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What is Red Clover Poisoning?

Red clover poisoning will cause your horse to slobber excessively. Red clover poisoning is also known as Slaframine poisoning or the slobbers. It is not life-threatening and many times horses do not show any other symptoms other than excessive salivation. 

Red clover poisoning can affect all horses of any age. However, young horses and senior horses are at a higher risk as are horses that are pastured where forage is limited and they ingest large quantities of red clover.

The actual red clover plant is not toxic; however, the toxin associated with red clover poisoning is slaframine and is produced by a fungus called Rhizoctonia leguminicola. This fungus grows on red clover during high humidity, drought, or continuous grazing. When infested red clover is mowed and dried for hay, the hay then becomes contaminated.

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Symptoms of Red Clover Poisoning in Horses

If you suspect that your horse has ingested contaminated red clover or has been poisoned in any other way, contact your veterinarian immediately. While you are waiting for your veterinarian to arrive, remove your horse from its pasture and do not feed any hay. Collect samples of any clover in the pasture as well as a sample of your horse’s hay for your veterinarian.

  • Excessive salivation
  • Tearing
  • Skin lesions
  • Difficulty breathing
  • Increased urination
  • Refusal to eat
  • Colic
  • Diarrhea

Causes of Red Clover Poisoning in Horses

Red clover poisoning in horses occurs when the red clover becomes infected with the fungus Rhizoctonia leguminicola or black patch disease. This fungus becomes more prevalent during wet, cool years but can also occur during times of drought. 

Overly grazed pastures can also have a heavy infestation of Rhizoctonia leguminicola. Hay can also be poisonous if it contains red clover that is infested with fungus. Hay can be stored for years and the toxins will remain active for several years.

Even though red clover itself is not toxic, it is good practice to remove clover from your horse’s pasture or ensure that there is plenty of quality forage available in its pasture. When cutting your hay, avoid including red clover. If you purchase your hay, ask about any clover that may be included in the hay.

Diagnosis of Red Clover Poisoning in Horses

Your veterinarian will first complete a full physical examination of your horse. They will begin by doing the usual checks including taking your horse’s temperature and checking their mucous membranes. A fecal examination, urinalysis, and complete blood count will be done to rule out any other possible diseases. 

There is a test that will provide a chemical detection of slaframine in your horse’s food. Prior to your veterinarian arriving, collect samples of your horse’s feed including hay, silage, and any clover found in the pasture.

Treatment of Red Clover Poisoning in Horses

While there are no specific antidotes for red clover poisoning in horses, there are certain treatments that your veterinarian can prescribe to make your horse more comfortable.

Stall rest may be required to keep your horse from eating any more infected clover. Closely examine the hay that you are feeding your horse to ensure that it does not have an abundance of red clover. 

Medications may be given to treat any symptoms that present. Atropine may be given to control some of the excessive drooling and any other gastrointestinal disturbances that may be occurring. 

When medications are prescribed, be sure to follow dosage instructions and finish all medications unless directed by your veterinarian. If you have any questions regarding dosage and side effects, contact your veterinarian.

Recovery of Red Clover Poisoning in Horses

Most cases do not require treatments to fully recover from red clover poisoning. However, in the instances where symptomatic treatments are required, follow all instructions to ensure that your horse recovers quickly and without complications.

Preventing your horse from developing red clover poisoning is a simple matter of pasture management. Pay close attention to any clover that is beginning to spread through your pasture. Remove it by mowing or by using an animal safe herbicide that is labeled for pasture use. If you are unable to eradicate red clover from your pasture then continue to mow the pasture until the brown fungal spots on the leaves of the clover are no longer present.

If you have enough space, rotate pastures and allow the grass to grow and remain tall on the pasture that is being rested. Taller grass will keep clover from growing. This is especially important during times of wet, cool weather when fungal growth is more prevalent.