(As of the writing of this article, it has been rumored that laws are trying to be passed preventing the sale of over-the-counter wormers. Please watch for this in your country.) Apparently is has to do with the human consumption of horsemeat. I feel another article coming up about this.
One of the most important routine health care procedures in the life of domestic horses is appropriate worming. Simply grabbing a boxed wormer at the store may not only damage your horse over time (build resistance) but will pass by many of the other damaging parasites that a single wormer will not destroy.
Uncontrolled strongyles (blood worms) can case severe damage to the blood supply of the horse's intestines. The worms migrate through the blood vessels and cause arteritis (inflammation of the arteries) and thrombosis (clots in the arteries). This damage may result in chronic loss of bowel function, pain (colic), and even death. The damage caused by strongyles, is the main reason that parasite control is so important to the health of your horse.
Worming Schedule, Brands and Compounds
Recommendations for worming are the following:
Worm adult horses every 60 days (this corresponds to the life cycle of the strongyles).
Use a safe effective paste wormer (anthelmintic). These Brands include:
Panacur: (fenbendazole) roundworms, large and small redworms MORE
Strongid-P: (pyrantel pamoate) large roundworms, large and small redworms, pinworms, tapeworms MORE
Eqvalan (ivermetin): large and small redworms, pinworms, large roundworms, lungworms, stomach hair worms, large mouthed stomach worms, neck threadworms, intestinal threadworms, bots MORE
Anthelcide: (oxibendazole) MORE
Additional worming Brands:
Bimectin: bots, small and large redworms, lungworms MORE
Embotape: large roundworms, large and small redworms, pinworms, tapeworms MORE
Equest: (moxidectin, praziquantel) bots, small and large redworms, lungworms MORE
Equi-Cide: (43.9% pyrantel pamoate) large and small strongyles, pinworms, large roundworms
Equimax: bots, small and large redworms, lungworms, tapeworms MORE
Equitape: tapeworms MORE
Eraquell: bots, small and large redworms, lungworms MORE
Pyratape-P: (Pyrantel ebonate) MORE
Pyrantel: large and small redworms, pinworms, large roundworms, intestinal threadworms, tapeworms. MORE
Fenbendazole: Large and small redworms, large roundworms, lungworms, large mouthed stomach worms. MORE
Moxidecrin: (Moxidectin) large and small redworms, large roundworms, lungworms (not for foals up to 6 months)
Quest: (moxidectin) (from vets only)
Rotectin: (ivermectin) roundworms, pinworms, stomach and hairworms, threadworms, bots
Safe Guard: (fenbendazole)
Strongid C2X (pyrantel tartrate) large strongyle (fed daily) MORE
Telmin: (mebendazole) roundworms, large and small redworms MORE
Vectin: bots, small and large redworms, lungworms MORE
Zimecterin Gold: (ivermectin) MORE
Benzimidazoles (fenbendazole, oxibendazole and mebendazole) MORE
Fenbendazole: ascarids, roundworms
Ivermectin: threadworms, large and small redworms, pinworms, large adult and larvae roundworms, lungworms,
stomach hair worms, large mouthed stomach worms, neck threadworms,
intestinal threadworms, bots
Mebendazole: (piperazine) pinworms, roundworms, tapeworms, hookworms, whipworms.
Macrocyctic lactones (ivermectins and milbemycins)
Moxidectin: (not to be used on severely debilitated and weak horses or foals up to 6 months) heartworms, intestinal worms, adult and larvae ascarids / roundworms. MORE
Oxfendazole: Adult ascarids / roundworms
Oxibendazole: Adult ascarids / roundworms
Pyrantel Ebonate (not to be used on debilitated horses) hookworms, roundworms MORE
Praziquantel: flatworms (tapeworms when paired with pyrantel pamoate) MORE
Many wormers may have more than one of these compounds.
Schedule for General Maintenance – North America
Jan-March Routine worming (Panacur, Safe-Guard, Anthelcide EQ)
April Tapeworm (Eqvalan, Equell, EquiMAX, Quest, Zimecterin)
May-June Routine (Strongid, TapeCare, Equi-Cide, Rotectin P)
July-Aug Routine (Anthelcide EQ, Panacur, Safe-Guard)
Sept-Oct Tapeworm (Equell, Equimectrin, IverCare, Quest, Zimecterin, Rotectin, EquiMAX)
November Encysted Redworm (EquiCide, Rotectin, Strongid, TapeCare)
December Bots (Rotectin, Bimectin, EquiMAX)
All horses should be on tailor-made worming programs from their vet. If that is not available to you then follow general guidelines.
