Since I started writing about winter laminitis several years ago the topic has appeared with increasing frequency in other places. Spreading the word is always good but several things have been transformed in translation.
Cortisol as a cause. While it’s true cortisol levels may be somewhat higher with cold stress, they are with heat stress too and we don’t recognize a parallel situation of summer induced hoof pain. If cortisol was a key mechanism it would also put all horses at the same risk, not just those with EMS. While cortisol can sensitize vessels to constrictors, it doesn’t cause constriction itself. Endothelin-1 is the most likely culprit here.
Thyroid hormone as a cause. It’s not true that thyroid hormone reduces blood flow to the hooves.
Arteriovenous shunts function. Several discussions of the role of arteriovenous shunts got the mechanism backwards. These shunts bypass the local tissues and send blood back…
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