Question Dewormer Safety

I have enjoyed and spoken highly of your publication since subscribing last year. However, the article ”Care For Your Older Horse Without Breaking The Bank” (December 2008) raised some concerns for me, especially the section on deworming. In that section, Zimecterin Gold is endorsed as an anthelminitic. My horses had what I believe was an adverse reaction to this drug, which I reported to Merial and the state veterinarian.

My veterinarian administered the drug, and later my horses had swelling in the mouth area. Both animals recovered without incident, but I’ve since read on the Internet about other horse owners who have reported problems. It appears to be due to the way the drug is administered.

If my veterinarian didn’t administer the product correctly, how can laymen be expected to administer it correctly (giving paste wormers can be very messy if the animal isn’t cooperative and even if they do cooperate), and why is it available over the counter’

Horse Journal Response

In the premarket field trials with this ivermectin-praziquantel combo product, no adverse reactions were noted even in foals or adults given 10 times the regular dose. However, the FDA Suspected Adverse Events reports do have reports of oral reactions for both ivermectin and moxidectin in combination with praziquantel.

The product instructions call for administering it over the back of the tongue and for holding the head up for a few seconds after dosing. It’s approved for over-the-counter because it passed the FDA safety studies with flying colors, although that would have included administering it properly.

Why some horses have problems and others do not is unclear. The MSDS, or ”Materials Safety Data Sheet,” is required by law for any chemical substance that people work with, even things as simple as dextrose and salt. The MSDS for praziquantel lists it as having little or no mucus membrane irritation, even in the eyes.

Praziquantel has been in use in other countries much longer than here. The information sheet from Portugal for Equimax, another combination product, does list oral reactions, but states they are rare, and they are considered an allergic/hypersensitivity reaction. If the reaction was truly a chemical burn, we would be seeing it in a lot more horses and the drug would also cause problems in the back of the throat and the esophagus.

Those tissues are just as sensitive as the gums and tongue. One contributing factor might be the presence of small cuts or ulcers in the mouth. These are fairly common, from bit irritation, sharp teeth, awns, tough grasses or hays. The product might be more irritating on an open area and/or this could contribute to developing a hypersensitivity.

Arena Footing

I have a small outdoor horse arena I use for training and easy riding on days when my pastures and trails are too wet to use. This past fall I made some improvements to the arena. Unfortunately a miscommunication led to limestone chips being delivered and spread.

I have had both a vet and natural trim farrier state that the chips should be OK, but I have not found anywhere that chips are considered appropriate for arenas, except for some mention of them on a European website. Again, these are limestone chips, not screenings. Should I have them removed or can I place washed sand over the chips’

Horse Journal Response

We asked Nick Attwood, president and founder of Attwood Equestrian Surfaces, in Garden Grove, Calif., to help us with this question:

Much of your decision depends on the size of the chips and how much stability they’re offering. I wouldn’t worry too much if the chips are one-quarter inch in size or less. Using limestone screenings is not unusual, but if the chips are an inch or more deep, and larger-sized, then I’d question their ability to offer stability and do the job properly.

The washed sand you’re putting over them could sift down, while the chips will begin to work their way up to the surface. If there’s a lot (one inch or more deep), and the chips are one-quarter inch or more in diameter, then I’d recommend you get rid of them and start over.

Exercise Intolerance

My horse, Jack, looks pitiful after we have worked, especially in the warmer weather. He doesn’t seem to tire while we are working, but the moment I get off his back he looks like he has just finished a three-day event without the benefit of the three days. This inability to generate energy is apparently a normal part of the aging process. I did some more research and ordered Alpha Lipoic Acid and Acetyl L Carnitine for Jack and myself. The company NutraBio has been helpful in recommending the amount of dosage for horses in using L-Carnitine, but they were unable to help where ALA and ALC were concerned. Can you suggest the proper dosage’

By the way, Jack usually drinks an eight-quart bucket of Gatorade when we are done schooling, sometimes more, and returns to his notable opinionated self by the time he has had a bath and goes back to his stall.