Never use the worming drugs more frequently than recommended. It can lead to resistance. The Netherlands and parts of UK are now resistant to Ivermectin.
Keep accurate records of when and what you used.
No single wormer will kill everything. This is why it is so important to rotate and schedule. Your horse may be free of strongyles while the bots are damaging him. Rotation of wormers keeps the worms in the horse from building up resistance to the chemicals.
Make sure your horse gets the exact amount for his weight. Don't administer the full container to a foal or smaller horse or pony. Although most wormers have a safety margin, the ones prescribed by a vet must be administered exactly as stated. The thinner the horse the more susceptible he is from overdosing. Giving more wormer is a waste of money: giving less wormer is ineffective.
If there is residual wormer in your horse's feed, it must be thrown out by the next day.
Not all horses carry worms in large numbers. A vet exam will discover which horses show worm counts in lower numbers. Theses horses may not need a 2 month program. Consult your vet about this. There is no need to control a parasite that does not exist, and it wastes money.
These are the worms that damage and affect the life of the horse:
Large-Mouthed Stomach Worms
See all worms
Broodmares should be wormed as any adult horse at 60-day intervals. Worming with a safe effective wormer just before and immediately after foaling is important to ensure that the foal is born into an environment low in worm eggs and larvae.
Foals should be wormed monthly after 60 days of age for their first year and then every two months. Foals are normally coprophagic (eat manure). This, combined with intensive rearing, will increase the parasitic load in foals.
Worming a highly parasitic horse or new horse
Caution should be used when worming a highly parasitic horse for the first time. It's not the drug that causes the toxicity as much as the debris or dead bodies of the worms decaying in the horse that cause toxic problems. Too many dead parasites can block veins, the colon and intestines. While it may kill a horse, it will also cause extreme discomfort. Severely ill horses will need the support of vet care, including IV fluids and supplementation.
You may want to start with a pellet wormer (they are lower in strength – Strongid C2X), moving into the stronger brands one to two weeks later.
Outdoors: separate the horse from the others for 24-36 hours. Clean all pastures and paddocks.
Indoors: clean all paddocks and stalls. Use a disinfectant in the stall. Although there is much information stating you should leave the horse in his stall for 24 hours, this may not be a good practice as the parasites are already dead when passed and cannot infect other horses, and the stress of being kept inside may lead to colic , which is exacerbated from the worming.
Harrowing will scatter manure along with eggs and larvae. Harrowing in very hot dry weather will help destroy and dry up the parasites. In warmer wet climates, the parasites will thrive and grow prolifically if harrowed.
Cows and sheep have their own set of worm problems, but are generally not harmful to horses. They can live in harmony with horses, especially sheep, which are known to chew down every section of grass, even the tall grasses that grow from manures.
Do not overstock your paddocks and pastures with horses.
Try to time moving paddocks and pasture with the worming dates.
Treat all horses that are together in the same pasture, and use the same product.
Pick up all manure from paddocks and pasture frequently (no less than every week, every day or second day ideal). This is one of the best ways to minimize worm infestation and control the spread.
Try not to overgraze pastures.
Do not move new horses in and out of pastures frequently.
Ensure all horses co-habitating are wormed together regularly.
Young horses grazing with mature horses may have higher levels of worm counts.
In spite of more disciplined and routine worming of horses than in years gone by, parasite-caused disease still occurs. This emphasizes the need for a 'like clockwork' 60 day worming program. Intestinal worms are the cause of numerous medical problems in horses. Because of the worming programs available, horses no longer need to be bothered, damaged or die from parasite problems. It is important to remember that horses are never free from parasites.
Colic, loss of weight, poor skin and hair, depression, diahrrea and anemia are all conditions of a parasitic horse.
If you think your horse may be suffering from parasites, call a vet immediately. You should have your horse tested once a year for parasites (fecal egg counts). 20% of all horses on one property are the culprits for heavy worm infestation. It's wise to know which horses these are and manage them appropriately. Many horses have immune systems and diets that allow them to naturally eliminate many of the worm populations.