Worms in horses – why should I deworm my horse?

The topic of deworming is a recurring discussion among horse owners. For anyone wondering whether it’s even necessary to deworm their horse, the answer is: Yes! Anyone who has ever witnessed, during colic surgery, how vast numbers of worms can completely block sections of the small or large intestine will never ask that question again. Without treatment, a worm infestation can become a life-threatening danger to your horse. Initially, noticeably frequent rubbing of the tail root is a sign of this. As the condition progresses, internal organs can be damaged and colic can occur. Your horse loses weight despite adequate feeding. The parasites weaken it more and more. Regular deworming is necessary to reduce the infestation to a level that your horse’s body can tolerate. It is nearly impossible to achieve complete freedom from worms, as new infections occur repeatedly due to the environment. When it comes to deworming, there are two methods: strategic and selective deworming. You should avoid alternative deworming methods.

INHALT
Strategic Deworming Selective deworming Conditions for effective deworming
Strategic Deworming

In strategic deworming, which is commonly used in large stables, all horses are treated at the same time with the same medication at regular intervals. This is done seasonally during the grazing season from spring to fall, a total of two to four times per calendar year. To specifically target different types of worms and prevent the development of resistance in the parasites, different groups of active ingredients are used depending on the season.

Sunny the Horse Has Worms
Selective deworming

With selective deworming, a deworming treatment is administered only when a parasitic infestation has actually been detected. This type of deworming is less stressful for the horse’s body, as treatment is given only when an infestation has been confirmed. Another advantage of selective deworming over strategic deworming is that it leads to reduced development of resistance.

With selective deworming, fecal samples are taken from your horse every two to three months for three days and tested for parasites and worm eggs by a laboratory or your veterinarian’s office. If a worm infestation is confirmed, an appropriate, veterinarian-prescribed medication is administered. To prevent immediate reinfection, all stalls must now be thoroughly mucked out and the paddocks cleared of manure. If neither parasites nor their eggs are found in the feces, new fecal samples should be sent in for testing after two to three months. This is because even with a negative fecal sample, a worm infestation may still be present, as eggs are not continuously shed.

Horse manure with worms
A worm infestation isn't always obvious
Conditions for effective deworming

Whether strategic or selective—in a stable with multiple boarders and shared paddock and pasture use—everyone must participate. All measures should be implemented simultaneously. The subsequent stable hygiene routine must also extend to all stalls and all open areas used by the horses. After all, the entire deworming process is ineffective if one horse is not dewormed and excretes parasites in its feces, which the next horse in the pasture then ingests. It is recommended to implement special follow-up care for three days and to suspend group housing during this time.