I’ve noticed when the weather turns warm every spring my horse tends to lose hair in a circular pattern on his face and neck. This slight balding is accompanied by severe itchiness on his stomach and chest area. I spoke with my vet and he is attributing this to a reaction from the Onchocerca parasite. Can you recommend any preventive measures I can perform so my horse doesn’t suffer every spring? Thanks, LC, Massachusetts

Dear LC,

Good for your vet for recognizing this! I had to look in my veterinary parasitology textbooks for information on Onchocerca and even then there was less than one page on this particular parasite. But I do think I may have found some information that will help you, so let me share what I learned.

Turns out this is a nematode, or roundworm, and in its adult state it prefers connective tissue, specifically the nuchal ligament in the neck. But it’s the immature stage, called microfilariae, that’s causing your horse problems. These microfilariae don’t circulate in the blood like other parasite species (heartworms, for example), they migrate through the skin of the face, neck, chest, withers, forelegs and abdomen. That’s why you see hair loss, itchiness and probably scales, crusts and ulcers. Technically it’s called “onchocerca-associated dermatitis.” While Onchocerca has been blamed for such things as fistulous withers, poll evil, and even equine recurrent uveitis (“moon blindness”), the association has never been proven.

Many vets (like yours!) diagnose it based on response to treatment. That is, ivermectin or moxidectin is given, a mild inflammatory response may be seen, then the problem goes away. However, it can be diagnosed by a reasonably quick and simple procedure called a skin biopsy. Then you know for sure that you’re dealing with Onchocerca.

Since you’re interested in preventing this parasite from ever setting up house, though, and because it’s spread by Culicoides gnats, also called biting midges or “no-see-ums,” you might not see Onchocerca next spring if you take steps early to keep these insects away from your horse.

• Keep your horse in his stall when these gnats are most active, dawn and dusk
• Use screens, fans or misters to protect your horse when he’s inside the barn
• Cover him with fly sheets that wrap around the belly, fly masks and fly leggings
• Regularly apply fly repellent that contains permethrin

Culicoides ideal breeding ground is standing or slow moving water so do what you can to eliminate these sources where you keep your horse.

Finally, you may want to try supplements designed to improve the overall health of the skin, such as omega 3 fatty acids, and supplements that have natural anti-inflammatory properties, such as MSM. I hope some of these suggestions help you and horse eliminate these pesky parasite.

I have a horse with mild stringhalt symptoms. do you know if any supplements that could help him. I feed good timothy/alfalfa hay, a 10% pellet grain and give biotin and a vitamin/mineral supplement from Buckeye that has Vit E and selenium. the horse has had this problem before but a few days off usually gets it to go away. he is a 19 year old quarter horse. I think it usually has occurred in the cold weather. RC, Florida

Dear RC,

Just so everyone is clear, stringhalt is a neuromuscular condition of the hindquarters where the horse rapidly flexes or “snaps” a hind leg towards the belly. While some cases may be due to the ingestion of a certain pasture weed, most of the time a cause is never found. Because it can be difficult to distinguish stringhalt from other disorders of the hindquarters like shivers and PSSM, I recommend a veterinarian examine your horse so you know for sure what you’re dealing with.

If stringhalt is the diagnosis, unfortunately there is no treatment or cure for the condition. Some owners report improvement with the prescription medication Phenytoin—an anticonvulsant used for epilepsy—or the supplement ingredient Thiamine, or B1. Important in the transmission of impulses along nerves, Thiamine has a number of functions within nerve tissue and this may be why it helps some horses with stringhalt.

I like that you’re feeding a multi-vitamin/mineral supplement and that it contains Vitamin E and its antioxidant partner Se. Vitamin E seems to help many conditions that involve either the muscular system or the nervous system or both. Since experts aren’t really sure what the primary problem with stringhalt is, you’re covered either way!

I have a 13 yr. old thoroughbred with a chronic thrush problem in one front foot. I have tried the bleach/water mixture. A friend with horses says she puts Icthammol ointment on the hoof and covers it to draw out the thrush and dry it out. Is this a good remedy? LB, Nebraska

Dear LB,

The important thing to understand about thrush--an infection of the frog that results in black smelly discharge--is that until the underlying cause is diagnosed and corrected, the infection will keep coming back no matter how it is treated. That’s because thrush isn’t so much a problem of a dirty environment attacking a horse’s hoof as it is a problem of a horse’s hoof not being healthy enough to resist infection.

As long as a horse is sound, trimmed properly, and provided exercise and turnout, the natural cleaning mechanism of his hooves should keep thrush and other conditions at bay. But chronic lameness, improper hoof care, and too much stall time restrict the hoof’s ability to self-clean. The conformation of some horses’ hooves can set them up for thrush too. Deep, narrow grooves (sulci) on either side of the frog are built-in traps for dirt and moisture and do not have much exposure to air—conditions thrush-causing microorganisms thrive in.

I encourage you to work closely with your farrier and veterinarian to diagnose why your horse’s one front hoof is so prone to thrush then come up with a plan to correct it. It may take the better part of a year to grow a healthier shaped hoof, but the results will be worth it: no more thrush and no more daily medicating!

