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Plants Poisonous to Livestock in Montana and Considerations for Reducing Production Losses

Montana State University Extension Natural Resources Conservation Service University of Wyoming Extension Matrials Technical Note MT-124 Bulletin B-1359 Acknowledgements Poisonous to Livestock in Montana and Wyoming represents a cooperative effort among individuals within the Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS), (MSU) Extension, and University of Wyoming (UW) Extension. This publication is adapted with permission from Poisonous Range Plants of Montana (Leininger et al. 1977) and Plants Poisonous to Livestock in the States (Panter et al. 2011). We acknowledge and thank previous authors for those documents and contributions to this field of study.

Contributors (alphabetical order) Haylee Barkley, USDA-NRCS, Pathways Program, Bozeman, MT Karen Clause, USDA-NRCS, Range Management Specialist, Pinedale, WY Jane Mangold, Ph.D., MSU, Professor and Extension Invasive Plant Specialist, Bozeman, MT Ted Nelson, DVM, USDA-NRCS, Supervisory District Conservationist, Livingston, MT Noelle Orloff, MSc, MSU, Associate Extension Specialist, Bozeman, MT Monica Pokorny, MSc, USDA-NRCS, Plant Materials Specialist, Bozeman, MT Derek Scasta, Ph.D., UW, Assistant Professor and Extension Rangeland Specialist, Laramie, WY Barton Stam, MSc, UW, Range Extension Educator, Thermopolis, WY Susan Tallman, MSc, USDA-NRCS, Area Agronomist, Bozeman, MT Daniel Tekiela, Ph.D., UW, Assistant Professor and Extension Specialist of Invasive Plant Ecology, Laramie, WY

We express our appreciation to the following reviewers: Daniel Cook, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Plant Physiologist, Logan, UT Marko Manoukian, MSU, Phillips Extension Agency, Malta, MT Jennifer Paddock, USDA-NRCS, District Conservationist, White Sulphur Springs, MT J. Daniel Rodgers, Ph.D., UW, Associate Professor and Extension Rangeland Specialist (retired), Laramie, WY Joseph Scianna, USDA-NRCS, Plant Materials Center Manager, Bridger, MT Clinton Stonecipher, USDA-ARS Poisonous Plant Research Laboratory, Range Technician, Logan, UT Kevin Welch, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Toxicologist, Logan, UT

Suggested citation: USDA-NRCS, MSU, and UW. 2020. Plants Poisonous to Livestock in Montana and Wyoming, Considerations for Reducing Production Losses. USDA-NRCS Plant Materials Technical Note MT-124 and University of Wyoming Extension Bulletin B-1359. USDA-NRCS, Bozeman State Office, Bozeman, MT. 43 pg. This publication is available electronically (free) and in hard copy from the NRCS Montana and Wyoming Plant Materials Program, Montana State University Extension, and University of Wyoming Extension websites.

Cover photos: Front top and bottom left: lupine ( sp.) and hemlock ( maculatum), M.Lavin, MSU; Front bottom center and bottom right: larkspur (Delphinium sp.) and milkvetch (Astragalus sp.), USDA-NRCS. Back top and center: poison hemlock () and foxtail barley (Hordeum jubatum), M. Lavin, MSU; Back bottom: deathcamas (Zigadenus venenosus), T. Nelson, USDA-NRCS.

In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, /parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident. Persons with disabilities who require alternative means of communication for program information (e.g. Braille, large print, audiotape, , etc.) should contact the responsible Agency or USDA’s TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English. Table of Contents INTRODUCTION...... 4 Economic Impacts of Poisonous Plants...... 4 Identifying Poisonous Plants...... 5 FACTORS INFLUENCING PLANT TOXICITY FOR LIVESTOCK...... 6 Plant-related:...... 6 Dose...... 6 Season and Plant Growth Stage...... 6 Palatability...... 7 Growing Conditions...... 7 Component of Hay...... 7 Animal-related:...... 8 Animal Species, Gender, Size and Age...... 8 Animal Health...... 8 Animal Response to ...... 8 CONDITIONS LEADING TO LIVESTOCK POISONING AND MANAGEMENT TO REDUCE IMPACTS...... 9 Grazing Rangeland and Pasture that Are in Poor Condition...... 9 Hungry Animals on Infested Rangeland, Pasture or Cover Crop...... 9 Early Season Grazing on Rangeland...... 9 Livestock Familiarity with the Area...... 10 Improper Herding, Driving and Bedding...... 10 Inadequate Nutrient Supply...... 11 Water Quantity and Quality...... 11 Environmental Conditions...... 11 Cultural Practices...... 12 Grazing System...... 12 Multi-species Grazing...... 13 Crop and Cover Crop Grazing...... 13 CARE FOR IMPACTED ANIMALS...... 13 CONTROL OF POISONOUS PLANTS...... 13 POISONOUS SUBSTANCES AND OTHER FORAGE PROBLEMS...... 14 PRINCIPLE ...... 14 Alkaloids...... 15 Cardiac Glycosides...... 15 Cyanogenic Glycosides...... 16 Nitrate...... 16 Oxalates...... 17 Saponins...... 18 Selenium...... 18 OTHER FORAGE PROBLEMS AND DISORDERS...... 19 Bloat...... 19 Mechanical Injuries...... 19 Mycotoxins...... 19 Photosensitization...... 20 Volatile Oils...... 20 RESOURCES AND REFERENCES...... 40 GLOSSARY ...... 42

