Ask Horse Journal: 11/06

Supplements For Insulin-Resistance
What information can you provide me about an insulin-resistant horse’ I know the symptoms, but what are treatment recommendations since vets don’t really have anything to help. My horse is mighty fat, cresty necked, etc. He has all the symptoms, plus he has been tested and insulin is 253.

He gets no grain, and is on pasture 4 to 5 hours day. And, at this time of year, pasture is getting thin. My question is: Is there a product already formulated I can buy to add to his diet’ Increased exercise is a must, I know. He is a 10-year-old Tennessee Walking Horse pleasure horse. I’ve see a product called Carb X and another called D-Carb (Balance) that are advertised for insulin-resistant horses. Can you recommend one’

This pony is insulin-resistant and has Cushing’s syndrome. He is overweight, long-haired, cresty necked–and out on grass, which he should lnot be allowed. There’s no reason to worry about feeding preground stabilized flaxseed-based supplements. You need to start with the base of the horse’s diet, his hay, before determining what you need to supplement and how much. Horses and humans simply do not move in a way that they can be compared. Hoof quality has to do with the horse’s overall diet and the regular care he gets from a good farrier.

Horse Journal Response
You’ve taken the important first step of confirming the diagnosis by involving your vet and testing. We will be doing an in-depth article on insulin resistance in the near future. The solution to this problem isn’t in a supplement container, it’s found in the horse’s diet. Briefly, an all-hay diet is appropriate, but you must have the hay tested to make sure that the sugar and starch level combined, called the NSC (nonstructural carbohydrates) are low, preferably less than 10% at this stage of the treatment.

Grass is out completely — not even four to five hours on a ”thin” pasture. The sugar and starch levels can vary tremendously, even over the course of a day. You can still turn your horse out for exercise, but use a sealed grazing muzzle. Careful mineral balancing, with mineral supplementation matched to the mineral profile in your hay, can help insulin sensitivity. As you mentioned, formal exercise is extremely important to these horses.

Manure For Bedding 
Six years ago, we began running manure thru a chipper-shredder machine. When dry, it has a sawdust texture. It is odorless, absorbent, fly-free and cheap. It provides a four-inch cushion for our 23- and 28-year-old shoeless retirees. Any comments on this practice’

Horse Journal Response
Animals normally have a good level of immunity to the organisms that are naturally present on their skin and in their digestive tracts, but if they have a wound this might not be enough when their environment has a high bacterial count. ”Curing” of manure by drying does eliminate odors but not necessarily the bacteria.

Even with composting, temperatures adequate to kill bacteria are only reached at the center of the pile. You’re on the right track, but we would wait a bit before incorporating this technique in our barn management.

Experiments are currently underway looking at manure ”digesters.” These processors break down manure under anaerobic (low-to-no oxygen) conditions to generate heat, methane gas as a source of biofuel and ultimately an essential sterile dry material that has a lower bacterial count than sand.

Heat Cycles
My then two-year-old filly had nasty heat cycles. She squeals and kicks the walls of her stall and gets agitated when horses come around. She was better on turnout than in the stall, so we kept her out as much as possible. We put her on Regumate for a couple of years, but I worried about its long-term effects and hated having it around my two teenage daughters. My husband gave it to the mare, and it did resolve the heat problems.

Last year, my daughter tried progesterone cream for her debilitating menstrual cramps, and it helped immensely. Last year, I tried it on our mare, and she is much better. I prefer it over Regumate, and you don’t need a prescription to get it. What do you think about this’

Horse Journal Response
First, two-year-old fillies often have heat cycles like you describe, but by age 4 or 5 they usually normalize. Stall confinement certainly worsens the stormy cycles. We doubt there was anything wrong with your filly’s hormones, and simply being an older mare may well explain the improvement you’ve seen using progesterone cream instead of Regumate. It’s also possible you’re seeing a carryover effect from the Regumate use. Its effect can last for as long as two years after long-term use.

We don’t advocate the use of hormones for behavior control. Progesterone is a form of ”doping” as much as a tranquilizer, although the regulatory bodies seem to turn a blind eye to its use. If you’re going to continue to use the progesterone, you should know a few things about it.

Products billed as ”natural” progesterone sources are of two types – plant products exactly as they occur in nature, or products that have been treated to convert the plant chemicals into forms identical to those that occur naturally in the horse’s (or human’s) body. Wild yam (aka Mexican yam) is the usual ingredient in progesterone creams. If the yam has not been altered in any way, it has little to no effect on either estrogen or progesterone, although a slight estrogen effect is possible.

If the label lists an actual progesterone content, as ”mg of USP progesterone,” it has been fermented or otherwise treated with enzymes to convert the plant hormone precursors into progesterone. The label of ”natural” doesn’t mean as found in nature or as found in the plant, it means the plant chemicals have been altered so they are now in a form that is ”natural” for the animal/human body.

