White Snakeroot Poisoning in Horses

White Snakeroot Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
White Snakeroot Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is White Snakeroot Poisoning?

White snakeroot is a plant commonly found in wooded areas of the Midwest. It is a large herbaceous  plant that can cause toxicity in your horse if he ingests it. If your mare ingests it, she can actually pass the toxin on to her nursing foal as well. Symptoms may develop days to weeks after initial ingestion of the plant depending on the amount eaten and frequency that it is ingested. There is no cure for white snakeroot toxicity, but your veterinarian can offer your horse supportive therapies as needed as the toxin is flushed from his system. Prognosis of recovery is guarded as one result of ingestion can be death.

White snakeroot poisoning comes from ingestion of the plant itself. Consumption of the white snakeroot can cause mild or severe symptoms and may even result in death. If you believe your horse is experiencing some type of toxicosis, contact your veterinarian immediately.

Symptoms of White Snakeroot Poisoning in Horses

Symptoms of white snakeroot poisoning may include:

  • Depression 
  • Tremors
  • Wide, abnormal stance
  • Stiff gait 
  • Sweating
  • Swelling in lower neck
  • Stumbling 
  • Bloody urine
  • Choking
  • Jugular pulse
  • Rapid heart rate
  • Arrhythmia 
  • Jaundice
  • Toxic milk 
  • Death 

Your horse can be poisoned by ingesting a large amount all at once or by grazing on small amounts over a longer period of time.


White snakeroot is an erect, on average three feet tall, branched herb-like plant. The stems of this plant are round with pointed, oval leaves on the branches. The leaves themselves are three to five inches long with sharply toothed edges. It is found along all types of landscapes but more commonly in wooded areas of the Midwest.



Causes of White Snakeroot Poisoning in Horses

White snakeroot contains the toxin trematone, also known as tremetol. It is highly toxic and can be passed along in the milk to nursing foals. The common name for this toxicity is known as milk sickness. The toxin causes metabolic disturbances when ingested and can cause ketosis and related acidosis. It is believed the leaves and the stems are the most toxic part of the plant.



Diagnosis of White Snakeroot Poisoning in Horses

Your veterinarian will begin by performing a full physical exam on your horse. She will take note of any and all symptoms he is experiencing in order to come to a complete diagnosis. Since some of his symptoms may be vague and can occur with many illnesses, the veterinarian may need to come to a proper diagnosis by rule out method. She will want to collect a history from you as to what your horse has been eating, where he has been, when his symptoms began, and how quickly they have progressed. 

She may also want to run some lab work to check how your horse’s organs are functioning. Blood work will begin with a complete blood count and chemistry panel. The results will indicate how the organs are filtering the toxin. Jaundice is indicative of hepatic issues and the chemistry will provide information on how the liver is functioning. She may want to run more diagnostic lab work depending on the results of the initial tests. For example, if your horse is producing bloody urine, the vet may want to perform a urinalysis to see if there is an underlying infection or other reason for the symptom. 

Your veterinarian may want to do an electrocardiogram to check the heart. In cases of white snakeroot toxicity the ST can be elevated, the QRS complex is variable and sometimes experiences premature ventricular beats. She may also want to take a radiograph of his chest to evaluate the size and physical condition of the heart to ensure there is not something else affecting your horse.



Treatment of White Snakeroot Poisoning in Horses

Unfortunately, there is no cure for white snakeroot poisoning in your horse. The treatment for this condition is supportive therapy. 

If your equine’s heart is being affected, the veterinarian may administer medications to adjust the rhythm accordingly. If he is experiencing difficulties standing or walking, she will want to keep him in a calm, quiet place to avoid excitement. Keeping him settled will prevent injury he may cause himself, you, or veterinary staff accidentally.

If your horse is sweating, your veterinary caregiver may begin fluid therapy to prevent him from developing dehydration. If you happen to have a mare with this condition, you will want to get the foal to stop nursing immediately and monitor him as well now to signs of toxicity. In many cases, the mother does not present symptoms, and the foal may die without exhibiting any signs of illness at all.

The symptoms your horse is experiencing will determine the course of supportive treatment the veterinarian will recommend. Each case of toxicity varies so your horse’s treatment plan may differ from another.



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Recovery of White Snakeroot Poisoning in Horses

The prognosis of recovery will depend on how much white snakeroot your horse ingested and for how long of a period. Symptoms may not appear until several days to weeks after ingestion of the plant has begun. This delay of symptom development may mean your horse has actually ingested more than originally thought. Prognosis in any type of toxicity related case is considered guarded. There are many factors that can affect his prognosis such as age, current health condition, and speed of treatment for the toxicity. As a proactive measure for the safety of any equines on your property, keep an eye on what vegetation is growing in your pasture and along the fence lines of neighboring fields.



White Snakeroot Poisoning Questions and Advice from Veterinary Professionals

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