Deworming FAQs
Deworming your horse is a crucial part of their routine health care. Not only can it prevent illness and colic, it can prevent illness form spreading to the whole herd. Here are some frequently asked questions from our clients:
What types of "worms" might my horse have?
Mostly nematodes and insect larva.
Are the "parasites" confined to my horse's stomach or intestines?
NO! In the normal course of their life cycle these parasites migrate throughout your horse's liver, lungs and arteries.
If my horse has a negative "fecal exam" is he or she free of "worms"?
NO! It only means that here are not mature eggs laying parasites in your horse's intestine. It does not rule out migrating stages, encysted small strongyles or bots in your horse's stomach
Is regular "deworming" sure to eliminate all of my horse's parasites?
NO! Some - encysted strongyles and ascarids - are very hard to kill and resistance to anthelmentics (deworming medication) has been shown.
How does my horse get infected?
Eggs are passing the manure of other (or your own) horse and can survive up to 10 years in the environment. Once contaminated, a pasture will remain infective for a long time. Once trick is to decontaminate a pasture is to graze cattle instead of horses for a year - cattle will ingest the parasites but the nematodes will not be able to complete their life cycle and new eggs will not be passed. Your foal can also get infected from his or her mother's milk, and you horse will get bot eggs of her or her own hair.
Things To Consider When Deorming Your Horse
When it comes time to deworm your horse, there are some things to consider to ensure the effectiveness of your program.
Regular fecal exams
Although a negative result down not guarantee your horse is parasite-free, a positive result says a lot about the extent of any problem and the types of parasites you need to worry about. If re-infection rates are high, you might consider pasture management changes and/or daily deworming (Strongid).
Moxidectin (Quest) or Panacur Powerpac
Small strongyles encyst in the walls of your horse's intestine. Their presence cannot be determined by fecal exams, and they often emerge simultaneously in large numbers in the spring causing severe intestinal inflammation and possibly colic. Encysted strongyles are resistant to most dewormers. The two choices listed above have been shown to be effective.
Ivermectin and Praziquantil
Bots and tapeworms are not nematodes and will not be killed by most dewormers. Use this combination in the fall to protect your horse against these parasites.
Benzimidazoles and Strongid
Very effective and safe. They are better than Ivermectin against some parasites and should be part of your deworming program. Rotation between multiple anthelmintics is always recommended to avoid resistance and maximize effectiveness.