What is Sweet Clover Poisoning?
An overgrowth of sweet clover in your horse’s pasture can cause sweet clover poisoning, or Slaframine poisoning. Hay can also become contaminated with mold and fungus from clover and can cause your horse to become ill.
Horses, when they ingest too much sweet clover infected with slaframine, can develop the slobbers. This is where excessive slobbering occurs. Your horse can also develop photosensitivity, or excessive sunburn, which can lead to liver damage.
Most people do think that sweet clover is toxic to horses, and in most cases it is not. However, when the clover is infected with a specific fungus, slaframine, horses can become ill and have excessive salivation.
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Symptoms of Sweet Clover Poisoning in Horses
Your horse will begin acting strangely after ingesting tainted sweet clover and you will notice physical symptoms as well. Contact your veterinarian immediately if you suspect that your horse is suffering from any form of poisoning and have a full physical completed to figure out what is causing the distress.
- Pale mucous membranes
- Excessive blood loss or bleeding abnormalities
- Difficulty swallowing or breathing
- Spontaneous unilateral nosebleeds
- Stiffness or lameness
- Tarry or black manure
- Localized swelling over different parts of the body
- Excessive drooling
- Increased urination
- Skin lesions
- Refusal to eat
Causes of Sweet Clover Poisoning in Horses
Sweet clover poisoning becomes more problematic during wet years or periods of high humidity. These conditions allow molds and fungus to grow within the sweet clover. It is the mold and fungus that cause sweet clover poisoning in horses. The main culprit is slaframine, a fungus that will cause your horse to begin slobbering excessively.
Keeping your pasture mowed will create air movement among the grass and clover and will keep mold and fungus at bay. Proper drainage will also help eliminate standing water and allow the clover within your pasture to properly dry without creating an unhealthy situation for your horse.
Hay that has been left out and is molding or was put up moist can also foster the proper environment for mold and fungus growth. When using hay that is heavy in clover, be sure to properly store your hay to avoid moisture from infiltrating the bales. It also takes longer for hay that is heavy in clover to dry once it has been cut, therefore, if baling hay yourself, be sure to give plenty of time for proper drying before you begin baling.
Diagnosis of Sweet Clover Poisoning in Horses
As soon as you suspect that your horse is suffering from sweet clover poisoning, or any kind of poisoning, remove your horse from their pasture. Put them into their stall with clean, fresh bedding and keep all hay away from them.
When you suspect sweet clover poisoning has occurred, have your veterinarian perform a full physical on your horse. They will begin by asking you about the symptoms that you have seen your horse’s diet and also about your horse’s daily exercise routine.
Once all that information has been gathered, your veterinarian will perform fecal and blood tests to try and determine the exact cause of the toxicity. Your veterinarian will also want to complete a feed and hay analysis to try to locate the mold or fungus that is causing your horse to become sick. They may even take samples of the clover found within your horse’s pasture for analysis.
Treatment of Sweet Clover Poisoning in Horses
Your veterinarian will suggest supportive care for your horse to keep them well hydrated and stable. This will mean a hospital stay. While your horse is being administered intravenous fluids, your veterinarian will probably include daily intravenous injections of Vitamin K3, four times a day. Calcium may also be added to their supportive care.
Your horse will also need to be given whole blood transfusions. These transfusions can be done using fresh frozen plasma or as direct transfer.
Your veterinarian will set an appropriate treatment plan that will give your horse their best chance of survival. Listen to your veterinarian’s advice and follow any instructions given exactly. Always direct any questions about your horse’s care to your veterinarian clinic.
Recovery of Sweet Clover Poisoning in Horses
Your horse’s prognosis will be dependent upon how much of the toxin your horse has ingested, their reaction to the toxin and how quickly treatments were begun. Once treatments have begun, your veterinarian will be able to give you a better understanding of your horse’s prognosis.
Preventing sweet clover poisoning can be a matter of making small changes to your horse’s daily care. Feed hay that is heavy in sweet clover or silage that has sweet clover in it for only two weeks at a time, then feed different forage for two weeks. This alternating schedule keeps any toxicity from building up. Keep your pasture well drained and any clover thinned. Supplement with vitamin K and calcium to neutralize toxicity and prevent hemorrhaging.