A:   You are right in that sorghums and sudangrasses may have the prussic acid issue and in some cases, nitrates brought on by the stress of light frosts on the plants. This is usually more of an issue when they were planted after wheat in mid-July, hayed in late August, and then any regrowth is planned for fall grazing. All in all, it can become a guessing game until there is a hard, killing freeze. All of these, including pearl millet, are safe to graze beginning about 5 days after a complete killing freeze. Although this standing, stockpiled forage will have lost its green color, the quality will hold for a period into the fall and not be too much less than its quality (based on stage of growth) at the time of the killing freeze. I think the best alternative to these would be oats with a small amount of turnips in the mix. Oats planted in late July will grow fairly quickly and should reach about 18 inches in height by mid-September. It will continue growth into October and really does not begin to freeze down significantly until later November. Total tonnage or grazing days produced from an oats-turnips mix would be less than sorghum, sudangrasses, or pearl millet. One option might be to have some acres planted in oats-turnips and some acres in sorghum-sudangrass with the intention of not grazing the sorghum-sudangrass until after a killing freeze, and/or periodically graze it in September when there is no threat of frost..