When it comes to managing internal parasites in horses, it takes more than just giving a generic wormer a few times a year. Especially since horse parasites are becoming more and more resistant to treatments. This is why it's important to use the best horse wormers alongside a worming program for complete parasite control.
Discover below, all the information you need to provide the best protection for your horse against parasites.
How Do Horses Get Worms?
The most common way that horses become infested with worms is by grazing on contaminated pasture or from being around other infected horses.
Most worms are ingested as tiny larvae and then develop into worms in your horse's digestive tract. The worms or larvae are then excreted out back into the pasture as manure and may be ingested again by your horse.
When you use a wormer for horses, you're interrupting the parasites life cycle, aiming to kill and eliminate it completely from both pasture and horse.
How Can You Tell If Your Horse Has Worms?
One way to tell if your horse has a worm infestation is if you notice a deterioration in its condition. It may become lethargic and lose its appetite which will lead to weight loss, loss of condition and a dull coat.
If the horse is heavily infected the worms will cause diarrhea and regular bouts of colic. Other signs to look out for include wounds on the skin that aren't healing and coughing.
What Are The Most Common Types of Worms?
Below we'll take a look at the most common type of horse worms and their seasonal habits and life cycles. In order to provide the best worm treatment for your horse, it's important to identify exactly what one you're treating it for.
WORMS | TREATMENT |
|---|---|
Bots | Ivermectin, Moxidectin |
Tapeworms | Praziquantel, Pyrantel Pamoate |
Pinworms | Pyrantel Pamoate |
Threadworms | Moxidectin, Ivermectin, Oxibendazole |
Ascarids (Roundworms) | Pyrantel and Fenbendazole based |
Large/Small Strongyles (Boodworms/Redworms) | Fenbendazole and Moxidectin based |
Bots
Bots first appear as small yellow eggs, laid by flies on the horse's forelegs, neck and chest. These eggs are then ingested through the horse's mouth when they're grooming themselves or each other. The eggs stay in your horse's mouth for three weeks where they develop into larvae. The larvae then travel to the stomach where they attach themselves. This can cause digestive problems, irritation and possible obstruction in the digestive system. After eight months in the stomach, the larvae are then passed out in faeces, hatched out as flies and the cycle starts again.
The best horse wormer to use against bots contain ivermectin or moxidectin and traditionally this is given a month after the first frost.
Tapeworms
This is the same type of worm that can also be found in a cat, human or dog. Tapeworm eggs are first eaten by foraging mites that live in the grass. Horses then eat these mites when they’re grazing. The tapeworm eggs develop in the gut and attach as worms to the ileocecal junction. Here they grow and steal away the nutrient supply from your horse and can cause inflammation, obstruction and even gastric rupture. Tapeworm eggs are passed out in faeces and the cycle starts again.
The best wormers for tapeworm are praziquantel or pyrantel pamoate, traditionally given twice a year March and September for spring and fall outbreaks.
Pinworms
Pinworms mature and develop in the large intestine and rectum of horses which causes them to be very itchy around the tail. The horse will then smear the eggs onto any surface it's rubbing on. These eggs can be picked up by another horse and they can also be passed on through contaminated food or bedding. As well as causing lots of uncomfortable itching, pinworms can cause many digestive complaints.
They have a five-month life cycle and the best horse wormer for pinworms is pyrantel pamoate based.
Threadworms
These threadworms are common in foals and have a two-week life cycle so it's a quick turn around. Foals can be infected from their mother's milk if she is infected and also by contaminated pasture or bedding. Foals will generally develop immunity at 90 to 120 days but the worry is the diarrhea caused by the parasite. It's easy for them to become fatally dehydrated at such a young age. The mare can be treated prior to foaling to reduce the risk.
The best horse wormer to treat threadworms is a moxidectin, ivermectin or oxibendazole based one.
Ascarids
These are also known as roundworms and are ingested as eggs. They are hatched out in the stomach and then enter the horse's bloodstream. The worms are then deposited in the small intestine, liver and lungs. As you can imagine, if this worm isn't treated it can do a lot of damage to your horse's health.
It's thought that roundworms are becoming increasingly resistant to ivermectin and moxidectin. A pyrantel or fenbendazole based horse wormer is the best horse wormer to choose for treating roundworms. Ascarids can particularly be a problem in young horses and they will need regular treatments against them. These worms have a three-month life cycle but eggs can live dormant for years in the earth.
Large and Small Strongyles
These worms can be highly damaging to your horse and are also known as bloodworms or redworms. The two common types are small strongyles and large strongyles. They start out as larvae that live on grass which is eaten by your horse. As they travel through your horse's digestive system they are deposited into the blood and can cause clots as well as liver damage. The small strongyles are associated with colitis in horses.
It's best to treat for strongyles in the winter months as they tend to die out in hot weather. The large strongyles have an eight to eleven-month life cycle while the small strongyles take six to seven months to completely reproduce. Large and encysted small strongyles are best treated with fenbendazole or moxidectin based wormer for horses.
What Is the Best Way to Manage and Prevent Worms?
Lots of veterinarians are now recommending that instead of giving a horse wormer every few months, it's better to tackle parasite control in a more holistic way. This not only minimizes the amount of chemicals your horse is ingesting but it also stops parasites building up a resistance.
