While many experts agree that fleas are an uncommon parasite for horses, ticks can be prevalent and potentially present a danger to your horse’s health.

Ticks are becoming an increasingly significant problem for horse owners in many areas of the country. These parasites can invade your pasture, but they also hang out in places you might routinely ride, such as cool, shady areas near creek beds or among tall grass where they wait to hitch a ride.

Protect your equine by watching for signs of flea or tick problems and treating issues right away or preventing them altogether.

How Common Are Tick Infestations with Horses?

“Horses aren’t the preferred hosts for fleas like dogs, cats and foxes are,” says Laura Stern, DVM, DABVT, director of training and quality assurance for the ASPCA Animal Poison Control Center. “The reason horses aren’t commonly affected by fleas, but do get ticks, is simple: They’re in places where they commonly encounter ticks, but not fleas. Fleas like dark areas, like dens. Those aren’t the places where horses like to be. However, ticks like long grass and wooded areas—places where horses are commonly found—making them a common target for ticks.”

“Fleas don’t like horses,” agrees Garrett Metcalf, DVM, DACVS-LA, an equine veterinarian at Pine Ridge Equine Hospital in Glenpool, Okla. “Fleas are species-specific, and horses aren’t a suitable host for fleas, so it’s rare to have fleas on horses. Ticks are a common problem and rather good at transmitting diseases to horses.”

Signs of a Tick Problem with Your Horse

Horse owners are very protective of their animals, and typically attuned to changes in their behavior. However, a tick’s small size makes it easier for them to hide, so it’s essential to be aware of signs you might blame on something else that could indicate a tick issue.

The first step is to stay alert and physically look for ticks on your horse’s body while being aware of any potentially serious side effects of a tick bite. Besides the actual tick body, Stern says to look for a raised, hard bump where a tick was feeding. She says you might see your horse rubbing a particular spot where a tick is or was, and experience hair loss due to excessive rubbing.

“If your horse has a severe tick infestation or if he seems weak, wobbly or has pale gums, contact your veterinarian immediately before trying to remove any ticks, as you may cause damage to the skin or stress the horse in his weakened condition,” she cautions.

Metcalf advises looking around the groin, head, and region under the tail where ticks often like to accumulate. He says that you might notice swelling in areas where ticks have bitten a horse and edema around the bite site.

“If a horse is head-shy while haltering, lethargic, or has a fever, and ticks are present on the horse, it would be best to have the horse examined by a veterinarian,” he says. “Ticks are a common [cause of] swelling and pain around the ears, and most tick-borne diseases will cause fever and lethargy as the main clinical signs.”

Health Hazards of Infestation

Ticks infected with serious diseases don’t usually transmit those pathogens immediately. Instead, they usually must feed on the host—namely your horse—for a while before disease transmission occurs. This delay in disease transition makes it extremely important to remove ticks as soon as possible.

While less critical issues such as itchiness, hair loss, poor hair coat and local irritation can occur, Stern stresses that more serious problems such as infection at the site of tick attachment, anemia from blood loss in severe cases, and tick-transmitted disease could occur.

“Ticks can transmit a number of diseases to horses, including Lyme disease, equine granulocytic anaplasmosis and equine piroplasmosis,” says Stern. “Rarely, we may also see tick paralysis. There’s typically a delay of 24 hours between when the ticks attach and when they can transmit diseases, which makes it very important to find them quickly and remove them before they have the chance to transmit any diseases.”

An Ounce of Prevention

Prevention is always preferable to treatment, which is true of fleas and ticks. If you can keep your stable and pasture free of these parasites, you avoid having to remove ticks from your horse and could prevent potentially serious problems.

Metcalf suggests using permethrin-based products, which he says are the best store-bought products to combat fleas or ticks on horses.

“It’s rather difficult to prevent ticks from getting onto horses,” he cautions. “Concentrated, topically applied permethrin products may be the best option at this time. Some of these products need to be applied every three weeks.

“Natural remedies aren’t very effective against reducing ticks on horses,” he continues. “Some essential oil recipes use geranium oil as a possible tick repellent. Physical barriers, such as fly boots, may help reduce ticks from getting onto the limbs of horses.”

Stern also touts various tick repellents and products that kill ticks. She says there are some sprays you can use before a ride and topical spot-on products that work longer for horses more consistently at risk of encountering ticks.

“You can use a repellent to help keep ticks off your horses,” says Stern. “Repellents often contain a pyrethroid insecticide, such as permethrin or cypermethrin. Repellents have the advantage of not requiring the ticks to bite and take a blood meal. Avermectins, such as moxidectin and ivermectin, can also kill ticks, but [the ticks] need to take a blood meal first.”

She cautions the importance of always reading the label of any flea and tick product you use to ensure it’s appropriate for use on horses.

“Some cattle products can cause significant toxicity in horses,” warns Stern. “[And] some products won’t be labeled for use on certain horses, especially foals under 3 months of age. Always apply per the labeled [instructions] to minimize the risk of side effects, as well. Your veterinarian can help you determine what product will be best, based on the risk of exposure to ticks, the risk of ticks carrying disease, and your horse’s lifestyle and health history.”

Other Remedies

Besides treating your horse, you should always pay attention to his surroundings. Stern says ticks are generally more of an issue outside of barns, so you don’t typically need tick control inside your barn.

“If fleas are present in the barn, it’s generally not an issue for horses,” she says. “But you can minimize risk by preventing wildlife from entering the barn and ensuring that cats and dogs who have access to the barn are treated with flea preventatives. Treating the environment may be needed for heavy flea infestations.”

One of the best all-natural ways of minimizing tick exposure is to keep horses out of areas that contain a lot of ticks. Of course, that isn’t always possible.

“Ticks are often found in tall grasses and wooded areas,” says Stern. “They dislike hot, sunny areas with no plant cover. An easy way to minimize the number of ticks your horses are exposed to is by mowing any tall grass, removing weeds, and preventing your horse from entering wooded areas or hanging around the boundaries between woods and pasture. Preventing wildlife, especially deer, from entering pastured areas is another important step you can take to decrease the number of ticks in your pasture.”

