Americanfarrier.com - Full Article
By Eleanor Kellon VMD posted on February 8, 2017
For the insulin resistant horse, winter laminitis can strike seemingly out of nowhere, with no change in diet or management and some puzzling inconsistencies.
The horse may not necessarily have a prior history of laminitis. The pain is often severe, but the feet aren’t hot as they are in classical acute laminitis cases. The digital pulses may or may not be elevated. Radiographs tend to remain stable in most cases; without major changes with rotation or sinking. NSAIDs (Non-Steroidal Anti-Inflammatories) like phenylbutazone, which are commonly used any time there is foot pain similar to this, have no positive effect.
It can be confusing when the horse looks like a typical laminitis case, but without the heat and high pulses. Inadequate blood supply is the perfect explanation. The body’s normal response to cold is to constrict blood vessels in the periphery to reduce heat losses, but in IR horses the reaction appears to be exaggerated. This is because of the well-documented role of the potent vasoconstrictor endothelin-1 in IR horses, with the most recent study confirming that endothelin-1 is involved with laminitis because of elevated blood insulin...
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