What is Prince's Plume Poisoning?
Your horse will eat unpalatable plants such as prince’s plume that they would not usually eat if they are very hungry and feed is scarce. Poisoning can occur through eating hay that has prince’s plume in the mix, especially if the hay comes from an area where there is a high selenium content in the ground and therefore the plants as well. Prince’s plume is an erect herb or shrub which bears long plume-like stalks covered with white to bright yellow flowers with long stamens. They are toxic because they concentrate selenium in their tissues from the rich soil.
Prince’s plume poisoning occurs when bad weather conditions cause a lack of good foraging in the pastures, forcing your horse to eat plants that they normally wouldn’t eat.
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Symptoms of Prince's Plume Poisoning in Horses
- Acute symptoms in your horse may include nervousness, loss of appetite, diarrhea, fever, weakness and respiratory distress. There is no cure for acute or sudden selenium poisoning leading to its demise within hours or days
- Chronic selenium poisoning includes lameness due to hoof cracks that may ooze, hair loss, drooling, respiratory distress, inability to stand still, and unsteady gait
- Hair loss from your horse, usually the tail and mane are the symptoms seen with this type of poisoning
- Cracks in the hoof wall caused by abnormal hoof wall growth
- Lameness due to the cracking of the hoof wall
- Sudden or acute toxicity occurs when your horse consumes a large amount of prince’s plume or similar plant that contains large amounts of selenium in their leaves over a short period
- Chronic selenium poisoning occurs with grazing over a longer period of time allowing a build-up of the toxins caused by too much selenium in your horse’s diet; this condition is also known as alkali disease or bobtail disease
Causes of Prince's Plume Poisoning in Horses
- Poisoning occurs because of the type of selenium present in the plant and the interaction between it and other elements such as sulphur or arsenic that are present in the diet
- Usually, the poisoning occurs in spring and summer months with the temptation of fresh lush growth in weeds such as prince’s plume
- Selenium is a necessary trace mineral needed by your horse in very minute quantities
- There is a fine line between not enough selenium and too much
- An oversupply of selenium is dangerous for your horse
Diagnosis of Prince's Plume Poisoning in Horses
If you suspect your horse has selenium poisoning caused from prince’s plume, you are advised to send samples of hay or forages for analysis as picking it up from a blood test is not always possible due to the minute amounts of selenium in the bloodstream.
Water levels should also be checked, with a reading of less than 0.05 ppm (MG/1) – selenium levels above 5ppm are toxic. Your veterinarian will be able to advise you who to contact if you are not sure, and he will check your horse for the severity of the symptoms. Hair and hoof samples can be used to diagnose selenium as these areas retain high levels of the mineral. Samples from the hair that show an excess of 10 ppm of the mineral confirms the presences of excess selenium in the diet.
Treatment of Prince's Plume Poisoning in Horses
There is no treatment available for acute selenium poisoning, and only supportive treatment for chronic poisoning, so the urgency to act as soon as possible is imperative. Knowing your pasture is essential as you will notice the moment prince’s plume raises its decorative stems. Observation during routine grooming provides an opportunity to check the feet, coat, tail and mane on your horse and if there is excessive thinning of the hair or hoof cracks starting it should be an immediate signal to take action.
Remove your horse from the high selenium feed or pasture immediately, and provide a balanced a well-balanced high protein diet is essential. The effect of treatment relies on the early detection of this condition, the sooner it is noticed the better. The cumulative effect can be devastating so it is essential to be aware of your horse’s health and observe your pastures for clues. Your farrier will be able to advise on care for the cracking of the hoof, while your veterinarian will advise on diet (adequate sulphur and copper are necessary) and health for your horse.
Recovery of Prince's Plume Poisoning in Horses
The main message in regards to protecting your horse from excessive selenium comes down to knowing your pastures, and identifying your soil type because the mineral level of the soil will affect the selenium content in the forage. Prevention is always the best course of action, and being aware of the source of your hay supply is important. Some areas that have high selenium content are very high hay producers. You can get your hay tested to determine the quality of feed.
Remain observant and if you notice any unexplained shedding of the mane hairs or tail, then it is time to take appropriate measures. For recovering horses, it requires time and care to get them back to optimal health. Quality feed and water (test the water system to ensure it is not high in selenium content) will aid recovery.