Acorns and Oak Leaves

Oak LeavesDoes your horse treat acorns and oak leaves like a delicacy? Acorns and oak leaves contain tannin which in large quantities can be poisonous to your horse. Red or black oak varieties contain the most tannin; white oak varieties contain the least. The concentration of tannin in early spring leaves and green acorns is much higher than in mature leaves or ripe acorns.The most common problem we see in horses eating acorns is mild colic from indigestion. Horses with any predisposition to founder should not be allowed access to acorns as they are high in carbohydrates and can induce laminitis. Severe cases of acorn poisoning are extremely rare. The signs of acorn poisoning can be loss of appetite, excessive salivation, blood in the urine or manure, colic like pain, slow or irregular heart-rate, elevated temperature, pale mucous membranes, watery eyes and depressed attitude. In extreme cases liver and kidney failure ensues and other organs begin to hemorrhage. If you feel your horse is showing any of the above signs and has access to acorns remove them from the area and contact us.

August 2012 Summer Sore Alert

Recent outbreaks of ‘summer sores’ on horses have prompted us to issue this alert to let horse owners know how to recognize this alarming condition.

Summer sores, also known as Habronemiasis, are seen in the summer during fly season, and are the results of infected flies depositing the larvae of the equine stomach worm Habronema on wounds and moist areas of a horse’s body.Commonly affected areas are the eyelids, the sheath, the corners of the mouth and skin wounds.Infected tissues become inflamed and swell suddenly, with affected skin wounds producing excessive granulation tissue which protrudes above the surrounding skin.Severe itching is often seen.Infected wounds often have characteristic yellow granules which can be seen in the reddish wound surface that are about the size of a grain of rice.These are the dead larvae surrounded by inflammatory debris.

During fly season if your horse has a minor skin wound that suddenly looks much worse, or suddenly develops swelling of the eyelid, lips or sheath it may be Habronemiasis.Have your veterinarian examine your horse.

The treatment of Habronemiasis involves administering an avermectin dewormer (ivermectin or moxidectin), as well as topical treatment of the area.Systemic medications may also be given to control the severe inflammation which can result.

If caught early, summer sores are easily treated.In all cases treatment needs to be aggressive.In severe cases treatment may need to continue until fly season ends in the fall.

Life Cycle

The life cycle of the stomach worm is dependent on house and stable flies.Adult stomach worms live in the lining of the stomach and lay eggs which are shed in the feces.House and stable flies then lay their eggs in the same feces and the developing fly maggots ingest the Habronema larvae which develop within the growing fly maggots.The maggots then pupate into adult flies which then deposit the Habronema larvae on the lips of horses.The horses swallow the Habronema larvae which develop into adults in the stomach, and the life cycle is complete.

Prior Newsletters

On this page download prior newsletters in PDF form:

 May 2011: Feeding Beet Pulp


Nov 2009: Piroplasmosis


Aug 2009: Equine herpes virus myeloencephalopathy (EHM)


Nov 2008: Cushings Syndrome


Aug 2008: Equine Metabolic Syndrome Newsletter


Mar 2008: Breeding Season Newsletter


Dec 2007: Durable Equine Athletes Newsletter


Oct 2007: Chiropractic Care Newsletter


Mar 2007: Equine Viral Arteritis (EVA) Newsletter


Jan 2007: IRAP Newsletter