TABLE 1. Signs of poisoning and conditions under which plant species can be dangerous to livestock. Symptoms listed for each plant 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 toxins...... 21 TABLE 2. Toxic doses for commonly diagnosed plant poisonings in Montana and Wyoming. For some plant species, signs of livestock poisoning may not be evident until a toxic threshold is reached...... 31 TABLE 3. The origin and habitat of plants with toxic properties in Montana and Wyoming...... 34 Introduction Poisonous plants contain or produce substances that cause sickness, metabolic disorders, death, or health concerns in animals when ingested. Each year these plants adversely affect 3 to 5% of the cattle, sheep, goats, and horses that graze rangelands, pasture, and forest lands. There are many plants in Montana and Wyoming that have been suspected of being poisonous. However, these plants vary in their toxicities, the types of animals affected, and the environmental conditions when poisoning occurs. For example, a plant species might provide good forage for sheep yet be poisonous to cattle and horses. Another plant may provide excellent nourishment in small amounts or during certain seasons but be poisonous under different conditions. Photo: USDA-NRCS Poisonous plants will always be present on rangeland, Wild onions (Allium sp.) are native plants that emerge in the early pasture, and forest lands, and may be intentionally in a variety of plant communities. Livestock can exhibit planted as cover crops or forages on croplands. Many poisoning effects if their diets contain large quantities (e.g. 25% poisonous plants are native to Montana and Wyoming diet) of onion . and naturally occur in plant communities. Other poisonous plants are introduced (i.e. non-native) This publication describes signs of poisoning and species, and some of these introduced species are livestock affected (Table 1), toxic doses and factors invasive and spreading across the region. influencing toxicity (Table 2), and the habitats where Mismanagement of rangeland and pasture can these poisonous plants grow in Montana and Wyoming allow these introduced and native poisonous plants (Table 3). The publication also describes environmental to increase since some of them are unpalatable. and management conditions leading to livestock Additionally, poor livestock management may increase poisoning along with management considerations to the likelihood of poisoning. Rangeland and pasture prevent or minimize impacts. should be regularly inspected for poisonous plants and the information used to make prudent livestock and Economic Impacts of Poisonous Plants grazing management decisions. Poisonous plants cause an economic loss to the livestock industry. In 1992, the economic value from direct losses of cattle and sheep in the 17 western states was $340 million dollars, which would exceed $600 million today when adjusted for inflation. In addition, there are indirect economic impacts from poisonous plants associated with increased management costs. Direct impacts include the following effects on animals: • Death • Abortions • Birth defects • Weight loss due to illness or decreased feed intake • Lengthened calving interval • Decreased fertility • Decreased immune response Photo: USDA-NRCS • Increased organ damage (e.g. lungs, liver, nervous Black henbane (Hyoscyamus niger)1, an introduced invasive system, etc.) species from , can increase with poor pasture management. • Loss of breeding stock due to mortality, functional Its foliage has a pungent odor and is not usually consumed by livestock unless desirable forage is lacking. When consumed, inefficiency, etc. symptoms of poisoning include dilated pupils and convulsions.

1 Nomenclature, common and scientific names, follows USDA PLANTS Database, 2019.

- 4 - The maintenance of regular, detailed livestock management records can be a useful tool when diagnosing plant poisoning for an animal displaying symptoms. For example, information about the date animals entered a pasture, where they moved from, their general health prior to symptom onset, and utilization of suspected plants can all be important. If the animal is alive, careful observations and notes about its behavior should be made. If the animal has recently died, an inspection in the digestive tract (or a complete necropsy) for identifiable plant parts is recommended, along with an examination for abnormal-appearing organs. Contact a veterinarian or other qualified Photo: M. Lavin, MSU individual for help making a diagnosis. Whether or Halogeton (Halogeton glomeratus) has red stems and fleshy not an animal is treated for plant poisoning may be leaves. It has caused hundreds of livestock deaths in a single decided by behavioral observations, noted above, and day at one location in various western states. Livestock should by correct identification of the suspected poisonous not be allowed to become hungry or thirsty while grazing in areas infested with halogeton, as they will graze indiscriminately. Proper plant. Ultimately, correct identification of the plant is rangeland management is the best way to minimize livestock essential for any long-term proactive corrective action losses. and should be considered an important starting point if problems occur. Indirect losses include the following management costs: When the presumed causal plant is identified, it should be collected for verification by someone with plant • Building and maintaining fences identification expertise. Collect the entire plant or, if • Increased feed requirements too large, representative parts of the plant (roots, stems, • Increased medical treatments leaves, flowers, fruits, and unique attributes). Record • Altered grazing programs information regarding date, location, habitat, plant • Decreased forage availability size, and plant growth characteristics. Photographs • Decreased land values of the plant and its habitat are also useful. Soon after • Increased stress on livestock managers collection, press the specimen between two pieces of newspaper or cardboard to air dry. Alternatively, place Identifying Poisonous Plants the plant in a bag in a refrigerator for short term storage There is no single rule or characteristic that can be if needed. If mailing the specimen for verification, used to determine a toxic plant from a non-toxic place the pressed sample or bag in a padded envelope plant. To protect animals from poisoning, learn to or box. Use caution when handling specimens as some identify poisonous plants that are common to the plants are toxic to humans too! and obtain reliable information on their poisonous properties. Some poisonous plant publications focus on plant identification; however, this publication does not because plant identification resources are readily Submit samples to one of the following: available. We provide a list of resources to aid in • Local Extension or USDA-NRCS offices identification in the Resources and References Section • Montana State University Schutter below. Diagnostic Laboratory (http://diagnostics.montana.edu/) Sudden onset of illness with no apparent cause may indicate poisoning by a toxic plant. If plant poisoning is • University of Wyoming Herbarium suspected, the responsible plant(s) must be identified, (http://rmh.uwyo.edu/data/search.php) which is sometimes a difficult task. Symptoms may be • USDA-ARS Poisonous Plant Research similar across multiple poisonous plants, all symptoms Laboratory (https://www.ars.usda. may not manifest, and some symptoms may be atypical. gov/pacific-west-area/logan-ut/ Sometimes poisoning is even caused by a plant not poisonous-plant-research/) commonly recognized as toxic. Examine the rangeland or pasture for poisonous plant species.