Metcalf also suggests using pasture insecticides to help reduce fleas or ticks in your pasture. He cautions that whenever a heavy amount of wildlife traffic is present, there’s more of a reservoir of future ticks or fleas to re-establish residency in the pasture.

Tick Removal Tips

Any time you’ve been out riding—or at least once a day if your horse is on pasture—you should check him for ticks. A visual inspection is an excellent first step, but using your fingers to feel around for small ticks that might not be easy to see is also important.

“Deer ticks that transmit Lyme disease only reach 3mm when fully grown and can be hard to see,” says Stern. “The most important areas to check your horse for ticks are the chest, belly, flanks, mane, tail and ears—places where the skin is thinner and ticks can more easily attach.”

Even if you take precautions such as using tick repellents and keeping your horse out of areas ticks might frequently hang out, your horse will inevitably pick up a tick or several during tick season. Stern cautions that there are a lot of myths about the best way to remove a tick from a horse.

“You don’t want to crush the tick, use a hot match, or apply something like baby oil to try to smother it,” she says. “Instead, put on a pair of gloves and take tweezers and grasp the head of the tick close to the site of attachment to the horse. Then, slowly pull the tick away at a 90-degree angle from the horse. This will allow you to remove the entire tick.

“After you remove the tick, wash the skin in the area where the tick was attached with a mild soap and then wash your hands,” Stern continues. “Ticks should be placed in a jar of isopropyl alcohol, which can be disposed of when full. If you notice that the head of the tick wasn’t removed from the horse, contact your veterinarian, as the site can become infected.”

Metcalf agrees that physically removing ticks from horses with your fingers or a hemostat-like instrument is a safe removal method. However, he says some owners might want to kill the ticks first with a permethrin spray, then use physical removal methods.

“Your veterinarian is your best source of information about preventing or controlling ticks,” adds Stern. “They have knowledge of which products work best in your area and the best control strategy, given your horses and your facility. Having preventative measures in place before you have an issue is best. Scheduling a visit with your vet in the late winter or spring is an ideal time to get a holistic tick-control program set up for your horses, but it’s never too late in the year to reach out and get an expert opinion from your vet.”

Ticks and Horses: Key Takeaway

Because ticks can transmit serious diseases, it’s crucial for horse owners to stay vigilant by regularly checking their horses for ticks and taking preventive measures to reduce exposure. By staying informed and taking action early, you can minimize the risk of tick infestations and ensure your horse remains healthy and comfortable.

This article about ticks with horses appeared in the September 2023 issue of Horse Illustrated magazine. Click here to subscribe!

The post The Risk of Ticks with Horses appeared first on Horse Illustrated Magazine.

How Equine Microbiome Work

Horses evolved to extract a remarkable amount of nutrients out of relatively poor-quality feed. In the wild, they walk around all day, eating for the majority of a day’s 24 hours. Here’s how the system works.

◆ First, the food passes through the mouth and gets mixed (chewed) with a lot of water and enzymes in the saliva; enzymes help speed up the chemical reactions that occur when food is digested.

◆ Next, the food goes into a tub (aka the stomach): a fairly small tub, actually, given the size of the horse. In the stomach, the food gets mixed with more enzymes and acid, and proteins in the feed start to break down. From the stomach, the feed gets released into a long tube.

◆ The small intestine of the horse is long. Really long. Seventy feet long. But the food moves through quickly, biologically speaking. It travels about a foot per minute and can get back to the hindgut in as little as 45 minutes, depending on how much and what kind of food. In the small intestine, carbohydrates, fat, and protein get digested (by more enzymes and absorbed.

◆ The horse’s hindgut is where the things that make the horse’s digestive system so unique happen. The hindgut (cecum, large colon, small colon and rectum) isn’t nearly as long as the small intestine, but it can handle a lot more feed.

In the hindgut, the horse has countless numbers of microbes (bacteria, protists, fungi, even viruses) that help break down the stems and woody parts of the horse’s forage. The microbes do the important work of fermentation, which in addition to producing fatty acids, amino acids, and B vitamins for the horse, also make the horse gassy.

It’s in the hindgut that a great deal of water is absorbed, as well.

The Equine Microbiome

The microbiome breaks down food to release energy—but that’s not all. It also protects the horse against “bad” bacteria; is involved in the horse’s immune system, helping keep the animal from getting sick; and even produces many of the vitamins that the horse needs.
It’s an area of current research because understanding the equine microbiome is critically important for understanding the horse’s health, as well as for understanding what we can and cannot do for the horse.

Before you can effectively try to modify the equine microbiome, it’s important to know what’s in it. Using genetic sequencing of bacteria (instead of trying to grow them), scientists are finding out that the horse’s GI tract has many more kinds of bacteria in it that was initially thought, especially those that live without oxygen (anaerobic bacteria).

As it turns out, the microbiome of most horses is actually quite similar. The microbiome of a Quarter Horse in Texas is about the same as the microbiome of a warmblood in Connecticut. For the vast majority of horses in different seasons, on different diets, and in different locations, there seems to be something of a normal range for the bacteria in the horse’s GI tract.

What Alters the Microbiome?

Certain things can rather predictably alter the equine microbiome. For example:
Nutrition: When horses eat large amounts of grain in their diet, their microbiome changes. Veterinarians have long known that large amounts of grain are associated with all sorts of diseases, including laminitis and colic.

One reason is that large amounts of grain change the bacterial population. As long as a horse gets enough forage (fiber from hay or pasture), giving him some grain doesn’t seem to affect the microbiome. It’s at high concentrate levels—such as are fed to racehorses—that the microbiome changes.

While changes in the horse’s microbiome probably also changes some of the physiologic processes of the horse, it’s too early to say if this change directly causes disease. In many other species, it’s been shown that the microbiome is slightly sensitive to things like diet, season, and acute changes in diet; however, these changes aren’t necessarily associated with disease. This is food for thought and future research.

Antibiotic use: Antibiotics kill bacteria. The gut is full of bacteria. Antibiotics can affect the microbiome, and different antibiotics affect different bugs. That’s easy to understand. Perhaps less easy to understand is why antibiotic-induced diarrhea isn’t more of a routine problem in horses.

