Rangers Buttons Poisoning in Horses

Rangers Buttons Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
Rangers Buttons Poisoning in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

What is Rangers Buttons Poisoning?

An unusual looking plant that appears just as the name says, Rangers Buttons looks like varying sizes of buttons on the end of the stem. The toxins within this plant cause the skin of the animal to become very sensitive to exposure to the sun. It produces a similar effect to extensive sunburn, and develops into ulcers or lesions on your horse’s skin which then can become inflamed and infected. These lesions attract insects such as flies which then compound the injury by infection. This plant is also known by the unlikely name of Woolly Head parsnip, or Swamp White Heads.

This distinctive plant causes your horse’s skin to be sensitive to the sun, resulting in an ulcerative skin condition around the hairless or lighter areas.

Symptoms of Rangers Buttons Poisoning in Horses

  • The symptoms demonstrated by your horse after eating Rangers Buttons, is very similar to severe sunburn and is different from other poisonous reactions 
  • Itchy inflamed skin especially in areas where there is little hair to protect the skin 
  • Damage to the eyesight 
  • Lack of appetite
  • Depression
  • Lesions and ulcerated sores 


  • Rangers Buttons is a perennial herb of the Apiaceae plant; its flowers are cute clusters of fluffy buttons nesting on the long spikes of the plant
  • The flowers are white or tinged with a pretty pink colour and are quite hairy or wool like hence its other name, Woolly Head parsnip
  • The plant grows alongside streams, marshlands as well as forests 
  • Native to western North America and grows best in damp areas


Causes of Rangers Buttons Poisoning in Horses

  • Exposure to the toxin plus exposure to UV light from the sun causes phytophotodermatitis which causes the sunburn like effects on your horse’s skin
  • If your horse has eaten a large portion of this plant, it can take several months to be completely cleared from your horse’s system 
  • The toxin responsible for the poisonous reaction is known as furanocoumarins
  • Photosensitivity and dermatitis are often the result from contact with this plant 
  • Even when mixed with hay, it retains its poisonous touch 
  • Any pink skinned areas on your horse will be affected


Diagnosis of Rangers Buttons Poisoning in Horses

If by chance you have noticed your horse eating this strange plant, then take a sample to show the veterinarian when they come to examine your horse. This will speed up the process of the diagnosis.  The first thing the specialist will do is to do a thorough examination followed by investigating your horse’s history of health. The veterinarian may take both blood samples and skin scrapings to view under the microscope. Other ways the specialist may diagnosis what is affecting your horse is to check to see if there is a bacterial infection and a urine test to determine any abnormalities.

Rangers Buttons reactions don’t always present themselves as poisoning, so your specialist will work on refining what is happening to your horse. Needless to say, it would be prudent to remove your horse from direct exposure to a shady stall while it regains its health. The fact that Ranger Buttons can cause problems with your horse’s eyes is another concern, and the veterinarian will need to do a thorough eye check to enable them to promote treatment.



Treatment of Rangers Buttons Poisoning in Horses

Supportive care is usually the only way to manage the condition caused by Rangers Buttons. Because exposure to the sunlight will only make the condition worse, you are advised to remove your horse from the pasture and settle it into a quiet stall. Your horse may need to spend several days away from the sun. The problem can worsen and cause weeping of the crusted lesions and sores on the skin, and this in turn can attract annoying insects which can lead to infections. It takes a while for the photosensitivity and dermatitis caused by this plant to eventually heal and be flushed from your horse’s system.

Putting a light cover over your horse during the day and using special topical medications as advised by your veterinarian will provide protection until your horse recovers. As it takes some time for the effects of Ranger Buttons to work its way out of the system, you will need to wait till the sores and dermatitis have healed and the photosensitivity is gone before life returns to normal. Until then, plenty of supportive care and fresh food and water away from direct sunlight until healing occurs is required. If there is eye involvement, the veterinarian will prescribe ointment or drops.



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Recovery of Rangers Buttons Poisoning in Horses

Part of any good farming program includes pasture maintenance and care. Be vigilant when walking around and take notice of weeds starting to invade the pasture. Rangers Buttons looks quite unusual so it will be an obvious plant to spot. Be careful handling it as it can affect human skin just as easily as it does to your horse. Wearing gloves to dig it up and pull it out will help. Another point is to check the hay if you can’t find it growing in the field – your horse may have encountered it amongst a new supply of hay where it can still be active, even though dried. Rangers Button poisoning is not a common occurrence, but it pays to be aware of the damage it can do if it gets a hold on your property.



Rangers Buttons Poisoning Questions and Advice from Veterinary Professionals

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