- 5 - Factors Influencing Plant Toxicity to Livestock Plant-related Season and Plant Growth Stage Poisonous plants vary in their toxicities and palatability Dose with season and growth stage. Rangeland and pasture The dose (i.e. amount consumed) needed for a plant should be examined for the kinds, quantities, and to cause undesirable effects to livestock depends distribution of poisonous plants before livestock are on factors like the amount and concentration of a allowed to graze. Some areas should be avoided during toxin and how rapidly it is consumed. In plants, the the most dangerous season if dense stands of poisonous dose is influenced by growing season, growth stage, plants grow there. For example, some plants are most palatability, and growing conditions. Some plants palatable during their early growth stages, making are lethal after one exposure or a short duration of spring the most dangerous period for poisoning. time, other plants may require ingestion of large amounts before affecting livestock, and other plants cause poisoning weeks or months after ingestion. Acute poisoning occurs when animals are exposed to a toxic dose on one occasion or for a short time and symptoms are relatively instantaneous. For example, cattle or sheep consuming small amounts of poison hemlock will exhibit symptoms of poisoning within an hour. Chronic poisoning is long-term, repeated, or continuous exposure to a toxin. The toxins accumulate in the animal’s body over time, symptoms are delayed, and damage is usually irreversible. For example, cows consuming lupine during their early gestation period may show no evidence of poisoning until they give Photo: M. Lavin, MSU birth to calves with cleft palates and skeletal defects Chokecherry (Prunus virginiana) leaves have finely toothed (i.e. crooked calf syndrome). margins and a short, pointed tip. The toxic substance in chokecherry, hydrogen cyanide, is found principally in the leaves. Information on what constitutes a toxic dose is Leaves become less toxic as the growing season progresses. only available for commonly problematic species in Montana and Wyoming (Table 2), and, in many cases, Some poisonous plants are most toxic when they are is based on limited scientific research. The toxic dose is immature, others when mature, and still others are dependent on plant-related factors discussed below, as equally toxic at all growth stages (see Tables 1 and 2). well as animal-related factors such as animal health, Toxic substances are often concentrated in certain plant species, and age. tissues, and negative impacts may only be apparent

Photo: USDA-NRCS Photo: A. Oomen, bugwood.org Photo: T. Nelson, USDA-NRCS

Lupines (Lupinus spp.) have palmately Poison hemlock (Conium maculatum) is 2 to 20 feet tall with white flowers, compound leaves which radiate from a central finely dissected leaves, and purple spots on the stem. Livestock poisoning point. Lupine poisoning can be reduced by is most common in the early spring when tender, succulent, highly toxic keeping hungry animals away from lupine in new leaves begin growth. early growth stages and in late summer when the plant contains seeds that are very toxic.

- 6 - when consumed at the time of year when these tissues problem can be exacerbated by a lack of palatable are available. For example, plants with toxins most forage during drought which can cause livestock to eat concentrated in seeds should not be grazed during any plant available, even species with toxic properties. seed development and ripening. The concentration of different elements in soil can Palatability influence several species of poisonous plants. For example, certain species of saltbush and milkvetch Palatability is important because it determines livestock growing in soils high in selenium accumulate toxic utilization of poisonous plants. Many poisonous plants quantities of this element, whereas the same saltbush are not very palatable, so animals will usually select species may provide good forage on soils low in more palatable, non-poisonous species. If an area does selenium. not offer enough palatable non-toxic forage, however, animals are more likely to consume toxic quantities of poisonous plants. In addition, palatability is highly variable and can change over the growing season or in response to recent climatic events (e.g. frost) or vegetation management. For example, many species, including poisonous plants, are more palatable for a few weeks following herbicide or fertilizer application.

Photo: M. Lavin, MSU

Shadscale saltbush (Atriplex confertifolia) has grayish bark, alternate leaves, and fruits with four conspicuous wings. It accumulates high levels of selenium when growing in selenium-rich soils and can cause chronic selenium poisoning when consumed by livestock .

When certain species grow in the same vicinity and are grazed in combination, toxic effects can vary. For example, sheep feeding on horsebrush just following or in conjunction with black sage and then exposed to bright sunlight may develop a characteristic swelling of the head called bighead (i.e. photosensitization). Sheep grazing horsebrush alone may experience toxic impacts without developing bighead.

Component of Hay Photo: K. Clause, NRCS Plant toxicity may increase, decrease, or remain Arrowgrass ( maritima) has fleshy, dark- static when foliage dries. This factor and the plant’s green, grass-like leaves and a slender flower stalk. Arrowgrass plants quickly become toxic when stage of development when harvested, is important stressed or damaged from drought, frost, or cutting. in determining toxicity of hay containing poisonous Foliage that re-grows following harvest is also toxic. plants. When poisonous plants are mixed with non- poisonous plants and fed together in hay, livestock Growing Conditions are unable to discriminate between them as readily Plants growing during stressful conditions (e.g. as when grazing in a field and are consequently more drought, freezing) commonly have increased toxicity vulnerable to poisoning. Areas containing substantial levels. For example, arrowgrass grown with adequate amounts of poisonous plants should not be hayed, and moisture does not cause hydrogen cyanide poisoning, hay containing poisonous plants should not be fed to but when growth is stressed or stunted from inadequate livestock without consulting with the local Extension moisture, arrowgrass quickly becomes toxic. This agent, NRCS employee, or another qualified person.

