In the treatment of equine laminitis , medicinal leech therapy (hirudotherapy) works through a combination of mechanical pressure relief and the injection of potent medicinal substances.

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1. Pressure Relief (Mechanical Action)

Laminitis often results in what is known as "compartment syndrome": inflammation and narrowed blood vessels lead to a massive rise in hydrostatic pressure within the rigid hoof capsule. Because the hoof wall cannot expand, this pressure impedes blood flow to the lamellae (the connection between the hoof bone and the hoof wall), causing tissue death.

• Siphon Effect: Leeches function as a natural "siphon". By extracting blood from the specific area where it is most needed—often the coronary band or the pastern—they directly reduce the local blood supply and relieve the high internal pressure within the hoof.

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2. Injection of Bioactive Substances (Chemical Action)

As soon as a leech bites, it injects a "cocktail" of between 60 and 100+ different medicinal proteins and enzymes into the horse's bloodstream. For laminitis, the following substances are vital:

• Hirudin: A powerful anticoagulant that prevents blood clots and can help dissolve existing blockages.

• Vasodilators: These substances widen the narrowed blood vessels in the hoof, significantly improving blood flow to the damaged lamellae.

• Anti-inflammatories and Analgesics: These target local inflammation directly and provide a numbing effect, making the procedure virtually painless for the horse.

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3. The Importance of Post-Bleeding

After the leech is saturated and detaches (typically after 30 to 120 minutes), the wound continues to bleed for another 4 to 12 hours due to the substance Calin.

• This post-bleeding is a critical part of the therapy: it drains "contaminated" blood, reduces edema (fluid accumulation), and stimulates the supply of oxygen-rich blood to the affected tissue. A healthy post-bleeding response is often a sign that circulation in the hoof is being restored.

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Effectiveness

Research into this specific application has shown positive outcomes:

• In a German scientific study, 84% of horses with acute laminitis showed significant clinical improvement after hirudotherapy.

• In a small trial involving four horses with acute laminitis, all animals resumed a normal pacing behavior within 12 hours of treatment.

While acute cases often yield rapid results within 1 to 3 treatments, chronic laminitis may require more sessions to provide long-term circulatory support.