In the meantime, any number of antiseptic or astringent products should keep the thrush at bay while you’re treating the underlying issue. There are many commercial products available such as Thrush-XX, Thrush Buster or Thrush Remedy. Your healthcare team may recommend a homemade recipe that contains ingredients such as iodine, vinegar or hydrogen peroxide. While some farriers and veterinarians use poultice or hoof packing as drawing agents, I have not heard of using ichthammol on the hoof for thrush. However, I don’t think it would hurt anything. Just please don’t use any caustic substances like bleach or formalin because these may do more harm than good near sensitive structures of the hoof.

Can you give Strongid C to a mare that is being bred or that is pregnant? My horse is having her first baby and we are wanting to get her back on this product but have concerns. QP, Illinois

Dear QP,

Original strength Strongid® C™ and double-strength Strongid® C 2X™ are equine dewormers designed to be fed on a daily basis to provide a continuous, preventive level of pyrantel in the intestinal tract. According to the manufacturer, Pfizer Animal Health, Strongid C and C 2X are safe for foals at any age. It is recommended that you start them on the product after they are eating grain consistently – usually at about 2 to 3 months of age. This ensures they get the proper dose of the dewormer. Strongid C and C 2X are safe for all breeding animals, including pregnant and lactating mares as well as stallions.

I can understand why you want to get your mare back on one of these products, as they not only control adult large strongyles, small strongyles, pinworms and ascarids (roundworms), but also prevent migration of parasite larvae. Horse owners have noticed a number of benefits from using daily dewormers like Strongid C and C2X. These include fewer cases of parasite-induced colic, decreased incidence of pneumonia caused by ascarid larval migration, and improved overall condition. When parasites are prevented, many horse owners see an improvement in feed efficiency and optimized athletic ability.

Couple pieces of advice:

Unprotected animals that have grazed may already have an established strongyle larval infestation. Before starting your mare on Strongid C or C 2X, treat her with a therapeutic dose of a larvicidal product such as ivermectin or moxidectin.

Once your mare is on the daily dewormer, give her a product that is effective against tapeworms once or twice a year as well as ivermectin or moxidectin once or twice a year to control bots.

Finally, be sure and include your veterinarian in your parasite management program. Ask him or her about Pfizer’s PreventiCare ™--a unique wellness program administered by your veterinarian that includes a Colic Assistance Plan.

I have a 6 YO small pony (40" & about 450 lbs.) and I think she needs to lose weight. She eats Timothy hay and 1/3 Cup of Omolene 100 2X's a day. I am not certain that this small amount of grain is supplying the nutrition she needs. There is little to no grass in her paddock so I give her 4-5 lbs. of Timothy a day. I am interested in the SmartVite EZ keeper-grass formula. Please advise on dosage if appropriate for her. Thank You, AR, Florida

Dear AR,

Without knowing the breed of your pony or her body condition score, I’ll just have to take your word for it that she needs to lose weight. First, let’s analyze her diet starting with the forage. She doesn’t get any pasture grass and that’s probably a good thing. Ponies are especially prone to laminitis from the sugars in grass. Four to five pounds of grass hay per day though is only 1% of her body weight, if you’ve estimated or measured her correctly at 450 pounds. Experts recommend that horses receive a minimum of 1.5% of their body weight per day in forage so I’m concerned she’s not getting enough long-stem forage for GI health. If you think your estimates of the weight of your pony and the weight of your hay are accurate, try soaking her hay for 30 – 60 minutes before feeding to remove simple sugars and starches from it that she doesn’t need. That way, you might be able to feed her closer to the recommended six or seven pounds of hay per day.

Next, let’s look at her grain. Unless you’re using the sweet feed to mix supplements in, I see no reason to give her any grain at all. Instead, meet her protein, vitamin and mineral needs with either a ration balancer or a multi-vitamin/mineral supplement. I’m sure 1/3 a cup of grain twice a day is less than the bag recommends, meaning right now she’s deficient in these nutrients. So take away these extra calories and add back in protein, vitamins and minerals to bridge any gaps between the grass hay and her daily nutrient requirements. Because of her size, I recommend a half-dose of any regular horse supplements such as the SmartVite EZ Keeper Grass.

And don’t forget about exercise, which has been shown to be a valuable component of a weight loss program whether you’re a horse, human, dog or other species. Turn out is nice, but most overweight animals are going to need to be encouraged to move around. Daily round pen work, lunging, riding, driving, ponying and even handwalking are all excellent ways to burn calories and increase metabolism.

Finally, keep your veterinarian in-the-loop regarding your plan to slim down your pony. He or she can help you weigh and body condition score her now so you can keep a journal of her progress. Your veterinarian can also review your nutritional and exercise programs to make sure they are appropriate, as well as assess your pony for medical conditions such as Equine Metabolic Syndrome that may make weight loss more challenging. If this is the case, there are prescription medications such as Thyro-L that can “jumpstart” her metabolism as well as supplements designed to support health metabolic function.