Ask Horse Journal: 02/00

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NSAIDs And Impaction
In reference to your article on impaction colic (November 1999), I want to mention an article that appeared in EQUUS’s November 1999 issue that stated NSAIDs inhibit gut motility, which counters to the common practice of giving Banamine to control colic pain. It’s interesting, I think.

-Elise Lufkin
Ketchum, ID

We saw the EQUUS report on Dr. Linda Van Hoogmoed’s research, too. Freeman et al in 1997 had reported similar findings. However, we disagree with the broad conclusion that NSAIDs can directly influence the risk of impaction colic or are unsafe in the treatment of colic.

Van Hoogmoed’s research involved taking tissue samples and adding a NSAID to them. They then checked muscle activity, which they say slowed or stopped. The EQUUS article states, “Exactly how NSAIDs affect gut motility is not clear, she {Van Hoogmoed} says, but researchers have a theory: 'Muscle activity in the intestine is controlled by prostaglandins, and we think that NSAIDs might act to inhibit the enzymes that make prostaglandins.’”

Prostaglandins can influence intestinal motility, but studies done on live horses show this effect is not very important. Roger and Ruckenbusch (1987) injected various substances into horses, including the prostaglandin PGF2 alpha, and found that the prostaglandin had an irritative affect on the colon and produced some increased activity, but it was disorganized. Flunixine (Banamine) did not block this effect, but drugs that abolished the influence of the parasympathetic nervous system (which has nothing to do with prostaglandins or NSAIDs) prevented it entirely. In 1998, Lister et al reported on motility of the small and large intestine in ponies and found that Banamine, the most commonly prescribed NSAID for colic pain, had no affect at all on motility. Similar findings have also been reported by Adams et al (1984), Stick et al (1988), Lowe et al (1980) and Koch and Muir (1988).

Some commonly used colic drugs (e.g. narcotic analgesics and xylazine/Rompun) do have the potential to worsen impaction colic, or contribute to causing one, but NSAIDs are not among them. In fact, there are studies that show Banamine and bute are beneficial for colic cases and can actually improve motility.

Both bute and flunixine can block or reverse the decreased motility caused by harmful endotoxins — chemicals with potent effects on the horse’s body that can be produced by overgrowth of harmful intestinal bacteria when gut conditions are disrupted by things like grain overload or any alteration in normal conditions in the intestine — according to Valk et al (1988) and King and Gerring (1989). The study by Valk also reported that phenylbutazone given to normal horses not injected with endotoxin had no affect on intestinal motility. Plus, Valk and King/Gerring showed bute and flunixine can block or reverse the decreased motility caused by endotoxins. In other words, both these drugs can help RESTORE normal motility in the intestinal tract by blocking the effects of endotoxin and have no effect on motility when given to normal horses.

The EQUUS article said vets over the years report an increased incidence of impaction colic in horses on chronic NSAIDs. This may be true, but, as we explained in our impaction article, horses that are in pain (whether it be from the condition being treated with the NSAIDs or from intestinal ulcers caused by the NSAIDs) do not move around as much as normal horses and are likely to have decreased feed and water intake. We believe these factors are likely to be at the root of any increased problem with impaction in NSAID-treated horses, not changes in intestinal motility.

The bottom line is that if you look at a live horse, under conditions of normal intestinal health or experimentally induced impaction, Banamine has no effect on the motility of the colon. The pain-relieving affects of Banamine in mild colic are not well understood but are believed to be related to its ability to block pain pathways mediated by prostaglandin, not by an effect on motility.

That said, we agree with the EQUUS article’s real bottom line: “Only a veterinarian can determine exactly what type of colic a horse is experiencing” and that it’s unwise to medicate a colicky horse without a vet’s diagnosis.

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Won’t Slow Down
I have a 15-year-old Arabian gelding who rushes at the trot and canter. His head is up, his back hollow, and it is impossible to get him to relax, stop rushing and get on the bit. If I circle him, his circles are rushed. I longe him for 15 to 20 minutes before I ride him. I recently switched from a snaffle to a kimberwick. This slows him down, but he raises his head even more and gets “light” on the front end. I am worried about creating more problems than I am solving. I ride about three times a week, except during the winter (no indoor arena).

-Janet Lewis
Internet

We’re sympathetic about time constraints, but the strength and stiffness problems that your horse has built over a lifetime can only be remedied though consistent conditioning, and this needs to be done at least five or six days a week.

If you can’t get to the barn every day, perhaps you can find a friend who can work with the horse along a conditioning plan that you determine. Try not to stop over the winter. Even if you can only walk in the snow or on a “chips track,” leg-yielding and “long-and-low” at the walk will go a long way toward giving your horse a head start in the spring.