Disease: When there’s intestinal disease, e.g., colitis, there are also big changes in the microbiome. It’s been shown in at least one study that the microbiome of horses that colic is different from the microbiome of horses that don’t colic, but it’s too early to say that a change in the microbiome will always cause a horse to colic. It’s another area for future research.

To make things even more complicated, all disease-caused changes to the equine microbiome are not created equal. For example, horses with diarrhea caused by Salmonella bacteria appear to have a different microbiome from horses with diarrhea caused by antibiotics.
If that’s the case, it may be possible to develop a microbiome index to see if it’s possible to tell what might have caused the changes. Such efforts are underway.

The Question of Probiotics

People with GI disease, such as Crohn’s Disease, inflammatory bowel disease, and the like, have different microbiomes than healthy people. However, it’s not yet known if that’s the case in horses.

Although “supporting,” “improving,” or “protecting” microbiome is a goal of equine digestive products everywhere, giving such products—for example, pre- or probiotics—doesn’t magically make a horse’s GI tract safe, secure, and efficient.

While the relatively few bacteria that are in equine probiotic products may provide some benefit, they do not “normalize” the equine GI tract. There are a few other things that are known.

◆ The horse’s stomach is, among other things, a vat of acid. Acid is one of the worst things you can run into if you’re a bacterium, and there’s a lot of question about how much, if any, bacteria can survive the stomach if you squirt some in a horse’s mouth.

◆ Probiotics are not drugs, and they aren’t regulated as drugs. This is to say that you really have very little idea what you’re giving when you’re giving a horse a probiotic.

◆ There’s also the problem of content. Various products may not contain the bacteria that are said to be in them, the bacteria in the product may not be alive, and the cell count (the colony forming units, or CFU) may not be as advertised.

◆ There’s the question of dose. In humans, products may have as many as 900 billion CFUs, and humans are about 10 percent of the size of most horses. While equine products vary, the doses are usually much, much smaller. Even if a product were to be effective, a dose of 2 billion CFU (or even 25 billion) isn’t like to go very far in a horse.

When it comes to the equine microbiome, scientists don’t yet know enough about what’s normal to go about making any strong recommendations or having any firm conclusions about what to do when things are abnormal. Happily, horses seem to do pretty well without any help, even though there’s certainly a lot more to learn.

The post Equine Microbiome: Helpers in your Horse’s Gut appeared first on Horse Illustrated Magazine.

If you answered, “Within the last six to 12 months to see how my deworming program is working,” congratulations. You’re paying attention to current recommendations.

If you answer, “Why on earth would my horse need that?” odds are your deworming plan needs updating.

However you answered, read on to learn what you’re doing right and what adjustments need to be made to keep your horse healthy and parasite-free with a deworming plan suited to your regional climate and individual horse.

The Link to Grazing

It might have been convenient in the “old days” to deworm every horse in the barn at the same time with the same product, but remember, that’s what got us in trouble with resistance. (See “Why Dewormer Rotation is Over” for the explanation.) So how do you know when your horse needs deworming—or if he doesn’t?

For owners whose horses have access to grazing, it may help to think of it this way: time on pasture = parasite exposure.

“The longer horses are on pasture, the more they are exposed to strongyle and tapeworm infection,” says Martin Nielsen, DVM, Ph.D., Dipl. ACVM, associate professor and equine parasitologist at the University of Kentucky Gluck Equine Research Center and co-author (with Craig Reinemeyer) of the Handbook of Equine Parasite Control.

“Climate has a huge effect on parasite transmission patterns, as it affects the duration of the grazing season and defines periods of high strongyle infection pressure,” he says. “In some areas, the grazing season may be just four to five months long, while other regions allow horses to be turned out on pasture year-round.”

Consider the grazing season in your region. All horses should be dewormed at the beginning and end of that season, or in other words, at least two times per year.

Some horses (the “high shedders,” who shed more strongyle eggs in their manure than the “low shedders”), will need additional deworming treatment during the grazing season, particularly in regions where that time period is lengthy or year-round.

“If [grazing season] is six months or less, the high shedders could get one additional treatment in the middle of the season, making it three treatments total,” says Nielsen. “In case the season is more like nine months long, perhaps add one more—but only for the high shedders.”

The Trouble with Fecal Egg Testing

Fecal testing is currently the most accurate way to detect the presence of adult strongyles and roundworms, two of the most common parasite species. However, fecal tests aren’t reliable when checking for tapeworms, bots or pinworms.

Tapeworms pass their eggs in tiny packets called proglotids. In dog and cat feces, these little bags full of tapeworm eggs look like grains of white rice. In horses, we don’t usually see intact proglotids because they tend to break up and the eggs disperse before the horse passes manure.

Researchers have proposed blood and saliva tests to check titers and determine if a horse is “positive” for tapeworms. Since such testing is not widely available for horse owners, general recommendations for treating a horse for tapeworms are based on his potential exposure, which includes region and exposure to pasture. Horses in a stall or dry lot have far less exposure than horses on pasture, but there is still some risk.

Generally speaking, the best time to treat for tapeworms is in the fall, although two treatments per year might be needed in some regions. This requires a dewormer containing praziquantel or pyrantel pamoate, as these active ingredients are effective against tapeworms. In arid climates or when horses have no access to grazing, tapeworms may not be a problem.

Bots are not detected in fecal tests either. Their yellow eggs are easily spotted after female bot flies lay them on the ends of the hair, typically on the horse’s front legs and shoulders. Egg presence is an indication to deworm your horse with a product containing an active ingredient (ivermectin, moxidectin) that’s effective against bots.

Pinworms won’t show up in a fecal test, but horses infected with them often show obvious signs of tail rubbing due to itching caused by these parasites. When treating, be aware that pinworms have shown resistance to ivermectin and moxidectin.

The Non-Grazing Horse and Parasite Control

The vast majority of parasites infect horses when they graze, so what about horses who have zero access to turnout on grass?

“Some clients insist on deworming because they’ve been told they have to, but once people understand parasite lifecycles, they realize it’s really hard for horses to get parasites in a place like Southern California,” says David Ramey, DVM, whose practice, Ramey Equine, has been based in the Los Angeles area since 1984.

