors, and consumers.”

Scientific research directed toward understanding the regulation of nutrient use in agricultural animals has led to commercial development, approval by the U.S. Food and Drug Administration (FDA), and the use of metabolic modifiers. The three classes of metabolic modifiers in use include

These compounds modify animal metabolism in specific, targeted ways to increase weight gain and the amount of meat or milk per unit of feed consumed, thus improving overall productive efficiency of meat and milk production.

“Rigorous evaluation required for approval by the FDA ensures safety in all aspects of metabolic modifier use: animal well-being, farm worker safety, and wholesomeness and safety of the food products derived from the animals,” concludes John Bonner, CAST Executive Vice President. “The ultimate benefits affect not only producers and meat/milk processors, but consumers because of healthier, less expensive products and the assurance that stringent animal and human safety requirements have been met.”

The full text of the paper Metabolic Modifiers for Use in Animal Production (Issue Paper No. 30) 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.

This paper is third in a nine-part series on the topic “Animal Agriculture’s Future through Biotechnology.” CAST is an international consortium of 36 scientific and professional societies. It assembles, interprets, and communicates credible 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.

Help Support CAST

Your donation to CAST helps support the CAST mission of communicating science to meet the challenge of producing enough food, fiber and fuel for a growing population. Every gift, no matter the size, is appreciated.