Kleingrass Toxicosis in Horses

Kleingrass toxicosis is rare in horses. Horses living in the southwestern United States are more likely to ingest kleingrass. Toxicosis is more common during warm months, from late spring to early fall. The ingestion of young plants is more likely to cause severe toxicosis.

Liver failure caused by kleingrass ingestion is a life-threatening condition and, as such, must be treated as an emergency. Horses showing unusual behavior such as head pressing, circling, or uncoordinated movements also require emergency veterinary attention.

Photosensitivity caused by kleingrass ingestion is generally not an emergency, with most animals recovering rapidly once the source of the toxin is removed, but indicates that liver damage has occurred and requires prompt veterinary attention.

Most horses with kleingrass toxicosis are only diagnosed after significant liver damage has occurred, and have a guarded to poor long-term prognosis.

Ingestion of kleingrass can cause photosensitivity; common symptoms include:

• Swollen skin
• Red skin after exposure to sunlight
• Crusting or scabbing of the skin, particularly over areas with white markings

Photosensitivity caused by the ingestion of kleingrass can affect the animal’s coronary band and can cause lameness.

Horses with liver damage are at risk of developing neurological disease. Symptoms of hepatic encephalopathy include:

• Circling
• Head pressing
• Uncoordinated movement (ataxia)
• Abnormal behavior, including violent behavior or severe lethargy

Kleingrass is a perennial grass native to Africa and found throughout the southwestern United States. Kleingrass toxicosis is caused by the ingestion of the kleingrass plants (Panicum coloratum). Kleingrass, as with all plant members of the Panicum species, contain toxins that cause liver damage and skin photosensitization when ingested.

The toxicosis is more common during late spring and early fall. The ingestion of young plants causes severe toxicosis as they contain higher amounts of toxins.

Horses presenting symptoms of kleingrass toxicosis generally undergo the following diagnostics:

• Physical examination
• Blood tests

There is no specific test for kleingrass toxicosis, so most cases are diagnosed based on symptoms observed and a history of exposure to the grass.

There is no antidote or specific treatment for kleingrass toxicosis. Treatment is of a supportive and symptomatic nature. Options include:

• Removal of the toxin source
• Topical treatment of skin damage
• Keeping the animal out of direct sunlight
• IV fluid therapy

Prognosis of kleingrass poisoning is dependent on the amount of toxin ingested, the extent of liver damage, and the promptness of treatment. Most cases of kleingrass toxicosis are only diagnosed once significant liver damage and scarring has occurred, which makes the overall prognosis guarded to poor for long-term survival.

Kleingrass toxicosis is not contagious.

Horses that do not ingest kleingrass do not develop toxicosis. Prevention strategies include:

• Eradicating kleingrass from pastures
• Providing abundant uncontaminated feed
• Inspecting hay prior to feeding

Kleingrass toxicosis is a rare condition.

• Removal of the toxin source
• Topical skin lesion treatment
• Keeping the animal out of direct sunlight
• IV fluid therapy