Why the FDA allows these products to be sold without a prescription is a complete mystery to us. They have only been in use for a relatively short time in terms of hormone exposures though, so it may take another 10 to 20 years to determine if they truly are as safe as they are claimed to be. In the meantime, there is a large body of scientific evidence that shows progesterone excess is not a good thing. In fact, progesterone excess is behind many of the same conditions that these creams are supposed to be treating, including: depression, anxiety, mood swings, PMS, and menopause.

Furthermore, progesterone, not estrogen, drives many serious health problems such as heart disease, loss of bone mineral density, and cancer of the breast or uterus.

If this is true, how can progesterone creams possibly help these things’ Progesterone in the body is the precursor to the stress hormone cortisol, as well as to estrogen and even testosterone. As long as the pathways needed to convert progesterone to these other substances are functioning normally, as in a young animal, it could be used by the body to make other hormones as needed. In fact, the beneficial effects of these creams on PMS, early menopause (doesn’t work in late menopause) and in heart disease prevention are almost certainly coming from the progesterone being converted to estrogen.

So far, so good, but even natural health care practitioners are starting to advise extreme caution when using progesterone creams because they are finding that with long term use and/or inappropriately high doses the progesterone is being accumulated in the body fat and not used, leading to progesterone excess that has the potential to be every bit as dangerous as Regumate. In fact, since it has effects on multiple hormonal systems, possibly even moreso.

We would suggest you try getting your mare off hormones entirely. Because of the period they have been in use, she may experience a period of irregular or strong cycles. If this occurs, consult with a reproductive expert about hormone testing and short- term treatments to get her through this phase while her body attempts to return to normal. If you are going to continue to use the creams, at least take the same personal precautions for yourselves as you would when using Regumate.

Cyanide In Flaxseed
I’ve heard that if flaxseed is mixed in a mash it omits a toxic substance that can kill horses. I found it hard to believe, but I wouldn’t want to harm my horse. I feed ?? cup daily of ground flaxseed in my horse’s mash.

Horse Journal Response
Cyanide, in the form of hydrocyanic acid, is produced when freshly ground whole flaxseed is wet. Flax contains varying levels of compounds called ”cyanogenic glycosides.” These are cyanide precursors that can be converted to cyanide when they contact an enzyme that is also in flax.


The two do not come into direct contact in an intact flaxseed, but grinding the flax can release the enzyme, and adding water can accelerate the reaction. This is why whole flaxseeds should not be soaked in water to expand and soften before feeding.

If you are feeding preground stabilized flax, you’re using a human-grade product that is low in hydrocyanic acid potentional. Also, it has been determined that flax can be included in the diet of people up to 10 to 12% of their total food intake before any concern arises about possible toxicity.

DSLD Tendons
Thank you for the comprehensive article on DSLD (August). From the information stated, it would not surprise me if DSLD would turn out to be an autoimmune disease. It seems to follow a similar pattern of flare ups and remissions. Are there any speculations on this subject’

Horse Journal Response
You’re correct that autoimmune diseases are characterized by flares and remissions, but a big difference here is that autoimmune diseases are associated with an inflammatory response, and DSLD is not.

If DSLD turns out to be a genetic disease, at least in some horses, there is a theory on why genetic diseases can present very differently in different individuals (true of DSLD too), and why they show a relapsing and remitting pattern.

The theory is that the individual will have a variable number of copies of both normal and abnormal DNA in the body tissues. Depending on what cell structures or enzyme systems might be involved (unknown with DSLD) there could be hundreds to thousands of copies of the DNA inside a cell. These are reproduced in a random fashion. When a critical number of copies of the abnormal DNA have been produced, a flare occurs. Flares in DSLD could also be precipitated by things like shipping or an unusual amount of exercise, with the result that a weakened area of tendon or ligament becomes damaged.

I have recently received a subscription to Horse Journal and thoroughly enjoy the varied educational articles. I was particularly interested in the September article ”A Firm Stifle-Lameness Diagnosis May Require A Specialist,” since I am a sports-massage therapist and observe a good amount of stifle problems in my practice. In reading the Horse Journal article on stifles, I found what I believe to be an error in the description of the action of the quadriceps femoris. The article describes the action of this muscle as a stifle flexor. The quadriceps femoris muscle actually comprises four muscles and extends the stifle, rather than flexes, for both horses and humans.


Horse Journal Response
If the equine leg was shaped like a human leg, and if the quadriceps femoris could act on the stifle independently, you could draw direct parallels, but that’s not the case. Functionally (i.e. in the sense of what happens in the live horse), the quadriceps femoris is a ”lateral rotator,” abducts the stifle, which is how the horse unlocks the stay apparatus so that the leg can be flexed, then advanced. The function of the quadriceps is therefore to ”enable” the limb to be moved, which first involves flexing it to get the hoof off the ground.

Because of the stay apparatus and the connection between the hock and stifle via the peroneus tertius muscle, the major flexors and extensors of the stifle will have opposite effects depending on whether the leg is weight-bearing or not so it’s not correct, or helpful, to think of the horse’s hind leg as having muscles with pure flexion or extension activity.

