| New Bulletin 415 |
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Poisonous plants are a major cause of economic loss to the livestock industry. Each year these plants adversely affect 3-5% of the cattle, sheep, and horses that graze western ranges. All too often the losses to individual livestock operations are large enough to threaten the viability of that ranch
Livestock losses can be heavy if animals:
Graze poisonous plant-infested ranges when plants are most toxic.
are driven or trailed through or unloaded from trucks onto range or pasture areas infested with poisonous plants.
are not watered regularly or are allowed to become hungry. Such animals are more likely to eat lethal quantities of poisonous plants.
are allowed to graze in heavy stands of plants that are highly poisonous, such as locoweed or larkspur.
are grazed on rangelands early in the spring when there is no other green vegetation except poisonous plants.
are less selective in their grazing at times of stress such as occur when they are trailed, trucked, penned, or handled (branding, vaccination, etc.)
poisoning depends, to a large extent, on how much and how fast the animal consumes the plant
There are no known treatments for animals poisoned by most poisonous plants. Where a treatment is available, affected animals are usually in remote places and cannot be reached until it is too late to provide the treatment. The stress of handling poisoned animals may enhance the probability of death. If they recover enough to be handled, treatment should consist primarily of symptomatic treatment except where a specific treatment is known.
Prevention of loss from poisonous plants in general is a problem of range and livestock management. Proper diagnosis of livestock poisoning is essential in the identification of specific plant poisoning. However, under range conditions, livestock may eat large quantities of poisonous plants in a short time. Under these conditions, animals may not exhibit typical signs or lesions characteristic of the poisoning. Some plants that are poisonous may form part of the grazing animal's diet. Poisoning occurs when these animals are enticed by hunger or other stress conditions and they eat too much too fast.
Many of the death losses of livestock from grazing poisonous plants are due to management error. This includes failure to examine a pasture or range prior to use. The growth of some of these plants varies from year to year. Failure to know and understand plants in your area that are toxic to livestock can lead to catastrophic losses.
Hundreds of plants are poisonous to livestock. Many are toxic at all times, whereas others are toxic only under certain conditions. Livestock producers are urged to become familiar with the plants on their ranges and pastures that are potentially dangerous to their livestock. Under normal conditions, some poisonous plants form an important part of livestock diets without negative effects on the animals. Intoxication occurs only when they eat too much too fast. Some plants, such as sneezeweed, can be grazed only a short period of time then the livestock must be removed from them before poisoning occurs. Help in identifying these plants can usually be obtained from the local county agricultural agent or mail a sample to the Poisonous Plant Research Laboratory for identification. Help with poisonous plant problems can also be obtained from local veterinarians.
Symptoms listed for each plant toxicity are those most likely to be observed. Not all symptoms will be seen in all toxicities and signs of poisoning may vary greatly, depending on dosage and the time taken to consume the dose. Also, individual animals respond differently to specific poisons.
To protect your animals from poisoning-
Learn to identify the poisonous plants that grow on your range.
Learn the conditions under which these plants can be dangerous to your livestock.
Develop a grazing plan to improve your range and prevent poisoning of your livestock by plants. These plans should take into account the poisonous plants on the range thus allowing animals to graze them at the most appropriate time and/or avoid them.
Do not allow animals that have been under stress or that are overly hungry to graze in areas infested with poisonous plants.
Provide adequate water for your livestock.
Be especially careful when grazing newly acquired livestock on your range.
Provide adequate salt and other supplements as needed, but do not put them in an area where poisonous plants are growing
Control poisonous plants where feasible.
If your animals get sick, consult your local veterinarian to insure proper diagnosis and treatment. If a poisonous plant is involved, identification of the plant by an experienced botanist or poisonous plant expert is essential for any corrective action.
Many poisonous plants can function as useful forages. Poisoning occurs when conditions develop that allow, or cause, the animal to eat too much too fast.
Plants such as poison hemlock, water hemlock, arrowgrass, kochia, hounds tongue, and lupine may be growing on land from which hay is harvested. This is especially true on native grasslands. Care must be taken when feeding this hay.
For additional information on poisonous plants contact us:
USDA-ARS Poisonous Plant Research Laboratory
1150 East 1400 North
Logan, Utah 84341
435-752-2941
