A vat filled with chicken feet, beaks, and viscera is going to make available a lower amount of protein than a vat of breast meat. James Morris and Quinton Rogers, professors with Department of Molecular Biosciences at the University of California at Davis Veterinary School of Medicine, assert that there is virtually no information on the bioavailability of nutrients for companion animals in many of the common dietary ingredients used in pet foods. These ingredients are generally byproducts of the meat, poultry and fishing industries, with the potential for wide variation in nutrient composition. Meat byproducts, the catch-all term of the pet food industry, is a misnomer because these byproducts contain little if any meat. Byproducts contain little if any meat.
Byproduct are animal parts leftover after the meat has been stripped from the bone.
Chicken byproducts include heads, feet, entrails, lungs, spleens, kidneys, brains, livers, stomachs, noses, blood, and intestines free of their contents. What the pet food manufactures fail to mention is that most byproducts, digests and meals are also filled with other substances, such as cancerous tissue cut from the carcass, plastic foam packaging containing spoiled meat from supermarkets, ear tags, spoiled slaughterhouse meat, road kill, and pieces of downer animals. Another source of meat that isn't mentioned on pet food labels is pet byproducts, the bodies of dogs and cats. In 1990 the San Francisco Chronicle reported that euthanized companion animals were found in pet foods. Although pet food company executives and the National Renderers Association vehemently denied the report, the American Veterinary Medical Association and the FDA confirmed the story.