Equine laminitis: its development coincides with increased sublamellar blood flow

Area of Science:

• Equine medicine
• Veterinary physiology
• Laminitis research

Background:

• Equine laminitis is a debilitating condition affecting horses.
• The early vascular changes preceding laminitis are not fully understood.
• Alimentary carbohydrate overload is a known risk factor for laminitis.

Purpose of the Study:

• To investigate the relationship between hoof temperature and sublamellar vasculature changes.
• To determine if hoof temperature can predict the onset of equine laminitis after carbohydrate overload.
• To identify vascular events preceding laminitis in horses.

Main Methods:

• Continuous monitoring of hoof, core, and ambient temperatures, and heart rate in horses.
• Induction of carbohydrate overload using a wheat flour slurry via nasogastric tube.
• Noninvasive hoof temperature measurement to assess digital blood flow changes.
• Histological examination of lamellar tissues for laminitis confirmation.

Main Results:

• Horses developing laminitis showed prolonged digital vasodilation (indicated by high hoof temperatures) 16-40 hours post-carbohydrate overload.
• Laminitis-negative horses did not exhibit this vasodilation period.
• Hoof temperature was the most significant differentiator between laminitis-positive and negative horses between 12 and 32 hours.

Conclusions:

• A period of sublamellar vasodilation, 12-40 hours after carbohydrate overload, precedes equine laminitis.
• Maintaining digital vasoconstriction during this phase may prevent laminitis.
• Increased digital blood flow may expose lamellar tissues to factors triggering separation during metabolic crisis.