- 7 - example, ingestion of ponderosa pine needles by male cattle appears harmless while it may cause abortions in pregnant females. Additionally, the size of animals within a class of livestock may be proportional to the quantity of toxin required to cause poisoning. As animal size increases, the amount of poisonous plant needed to be consumed to cause toxicity symptoms also increases. Younger animals are usually more

Photo: T. Nelson, susceptible to poisoning than older animals. It has been USDA-NRCS Photo: USDA-NRCS shown that yearling steers may be more susceptible to Horsetail species (Equisetum spp.) have hollow, jointed stems, larkspur poisoning than two-year-old steers. and grow in moist to wet meadows and pastures. Horsetail can have whorls of branches at the joints (left photo) or a single, unbranched stem (right photo). It is often cut and incorporated in Animal Health hay where it retains toxic properties when dry. Cattle or horses Animals within the same livestock class or breed fed hay containing more than 20% horsetail can experience gastrointestinal and nervous system poisoning effects. may vary in their susceptibility to plant toxicity. For example, in a study that dosed Angus steers with Animal-related larkspur and then imposed the steers to stressful Animal Species, Gender, Size, and Age conditions, 40% were considered resistant and the Some poisonous plants have a more negative effect on remaining 60% were too sensitive to even impose one specific class of livestock, while other plants are the stress without risk of death. Livestock in poor equally toxic across all classes. Different classes of condition or subjected to adverse conditions or stress livestock preferentially graze certain types of plants. (e.g. temperature, exertion, etc.) are usually more For example, cows and horses prefer grasses, while susceptible to poisoning than non-stressed animals sheep prefer forbs and shrubs. Rangeland and pasture in good condition. Hungry animals may ingest higher should be inspected for the kinds and quantities of quantities of a poisonous plant, while satiated animals poisonous plants before grazing. This information are more selective and tend to consume lower doses of can be used to decide what class of livestock should a toxic plant. In general, an animal will consume less be grazed. Livestock losses may be prevented by poisonous plant tissue when it can graze selectively. grazing those animals that will not be harmed by the poisonous plants present. Also, skin color can determine susceptibility of animals to photosensitivity after eating certain poisonous plants. For example, light- to white-skinned individuals (Hereford cows, white-faced horses) are more photosensitive and will suffer sunburned faces or udders. Toxicity to some poisonous plants is gender-specific, particularly as it pertains to animal reproduction. For

Photo: M. Lavin, MSU Photo: M. Lavin, MSU

Milkvetch species (Astragalus spp.) have pea-shaped flowers and grow in a variety of native habitats. Many milkvetch species can cause acute or chronic poisoning of livestock. Cattle will readily eat some toxic milkvetch species even when other forage is available. To reduce livestock losses, prevent animals from grazing these plants for extended periods, feed protein supplements, and avoid stressing cattle that have grazed toxic milkvetch species.

Animal Response to Toxin Photo: USDA-NRCS Some toxins quickly change to harmless substances Ponderosa pine () can cause abortions during the last trimester of pregnancy if upon ingestion or are rapidly eliminated after entering cattle graze approximately 5 to 6 pounds of needles. the body and are therefore usually of little danger to The needles are generally grazed during the winter an animal. Alternatively, toxins rapidly absorbed into when forage is lacking or -covered. Prevent poisoning by limiting access to ponderosa pine during the animal’s following ingestion are the last trimester. very dangerous. - 8 - Conditions Leading to Livestock Poisoning and Management to Reduce Impacts

The most effective way to prevent livestock loss from palatable species are reduced in abundance and less poisonous plants is to properly manage rangeland, palatable species, including invasive and/or poisonous pasture, forest, and livestock. Develop a grazing plan plants, increase. As pasture condition continues to that improves or maintains rangeland or pasture decline, animals have to consume increasing quantities condition and prevents poisoning. Plans should of less palatable and possibly poisonous plants to consider poisonous plants in the area, allowing animals meet their nutritional requirements. The association to avoid them or graze them at the most appropriate between scarcity of forage and increased consumption time. Poisoning typically occurs when livestock of poisonous plants cannot be ignored when trying to are enticed by hunger or other stressful conditions, mitigate toxicity issues. Livestock managers should use although there are exceptions where animals may good grazing management, graze during the correct show an unexplained preference for a poisonous plant. season, and use appropriate animal stocking rates. Livestock managers should know what poisonous plants are present and how to prevent animal intake. Hungry Animals on Infested Rangeland, Hundreds of plants are poisonous to livestock at certain Pasture or Cover Crop doses. Many are always toxic, whereas others are toxic Hungry animals graze less selectively than satiated only under certain conditions. In some situations, a animals and tend to eat whatever is within close poisonous plant may even form an important part of proximity. Hungry animals should never be exposed to livestock diets without negative effects on the animals areas with large concentrated populations of poisonous (e.g. greasewood). plants. Poisoning often occurs when animals consume too much or eat too rapidly, behavior typical of hungry Grazing Rangeland and Pasture animals. that Are in Poor Condition A common condition under which plant poisoning Early Season Grazing on Rangeland occurs is grazing rangeland and pasture that are in When native rangeland or pastures are grazed too poor condition. Generally, as vegetation is overgrazed, early in the growing season, the earliest growing

Photo: USDA-NRCS Photo: M. Lavin, MSU Many invasive plants have poisonous properties including houndstongue, blueweed, field bindweed, hoary alyssum and more (see Table 3). Houndstongue (Cynoglossum officinale) is an invasive biennial forb that is sometimes harvested in hay where it can cause poisoning. Animals may graze pasture containing poisonous invasive plants without ill effects if ample good forage is available.