“Horses here live in confinement situations where they never see any grass and their manure is removed once or twice daily, so it’s extraordinarily difficult for [pasture- borne] parasites to reproduce in this environment,” Ramey continues. “[Horses] poop onto desert sand where manure bakes in the sun and is picked up and removed anyway.”

When he sees a new horse or an existing client moves a horse in from another region, Ramey recommends a fecal test to get a baseline for parasite egg presence. “If the fecal test reveals parasites, we deworm,” he says. “From then on, we do fecal tests twice a year, and if they don’t have parasite eggs, we don’t deworm.

Because parasite resistance to deworming drugs is a real problem, Ramey encourages horse owners to use fecal tests, only deworm as needed, and to use management practices that reduce the chance of parasite infection, including daily manure removal.

“Climate has a huge impact,” says Nielsen. “In a state like California, some areas have very arid conditions and limited access to pasture. This means that pasture-borne parasites, such as strongyles and tapeworms, are less prominent, and in some areas they are no longer the main target parasites.”

Although horses without access to grass don’t have a “grazing season,” the American Association of Equine Practitioners (AAEP) guidelines recommend a baseline foundation of one, or possibly two, treatments per year be given to all horses. Your veterinarian can determine the best time for those treatments if your horse has no grazing season.

Nielsen explains that these recommendations are primarily to keep large strongyles from re-emerging as a problem.

“We have seen tremendous increases in the prevalence of Strongylus vulgaris in countries like Denmark and Sweden, where a large proportion of horses never or rarely get dewormed because of a tight administration of prescription-only restrictions,” says Nielsen.

He adds that another valid reason for baseline treatments are stomach worms, Habronema, which will not show up in fecal tests. Flies are responsible for the transmission of Habronema, so stomach worms can occur in arid places, like California, even in horses that aren’t on pasture. Flies deposit the larvae on wounds, as well as other moist areas, such as the horse’s lips, nostrils, et cetera. The larvae can create so-called summer sores: oozing, expanding infections that are tough to heal and tend to reappear.

Make Your Parasite Control Plan

“Bottom line, you have to adjust to the climate you’re in, how horses are kept there, and formulate a deworming plan based on that,” says Ramey.

The good news is, you’re not in this alone. Work with your veterinarian, use fecal testing to determine which dewormers work for your horse, deworm only when needed, and while you’re at it, keep your horse’s environment as manure-free as possible.

You’ll be doing your part to not increase parasite resistance and keeping your horse healthy at the same time.

Get familiar with the latest recommendations covered in “Internal Parasite Control Guidelines” from the American Association of Equine Practitioners, which can be found at www.aaep.org.

This article originally appeared in the April 2019 issue of Horse Illustrated magazine. Click here to subscribe!

The post Regional Parasite Control for Horses appeared first on Horse Illustrated Magazine.

Unfortunately, there are plenty of horse owners still following an outdated program (from the 1960s!) of deworming by rotating products and treating their horses every two months or even more often. There’s more to worry about here than simply wasting money on excessive treatments. Here is an insight on why dewormer rotation is over and how parasites are becoming resistant to them.

Over time, overuse of dewormer allowed parasites to develop a tolerance for the drugs. Some parasites were killed, of course, but those that weren’t had better immunity to the deworming drugs, resulting in a parasite population that is becoming increasingly resistant.

We are now seeing widespread resistance to deworming drugs, particularly in the case of small strongyles, one of the most common equine parasites. Roundworms (ascarids), common in young horses, are also showing resistance. Because we only have three classes of deworming drugs available at this time, resistance is a serious issue, as it limits the available options to control parasite populations.

At present, fecal egg count reduction testing (FECRT) is the only method to detect resistance in strongyles, so it should figure into every horse’s deworming program. Your veterinarian can explain how and when to perform this simple test—and discuss the results with you so you know that you’re deworming properly.

Guide to Dewormer Resistance

Resistance among the following common parasites is cause for concern.

Small Strongyles

• Widespread resistance to fenbendazole, oxibendazole
• Resistance to pyrantel pamoate
• Emerging resistance to ivermectin and moxidectin (also referred to as macrocyclic lactones)

Large Roundworms (ascarids)

• Some resistance reported to fenbendazole, oxibendazole, pyrantel pamoate
• Widespread resistance to ivermectin and moxidectin (also referred to as macrocyclic lactones)

Pinworms

• Resistance to ivermectin and moxidectin (also referred to as macrocyclic lactones)

Tapeworms

• No resistance currently reported, but because there are no good resistance tests available for tapeworms, resistance could well be present.

Read more about Regional Parasite Control for Horses >>

This article originally appeared in the April 2019 issue of Horse Illustrated magazine. Click here to subscribe!

The post Why Dewormer Rotation Is Over appeared first on Horse Illustrated Magazine.

Read to learn how to have an effective horse deworming program.

Picture this: You’ve moved your horse to a new boarding stable. In your initial conversation with the barn manager, she tells you that all horses will be given a dose of antibiotics on the first of each month.

That sounds strange to you, but the manager says it’s just a precaution in case one horse might be sick.

If this scenario sounds perfectly ridiculous to you—and it should!—stop and consider that deworming horses every two months and rotating dewormer products is really just as irresponsible and is an unnecessary use of drugs.

Fighting Parasites

But wait. Shouldn’t you be concerned about internal parasites in your horse and do everything possible to get rid of them?

Yes. And no.

Yes, you need to have a responsible deworming program. No, you shouldn’t try to eradicate every worm in your horse. (Not that it would even be possible.)

The truth about equine parasite control is that there is no black and white, one-size-fits-all program. If you want to learn how to protect your horse now and in the future, read on to learn about the latest deworming recommendations and how to put them to use.

Getting Realistic

Here’s a basic fact: All grazing animals—including your horse—have internal parasites. The way this typically happens is that horses pick up infective larvae while grazing; those larvae migrate in the horse’s body, mature and lay eggs. These are excreted in the horse’s manure, and thus the cycle continues.

Before the advent of the first modern-era deworming drugs, many cases of colic with fatal outcomes were attributed to gastrointestinal parasites. In the 1960s, researchers discovered deworming drugs that were effective in fighting internal parasites. Many horse owners began routine use of dewormers, following the early recommendations of deworming every 60 days and rotating products.

