Colic: One inside story.

An article by Clare Illingworth, SPARK writer, University of Guelph.




Colic, a common digestive upset that causes mild to fatal signs in horses, has many causes. But when a recent British study linked colic risk to an intestinal parasite, Guelph researchers took note. Now they’re investigating the parasite to see if the same is true in Canada. The intestinal parasite commonly called equine tapeworm inhabits the large intestine in at least four per cent of Ontario horses. But Prof. Andrew Peregrine, Department of Pathobiology, says about 50 per cent of colic cases brought to the Ontario Veterinary College have equine tapeworms. He is now investigating the parasite’s association with an increased risk of certain colic types on Ontario farms.

His research could have owners and veterinarians changing the rou-tine care they give their horses in the future. “Colic is not only painful for the horse but also time-consuming and expensive for owners,” says Peregrine. “If something as simple as a tapeworm infestation increases colic risk, then horse caregivers should be made aware.”

Where it all began.

Equine tapeworms originate inside mites the horse ingests in pasture. The parasites are released from the mites, grow in the colon and use small suckers to attach to the intesti-nal wall. This attachment is believed to cause intestinal inflammation that could interfere with digestive flow, causing colic, Peregrine says. To determine a link between equine tapeworm and colic, he will examine 120 on-farm colic cases in Ontario this year. Each horse will be checked for intestinal parasites and compared with another horse of similar age, breed and care at the same facility.

From this information, he will determine whether tapeworm infections occur more commonly in colic cases. “Not every horse with equine tapeworms will develop colic,” says Peregrine, “but we suspect larger infestations are more likely to be a contributing factor than lower infestations.” Once the information is gathered, researchers hope to assess the need for regu-lar preventive treatment. Currently, only one Canadian dewormer is effective at eliminating the parasite, and that’s at double dose.

Pulling it all together.

In a second phase of this study, Peregrine will determine if colic incidence and equine tapeworm numbers are affected by season.

Other researchers involved in this study include Profs. Wayne Martin and Peter Physick-Sheard, Population Medicine. The project is sponsored by the E.P Taylor Equine Research Fund.