- 9 - species must carry the grazing load. If palatable, Improper Herding, Driving and Bedding non-poisonous plants are unavailable, livestock Crowded animals need time to scatter across an area will eat whatever is available, including poisonous large enough to allow selective grazing. When animals plants. Several poisonous plants (e.g. low larkspur, are crowded, they may be forced to eat whatever lupine, deathcamas) are among the first to emerge vegetation is available. Livestock managers can minimize in the spring and are in their most succulent stages. poisonous plant consumption by using open or loose Livestock should not be released onto rangeland or herding methods with slow movement. pasture until adequate desirable forage is available to support grazing. Animals often become nervous when they are driven or trailed. When being moved, animals are also unable to Livestock Familiarity with the Area quickly satisfy their hunger like they would under normal Animals new to an area, especially previously pasture conditions, and they become less selective in their confined animals, tend to graze less selectively and plant consumption. Animals that are both hungry and may consume a greater diversity of plants (including driven quickly are even more susceptible to poisonous poisonous plants) than animals which are familiar plants. To minimize losses, animals should be satiated with the area. In other words, they are naïve to toxic and driven slowly through areas with poisonous plants. plants in a new pasture. Where livestock are grazed Livestock prefer to graze late in the evening and in the in unfamiliar areas, handlers should watch animals morning after leaving their bedding grounds. They are carefully. Be especially careful when grazing newly less selective in their grazing habits during these times acquired livestock that are in unfamiliar rangeland and are more likely to consume toxic quantities of or pasture. Once an animal becomes familiar with an poisonous plants. The risk of plant poisoning increases area and its toxic plants, it may be safe to graze the when animals are bedded down in the same area for pasture. For example, on rangelands where locoweed several nights. is abundant, it is safe to graze only those animals High-use areas are subject to overgrazing of palatable which are acquainted with locoweed but do not seek plants, resulting in an increase of unpalatable plants, it out for consumption. many of which are poisonous. Livestock managers can

Photo: USDA-NRCS Photo: M. Lavin, MSU Photo: USDA-NRCS

Meadow deathcamas (Zigadenus Locoweed species (Oxytropis spp.) are Greasewood (Sarcobatus vermiculatus) is venenosus), a perennial with long poisonous at all stages of growth throughout adapted to saline soil where it uptakes and linear leaves, is one of the first the year including when dried. Livestock that accumulates soluble sodium and potassium plants to begin growth in early have never grazed locoweed will usually oxalates in the fleshy leaves. It can be safely spring. Without enough other avoid it; however, once consumed, an animal eaten by livestock in moderate amounts with forage, deathcamas species may can become habituated to grazing locoweed. other forage. However, poisonings can occur be heavily grazed and will cause Livestock owners can reduce losses by when livestock eat large amounts of greasewood livestock losses. removing locoweed-eating animals from the leaves or buds in a short period of time. herd.

- 10 - reduce losses by selecting new and bedding difficult for livestock to graze as discriminately as under grounds when possible. drier conditions. When this situation arises, consider moving livestock to other areas or feeding supplements Inadequate Nutrient Supply to reduce consumption of poisonous plants. Animals with nutrient deficiencies often seek plants Drought can lead to early maturation of many that contain high levels of the nutrient that the animal palatable plants. In contrast, several poisonous plants is lacking. For example, salt-deficient animals may remain green during drought (e.g. deep-rooted lupines seek out and excessively consume salt-accumulating or locoweed; evergreen yew or laurel). As a result, plants like greasewood. To minimize losses, place salt these poisonous plants may become more attractive and phosphorous supplements in several locations in to livestock, receive more use, and increase the risk of the pasture and throughout the entire period of use of poisoning. The adverse effects of drought are worsened the pasture. Salt and phosphorous supplements can also be used to improve livestock distribution and lure them away from areas supporting poisonous plants. Do not place salt and other supplements in an area where poisonous plants are growing.

Water Quantity and Quality Animals tend to graze indiscriminately when they have been without water for more than two days and are finally given the opportunity to drink. Therefore, do not place or develop water in areas where toxic plants are present. Always provide animals with an adequate supply of water. Water quality is an important aspect of livestock management and animal performance. If water sources become contaminated with fertilizers or manure, blue- green algae can proliferate and lead to poisoning. Pesticide drift may also contaminate water sources and endanger livestock. Additionally, elevated levels of nitrates, metals (e.g. , lead, zinc), and other elements (e.g. selenium, arsenic, boron) in soil can lead to unsafe levels in surface and groundwater. Have water sources tested annually, determine if results are within recommended water quality standards, and take steps to determine the source of any problem.

Environmental Conditions Late spring and early fall snowstorms may cover shorter, more desirable species, leaving taller statured poisonous plants like tall larkspur, deathcamas, and lupine as the only vegetation available to livestock. Poisoning potential may be compounded in the fall if fruiting (podded) plants extend above the snow, and those fruits are highly toxic. To minimize losses, either Photo: T. Nelson, USDA-NRCS move or feed supplements to livestock subjected to Many plant species with poisonous properties, including these conditions. tall larkspur, water and poison hemlock, , and buttercup, grow near livestock water sources such as seeps, springs, Following heavy rain, some poisonous plants become or wet meadows (see Table 3). Livestock should be more palatable or toxic because the rain stimulates new moved from areas where poisonous plants surround water developments, especially during the species’ toxic window. plant growth. This is especially problematic if other Tall larkspur (Delphinium occidentale) poses a risk of vegetation becomes matted and entangled, making it poisoning during flower and early seedpod growth stages.