Today, the large strongyles (“bloodworms”) that were once a common and dangerous equine intestinal parasite are now considered rare.

That’s good news, isn’t it? The fact that widespread use of dewormers over the past five decades has all but eliminated a deadly parasite is positive news. However, the downside is that other commonly found parasites have developed resistance to deworming drugs. This can occur when a dewormer is used repeatedly and frequently.

Once the parasite population contains a significant number of resistant worms, they can no longer treated with that drug class. The big concern is that we currently have only three basic chemical classes of deworming products to control internal equine parasites:

1. benzimidazoles (fenbendazole and oxibendazole)
2. tetrahydropyrimidines (pyrantel salts)
3. avermectin/milbemycins (ivermectin and moxidectin), also referred to as macrocyclic lactones

“We thought for a while that rotating products would be useful, but the data is loud and clear: it doesn’t do anything to prevent or reduce resistance,” says Martin Nielsen, DVM, Ph.D., DipEVPC, associate professor at the University of Kentucky.

Beware of Resistance

Dewormer product labels don’t mention which parasites have shown resistance to particular drugs, so you need to do your homework. Below are some common equine internal parasites that have shown resistance to the drug classes noted.

• Small strongyles: Widespread resistance to benzimidazoles and pyrantel salts has been reported
• Pinworms: Resistance to ivermectin has been reported
• Large roundworms (ascarids): Resistance to ivermectin and pyrantel salts has been reported

Common Mistakes

If resistance is a concern, then how can you protect your horse from parasites? You start by avoiding common mistakes.

“The most common mistake made by horse owners is to not use fecal egg counts, and to deworm far too often,” says Nielsen, whose focus of study is equine parasitology, including understanding the level of parasite resistance to deworming drugs.

“Some horse owners try to deworm their herds down to ‘ground zero,’” observes Craig Reinemeyer, DVM, Ph.D., a veterinary parasitologist and president of East Tennessee Clinical Research in Knoxville. “In terms of equine health, such intensity is unnecessary, and is likely to have unintended consequences.” (Reinemeyer and Nielsen are the authors of Handbook of Equine Parasite Control, published by Wiley-Blackwell.)

The unintended consequences of deworming too often and not using fecal testing are twofold:

• You may contribute to resistance
• Your horse may not be as protected as you think

“You need to know what you’re treating and if the treatment worked,” says Nielsen. “It’s as simple as that. Most adult horses do not need more than a couple of treatments a year. The risk of sticking to the old regimes is that we will just keep getting more resistance. And there are no new dewormers on the horizon, so we will eventually run out of treatment options.”

It would help to think of dewormer products with the same caution you have for other drugs, such as antibiotics, that are occasionally administered to your horse when needed. Because anyone can go to the equine supply store and buy dewormer, we tend to forget these are FDA-regulated drugs that should be used wisely and only as necessary.

How to Use Fecal Testing

In order to use dewormer drugs most effectively, you need to talk with your veterinarian and create a selective deworming program targeted to your individual horse, based on his age, exposure to parasites, climate and season.

Any responsible modern deworming program must incorporate fecal testing, which is a catch-all term for fecal egg counts (FEC) and fecal egg count reduction tests (FECRT).

Reinemeyer explains that fecal egg count testing is the only practical test currently available to demonstrate resistance to deworming drugs, and to identify which horses carry a heavy or light parasite egg count, which in turn determines how often—or not—they need treatment. (Note: Such testing applies to mature horses. Foals and young horses are more at risk for parasite infection and therefore need more frequent deworming than older horses.)

“Fecal egg counting is the way forward,” says Nielsen. “It can be performed at any time, but it makes the most sense to do it during or around the grazing season.”

Performing an egg count when you deworm and then again 10 to 14 days later will clearly reveal how effectively the deworming drug worked. If results show parasite resistance, your veterinarian can recommend a different dewormer, depending on the parasites involved.

Unfortunately, many horse owners still aren’t utilizing fecal testing in their deworming program, but for the sake of the horses, parasitologists hope this changes.

Reinemeyer explains that if you’re not using fecal testing, you have no way of knowing whether deworming treatments are actually working and what kind of parasites the horse harbors.

“This means horse owners are likely to choose an ineffective product, and then they have accomplished nothing,” he adds.

Identifying the Shedders

Fecal testing can also reveal whether your horse tends to carry a high or low egg burden. This refers to internal parasite eggs in the horse’s body that are shed in manure and into his environment.

Most horses fall into the category of “low shedders” (less than 200 eggs per gram of feces when tested). These horses typically only need deworming treatment once or twice a year.

“High shedders” (greater than 500 eggs per gram) are horses that are more susceptible to parasites and may need to be dewormed more often per year than low shedders. And about one-third of herd members might be “moderate shedders,” with egg counts between 200 to 500 eggs per gram (EPG).

Your veterinarian can review the fecal test results with you and use those results to determine what time of year deworming will be most effective for your horse, how many times treatment is needed, and which drug class of dewormer to use, depending on the parasites you’re trying to control.

How to Collect a Fecal Sample

Turn a zip-top plastic bag inside out. Place your hand inside and pick up several “apples” of very fresh manure. Turn the bag right side out, squeeze out excess air and close securely. For most accurate results, keep the sample refrigerated or on ice until your vet picks it up or you drop it off at the lab for testing.

Time for a Change

“Resistance to change is probably the single biggest obstacle to effective adult education,” says Reinemeyer.

Getting horse owners to change traditional deworming practices and follow the latest recommendations is a challenge. But it’s important that we heed the most current research. Otherwise, we will find ourselves with even more limited options to controlling internal equine parasites.

For the health of your horse, make it a point to talk with your veterinarian about updating your deworming program and, if you’re not doing it yet, to incorporate fecal testing. As a responsible horse owner, you want to follow an effective deworming protocol that provides adequate control of parasites without over-treatment that can further the development of resistance to dewormer drugs.

This article originally about horse deworming programs appeared in the April 2018 issue of Horse Illustrated magazine. Click here to subscribe!

