Many horse owners live in near-superstitious dread of the word "colic." The often fatal condition caused by intestinal blockages can bring even the strongest horse to its knees, and its cause frequently remains a mystery. For many years, dewormer has been rumored to cause acute cases of colic in some horses, though no one could explain exactly how or why. Although your dewormer is unlikely to cause trouble for you or your horse, you should be aware of its potential to spur a bout of colic and watch your horse closely for several days after worming.
Explaining the Basics of Colic
Colic occurs when food cannot pass through your horse's digestive system as it should, becoming blocked and quickly plunging your animal into septic shock. This can occur at several points along the intestines through a few different means, such as excessive gas or debris like sand. When this happens, the intestines fill with backlogged fecal matter until they rupture.
Understanding How Dewormer Can Impact the Intestines
Dewormer itself is not really to blame in cases of post-dosage colic. Instead, the trouble is caused by dead and dying worms, which in sufficient numbers can collect in the intestines and form a blockage of their own. This usually only occurs in horses with poor immune systems, such as older or younger horses, or horses that have a significant worm infestation beforehand. If your horses are on a regular deworming schedule and are otherwise healthy, you likely have nothing to worry about.
Administering Dewormer Safely
If, on the other hand, your horse falls into one of those at-risk categories, it may be best to visit a horse vet to oversee administration of the dewormer. Your veterinarian may give your horse a shot of steroids at the same time to minimize intestinal inflammation and keep things moving. He or she may also recommend giving your horse only a half dose and then finishing the deworming at a safer time, once your animal's worm load is reduced.
Recognizing the Signs of Colic
You should always be watching for the earliest symptoms of colic, a small act of diligence which may one day save your horse's life. While your horse is recovering from deworming, however, it becomes especially important. Look for irritable behaviors and signs of pain, such as biting at the flanks or twitching along the spine. Your horse may appear listless and stop eating and drinking as well. Whenever you suspect colic, call an equine veterinarian like Edisto Equine Clinic immediately for an emergency appointment; the faster you act, the more likely your horse will be saved.