Karen’s Musings & Endurance Ride Stuff

I’m going to be adding more information about insulin resistance in horses to this page.  If you have something that you’d like to share, please send it to me.

Research article from the Journal of Animal Science:  Insulin resistance in the horse: Definition, detection, and dietetics

Search various horse hays and feeds for sugar and starch content at Dairy One.

Another Research Article: Insulin Resistance in Equids: Possible Role in Laminitis

Insulin Resistant Endurance Horse

Plus, here are some additional links to other information that is worth reading if you have an IR horse:

Feeding the insulin resistant horse

IR in horses fact sheet, by the U of CT

I’m working on a feed chart that I’ll post later.  If anybody would like to contribute to it please email me!

To learn more, join a Yahoo group.  Here is a link to the Equine Cushings list.

AVOID OR USE CAUTIOUSLY WITH CUSHING’S & IR HORSES

ACEPROMAZINE, referred to as Ace, is the only commonly used drug that actually has the potential to directly interfere with pergolide. Phenothiazine tranquilizers suppress dopamine therefore having the exact opposite effect of pergolide.
ALFALFA tends to test lower *on the average* for sugar than some grass hays, but also contains starch, & contains more actual glucose than an equivalent amount of grass hay. Some IR horses just don’t tolerate it. Others are fine on it.
CORTICOSTEROIDS should be avoided in horses prone to laminitis. This includes low dose administration for the Dexamethasone Suppression Test. The exception would be in a life-threatening situation.
FATS in large amounts can cause or worsen IR. Stay at lower than 3% to 4% of the entire diet (percentage subject to change as we learn more specifically related to horses regarding fat’s ability to cause IR). The exception to this, of course, would be the horse with PSSM/EPSM.
FREE CHOICE MINERALS is not an effective way to supplement and balance a horse’s minerals. Contrary to popular belief, horses do not instinctively know what minerals they need. They will eat these sporadically, depending on the flavoring added to the mineral. Mineral supplements should be based on a complete diet analysis, and then fed on a daily basis.
GLUCOSAMINE administered intravenously is definitely not recommended and a most recent study showed oral glucosamine has the potential to worsen IR in individuals that have it. Prior studies, however, have shown it does not cause IR. Caution is recommended with very sensitive IR horses.
METHYLSULFONYLMETHANE (MSM), also known as methyl sulfone or dimethylsulfone, in some cases can be an effective anti-inflammatory but be aware it can influence mineral uptake, particularly selenium and copper. Check your horse’s blood levels for these minerals regularly.
MONO and DICALCIUM PHOSPHATE salts commonly run 20,000 to 30,000 ppm iron per Dr. Kellon. Avoid any supplement containing mono or dicalcium phosphate, bone meal, colloidal clays, clays or rock phosphate as all these may have extremely high iron levels. To supplement phosphorus use mono sodium phosphate instead.
NITRATES have the potential to interfere with thyroid function with chronic low-level ingestion. Severe nitrate poisoning can cause abortion. If you are in an agricultural area, testing well water for nitrates is advisable.
NSAIDs like Phenylbutazone (Bute) and Banamine® (flunixin) given long-term and/or in high doses increase the risks of ulceration of the stomach and GI tract and can cause kidney damage. They also have negative effects on circulation and healing.

· PRAZIQUANTEL a wormer often combined with moxidectin (Quest Plus) and ivermectin (ie. EquiMAX, Zimecterin Gold), significantly increased serum glucose level in both hyperglycemic rats and after glucose load. Since insulin levels are not significantly altered by praziquantel, the hyperglycemic effect of this drug may be attributed to inhibition of peripheral glucose utilization. It is NOT known if the same would occur in a horse when using the combination dewormers but it’s worth bearing in mind. Risks vs. benefits should be discussed with your treating vet if your horse or pony is IR.
RED MINERAL SALT BLOCKS are typically very high in iron and the trace minerals in them are not specifically formulated for horses. They are intended for cattle.
SOY should only be fed in small amounts & cautiously as researchers have identified that the isoflavones act as potent anti-thyroid agents, and are capable of suppressing thyroid function, and causing or worsening hypothyroidism in humans.
SULFA and trimethoprim-sulfa combinations have the potential to increase insulin secretion in other species. This has not been studied in horses. In humans, the complication of increased insulin most likely occurs with kidney disease. Since it is now known that insulin itself can trigger laminitis (mechanism not known, but it makes blood hypercoagulable in humans – prone to clotting), caution is indicated with sulfas. For list of sulfa drugs see: http://en.wikipedia.org/wiki/Sulfa_drug.
VACCINATIONS should be discussed with your veterinarian to assess risks of the actual diseases in your area and in your particular situation. When given, only give one at a time, spacing them out 2-3 weeks apart. A number of these horses seem very sensitive to vaccinations.
VITAMIN C is a powerful antioxidant but it enhances iron absorption and many IR horses are already iron overloaded.
WILD YAM powder is estrogenic and will increase symptoms of estrus.
YUCCA has a corticosteroid effect and the Yucca saponins can induce IR. Yucca may also be irritating to the stomach lining.
XYLAZINE should be avoided because it causes elevated blood sugar.