Further reading:

Parasite Resistance and the Effects of Rotational Deworming Regimens in Horses

Internal Parasites: Strategies for Effective Parasite Control 

The post Deworming Decoder appeared first on Horse Illustrated Magazine.

Fecal Egg Count Tests

Fecal egg count tests are a critical component of a smarter deworming plan. Identifying your horse as a high, medium, or low shedder will help you and your veterinarian develop a deworming plan that’s right for your horse.

Thumbs down

Deworming Rotation Chart

Rotating three chemical classes of dewormers is no longer the best defense against parasites and may be doing more harm than good. Learn more at SmartPak.com/DewormSmarter

Related articles:

Deworming Myths Busted

We get a lot of questions about deworming, and often hear horse owners confused by myths and rumors. So we’re clearing the air and demystifying deworming!
https://blog.smartpakequine.com/2016/08/deworming-myths-busted/

D is for Deworming

Deworming may be something you’ve been doing the same way for as long as you can remember. However, as parasite resistance and the lack of new dewormers in the pipeline become increasing concerns, more and more horse owners, barn managers, and veterinarians are rethinking the way they deworm horses.
https://blog.smartpakequine.com/2016/05/d-is-for-deworming/

Deworming Q&A

Experts now agree that switching between classes of dewormers based on the calendar isn’t the best way to protect our horses from parasites or to prevent resistance from developing in the worms themselves. While rotating between the three chemical classes of dewormers made sense when it was introduced years ago, it’s no longer the best defense against parasites and, in fact, may be doing more harm than good.
https://blog.smartpakequine.com/2013/03/deworming-q-a/

Demystifying Feed-through Daily Dewormers

“Would it be overdosing my horses if I gave them a daily dose of dewormer “Strongid C” every morning with their feed, and still do a rotation de-worming paste every other month?”
https://blog.smartpakequine.com/2014/01/demystifying-feed-through-daily-dewormers/

The post June SmartTip of the Month presented by SmartPak: Parasite Control appeared first on Horse Illustrated Magazine.

Practice Makes Perfect

Grab an old syringe and fill it with corn syrup or apple sauce. Dip the pointed end in the corn syrup or apple sauce and then walk over to your horse. For safety reasons, your horse should be wearing a halter and you should be holding on to him securely with a lead rope. Slowly move the syringe toward his mouth and lightly rub his lips with it so he gets a taste of the corn syrup or apple sauce. If he’s like most horses, the yummy taste of the syrup or sauce will interest him and he’ll let you sneak the syringe in his mouth. Plunge the rest of the liquid into his mouth and then remove the syringe. Repeat this exercise for a few days before you plan to treat him with the actual dewormer.

Pellets, Please

You should be able to buy dewormer in pelleted form at the feed store. For example, safe-Guard Equi-bits are made from alfalfa and look just like tiny green hay pellets. Read the instructions on the bag to make sure you give your horse the correct amount for his weight. Mix the pellets into one of his daily feeds and he’ll gobble them down without knowing he’s eating dewormer.

Sneaky Treats

Grab a few of your horse’s favorite treats and stick a few in the corner of his mouth. As he munches on them, sneak the syringe into his mouth while he’s distracted.

Flavored Dewormer

When you’re looking at paste or gel dewormers at the feed stores, look for one that’s apple flavored. If the dewormer doesn’t taste too bad, your horse may not be so silly about being dewormed.

Apple Treat

Grab two apples and carefully cut the core out of one of them. Squeeze the correct amount of dewormer into the apple’s center and then cover the top with part of the core. Your horse should eat the apple without noticing the dewormer until it’s on its way down his throat. Let him have the other apple afterward as a treat.

Easy Wormer

You could try a product called Easy Wormer made by Miracle Corp. The Easy Wormer is made of a nylon headstall and plastic bit-like applicator. Slip the headstall over your horse’s ears and place the “bit” in his mouth. Then squirt the dewormer into an opening on the side of the applicator. You can order Easy Wormer from most equine retailers.

Scoop some poop

In the past, it was thought that you had to deworm your horse on a regular basis, for example every six weeks, and that you should rotate the different types of dewormers to prevent the worms from becoming resistant to the dewormers. Recently, research has shown that it’s a better idea to do a fecal egg count on your horse to find out exactly what kind of worms your horse has so you can choose a dewormer that targets those specific worms. This should result in you being able to deworm your horse less—a very good thing if your horse runs a mile at the dreaded syringe.

Ask your vet if his or her clinic does fecal tests. If it does, scoop up some fresh manure from your horse and pop it into a plastic bag. It’s important that the manure gets to the lab within a few hours, so give it to your vet right away or take it to the clinic’s lab to be tested as soon as you can.

A lab technician will look at the manure sample under a microscope and note how many eggs are in the sample and what kind of worms laid them. Then you can chat with your veterinarian about a deworming program that is made specifically for your horse. Your vet will probably suggest a specific deworming product for your horse and tell you how many times you need to use it.

After you deworm your horse, it’s a good idea to re-test his manure in a week or so to see if the worm count has gone down. Fecal tests aren’t expensive; they’ll only set you back about $10.

This article originally appeared in the January/February issue of Young Rider Magazine. Click here to subscribe!

The post Deworming the Difficult Horse appeared first on Horse Illustrated Magazine.

Q: I have been at my boarding barn for almost three years. Other horses rotate in and out for various reasons. I would like to try switching from the rotational deworming routine to the fecal count method. But can I when my horse is the only constant?

I feel better protecting her with the rotational dewormers since I don’t know what the other horses are bringing in. I don’t feel comfortable asking the other boarders to spend money on a fecal count. Any advice or tips from others who made the switch from rotational dewormers to the fecal count method?

Q: I love this question because it’s so practical! How do you implement the strategic, individualized deworming recommendations in a facility such as yours? Let me lead off by saying that your local veterinarian is still your best resource for developing a parasite control program because he or she knows your horse, knows your barn, and knows your climate. But hopefully I can at least get you started down a better path.

I say “better” because you may not be protecting your mare as much as you think you are by sticking with a rotational deworming program that is approaching 50 years old! There are three reasons for this. First, I’m sure you’re aware that some parasites have developed resistance to several chemical classes of dewormers (meaning these products no longer work anymore so you’re throwing money down the drain while at the same time under the false impression that your mare has been effectively treated).

