Sheep Industry News April 2023

Poisonous Plant Laboratory Identifies Harmful Forage

A s a sheep producer, you most likely spend a lot of time think ing about what your sheep will be eating. But how much do you know about the things they shouldn't be eating? Not all forage is good for sheep. Sheep are natural grazers, and a large percentage of the American sheep flock will spend at least part of the year grazing pastures and public lands. But researchers at the U.S. Department of Agriculture Agricultural Research Service Poisonous Plant Research Laboratory in Logan, Utah, want producers to be knowledgeable about plants that might cause the most problems. "Do we have any magic bullets? No, but we can offer some advice and consult with producers about ways to manage their flocks in these situations," said Research Leader and Plant Physiologist Daniel Cook. "Timing of grazing is an important tool with some of these plants." Losses to the livestock industry from poisonous plants in Western North America and across the world come in many forms. These include death losses from acute and chronic intoxication, reduced weight gains, reduced reproductive efficiency and animals which fail to thrive. Exposure to some toxic plants – such as locoweeds – might predispose animals to other health problems. Further, exposure to poisonous plants might reduce the effective ness of vaccines and other routine veterinary management practices, leading to subtle losses later in the production cycle. In expansive mountainous areas, dead or debilitated livestock attract and retain predators such as bears, complicating flock management and poten tially increasing death losses. Cook said poisonous plants pose less of a threat to livestock in the Eastern half of the United States because animals tend to run on improved pastures in those locations. "Fescue can cause problems with sheep," he said. "There are toxic plants in that part of the country, but it's generally less of a problem." The range livestock industry in the United States boomed after the Civil War as large numbers of cattle and sheep were trailed onto expansive Western rangelands. Soon thereafter, large losses of live stock from poisonous plants were reported as ranchers encountered unknown plants such as locoweeds and larkspurs, among others. USDA first began studying poisonous plants in 1895 in the Western United States, and the first permanent Poisonous Plant Research Laboratory opened in 1955 on the campus of Utah State University. A modern lab was constructed in 2004 in Logan and serves as a "Poison Control Center" for plants and livestock. "Learning to be aware of these plants is an important part of managing livestock around them," Cook said, adding that the lab is developing a smartphone app for producers to use out on the range.

Until it's ready to go – hopefully in late 2023 – producers can rely on Bulletin No. 415, also known as P lants Poisonous to Livestock in the Western States . It's online at ARS.USDA.gov/ARSUserFiles/oc/np/ PoisonousPlants/PoisonousPlants.pdf. Cook encourages producers to reach out to the lab with questions. Visit ARS.USDA.gov/pacific-west-area/logan-ut/poisonous-plant research for contact information. The bulletin lists three dozen plants of concern, ranging from acutely toxic to mildly toxic. Below are four such plants.

DEATH CAMAS Found throughout the Western United States, Death camas is the common name of several species of plants that are poisonous to livestock. Death camas is one of the first plants to begin growth in early spring. Without sufficient other forage, death camas may be heavily grazed and will cause severe losses. Spring snow storms might cover all forage except death camas, which can protrude through the snow and is available to the livestock. Sheep are most likely to be af fected by feeding on death camas.

Occasionally, cattle and horses are poisoned. Death camas contains toxic steroidal alkaloids that occur through out the plant; plants are dangerous at all times. The bulb may be mis taken for those of the edible camas or quamash and can cause severe illness in humans. Some species of death camas thrive on sandy soils; others grow on drier, rocky foothills. The more toxic species are seldom found above elevations of 8,000 feet. Death camas grows early in spring, matures, and enters dormancy during early summer when soil moisture de clines. The leaves appear very early in the spring. In the foothills, death camas generally flowers in April and May. At higher elevations, the plant may flower in late June and July. To avoid poisoning, delay turnout until adequate good forage is available. Do not introduce hungry sheep into heavy stands of death camas. Try to avoid feeding, bedding or trailing sheep through heavy stands. See POISONOUS PLANTS on Page 22

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