Frequent deworming has been identified as being the most important risk factor for the development of parasite resistance.2

Seemed like good idea at the time!

Interval deworming programs have been around, in some form or other, for quite some time. For decades, actually.

When they were first developed, these "by-the-calendar" deworming programs were considered state-of-the-art, based on then-current knowledge, accepted best practices and prevailing conditions. At that time:

  • Horses were heavily parasitized, because deworming was still new.
  • Horses were not dewormed as frequently.
  • It was believed that it was possible – and desirable – to eliminate all parasites in individual horses.

What we've learned since then...

  • As the (not always judicious) use of dewormers increased, resistance  to antiparasitic agents started to develop in equine parasites.
  • Resistance is a real threat to the continued effectiveness of current deworming products.
  • Frequent deworming has been identified as being the most important risk factor for the development of resistance.2
  • Using dewormers less often and more selectively appears to be the only way to preserve the value of current dewormers and to reduce the rate of development of resistance in equine parasites.

It's time for strategic deworming.

 

2. Peregrine AS. Deworming programs for horses: Are we doing more harm than good? Large Animal Veterinary Rounds, Department of Large Animal Clinical Sciences of the Western College of Veterinary Medicine, University of Saskatchewan, June/July 2005, vol. 5, issue 6.