Second, by giving a dewormer every eight weeks you’re not taking into account the different egg reappearance periods (ERP) between the chemical classes, which can be four weeks, six weeks, eight weeks, or even 12 weeks. Therefore depending on the dewormer used, you may not be giving another dose of dewormer soon enough or you may be giving it too soon. Third, the life cycle of most parasites is seasonal and coincides with the grazing season in your area. Since egg-laying slows down when the environment is not right for hatching and maturing to the infective larval stage, there’s little reason to deworm at these times (typically the winter in the cold North and the summer in the hot South).

Moving on to fecal egg counts or FECs. According to the Parasite Control Guidelines published by the American Association of Equine Practitioners (AAEP), there are four reasons to perform these:

1. To evaluate the effectiveness of a dewormer by measuring eggs before and after its administration
2. To monitor the egg reappearance period of the most recently administered dewormer
3. To determine the shedding status of the horse at the time of sampling
4. To determine whether parasite burdens in foals and weanlings are primarily roundworms or strongyles

Notice that identifying the parasite burden of a horse is NOT a reason. That’s because fecal egg counts do not accurately reflect the amount of worms that a horse may be harboring. So “fecals” should NOT be used to say “well, this horse had 0 eggs per gram or 25 eggs per gram or even 50 eggs per gram which is minimal so he doesn’t need dewormed.” What fecals SHOULD be used for is to say “well, this horse had less than 200 eggs per gram which classifies him as a low shedder and if the farm is managed properly he only needs dewormed once or twice a year because he’s not contaminating his area on the farm.”

Keep in mind that to be classified as a low, medium, or high shedder takes multiple fecals, not just one, which is a good reason for repeating this simple, inexpensive test (and they make great holiday gifts, I might add).

Now for advice on putting all this technical information into practice where you board! Absolutely have several fecal egg count tests performed on your horse so that you know what classification–low, medium, or high shedder—she is. Next, work on getting buy-in on this better strategy to individually deworm horses from the barn owner, barn manager, trainer, other boarders, and anyone else whose opinion matters. Wouldn’t it be great to be able to identify a small herd of low shedders, turn them out together, and remove manure from their stalls, paddocks, and pastures on a regular basis so they could only be dewormed once or twice a year!

If that’s not possible (or not possible YET), then concentrate on one method at a time to prevent reinfection in your mare, whether it’s turnout with low shedders, manure removal, or only administering effective dewormers at appropriate intervals. Before you know it, everyone will be following your lead because ultimately, everyone wants the best for their horse!

Liked this article? Here’s more on parasite control.
Testing for Tapeworms
Parasite Control for Boarded Horses

The post Ask the Vet: Parasite Control at Boarding Stables appeared first on Horse Illustrated Magazine.

Tapeworms were once considered a fairly benign parasite, unassociated with serious problems in equines. But recent studies show tapeworms are anything but harmless. Consider the statistics:

• 81 percent of ileal impactions (a blockage at the end of the small intestine, commonly referred to as an impaction colic) are associated with tapeworms.
• 22 percent of spasmodic (gas) colics are tapeworm-related.
• Ileocecal intussusception (a serious, surgical form of colic where one part of the intestine telescopes into another) is almost always caused by tapeworm infection.
• On average, more than 54 percent of horses in the United States have been exposed to tapeworms, including 96 percent of horses in the upper Midwest, more than 80 percent of horses in some Southern regions, and 56 percent of horses in the northern Plains and Mountain regions. Even in the lowest-risk areas of the West Coast, at least one out of every 10 horses has tapeworm exposure.

Why didn’t we know about this before?

Tapeworms Uncovered

“Tapeworms are intestinal parasites that infect horses, as well as other species, throughout the world,” explains Brady J. Bergin, DVM, assistant professor, Oregon State University. “They belong to the class of parasites known as cestodes. The three types of tapeworms that can infect horses are Anoplocephala perfoliata, Anoplocephala magna and Paranoplocephala mamillana, with A. perfoliata being by far the most common.”

Unlike other worms, horse tapeworms need an intermediate host to complete their life cycles. That host, the forage mite, becomes infective by ingesting tapeworm eggs; the horse swallows the infective mites while grazing, and the tapeworms mature in the horse’s intestine within six to 10 weeks.

Although much is unknown about the mite’s biology, they’re widespread, living in pastures, lawns and vegetation, says Craig R. Reinemeyer, DVM, Ph.D., immediate past president of the American Association of Veterinary Parasitologists, and president of East Tennessee Clinical Research Inc., the research group that identified tapeworm prevalence in the United States. The mite also seems to favor temperate climates.

“They live in the humus, the organic layer of the soil,” says Robert H. Dressler, DVM, manager of Equine Veterinary Operations at Pfizer Animal Health. “In the arid desert areas of the Southwest, there isn’t a whole lot of humus, and that’s where there is a much lower incidence of tapeworms.”

Bottom line: Any horse that grazes on pasture is at risk for ingesting infected mites.

Although studies now demonstrate that tapeworms are everywhere in the United States (albeit in varying numbers), experts had been unaware of their prevalence because of the inability to accurately diagnose tapeworm infection in the horse.

“Traditionally, we looked for tapeworm eggs in fecal exams, but that’s been very ineffective,” Dr. Reinemeyer says. “With most other parasites in horses the females stay in the gut and pass out eggs, and the eggs leave the horse in the manure. With tapeworms, the eggs develop in a lower segment of the worm’s body, which separates and passes out in the fecal matter into the environment, but it’s not an ongoing process. The tapeworm body is like a freight train with a bunch of boxcars, one chained to the other. The end of the tapeworm matures faster than the rest of it, so every once in a while the caboose (which is like a bag of eggs) drops off. That bag may not rupture until it gets outside the horse or gets farther down the track, we don’t know.”

Consequently, detecting tapeworm eggs in the manure is a hit-or-mostly-miss procedure. And because veterinarians weren’t seeing tapeworm eggs in fecal exams, they assumed there was no tapeworm problem.

Further, although tapeworms were detected during surgery or postmortem, they weren’t associated with any disease process.