If you have not done so lately, could you please address the issue of lysine’ I had hay analysis and ration balancing for my very important broodmare done by a reputable company. The ration, with their vitamin/mineral especially for in-foal mares, came back one ounce short of lysine.

The daily ration had 0.12 ounces of lysine, while the Kentucky Equine Research requirement was for 1.12 ounces. All the supplements I’ve looked at have at most about 3000 mg lysine. The recommended dose for various lysine or tri-amino supplements (with threonine and methionine) might supply about 10,000 mg. lysine. I figure I would need nearly three times those doses to get the full ounce needed. Help please.

Horse Journal Response
Whether you use a consulting company’s software or the NRC recommendations, the amount of lysine needed is not the amount you need from a supplement, it’s the amount that needs to be in the diet. The amount you need to supplement is the difference between the requirement and what’s already in the diet. Everything the horse eats has lysine in it, but in greatly varying levels. To figure out what you need to supplement, you need to know your starting point. If your non-pregnancy diet was adequate in lysine and all you do is increase the mare’s feed through pregnancy to hold the same body condition, your lysine deficit could be as low as 1 gram (.035 ounces). If not starting from a base of a lysine adequate diet, you could have a deficit of as much as 20 grams per day (0.7 ounces). You really need to know your starting point (see the article on Broodmare Feeding).

Nutrition Concerns
After reading the September issue, I came to several concerns regarding the nutrition for my two-year -old Thoroughbred/draft cross. She is currently pasture boarded and is not fed any hay. She is on a pelleted Ration Balancer/Supplement. It is a low-starch and low-calorie feed and has a fairly high amount of protein (32%) and has a relatively high amount of vitamins and minerals when compared to several other similar feeds by other brands. Should I be worried that this feed does not list fiber percentage as one of its main ingredients’


Also, I am very unsure about the amount vitamins/minerals that she should be fed. I know that there are instances when developmental problems may occur when young horses

are overfed vitamins and minerals that they don’t need. I really want to make sure that I am feeding her exactly what she needs (and not more). She is a very easy keeper and is looking like she is beginning to ”fatten up” a bit.

Horse Journal Response
An all-pasture diet is really the same thing as an all-hay diet. Hay is pasture with the water largely removed. They have to eat a lot more pounds of grass to get the same calories, fiber and protein than from hay, but in the end the fiber intake over a 24-hour period works out about the same. The only time there is a significant difference is when the pastures are young and rapidly growing, i.e. in the spring and during a strong fall regrowth. 

The balancer you are describing is really more a supplement than a feed. These are typically fed in low amounts, 1 to 2 pounds per day, and won’t have any significant impact on the fiber level of the diet.

The most important thing to remember with minerals is balance. Minerals compete with each other for both active and passive uptake from the intestinal tract, for entry into cells, for incorporation into tissues and enzymes and even for excretion from the body. Because of this, feeding one mineral in excess is much more likely to cause problems if it creates an imbalance than if the horse is also getting high levels of the other minerals, all in balance. In the situation you describe, horse on pasture, no supplemented grain receiving presumably the manufacturer recommended amounts of a balancing pellet, there is little chance she is getting any minerals in a level that could be directly toxic.

It’s very common to see them start to ”bulk up” at this age, now that the period of most rapid growth is over. You’re on the right track with your feeding approach, but should analyze you pasture grasses to make sure that the product you have chosen is actually getting the job done.

Grain And Hooves
There also seems to be growing evidence that grain diets can actually weaken the hoof structures to some extend without necessarily causing lameness, depending on how each individual horse deals with it. I have now heard from several horse owners that their horses’ hoof quality greatly improved when they stopped feeding grain.

Horse Journal Response
Grain does not weaken hoof structures. Millions of horses all over the globe eat grain their entire lives without any negative effects on hoof quality. Diet can certainly impact hoof quality, but grain per se won’t have anything to do with it unless the horse has a metabolic intolerance for concentrated carbohydrate sources or the horse is fed large amounts of grain that are significantly inflaming the large bowel.

Not all horses are insulin-resistant or fed excessive grain, and many high-performance horses require grain to maintain their weight and fuel their muscles properly. Grain may actually improve hoof quality in some instances, if it is well fortified with amino acids and key minerals the horse is lacking.

Beer For My Horses
I have an acquaintance who worked for a horse-drawn carriage company in a large city. He said they would regularly give beer to the horses pulling the carriages, that it helped with their electrolyte loss and sweating. I looked on the Internet for any information on this and couldn’t find anything. I know my horses like beer, but is it actually beneficial to them’

Horse Journal Response
According to the USDA Nutrient Database, beer on the average contains: 91.96% water, 3.9% alcohol, 3% carbohydrates and 0.46% protein. 

As for electrolytes, 3.5 ounces of beer supplies about 4 mg of sodium, compared to a bare minimum, resting daily requirement of 7,500 mg for a horse the size of a Thoroughbred; and 27 mg of potassium, compared again to a bare minimum (no sweating) requirement of 25,000 mg/day.

The bottom line is the beer is of no benefit on the nutritional front, but if your horse enjoys the taste there’s no harm in giving him a small amount.

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