Animal Feed

From SourceWatch
Jump to navigation Jump to search

Animal Feed includes feed produced for pets (companion animals), wildlife, and livestock. Animal feed can contain rendered animal products, manure, plant- and animal-based fats, antibiotics, and metals. For more information on the corporations that make up the industry and the structure of the industry itself, see the article on the Animal Feed Industry.

Animal Feed Ingredients

Rendered Animal Products

"Rendering plants transform slaughter by-products and animals that are unsuitable for human consumption into animal feed products using grinding, cooking and pressing processes."[1] "In 2003, the U.S. rendering industry produced over 8 million metric tons of rendered animal products, including meat and bone meal, poultry by-product meal, blood meal and feather meal (NRA 2005b). Most of these products were incorporated into animal feed."[1] However, the exact amount of rendered animal products used in livestock feed is difficult to determine.

Animal Waste

"Another major animal protein-based feed ingredient is animal waste" (i.e. manure), "including dried ruminant waste, dried poultry litter and dried swine waste."[1] Poultry litter includes bedding and dropped feed as well as manure. The use of manure in feed has occurred since the 1960's as a means of cutting feed costs. As of 2007, there was no national data on the amount of animal manure used in feed. However, an estimate from Florida in 2003 found that of the one million tons of poultry litter produced annually in Florida, about 350,000 tons were "available for use in feed."[1]

"The U.S. Food and Drug Administration (FDA) does not officially endorse the use of animal waste in feed and has issued statements voicing the agency’s concern about the presence of pathogens and drug residues in animal waste, particularly poultry litter (FDA 1998). In line with these concerns, AAFCO [Association of American Feed Control Officials], an organization that develops guidelines for the safe use of animal feeds, advises that processed animal waste should not contain pathogenic microorganisms, pesticide residues and drug residues that could harm animals or eventually be detected in animal-based food products intended for human consumption (AAFCO 2004). Nonetheless, these guidelines are not adequately enforced at the federal or state level."[1]

Plant- and Animal-based Fats

Fats from both plant- and animal-based sources are also used in animal feed. These "may contain contaminants, such as dioxins and polychlorobiphenyls (PCBs)."[1] As of 2007, the most recent data available showed that in 1998, approximately 1.3 million metric tons of fats were used in the production of U.S. primary animal feed. As much as 8% of feed could be comprised of fats.[1]


"The use of antibiotics in animal feed is also a public health concern. Antibiotics are administered at non-therapeutic levels in feed and water in order to promote growth and improve feed efficiency. This practice has been shown to select for antibiotic resistance in both commensal and pathogenic bacteria in:
  • 1) the animals themselves (Aarestrup et al. 2000; Bager et al. 1997; Gorbach 2001; Wegener 2003);
  • 2) subsequent animal-based food products (Hayes et al. 2003; White et al. 2001);
  • and 3) water, air and soil samples collected around large-scale animal feeding operations (Chapin et al. 2005; Chee-Sanford et al. 2001; Gibbs et al. 2006; Jensen et al. 2002)."[1]

Additionally, a 2009 study found antibiotic resistant bacteria in workers at hog operations.[2][3]

Antibiotics used include tetracyclines, macrolides, streptogramins and fluoroquinolones.[1] For more information, see the article on Antibiotics in Livestock Feed.


"Metal compounds are also administered in animal feeds, and the compounds currently added to both swine and poultry feeds that are particularly concerning from a public health perspective are organoarsenicals. The most commonly used organoarsenical, Roxarsone (4-hydroxy-3- nitrobenzenearsenic-acid), is administered to feeds at concentrations ranging from 22.7 g/ton to 45.4 g/ton to promote growth and improve feed efficiency (Chapman and Johnson 2002). When used in combination with ionophores, Roxarsone also act as a co-coccidiostat to control intestinal parasites."[1]

(A major disease concern in poultry is a parasitic disease called coccidiosis, which can be deadly.)

Once ingested by poultry, Roxarsone's arsenical compound can degrade into inorganic arsenite and inorganic arsenate, both classified as Group A human carcinogens by the U.S. EPA, in animal digestive tracts and animal waste.[1] See the article on Roxarsone for more information.

Other metallic compounds mixed into feeds include: copper, manganese, magnesium, and zinc compounds, and metal amino acid complexes.[1]

Resources and Articles

Related SourceWatch Articles


  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Amy R. Sapkota, Lisa Y. Lefferts, Shawn McKenzie and Polly Walker, "What Do We Feed to Food Production Animals? A Review of Animal Feed Ingredients and Their Potential Impacts on Human Health," Environmental Health Perspectives, doi:10.1289/ehp.9760, February 8, 2007.
  2. Study Connects MRSA in Swine and Swine Workers," Center for a Livable Future Blog, Johns Hopkins University, January 23, 2009.
  3. Tara C. Smith, Michael J. Male, Abby L. Harper, Jennifer S. Kroeger, Gregory P. Tinkler, Erin D. Moritz, Ana W. Capuano, Loreen A. Herwaldt, Daniel J. Diekema, "Methicillin-Resistant Staphylococcus aureus (MRSA) Strain ST398 Is Present in Midwestern U.S. Swine and Swine Workers."

External Resources

External Articles