That all changed in the mid-1990s when a British researcher developed a test that could detect an immune response to a specific protein exuded by tapeworms into the horse’s blood. Although this test only determines exposure to tapeworms as opposed to an active infection (much like horses that have been exposed to equine protozoal myeloencephalitis, or EPM, don’t necessarily have the active disease), it was a step in the right direction and enabled researchers to discover just how widespread tapeworms are.

Since then, researchers learned that tapeworms cause degrees of intestinal damage and disease. Dr. Bergin says, “This damage occurs when large numbers of tapeworms firmly attach to certain areas of the digestive tract, such as the small intestine or, more specifically, the ileocecal junction (the common opening of the ileum, colon and cecum). Their attachment can lead to inflammation, irritation and ulceration at this site, impairing normal function. This intestinal malfunction can also adversely affect the digestive tract, leading to three common types of colic associated with tapeworm infestation: ileocecal intussusception, ileocecal impaction and spasmodic colic.”

Those are the recognized problems caused by tapeworms. Undetermined are the problems a “typical” or low-grade tapeworm infection causes. “Does it cause low-grade diarrhea, low-grade colic, weight loss?” Dr. Reinemeyer ponders. “We don’t know. But anecdotal evidence suggests tapeworms may cause low-grade colic after intense exercise.”

Dealing With It

Even though prevention of tapeworms isn’t truly possible, you can successfully treat these parasites in a horse and prevent the onset of colic and other complications that may be related to tapeworm infection, notes Tom Kennedy, Ph.D., vice president of research and development, Farnam Companies Inc.

In the past, equine tapeworms were controlled with double or triple doses of pyrantel pamoate. “That did a fairly good job but was not 100 percent effective,” says Kevin Hankins, DVM, field veterinary consultant for Fort Dodge Animal Health. “It was costly plus it was sometimes a nightmare to get two or three tubes of dewormer into a horse.”

But the recent development of praziquantel in paste and gel formulations for horses offers an affordable, easier, and, to date, more effective alternative. “Praziquantel has been around for a long time, and has been used extensively in dogs and cats,” Dr. Hankins states. “It kills the tapeworms in the horse by destroying the worm’s protective, tough outer layer, thus making the parasite vulnerable to the horse’s immune system, which takes care of it from there.”

Explains Frank Hurtig, DVM, manager, Veterinary Professional Services at Merial Inc., “The addition of praziquantel to horse parasite control medicines containing macrocyclic lactone drugs (i.e. moxidectin and ivermectin) has been an advance in treatment and control of tapeworms in horses. Praziquantel has a wide margin of safety in horses.” Thus with one dose, praziquantel/macrocyclic lactone formulations offer treatment of tapeworms as well as broad-spectrum activity against strongyles, ascarids, pinworms, bots and other common horse parasites.

Currently, there are four praziquantel/macrocyclic lactone products available: ComboCare (Farnam), Equimax (Pfizer), Quest Plus (Fort Dodge) and Zimectrin Gold (Merial).

The only precaution is treating a horse infected with a lot of parasites or one that is clinically ill, Dr. Hankins says. “If they have a very high parasite load, you could end up causing an impaction from all of the parasites killed off in the gut. Also, when parasites die off, they can produce a toxin, and that can make your horse sick. If your horse is already ill or heavily parasitized, his immune system is likely suppressed and would react differently to a normal deworming schedule; that is why dewormers are labeled as only for use in healthy animals.”

Some veterinarians treat at-risk horses by either administering a reduced dose and/or administering mineral oil 24 hours prior to deworming to help with the passage of the dead parasites.

Currently, praziquantel is labeled only for treatment, not prevention. But Dr. Hurtig notes, “Since tapeworms are extremely difficult to definitively diagnose in the live horse, it is best to simply treat for tapeworms on a frequent basis.” This will benefit horses, since using praziquantel products routinely at labeled dosage recommendations removes tapeworms before they become a problem instead of after a problem (i.e. colic) is apparent.

Work with your veterinarian to develop a program that’s specific for your horse and climate. Dr. Bergin says that there is not a single catch-all recipe for controlling parasites that works for every horse in every area—it’s based on a number of factors that need to be evaluated, and from there your veterinarian can create a plan.

Although praziquantel is safe, don’t overuse it as parasites likely will build resistance to it. Dr. Reinemeyer explains, “Frequent use of dewormers puts tremendous pressure on the parasites to adapt to survive this continuous onslaught, so they select for resistance. We’re seeing that now with ascarids and ivermectin.”

Include management techniques in your deworming program. “Good pasture hygiene is a critical management technique for the control of tapeworms as well as other parasites,” Dr. Bergin says.

To reduce the spread of parasites, remove manure from stalls daily, dispose of fecal material away from pastures and feed/water supplies, and chain drag or harrow pastures to break up manure piles. Don’t feed your horses directly on the ground; this increases the risk of ingesting forage mites since it is where they typically reside. Avoid overcrowding or overgrazing pastures (rotate if possible). Finally, quarantine all new additions to the herd and perform fecal exams to determine parasite status in general and to avoid the introduction of parasites.

Expert Opinions on Tapeworm Treatment

Down the Line

While differentiating between tapeworm exposure and an active infection is still a guessing game, researchers hope to soon change that. Stephen Kania, Ph.D., associate professor, University of Tennessee College of Veterinary Medicine, has developed a test, with the support of the American Quarter Horse Association, that detects proteins released by the tapeworm parasite into fecal material. “This test differs from antibody detection in that a positive result is likely to indicate an active parasite infection,” Dr. Kania says. “We are currently at the stage of validating the test with samples from a large number of horses.” If all goes well, it’s possible this diagnostic test will be available in two or three years and could be a great aid in advancing knowledge on tapeworm infection.

Fortunately, you have the tools now to avoid tapeworm problems in your horse. Discuss the risks of infection in your area with your veterinarian and work out a responsible deworming program appropriate for your horse.

Marcia King is an award-winning freelance writer.

This article originally appeared in the May 2005 issue of Horse Illustrated. Click here to subscribe.

The post The Tapeworm Threat appeared first on Horse Illustrated Magazine.