For the very best worm prevention and treatment then its necessary to observe the following things.
Pasture Management
Pasture management and rotation is vitally important as this is where your horse will predominantly pick worms up. Make sure that the pasture isn’t overcrowded with too many horses per acre and rotate the pasture if possible. Ideally, you should leave a grazing area rested for six months. This rotation gives time for parasite life cycles to be disrupted.
When feeding roughage in the pasture, feed it from a rack to prevent the horse's mouth from touching the ground and possibly picking up worms.
To safe guard young horses it's a good idea to group horses of a similar age together. Keeping mares and foals away from adult horses, and yearlings away from old horses for example.
Lastly, it's vital to remove droppings every day, or as regularly as possible from the horses stable or pasture.
Fecal Egg Count
These days it’s very easy for your veterinarian to do a fecal egg count from a sample of your horse's feces. This will give you a very clear indication of the different worms present in the pasture and therefore what horse wormer will be most effective. By taking a regular fecal egg count, you can see if your worming management program is working.
The egg count won't show some parasites like tapeworm or encysted small redworm, your horse needs a blood or saliva test to monitor these.
Horse Worming Schedule
You should base your deworming schedule on at least a one year cycle and potentially as far as three years. For optimum results, discuss it with professionals and see what your vet says.
You should dose your horse depending on worm count or to suit the common, seasonal parasites. The best wormer for spring is a pyrantel pamoate or praziquantel to target tapeworms for example.
How Often Should I Use a Horse Dewormer?
Horses will develop their own individual immunity against worms and some will be more resistant to others. This is why they should be treated for their individual needs when it comes to their deworming schedule. Here are some general guidelines you can follow.
Age
Foals and young horses under the age of three may need more regular worming program, up to four times a year. This is because they haven’t yet built up a natural resistance which makes them particularly susceptible to worms (see a horses growth stages). Parasite infections can stunt the growth of a young horse cause a potbelly.
Weight
If your horse doesn’t get the right dosage then the treatment will be ineffective. Not having enough wormer will also harden the resistance of the worms. That’s why it's important to give the right amount.
You can use a weight tape to find out the exact weight of your horse in order to give it the correct dosage.
The Severity of Infection
Sometimes if a horse is severely infected, this may call for stronger dosing. The horse may require a course of treatments administered over several days. Moxidectin has no evidence of parasite resistance so should be used on a suspected heavy infection. Some herd worming programmes depend on an egg count to identify the high and medium egg shedders. In a herd situation, if your horse is a low shedder then it may require fewer treatments.
Special Conditions
Before introducing a new horse into a barn or pasture, it’s a good idea to treat the horse for worms and then stable it for 48 hours. This gives the treatment time to take effect and avoids contaminating the pasture or other horses. If your horse moves around a lot for showing or stud for example, then you will probably need to worm it more frequently. Giving your horse wormers in the depths of summer and winter can be unnecessary and ineffective due to inactivity of parasites.
Reviews Of The 8 Most Popular Wormers
1. Equimax Paste
This horse wormer from Equimax covers most of the major internal parasites found in horses. The active ingredients ivermectin and praziquantel will take care of bots and tapeworm in a single dose. This is the best ivermectin to give your horse.
2. Merial Zimercterin Gold
This horse deworming paste contains ivermectin and praziquantel which makes it a good wormer for spring. One dose will cover a horse weighing up to 1,250lb and will take care of most worms including roundworm and bots.
3. Durvet Ivermectin Paste
This ivermectin paste from Durvet will be particularly appealing to your horse with its apple flavour. It covers most of the major parasites including bots with just a single dose.
4. Zoetis Quest Gel
The active ingredient in this wormer is moxidectin, making it particularly good for bots and threadworms. It’s made in the USA by Pfizer Equine and it will cover all of your worming needs.
5. Safeguard Horse Dewormer
This wormer from Safeguard is a fenbendazole based wormer and can be used to treat strongyles, pinworms and a range of equine parasites. Your horse will find the cinnamon apple flavor very appealing and it can be used alongside trichlorfon for extra coverage.
6. Safegaurd Horse Deworming Pellets
If you have a horse who really can't bear a syringe in its mouth, then this product is a great alternative to worming paste. The tasty, alfalfa-based pellets contain fenbendazole, good for strongyles and can be added to your horse's food.
7. Panacur Horse Dewormer Paste
This apple flavor wormer is made in the USA and is one of the most common horse dewormers. The active ingredient is fenbendazole which gives it good coverage on a range of parasites including encysted small strongyles, pinworms and large strongyles.
8. Durvet Pyrantel Paste
This pyrantel based wormer from Durvet is particularly effective against pinworms and roundworms in horses. The added apple flavor makes these wormers a little bit more appetising for your horse.
Conclusion
As you can see, managing animal parasites in your horse isn't as simple as using a wormer twice a year. In order to fight parasites effectively and keep pastures parasite free, it's important to be conscientious about your deworming schedule as well as the products you use.
Pasture management and fecal counts may be used in conjunction with the best wormers for horses to eliminate parasites from your horse and its grazing environment. If you keep on top of the parasites, your horse will definitely thank you for it!
