There’s Potential for Poisoning During Fall Grazing

By Jordan Penrose

With fall fast approaching, it may be time to assess potential problems that could arise when livestock are grazing, such as trees and grasses. A good practice of walking or driving through your pastures will help you know what is growing in or around them.

Buckeye Poisoning

A potential problem that may be overlooked in the fall is Buckeye Poisoning. Buckeye poisoning occurs from the nuts that fall from the buckeye trees. According to the Ohio Department of Natural Recourses (ODNR), Buckeye trees prefer moist, well-drained soils. Back in 2017, we dealt with buckeye poisoning on the family farm with cattle. The cows and calves that were poisoned had no balance like they were drunk and seemed weak on the legs, especially the back ones. When lying down, they went on their side with their head on the ground pulled back and legs straight out with some muscle twitching. According to A Guide to Plant Poisoning of Animals in North America (2001), the principal toxins are the glycosides aesculin and fraxin, and possibly a narcotic alkaloid. Animals develop signs of poisoning 16 hours after consuming toxic quantities. As little as 0.5% body weight of the animal can produce severe poisoning. Laxatives may be given to remove the ingested plant parts as fast as possible, and if the animal is down for an extended period, keeping the cow hydrated is important.

Cyanide Poisoning

Another problem to watch out for this fall is cyanide poisoning, also known as prussic acid poisoning. Cyanide poisoning can be caused by serval different plants. The main ones are black cherry trees, johnsongrass, and members of the sorghum family, including Sudangrass, sorghum-sudan hybrids, forage sorghum, or grain sorghum. Black cherry trees can cause cyanide poisoning from wilted cherry leaves and branches. It’s best to remove downed limbs and leaves from pastures to prevent incidental intake or keep animals off that paddock until the leaves have completely dried and become a dark chocolate brown color. For grasses that can cause cyanide poisoning, johnsongrass is the most common one that we see in Ohio because it is a weed and grows along the road, in ditches, and in fields. Most of the different sorghums we plant to graze, harvest them for feed for our livestock in the wintertime, or a combination of both. When it comes to the johnsongrass and the different sorghums the things to watch for are frost and the regrowth of sorghums after a harvest. If there is a frost and you want to graze one or more of these grasses, do not graze after a killing frost until plants are dry, which usually takes 5 to 7 days. And after a non-killing frost, do not allow animals to graze for two weeks because the plants usually contain high concentrations of cyanide. In A Guide to Plant Poisoning of Animals in North America (2001), it notes johnsongrass and sudan grasses are the most common cause of cyanide poisoning in cattle and sheep and are especially toxic when growing rapidly. Fertilization with nitrogen increases the potential for cyanide toxicity. Regrowth of sorghums after cutting has a high potential for poisoning and there is an old saying that sorghum should not be grazed until they are above knee height. Cyanide-free hybrids of sudan grasses are available as forage crops for animal consumption. All species of johnsongrass and sorghum may also accumulate toxic levels of nitrate and are a common source of nitrate poisoning in cattle. According to A Guide to Plant Poisoning of Animals in North America (2001), the recommended treatment for cyanide poisoning is the intravenous administration of a mixture of 1 mL of 20% sodium nitrite and 3 mL of 20% sodium thiosulfate per 100 lb. of body weight. The dose can be repeated in a few minutes if no response is seen. Keep in mind that all poisons can be dose-dependent, so even if there is less poison in the leaves or nuts, eating enough of them can have negative consequences.