March 2004

Pasture Dangers

Many horsemen believe horses instinctively know which grasses are good and which are bad, but it’s not always the case.

Toxic plants are more appealing when the amount of vegetation in the turnout area is slim.

Most horses won’t experiment with potentially toxic plants unless the pasture contains slim pickings of safe plants. If it does, be aware that the toxic choices will more become appealing.

Onion Grass

Most horses will avoid onion grass. However, this hardy grass often gets the jump on other grass species in early spring, and poisonings occur every year, usually in the Northeastern and Southern states. Onion grass can damage the red blood cells, resulting in the formation of “Heinz bodies,” which results in anemia. When the toxicity is severe, the horse’s urine may be red and the horse has a greatly decreased exercise tolerance. …