- 11 - on overgrazed rangeland and pasture where more number of animals per acre) and is the cumulative palatable non-poisonous plants were already stressed. effect grazing animals have on forage during a time These areas are also susceptible to an increase of period. For example, an intensive grazing management poisonous plants when wet years follow drought. system does not necessarily lead to high grazing Well-managed rangeland and pasture leaves some intensity (utilization) but it does require management forage to carry-over for use during drought. During that optimizes stocking density and duration to achieve extended droughts, livestock numbers may need to be utilization objectives. reduced or supplemental feeding initiated. Timing can be manipulated to avoid grazing when plants are most toxic. Intensity can be manipulated in Cultural Practices some situations to alter the selectivity or amount of a Cultural practices, such as spraying herbicides or plant that is consumed by each animal. For example, spreading fertilizer, may increase the palatability of high intensity grazing systems (i.e. a higher density poisonous plants for a short time after application. of animals for a shorter amount of time in a pasture) Certain herbicides (e.g. glyphosate, 2,4-D) will increase result in lower forage selectivity. While this could lead the plant sugar content and sweetness, making it more to increased consumption of poisonous plants, and palatable to livestock. Salt-based herbicides can also must be carefully managed, this approach may also make poisonous plants more attractive. All animals limit the amount of exposure any single animal has to should be kept off rangeland or pasture supporting a poisonous plant, thus limiting dose. High intensity poisonous plants for at least two weeks following grazing systems are most effective when there is applications of herbicides or fertilizers, and always adequate non-toxic forage and fewer poisonous plants. follow grazing restrictions on the product label. It is important to note that pastures that are grazed Grazing System with high frequency and long duration can expose Grazing systems vary by timing, frequency, duration, livestock to higher risk of consuming a toxic dosage of and intensity of livestock use and can be manipulated a poisonous plant as the livestock exhaust preferred to help manage poisonous plants. Timing refers to the forages. However, when livestock are moved more season grazing occurs, and frequency is how often frequently to new pastures with adequate high- a pasture is grazed. Duration is how long a pasture quality forage, the risk of consuming poisonous plants is grazed. Intensity involves stocking density (i.e. decreases. Because some poisonous plants are more palatable or available at certain times of the year, seasonal grazing can be a consideration for avoiding poisonous plants at toxic doses. In the example of tall larkspur, infested pastures could be grazed early or late, ultimately avoiding the toxic window (or the time when toxicity is greatest) that occurs for about five weeks at

Photo: USDA-NRCS the start of the flowering stage and ends in the pod stage. However, a grazing system that relies on grazing a pasture every year Photo: M. Lavin, MSU during the same season can also result Locoweed species (Oxytropis sericea pictured here) grow in a variety of in decreases in palatable, non-poisonous habitats, have pea-shaped flowers that can be white, yellow, blue or purple, and can remain green when other vegetation is dormant. Livestock owners plants and increases in less palatable and can reduce locoweed losses by keeping animals off pastures until good poisonous plants, particularly in a rangeland forage is available. setting.

- 12 - Multi-species Grazing week after a killing frost. In addition, when selecting The use of different livestock species in a multi-species species for a cover crop mix that will be grazed, plant grazing approach is a strategy to mitigate toxicity. a diverse cover crop mix, use certified seed, and select For example, sheep can tolerate larkspur at doses varieties low in HCN to minimize the risk of poisoning. four times greater than cattle, so larkspur poisoning A cover crop sample should be tested for nitrates prior of sheep is rare. A strategy of grazing sheep prior to to grazing. grazing cattle could reduce larkspur abundance and decrease the risk of cattle consuming larkspur later.

Crop and Cover Crop Grazing Crop and cover crop management, harvesting, and storage may influence the risk of livestock poisoning. Most toxicity risks with grazing cover crops are associated with nitrates in small grains, hydrogen cyanide (HCN, also known as prussic acid) from sorghum and sorghum-sudangrass, and mycotoxins such as fusarium and ergot from various grass species. In general, monocultures or low diversity cover crops on highly fertilized land pose the highest risk of Photo: M. Henning, USDA-NRCS accumulating nitrates and affecting livestock if grazing is too heavy. Similarly, appreciable quantities of HCN Cover crops usually palatable and nutritious to livestock can pose a poisoning risk during periods of environmental can accumulate in new growth of cover crop species stress or as a result of crop management, harvest, or following clipping, drought, frost, hail damage, or storage. grazing. Risks of poisoning from crops can be reduced by waiting to graze until plants have reached the proper height, maintaining a six-inch stubble height, grazing Care for Impacted during daylight only, and waiting to graze until one Animals Preventing livestock poisoning is usually easier than curing a poisoned animal. There is often no antidote available for a plant toxin, and rangeland or pasture conditions may make treatment difficult. When a poisoned animal is found alive, if possible and without causing stress, it should be placed in a cool, shaded area with proper food and water. However, care should be taken when moving animals. Moving animals impacted from consuming a poisonous plant (e.g. larkspur) can exacerbate the problem. Contact a veterinarian as soon as possible to diagnose and treat the animal.

Photo: M. Lavin, MSU

Help with poisonous plant problems may also be obtained from local veterinarians: Photo: M. Lavin, MSU • Wyoming State Veterinary Laboratory Larkspur (Delphinium spp.) is highly palatable to cattle, and losses occur when cattle graze larkspur-infested areas when it is (http://www.uwyo.edu/wyovet/) abundant or growing in large patches. Low larkspur (Delphinium bicolor), with its characteristic blue-purple spurred flowers, • Montana Veterinary Diagnostic completes its lifecycle in the early spring. Livestock losses can Laboratory be prevented by deferring grazing until plants lose their flowers (http://liv.mt.gov/Diagnostic-Lab) and pods when it rapidly senesces.

