Welfare on the farm: Treating pain and distress in food animals

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Dr. Wendy J. UnderwoodPublic concern over the use and treatment of food animals in the United States has been building for years. Recent, well-publicized allegations of abuses at slaughter facilities have fueled the discussion. And yet there are few government regulations concerning the welfare of the millions of animals that are part of the U.S. agriculture industry.

In her lecture, Dr. Wendy J. Underwood, attending veterinarian for Eli Lilly and Company, addressed the balance between the economics of food animal production and animal well-being, and the need to increase awareness of food animal welfare and the need for adoption of producer-developed guidelines on agricultural animal care and use.

Some of the challenges inherit in any discussion of animal pain and distress are defining pain and distress; recognizing them; their causes; and management.

There is growing recognition among veterinarians and animal scientists that food animals do experience pain and distress.

The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage." The Department of Agriculture's Animal and Plant Health Inspection Service's working definition of distress is "a state in which an animal cannot escape from or adapt to the internal or external stressors or conditions it experiences, resulting in negative effects on its well-being."

Dr. Underwood, a diplomate of the American College of Veterinary Internal Medicine, noted that pain and distress are unique to the individual. And although it might not be appropriate to ascribe human qualities to animals, using a human physiologic reference does allow human experience to be used as models for animal pain. Also, animals may not anticipate pain as humans do, but repeated treatments or procedures can have a conditioning effect.

Complicating the veterinarian's job of alleviating animal suffering is the difficulty of recognizing pain. In evolutionary terms, Dr. Underwood said, sick or injured animals could expose themselves to predators, making it a matter of life and death to hide suffering. Studies have shown that pain can be too subtle to detect visually. Heart rate, blood pressure, activity level, weight, and food intake must all be closely monitored to determine whether an animal is hurting.

Recognizable signs of pain vary between species and individuals within a species, Dr. Underwood explained. Cattle may grunt or grind their teeth; swine may become sluggish or squeal or bark; sheep may appear disinterested or stand apart from the flock; goats may change their posture often or become agitated; and poultry may respond by excessive head and body movements or escape reactions.

Pain and distress can be caused by disease, as well as standard agricultural practices, such as branding, beak trimming, and tail docking. Transportation and handling can also lead to physical and psychological stress.

"Management practices that induce pain without provision of pain relief are both counterproductive and counterintuitive to farm production," Dr. Underwood said.

Few anesthetics and analgesics are approved for use in food animals. In 1994 the Animal Medical Drug Use Clarification Act allowed for extralabel use of approved drugs in food animals within a set of regulations. Proper withdrawal times must be followed before an animal can be slaughtered for human consumption. This information, Dr. Underwood noted, is available through the Food Animal Residue Avoidance Databank.

Dr. Underwood did point out that animal scientist Temple Grandin, PhD, has made a number of valuable recommendations for controlling pain and distress in food animals. Dr. Grandin suggests breeding calm animals to improve handling and transportation; training animal handlers to understand the concept of an animal's flight zone and to use electric prods properly; acclimating animals to change; and designing slaughter facilities to reduce fear, distress, and injury.

European countries have been far more aggressive than the United States in regulating farm animal care and use, Dr. Underwood said. For example, in the United Kingdom, food animals are afforded the "five freedoms": freedom from hunger and malnutrition; thermal and physical discomfort; injury and disease; suppression of normal behavior; and fear and stress.

The United States uses guidelines, rather than regulations, for food animal care and use. Producers, veterinarians, and other stakeholders have developed these guidelines. Dr. Underwood believes the guidelines should be followed by every U.S food animal producer and research facility. If not, she said, "our right to have [food] animals may become a privilege."

2001 AVMA Animal Welfare Forum - Pain Management