Horse Journal Response

The dosage of ALA, extrapolating from human, is 400 to 600 mg/day. Acetyl-L-carnitine is 1 gram per 100 pounds of bodyweight, once or twice a day. There’s nothing wrong with letting Jack drink Gatorade, but it’s not formulated to match equine sweat. If Jack does not freely consume generous amounts of salt, and/or get it added to his meals, his fatigue after works may be related to starting from a point of mild dehydration. You want to aim for an intake of at least two ounces of salt/day in warm weather, plus one dose of an electrolyte solution per hour of work.

Joint Supplement Help

I’m looking for the article you wrote that included a review on ProMotion EQ. I have a nine-month-old filly that has trouble with her stifle locking. The vet feels it is a growth issue without serious complications but suggests a joint supplement to help.

Horse Journal Response

ProMotion EQ was included in our two-part series on joint supplements in October and November 2007 (see for back issues). We plan an update to that article this coming fall.

Locking stifles in young horses can indeed be a temporary problem, especially in youngsters that are not getting enough exercise and are under-muscled. More serious causes are a conformation defect in the stifle that does not keep the patella tracking properly, or even pain the joint from OCD that is causing the horse to not use himself well. If conformation and joint disease have been ruled out as the cause, temporary use of a joint nutraceutical may be reasonable to help guard against inflammation/irritation, but we don’t think it’s likely to actually help the problem per se.

Trailering Problem

I own an 18-year-old Missouri Foxtrotter gelding who is kicking my trailer apart. I have owned this horse for 10 years, and until last year he has been an excellent trailer horse. At that time, he kicked out a wall in the trailer, ripped out the wall mats twice, cracked welds on the stall and manger divider and dented the ceiling. Amazingly, he didn’t injure himself, just my wallet.

This is the same truck, driver (me), and trailer I’ve had since buying him. Even though he is 16 hands and 1200 pounds, there’s ample room in my 1999 Sundowner Valuelite trailer.

I’ve not had an accident or any mishaps while trailering him. He hasn’t hurt himself in or around the trailer or truck. I haven’t modified the trailer. He’s in good health, will urinate in the trailer and has excellent ground manners.

Alone he’s a terrific ride but with other horses he is more than a handful but doesn’t kick. I have not changed tack, saddle, or diet. His stabling has not changed (my home with a donkey), and he spends his days in a small turnout. I’ve always used him for trail riding. He is ridden three to four times a week a minimum of four miles. He is a very confident, forward, smart horse.

This behavior occurs when he is trailered alone and borders on violent when in company. I have had the trailer floor checked twice. I’ve tried kicking chains. My veterinarian has suggested using acepromazine, which I have given with varying degrees of success and must use stronger medication for long trips. I realize this isn’t the ultimate answer. Do you have any suggestions’

Horse Journal Response

Problems like this aren’t easy to solve. You stated that you haven’t changed any equipment, so we assume you’ve tried bandages on and bandages off, and so on. We’re also going to assume you haven’t changed the way he’s tied (he should be tied at a safe but comfortable length, so he can move his head if he needs to) or the halter he’s wearing and so on.

In addition, since it’s the same trailer he has ridden in for a decade, we’ll skip the discussion of slant-load vs. straight-load trailers.

We’d start by asking a friend to help you. One of you should ride in the trailer (without the horse in there) while the other drives. Whoever is in the back of the trailer should listen for odd sounds, whistling, banging???anything out of the ordinary, even an annoying light that might come in through the window. Even a new set of tires might cause the trailer to feel or sound different as it travels down the road and bother your horse.

If this doesn’t show anything, take the trailer to the dealer for a thorough inspection. Don’t be afraid to call Sundowner either, to talk with them about whether they’ve had any difficulties with this particular trailer. Since it’s 10 years old, they may have made improvements in the design that may give you clues.

If the trailer checks out fine, the next step is to remove any center divider in the trailer and take him for a ride. Your now older horse may need more room to balance himself. Although a partial divider usually won’t interfere with his ability to move his feet outward for balance, since a second horse in the trailer causes his behavior to worsen, we’d be sure to check this, too. (Note: You stated that the horse is normally at home alone with a donkey for a friend. Does he act up if the donkey is in the trailer with him’ If not, you’re probably dealing with separation anxiety.)

We also are concerned about the ”mangers” you state the trailer has. Horses need to be able to lower their heads during a trailer ride in order to properly clear their air passages, and old-fashioned mangers don’t allow that. A horse rides better in a trailer with an open front(just a breast bar in front) and hay in a net that is well secured to the wall.

