published in

The Peace River Farmer and Rancher

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With the extended drought and hard winter of 2000-01 resulting in overgrazed pastures, this is a prime year for problems with toxic weeds. If given a choice cattle will not eat poisonous plants. Only after all pasture forage and nontoxic plants have been eaten will cattle consume poisonous plants.

Another time when cattle are enticed to eat poisonous plants is following treatment of these plants with herbicides. Apparently, the dying or dead toxic plant loses its identifying taste or odor that warn cattle not to eat the live plant.

Some of the common toxic plants in central and south Florida are nightshade, butterweed or senecio, horsenettle, elderberry, castor bean, pokeweed, crotalaria, wild cherry, bracken fern, and lantana. Like lantana, many toxic plants are ornamental flowers or shrubs grown in the yards of most homes. Other ornamentals include oleander, poinsettia, and allamanda. Cattlemen with pastures in urban areas need to be watchful of neighbors who might discard yard trimmings over the boundary fence. Most often the trimmings include leaves and stems of poisonous plants.

Especially during drought conditions, plants like sorghum, Johnsongrass, and sudangrass accumulate high levels of cyanide. Cyanide toxicity is more of a problem in central and north Florida where Johnsongrass is a common weed, and sorghum and sudangrass are frequently planted for grazing. Even rabbit tobacco, commonplace in north Florida, accumulates high levels of nitrate which can kill cattle if eaten.

Recently a rancher called to obtain information on a plant he identified as a rain lily. After burning a bahiagrass pasture this lily sprouted in abundance. It is a white lily that grows on a moderate-length stem, with leaves around the base. I had seen the lily many times as a lone flower in bahiagrass pasture, and know it as atamasco lily. The bulb of the atamasco or rain lily is the most toxic part, and not likely to be eaten by cattle. However, the leaves and stems are moderately toxic and without access to adequate grass or other forage cattle will eat this lily. The toxicity symptoms are staggering, bloody diarrhea, collapse, and death.

There are many other poisonous plants not mentioned above. A first-rate web site on toxic plants is available at: http://www.caf.wvu.edu/~forage/library/poisonous/index.htm. The site presents excellent photos of each poisonous plant, in addition to information on the plant's appearance, growth habits, and toxicity properties.

For questions or comments regarding this publication contact Findlay Pate

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