Scientist: Score Equine Pain with 'Research Pain Models'

Scientist: Score Equine Pain with 'Research Pain Models'

"Studies need to be conducted to test new analgesic drugs that could prove to be effective in horses, or to test new combinations of currently available drugs," Sanchez said.

Photo: Anne M. Eberhardt/The Horse

The dire need for new drugs to control pain and better ways to assess pain in horses has been widely addressed, but how exactly does one go about achieving this goal? By using well-designed research models of pain, say experts.

"Pain is extremely common in such conditions as colic and lameness, and to successfully treat these horses, alleviating their pain is essential," explained Linda C. Sanchez, DVM, PhD, Dipl. ACVIM, assistant professor at the University of Florida College of Veterinary Medicine's departments of Large Animal Internal Medicine and Large Animal Clinical Sciences.

According to Sanchez, who presented at the 2011 Florida Association of Equine Practitioner's Annual Promoting Excellence in the Southeast Convention, held Sept. 29-Oct. 2 in Amelia Island, Fla., "Studies need to be conducted to test new analgesic drugs that could prove to be effective in horses, or to test new combinations of currently available drugs. To do this, reliable pain models are needed."

Sanchez explained there are four necessary criteria when developing these research models of pain:

  • The subject cannot be anesthetized;
  • The experimental pain stimulus needs to mimic a natural stimulus;
  • The pain stimulus needs to be minimally invasive and ethically acceptable; and
  • The pain stimulus is controllable, reproducible, quantifiable, and the horse's responses to the stimulus also need to be reliable and quantifiable.

Some current pain models use heat or mechanical pressure. For example, a pneumatic device can be used to apply pressure to the coronary band, the pastern, or along the back muscles to simulate a variety of painful situations that are frequently encountered in equine medicine.

"Another useful model is a reversible model of lameness that uses a specialized shoe fitted with an adjustable screw to induce solar pressure," said Sanchez. "This type of model can test the efficacy of analgesics or non-steroidal anti-inflammatory drugs and uses a naturally occurring stimulus. Research models of pain such as these are an essential tool for finding better analgesics, which is a critical step in the advancement of equine medicine."

Additional information about the convention and Sanchez's presentation is available online.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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