We’d also suggest that you try to find a friend willing to allow your horse to take a ride in their trailer to see if he acts any differently, which may give you additional clues as to whether it’s the horse or him reacting to something in your trailer.

We definitely wouldn’t resort to kicking chains again, and we’d only recommend using acepromazine if you have absolutely no other alternative.

If all this fails, it may indeed be a new training problem, which means you need to go back to Square One, starting with loading the horse and letting him stay in there for a bit, then unloading him without going anywhere, progressing to very short trips (try to return home before you think he’ll start acting up) and lots of reward/encouragement for good behavior.

Corn Oil Use

Would you please comment on the use of corn oil as a feed supplement’ I know you have recommended it in the past, but with the escalating cost of corn oil is there any other oil that could be used as a supplement with similar efficacy’

Horse Journal Response

An alternative to corn oil depends on why you are using it in the first place. If you are after coat sheen, we would prefer ground stabilized flax or freshly ground flax, about 4 oz./day for the average-size horse. This has the advantage of providing the horse essential omega fatty acids in similar proportions to what he would be eating with fresh grass. You’ll probably agree nothing tops the shine of a horse on good pasture.

If you’re after non-grain calories, consider more hay or an easily fermented, high soluble fiber addition such as beet pulp. Oils have no nutritional value beyond calories, unless you use a nonrefined oil such as Uckele’s CocoSoya (, 800-248-0330). A high-fiber meal is also more satisfying to your horse and the heat of fermentation helps keep him warm.

If you only need it to help supplements stick to grain, try a canned cooking spray instead, such as PAM. You’ll use a lot less and save money. Otherwise, the best way to save on oil is to buy in 2.5 gallon jugs at places like Walmart or Sam’s Club.


I’ve been a subscriber for many years and highly regard and rely on the information you provide. I live in central Vermont with my two equines, and I have some questions about pelletized bedding (November 2008). First, are pellets advantageous compared to shavings if your stalls are used as run-ins and have no floor mats’ It seems counter-intuitive to spread urinated pellets around the stall when I always thought lingering urine was bad for horse feet, lungs and skin.

Second, since your November article on pelletized bedding, I’ve started experimenting with using pellets in one of our horse’s run-in stalls. Does it make sense to invest in mats to put over the dirt floor’ My use of shavings has been mostly in the winter to provide clean, dry bedding for the horse to lie down on.

Horse Journal Response

You don’t have to use stall mats in a run-in shed to achieve good results with pelletized bedding. In fact, if your run-in shed is sited in a low or wet area, you might find it advantageous to use pelletized bedding because it will soak up the water so well. The way they fluff up would actually make a nice bed for your horse.

But if your run-in shed is dry and the ground likely freezes in Vermont in the winter, you’ll probably find mats with the pelletized bedding to be more comfortable, and you’ll use far less bedding, too.

As we suggested in our November 2008 article, making the best use of pelletized bedding does, to an extent, require you to suspend some of the stall-cleaning dictums many of us grew up with . The pelletized bedding absorbs all moisture???whether water or urine???at an amazing rate, and, once you pick out the manure, you must ”flip” all the bedding to expose dry bedding to the wet spots. It’s only necessary to remove saturated areas. Then you mix the remaining bedding around with your pitchfork. Flipping and mixing are keys to cleaning these stalls.

Walking For Exercise

I have a 15-year-old Quarter Horse mare, and her insulin level is 100 points too high. I began treating her as an insulin-resistant horse immediately. I am feeding her properly and hand walking her twice a day (30 minutes in the morning and 20 minutes in the afternoon). I can’t ride her, and I have limited control over what happens, as she’s boarded. I’m concerned that I’m not providing the minimum level of exercise required for an insulin-resistant horse.

Horse Journal Response

While not impossible, it would be unusual for a Quarter Horse to be insulin-resistant if there is no Cushing’s disease. If she had eaten any grain within 1 to 3 hours of having the test, you might want to consider repeating it, only giving her hay before the test. If she is insulin-resistant, the best gauge of whether or not your efforts are adequate is how she is doing. If her weight is good, no foot soreness, no abnormal fat deposits, you’re doing well. Brisk walking for a total of 50 minutes a day is good exercise.

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