- 13 - Control of Poisonous Plants Many poisonous plants in Montana and Wyoming are invasive properties, and some are listed on county or native species and a natural part of plant communities. state noxious weed lists (e.g. leafy spurge, common Most native poisonous plants do not naturally tansy; Table 3). Be aware that some herbicides (e.g. 2,4- dominate the plant communities where they occur, or D) may increase palatability of the toxic plants. Also, their presence is the result of disturbance. Generally, herbicides may impact desirable non-target plants control of native poisonous plant species is not needed. and reduce diversity and quality of the vegetation. If Instead, good grazing management strategies should chemical control is necessary, obtain management be implemented to allow desired species to outcompete information from your local Extension, Montana Weed poisonous ones. Proper stocking rates and the initiation District, or Wyoming Weed and Pest office. of a good grazing system may reduce the abundance of poisonous species through competition with desired non-poisonous species. In addition, several poisonous native plant species have beneficial forage attributes which offset their poisonous properties. For example, greasewood is poisonous when eaten nearly exclusively but is valuable forage when consumed with a moderate amount of other desirable forage plants. If small scale management of native poisonous plants is necessary, mechanical (mowing, digging), cultural (exclusion fence, proper land management), biological (selective grazing, insects), herbicides, and/or revegetation can Photo: USDA-NRCS be used. Leafy spurge (Euphorbia esula) can form dense infestations that can cause skin and gastrointestinal In contrast, many introduced (i.e. non-native) issues for cattle but can be managed by sheep plant species with toxic properties can form dense grazing. Control methods for poisonous plants will infestations. Many of these species have weedy or depend on the species, site condition, and size of the infestation.

Poisonous Substances and Other Forage Problems Poisonous plants contain at least one of the • Substances absorbed from soil and accumulated following: to toxic levels by the plant. For example, several milkvetch species can accumulate selenium. • Substances that are directly poisonous to livestock. Alkaloids contained in certain • Substances which make parts of the affected lupine species and oxalates contained in animal hypersensitive. An example is the halogeton are common examples. pigment hypericin (contained in St. Johnswort) that causes white-skinned animals to be • Substances that are themselves harmless, hypersensitive to sunlight. but become toxic as they decompose slightly before or upon ingestion by the animal. • Miscellaneous substances such as toxic elements Chokecherry leaves, for example, contain or metals (fluorine, arsenic, etc.) that can the glycosides amygdalin and prunnasin accumulate on or in plants found near industrial which, upon hydrolysis (mixing with rumen developments, toxic products formed by fungi microbes), forms highly toxic hydrogen in moldy hay or silage, contact irritants, and cyanide (also known as prussic acid or poor water quality caused by blue-green algae hydrocyanic acid). blooms.

- 14 - Principal Toxins The most common toxic substances in Montana and Wyoming plants are described below. Less common toxic substances are described in the Glossary. Alkaloids Alkaloids are generally present in plants as an organic acid. There are over 40 different types of alkaloids that cause poisoning, and some plants may contain more than one. Alkaloids are always present and well- distributed throughout plant tissues. The relative toxicity and concentration of individual alkaloids varies among plant species and populations. Common human-consumed alkaloids include caffeine and Photo: USDA-NRCS nicotine. Types of toxic alkaloids include steroidal, Nightshade species (Solanum nigrum pictured here) have tomato- pyrrolizidine, indolizidine, piperidine, diterpenoid, like, star-shaped flowers with five petals. They are not usually palatable to livestock but cause issues when harvested with hay or quinolizidine, and tropane. grain crops then fed to livestock. Losses can be minimized through pasture management and weed control. Symptoms: Alkaloids ingested by livestock cause a strong in a progressive decrease in electrical conductivity physiological reaction. Alkaloids, such as those found through the heart and blocks cardiac activity. While in larkspur, induce muscular paralysis. Swainsonine, low doses of cardiac glycosides can be beneficial by associated with locoweed, causes significant poisoning slowing heart rate, increasing the contraction force issues referred to as “locoism.” Signs of locoism may and increasing cardiac output, animals consuming include depression, circling, staggering, reproductive toxic doses develop heart and digestive disturbances failure, heart failure, and weight loss. In addition, a leading to death. Additional signs of poisoning include compromised immune system stemming from locoism rapid breathing, cold extremities, and a rapid, weak, may lead to other ailments such as foot rot, pneumonia, irregular pulse caused by cardiac arrhythmias and warts, and other infections. Alkaloid symptoms of the heart block. Death typically occurs within 24 hours of extremities (i.e. feet and ears) include vasoconstriction the onset of symptoms. and reduced blood flow. Teratogenic species, including Plants containing cardiac glycosides: locoweed, groundsel, false hellebore, lupines, and poison hemlock, harm the developing fetus if plants Milkweeds and dogbanes can cause cardiac glycoside are consumed at certain stages of gestation. poisoning. However, cases of cardiac glycoside problems are rare, especially for dogbane. Plants containing alkaloids include but are not limited to: tall and low larkspur, monkshood, poison hemlock, deathcamas, nightshades, black henbane, locoweed, lupines, tansy ragwort, houndstongue, milkvetch, yew, false hellebore, and others. Cardiac Glycosides Cardiac glycosides have direct effects on cardiac func- tion. Cardiac glycosides are present throughout the plant, especially the leaves, and retain reduced toxic- ity when dried. Small quantities of ingested plants can cause symptoms.

