Rye grass staggers or "grass tetany" occurs in all grazing species, including horses, grazing on perenial rye (lolium perenne) or rye hybrids.
It occurs because of toxins in the sheath and seed heads of rye grass, particularly in warmer weather. Symptoms develop over 7 to 14 days from grazing on effected pasture.
Symptoms include head shaking and stiffness, difficulty getting up and down, lack or coordination and bounding movements. In severe cases - convulsions and sudden death.
Mycosorb A+ helps you prevent rye grass staggers by binding to the toxins in the digestive tract of the animal.
Dosage is 10g per day (a teaspoon). One $35, 1kg bag contains 100 doses. We sell Mycosorb A+ in 1kg heat-sealed pouches. It is a yeast culture, not a pharmaceutical, so it has no negative side effects. It is generally palatable to most horses.
If your horse is grazing on perenial rye or a rye hybrid, you may want to consider including Mycosorb A+ in their feed as a preventive measure.
You can find Mycosorb here:
There is more information about rye grass staggers here: