The 7 Best de-Wormers for Horses

For the ongoing health for your horse it is important that you work out relevant ways to keep your horse free from worms and use the best wormer available. Worms in horses are actually various parasites that infest a horse’s intestinal tract and there are a number of ways of reducing or eliminating them. Practically every horse will have some sort of infestation during its lifetime.

You can collect a sample of your horse’s dung to get it tested for worm burden by faecal egg counts (FEC). Spring and autumn are good times to carry out these counts. However, even without an FEC you can start an effective worming schedule.

Ascarids or Roundworms – large thick worms that can grow up to more than 30cm. The ingested larvae burrow through the horse’s small intestines into its blood system to infect the heart, liver, and lungs. From the lungs, they are coughed up and swallowed into the stomach to return to the small intestine where they develop into mature adults that in turn produce more eggs.

Older horses develop some immunity to these parasites but young stock are particularly vulnerable. Symptoms are respiratory problems, colic, and malnutrition.

Ascarids can be treated with broad-spectrum wormers like ivermectin and moxidectin however to avoid resistance, benzimidazole (BZD) and pro-benzimidazole compounds may be used too.

Bloodworms or Redworms (Large and Small Strongyles) – third-stage larvae are ingested by horses as they graze grass. The larvae migrate through the host’s small and large intestine arteries causing damage, blockages, and possibly ruptures. diarrhea, colic, and poor condition.

Large bloodworms can weaken abdominal artery walls. At some stages of the lifecycle strongyles can become encysted in the horse’s intestines so are highly resistant to chemicals. To kill these encysted parasites requires moxidectin or 5 daily doses of fenbendazole.

Threadworms – are especially dangerous for young animals that can actually become infected through the mare’s milk while suckling. The parasites then go on to live in the intestinal tract causing weakness and diarrhea. These can be controlled by drenching with Ivermectin twice a year.

Pinworms – these are not so dangerous as other parasites however, they cause irritation around the tail and anus. Your horse may start rubbing the area raw when it itches. The eggs may infest grooming items, tail wraps, stalls, and bedding so a thorough cleaning should be carried out at the same time as treatment.

Tapeworms – Horses grazing can ingest mites infested with tapeworm cysticercoids. These larvae attach themselves to the caecum and develop into tapeworms in and to feed off the horse’s food in the intestine so your horse may suffer mild colic or diarrhea. The mature tapeworms shed mature segments containing eggs. These eggs are in turn eaten by dung mites and develop into tapeworm inside the mites which are again ingested while the horse grazes.

Tapeworms can be treated with Praziquantel and Pyrantel

Bot Flies – Bots are large pesky flies active from spring through summer.  They depositing small yellow eggs that stick to a horse’s coat, especially legs and belly. If the horse ingests these eggs the larvae hatch and attaches themselves somewhere along the digestive tract. They can cause poor conditions, mild colic, ulceration, and complete blockages. Mature larvae are passed out in dung to pupate in the ground and emerge as mature flies some weeks later. An effective way to break the cycle is to remove the eggs from your horse’s hair with a bot knife. However, using a chemical wormer that kills bots at least once a year – Ivermectin and Moxidectin

Total girth (inches) x total girth x body length / divide 300 = approx. weight in lbs (NB This is for horses older than a year)

It might be tempting to purchase bulk lots but consider their expiry dates. Ensure maximum shelf life by storing in cool dry areas until required.

Use different products for different parasites at different times of the year. This ensures that the parasites do not build resistance or become immune to the wormer ingredients and that parasites are targeted at the right times.

It’s worth noting that, despite most parasites have part of their life cycle through pasture grazing, even stabled horses can be infected with worms. Good pasture management also decreases reinfection. If possible this management might include allowing pasture to rest from grazing at regular intervals, cross grazing with other animals like cattle or sheep, and removing horse feces on a daily basis.

 Large Strongyles, Small Strongyles, Pinworms, Ascarids, Hairworms, Large-mouth Stomach Worms, Bots, Lungworms, Intestinal Threadworms, plus others.

It is palatable for most horses and suitable for all ages, including pregnant or lactating mares.

It is a good one to start with if you don’t know your horse’s drench history.

Anthelcide EQ Paste is a paste formulation of oxibendazole, a broad-spectrum benzimidazole anthelmintic as an alternative to more frequently used.

This can be used for all horses including lactating or pregnant mares and can be used concurrently with trichlorfon bot treatments.

including bots and encysted strongyles. Great for using as a rotation of different anthelmintics so that parasites cannot build up resistance.

including encysted strongyles. Its unique cinnamon/apple flavor is highly palatable to most horses. It’s suitable for horses of all sizes, and ages, and conditions.

It’s suitable for horses of all ages and sizes, including pregnant or lactating mares. It can be used regularly so can also act as a preventative against reinfection.