Does hay grazer turn toxic after a freeze?

Question

HAY GRAZER -- that has been planted in pastures....so our horses won't die from eating it, if it freezes.

Answer 1

Under certain conditions sorghum or sorghum/sudan grasses are capable of releasing hydrocyanic acid (HCN or commonly called prussic acid). Prussic acid when ingested by livestock, is quickly absorbed into the blood stream resulting in death in many cases. Some plant factors that attribute to prussic acid accumulation include any stress condition such as drought or freeze damage will increase HCN amounts. If you have Hay Grazer growing in your pastures, you should keep the horses off of the pasture after the first freeze until the hay grazer has field cured.

Answer 2

cowboy said it all.