Most horses that rush and hold their heads too high don’t have good balance or elasticity across their topline, all the way from the poll through the rider to the tail and hocks. You may need instruction in how to develop leg-yielding and long-and-low, since these exercises are building blocks for suppleness. At this point, avoid circles smaller than 20 meters, both on the longe line and under saddle. Your horse doesn’t sound strong enough to keep his balance on a smaller circle, so he gets frightened and starts to rush.

The “light” front end you feel with the kimberwick is also cause for worry, since the horse won’t stretch toward the bit and accept your leg aids. Riding a horse that’s behind the bit is like trying to drive a car in neutral — you have no control. Go back to the snaffle and find an instructor who can lead you through the steps of learning to stretch toward the bit instead of backing away from it.

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Iodine Supplementation
I put my horse on a Vita Royal product called Untie. My horse has been great on it. He has never tied up, but he is an upper-level dressage horse, and I work him pretty hard. A friend suggested this product because it gave her horse a better recovery response from hard work. It also made him come out of his stall “looser,” as if he had just been massaged. My horse is always “tight” — even his skin is tight. I tried it and liked it, but it is horrendously expensive. With also giving joint supplements, I need to keep my daily cost somewhat manageable, so I am trying to duplicate the ingredients in a cheaper version.

I went back through all the old issues Horse Journal and read everything on tying up, magnesium, and copper and zinc. I found two products that you recommended, Vita-Key and Gateway Su-Per-Calm, that will duplicate all the ingredients — except for iodine. I wondered what the function of this was. I know iodine stimulates thyroid and good thyroid function is necessary for performance horses, but I didn’t understand what supplements would do.

-Marian O’Brien
Palos Park, IL

As you said, the iodine is for thyroid stimulation. Perhaps even more importantly is that environmental toxins containing elements similar to iodine may take up the real hormone’s spot on receptor sites, leading to defic iency of the hormone where it is needed — on the cell’s receptor sites — but blood tests that are normal. Iodine is also in scarce supply in most diets. On the flip side, however, iodine toxicity occurs at a fairly low intake, and it is easy to overdo it. If you take another look at the Vita-Key Anti-Oxidant product you’ll see it does contain iodine.

If you need supplementation above that level, try calling Uckele Health and Nutrition (800/248-0330), Omaha Vaccine Company (800/367-4444) or Big D’s Tack and Supply (800/321-2142). The latter two often carry those hard-to-find items and Uckele’s also has, or may get, individual ingredients and package them in the amount you need.

A word of caution on do-it-yourself duplication of supplements, though. You must exactly match the chemical form of each ingredient — e.g. don’t use a mineral inorganic salt (e.g. chloride, sulfate) if the original contained an amino acid chelate. Be careful about adding ingredients that were not in the original formula. Some may be harmless or of more benefit but others may interfere with the overall action of the combination. You need to know the exact dosages of each ingredient. Even such things as the base used in a formulation can affect how the individual horse reacts to it, as can the grade of ingredients used. Also be sure you add up the prices of your individual ingredients. You might not save anything in the end.

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Hay Before Grain, Please
Grain diets are sometimes associated with higher than normal acidity in the large intestine, which can be irritating and interferes with proper digestion of forage. The problem may not be too much grain per se but rather either too little hay/pasture or poor timing of feeding.

A horse that grazes all day produces 95 to 114 liters of saliva a day. Saliva assists in neutralizing stomach acid. But a horse that bolts grain on an empty stomach doesn’t produce as much saliva as one that is methodically chewing hay. To counter this, feed hay at least a half hour before grain and be sure plenty is available after grain as well.

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Use Quest In Early Spring
The ideal time to best use moxidecin’s (Quest) unique activity against the encysted stages of small strongyles is just prior to peak spring grazing. Some evidence suggests that these, and other dormant parasite stages, may be “programmed” to emerge at this time of year. A late winter/early spring deworming will therefore prevent heavy pasture contamination under conditions when the larvae are most likely to thrive. Remember, too, however, that maintaining an adequate deworming schedule with ivermectin as the cornerstone will help prevent your horse from acquiring these large burdens in the first place (see December 1997).

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Time-Honored Witch Hazel
Witch hazel is a water-based extract made from the twigs of the spotted alder. We like witch hazel instead of water to dilute full-strength liniments and braces for a stimulating rub for sore muscles. Witch hazel on cotton balls is excellent for cleaning the ears, as it cuts through wax and dirt without irritation.

Combined with aloe, it makes an excellent dressing for scratches, insect bites, girth and saddles sores, minor wounds or allergic skin lesions. Witch hazel causes blood-vessel walls to contract, helps stop bleeding, and has a cooling and pain-relieving like effect alcohol but without the stinging, irritation or drying the skin. It is good to use on bruised or cut coronary bands and heels.

Witch hazel is also excellent either alone or in mixtures under standing wraps. It won’t scurf but effectively reduces swelling. Witch hazel gently reduces vaginal swelling after foaling. Diluted with warm water, it can even be used on swellings and irritations of the eyelids.