Ask Horse Journal: 01/05

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Fighting Lactic-Acid Buildup In The Gut
I am a racehorse trainer and would like to know more about lactic acid and what we can give a horse by way of feed to lower lactic acid in the gut. Can we help ease the onset of lactic acid in the muscles while training'

Lactic acid is a normal end product of the breakdown of glucose. However, excessive amounts of lactic acid can damage the gut wall and lead to colic and laminitis, but this will only occur in the “horse got into the feed room” scenario. Lesser amounts of lactic acid in the hind gut are most likely to cause soft manure.

The best way to prevent excessive simple carbohydrate getting to the hind gut is not to feed large grain meals. Divide the daily feeding up into multiple smaller meals rather than two large ones.

In the muscles, lactic acid isn’t related to fatigue and tying up as was once thought. Lactic-acid levels begin to rise quicker and at slower speeds in horses that aren’t fit. However, when a horse is working near race speed, there will be a large production of lactic acid. This is because the only energy pathway available to the muscle cell that can generate ATP for contraction quick enough to meet the demands of speed is the breakdown of glucose to lactic acid.

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Old Hay
Can you tell me how to evaluate hay for nutritional content after storage' One farm near us buys one month of hay at a time so they don’t have to store it. Another buys enough for the year, while the third fills the loft and then uses it for years. Who’s right' How do we know'

The major nutritional loss in stored hay is vitamin A. Vitamin A levels start to decline at six months and are essentially zero after 12 to 18 months.

Many hays also have low-level mold infestation that will slowly rob it of its carbohydrate and protein value over time. Overdrying that makes leaves crumble also reduces the nutritional value. Mineral levels are stable with storage, but the profiles may change if there is leaf loss.

The only way to know the nutritional value for sure is to have the hay analyzed. However, you should use the same subjective criteria to evaluate hay of any age — color, aroma, freedom from dust (which could also be mold), and sections of hay come apart easily rather than being tightly matted together, another indicator of mold content.

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Shavings Dust
I’m having trouble with the amount of dust in the shavings at my boarding stable. I even start to cough when I walk in there. The dust gets in my horse’s eyes, nose, water and hay. He also has a colic problem I’ve been trying to control. Should I be concerned about the health effects of this bedding'

Yes, you should be concerned, and with colder weather here and barns getting closed up tighter it’s only going to get worse. If there’s enough dust to make you cough, you can be sure it’s irritating the horses’ respiratory tracts as well. If the stable isn’t agreeable to changing to a different type of bedding, the effects can be minimized if you:

• Always keeping the barn well ventilated, especially when putting down the fresh bedding.

• Take horses out of the barn when putting down the fresh bedding.

• Settle dust with a light misting of water.

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Cushing’s Diagnosis
My horse tested positive for Cushing’s with an ACTH reading of 58.7. My vet says that’s “mild.” She said to put her on Pergolide and a low-sugar, high-fat diet. She recommends 10-12% fat and believes Nutrena and Purina make special feeds for Cushing’s. My horse is a picky eater and hasn’t been eating her hay. We’re thinking about getting alfalfa cubes. Any suggestions'

If your horse’s ACTH was tested between August and November/December, you may want to recheck it. Information presented this year at the American College of Veterinary Internal Medicine meeting showed that even normal horses can have seasonal ACTH elevations that look like Cushing’s. At other times of the year, they’ll test normal. However, if your horse is definitely a “senior” and has classical symptoms of Cushing’s, including the coat changes, this is actually more reliable than any blood test in the opinion/experience of most veterinarians.

You need to get your horse’s insulin level checked. ??If this is elevated, and it often is with Cushing’s, you need a lower sugar/starch diet than most of the commercially available feeds. There are many “lower” carb feeds coming on the market, but they may not be low enough for a horse with insulin resistance. Check with the manufacturer to make sure the one you’re considering is no higher than 10% sugar and starch combined. The safety of high fat for a horse with insulin resistance is also unknown. Naturally occurring levels of fat are under 5% in equine diets.

If your horse’s appetite got picky after the Pergolide was started, it may be a side effect of the drug. This should improve over time. If the pickiness was before Pergolide, consider gastric ulcers. Many Cushing’s horses show gastric-ulcer symptoms and respond to treatment for that.

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Water Consumption
Is it OK for a healthy horse to drink six buckets — 30 gallons — of water a day' I have a new boarder that drains two buckets when he comes in from just three hours in the paddock. His owner insists this indicates how healthy he is. I’ve cared for hundreds of horses over the years, and I’ve never seen this.

No, that level of water consumption is definitely higher than normal for any horse. Possible explanations are:

• Psychogenic polydipsia. This means the horse drinks a lot but there’s really no medical cause for it and it falls under the category of abnormal behavior. Some think it may be linked to boredom.

• Excessive salt intake. Keep an eye on how much salt this horse eats free-choice. High salt intakes make the horse drink more.

• Diabetes insipidus. This is a rare hormonal disorder where the horse can’t concentrate urine normally and drinks excessively to make up for urine losses.

• Kidney disease with high urine output and again excessive drinking to make up for it.

• Advanced insulin resistance/diabetes with elevated blood sugar that causes increased urination and high water losses.

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Navicular Help
I have a 23-year-old Saddlebred mare who has navicular disease. She’s on isoxuprene and soloxine and is pasture sound.

She doesn’t walk quietly (she jigs) and if I ride her, she’s usually sore the next day. Would any cushioning boots help her' Are there any new treatments I should know about for navicular'

You could try boots and talk to your farrier and veterinarian about any soft inserts you could try inside the boots. Making sure she doesn’t go too long between trims and that her feet are kept meticulously balanced with the toes not too long are also extremely important. There are no proven new treatment breakthroughs per se, but many horses are helped by periodic intra-articular injections in the coffin joint. You might want to explore that possibility with your veterinarian.

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Sarcoids And Toothpaste
My horse has a terrible problem with sarcoids. I’ve tried almost everything, and they always grow back. I’m intrigued to hear about the toothpaste solution a reader mentioned in November 2004. Do you know how this is implemented' When do I apply it' For how long' I’ve tried everything else. Why not this' Also, what is the escharotic treatment you mention'

We have no direct experience with the toothpaste treatment for sarcoids. Anecdotally, it has worked for some horses. Crest is supposed to be the best. The toothpaste is rubbed in daily until t he sarcoid is gone, or it’s obvious you’re not seeing any benefit. Many people report a difference within a few days. The escharotics most commonly used are either a concentrated zinc-sulfate paste, or a combination of the zinc sulfate with “bloodroot” powder, also known as cansema. Some veterinarians use a combination product called Xxterra.