Instead of risking the whole herd, place one or two of the least valuable animals into the pasture before turning in all the livestock. Leave the tester animals in the pasture for several hours to test the forage for poisonous properties. Feed hay to hungry livestock before turning them into sudangrass for the first time. It might also be helpful to permit grazing for only a short period of time the first day. Livestock turned into a field of sudangrass which is high in prussic acid will usually stop eating in 10 to 15 minutes if they are not too hungry.
Livestock vary in the amount of prussic acid that it takes to be fatal.
If they are in a low state of vigor and very hungry, they are more likely to eat a fatal dose than if they are in good vigor and not hungry. Frosted sudangrass can be very dangerous if pastured before the plants have thoroughly dried. Immediately after frost, remove the animals from the pasture until the grass has dried out, usually 5 to 6 days. If new shoots develop after a frost, utilize the sudangrass as hay or silage rather than pasture. Frosted sudangrass can be safely utilized for hay or wilted silage.