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What is Kleingrass Poisoning?

Kleingrass, also known by its botanical name of Panicum Coloratum, is from the Poaceae family.  This grass is commonly found in many parts of the United States in the pastures and fields in which many horses graze.  There are components in kleingrass which, when being broken down in the digestive tract, result in hepatotoxicity (the ability of a drug, chemical or other exposure to injure the liver) in the horse.

Kleingrass poisoning in horses is defined as hepatotoxicity (liver toxicity) which stems from chemical-based liver damage, that causes both acute and chronic liver disease in horses.

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Symptoms of Kleingrass Poisoning in Horses

Since the mechanism behind the toxicity causes liver damage, the symptoms of kleingrass poisoning in horses are compatible with liver failure and photosensitivity:

  • Jaundice
  • Rough hair coat
  • Diarrhea
  • Prolapsed rectum
  • Anemia
  • Anorexia
  • Weight loss
  • Intermittent colic 
  • Fever
  • Lameness
  • Hepatic encephalopathy (HE) - confusion, altered consciousness level and coma

These symptoms can present in the afflicted equine fairly quickly after being exposed to the kleingrass (panicum coloratum) hay and can progress rapidly to more severe stages.

Types 

There are really no specific types of kleingrass poisoning in horses except as the symptoms apply to the severity of the toxicity.  One of the “side effects” of the hepatotoxicity is photosensitivity.  This is not like sunburn but rather more specific to photodynamic elements in the skin and their reaction with sun exposure.  And, those photodynamic elements are in the skin because the liver function is impaired and they aren’t being excreted appropriately by the liver.

Causes of Kleingrass Poisoning in Horses

Kleingrass, or panicum coloratum, causes the toxicosis in horses because of the high sapogenin (a plant detergent) content which is in the young plants in late spring to early fall (primarily in the Southwest U.S.) and is believed to be the toxic principle. There is a similar reaction or syndrome that is found in the eastern U.S. in grazing pastures and the hay being fed as it contains high levels of fall panicum.  A photodermatitis is generally the visible result of the photodynamic and sapogenin process.

Diagnosis of Kleingrass Poisoning in Horses

Diagnosis of kleingrass poisoning in your horse will have a great deal to do with your accurate and complete history.  This history will need to include the feeding habits of your equine, including the pasture content and hay content which is being fed, as well as the amount of time spent in pasture foraging and hay foraging.  

You might want to be aware of the grasses on which your horse is feeding so that you can give your veterinary professional some idea as to approximately how long the horse has been exposed to the kleingrass.  He will do a physical examination and will likely proceed with a what is known as a “presumptive” diagnosis until blood work and possibly tissue samples have been obtained and evaluated by a lab.  In the lab testing, he will be looking at the liver function testing, antibodies presence and the overall comprehensive blood panel.  An appropriate treatment plan will be developed and initiated as quickly as possible.

Treatment of Kleingrass Poisoning in Horses

One of the first steps in the treatment process will be removal of the equine from the kleingrass source and from exposure to sunlight.  Your afflicted equine will need to be fed a high quality hay and/or feed and provided access to plenty of fresh, clean water.  Your veterinary professional will likely treat the photodermatitis with an external cream, lotion or ointment which is antibacterial or containing softening agents if the condition is severe.  Depending on the condition of the horse, your vet may recommend supportive care which can consist of fluids (oral or IV administration), rest and quiet, dietary changes noted above and some much needed time under roof, away from sunlight exposure until his photodermatitis heals.

Recovery of Kleingrass Poisoning in Horses

Kleingrass is much like other poisonous weeds and plants in that it doesn’t have an appetizing taste or smell to please your equine’s palette.  So, since it doesn’t taste particularly good, he will only eat it if he has few other options for food or forage.  Providing plenty of high quality hay and feed and safe pasture forage will go a long way toward protecting your afflicted equine as well as the rest of your herd from the ravages of kleingrass liver damage.  If medical attention is provided in a timely manner, and if appropriate steps are taken as recommended by your vet, your horse should recover in time, though some residual liver damage may remain depending on the initial stage of the disease when treatment began.