Symptoms: Photo: USDA-NRCS Cardiac glycosides directly impact the gastrointestinal Milkweed species ( speciosa pictured here) can have tract causing hemorrhagic enteritis, , broad or linear leaves arranged alternately or in whorls. It is most dangerous when actively growing, but toxicity decreases with and diarrhea. Cardiac glycosides also inhibit the cellular drying. Livestock tend to consume milkweed when other forage is membrane sodium-potassium pump which results limited, after a frost, or when it is incorporated in hay.

- 15 - Cyanogenic Glycosides Cyanogenic glycosides are indirectly toxic in that they hydrolyze to produce hydrogen cyanide (HCN, also known as prussic acid) in the presence of certain enzymes and when acted upon by microorganisms in the plant or rumen. Hydrogen cyanide is a highly toxic, rapidly acting poison that inhibits oxygen utilization Photo: T. Nelson, USDA-NRCS by cells. Some plants naturally have high levels of cyanogenic glycosides, especially in early growth stages, rapidly growing plant parts, and seeds. In other plants, the level of cyanogenic glycosides is influenced by climatic conditions, soil factors, and other factors that slow growth. Enzymatic conversion to HCN is enhanced when plant cells are damaged from drought, wilting, freezing, or crushing, or when stressed from low soil moisture, high nitrogen, low phosphorous, or herbicide applications. Avoid grazing plants high in cyanogenic glycosides Photo: T. Nelson, USDA-NRCS while these conditions exist and wait at least Serviceberry (Amelanchier alnifolia) grows up to 13 feet tall and produces clusters of white flowers in early spring. The upper ½ to ¾ edge of the a week after a severe drought or frost before is toothed which distinguishes it from chokecherry whose leaves are grazing. Hydrogen cyanide deteriorates with toothed along the entire edge. Like chokecherry, serviceberry produces time; therefore, dried hay is safe to consume. hydrogen cyanide and foliage is especially poisonous in the early flowering stage. Symptoms: Hydrogen cyanide rapidly inactivates cellular Nitrate respiration leading to a characteristic cherry- Nitrate poisoning is caused by excessive consumption of nitrate red venous blood from the failure of oxygen (NO3) or nitrite (NO2). Under normal conditions, nitrates are releasing at the tissues. The heart and brain converted during digestion to nitrite; the nitrite then becomes are affected by a lack of oxygen, causing death ammonia which in turn is converted to protein. When high to occur within one to two hours or several levels of nitrates are consumed, nitrite will accumulate in minutes in acute cases. Signs of poisoning prior the rumen. Since nitrite is up to ten times more toxic than to death include difficulty breathing, frothing nitrate, poisoning can occur. Nitrate poisoning is a problem at the mouth, irregular pulse, dilated pupils, for ruminants (cattle, sheep) but is unlikely in monogastric staggering, muscle , bright red mucous animals (horses) because monogastric animals can’t readily membranes, and convulsions. Chronic ingestion convert nitrate to nitrite in their digestive systems. of low levels of cyanogenic glycosides can cause various neuropathies, musculoskeletal Nitrates are most concentrated in plant stems and stalks, and deformities, and goiter. Cattle and sheep to a lesser degree leaves; they do not accumulate in flowers or (ruminants) are more susceptible to HCN seeds. Nitrate levels are highest in young plants and decrease poisoning than horses (monogastrics). Fetuses with maturity. Nitrates decrease only slightly with drying, so are also extremely sensitive to HCN poisoning. feeding nitrate-rich hay can be a problem.

Plants containing cyanogenic glycosides: Symptoms: Hydrogen cyanide poisoning is most commonly Nitrite is absorbed into the bloodstream and converts associated with Johnsongrass, sudangrass, sor- hemoglobin to methemoglobin which interferes with the ghum-sudan grass, chokecherry, serviceberry, ability to carry oxygen from the lungs to the tissues. Signs and arrowgrass. of nitrate poisoning are related to the lack of oxygen in blood including: blue to chocolate brown mucous membranes

- 16 - Oxalates Oxalates cause problems when livestock are not accustomed to grazing oxalate-containing plants. Animals can tolerate grazing oxalate-containing plants if they have other plants in their diet to dilute oxalate in the rumen. For example, cattle can graze sites dominated by greasewood if there

Photo: M. Lavin, MSU is ample grass. However, if there is very little grass and greasewood leaves have dropped to the ground, cattle intake of greasewood may increase along with the risk of oxalate poisoning. Also, gradually introducing ruminants to oxalate-containing plants can increase rumen microflora that degrade oxalate and minimize impacts. Supplementing livestock’s diet with dicalcium before and during high-risk oxalate exposure, can effectively reduce losses.

Symptoms: Photo: M. Lavin, MSU Oxalates occurs in two forms: insoluble calcium Russian thistle (Salsola tragus), a highly branched herbaceous oxalate and soluble oxalates. Insoluble calcium weed with spine-tipped leaves, can accumulate nitrate. Many plants, including crop and weed species, can accumulate nitrate. oxalate, a needle-like crystal, causes severe damage Plants containing between 0.5% to 1.5% nitrates can have to kidney tubules. This chronic form of oxalate sublethal effects on livestock, while plants with more than 1.5% poisoning leads to renal failure and death. Soluble nitrates may be lethal to livestock. oxalates rapidly combine with and decrease serum calcium and magnesium, thus impairing normal cell or blood, difficulty breathing, rapid pulse, salivation, membrane function. This acute oxalate poisoning staggering, , and death. Sublethal or chronic nitrate causes muscle tremors, weakness, collapse, and poisoning can cause abortion during any stage of gestation death. due to lack of oxygen. Plants containing oxalates include halogeton, Plants containing nitrates: redroot pigweed, lambsquarter, kochia, sorrel, curly dock, greasewood, and purslane. Rangeland and pasture plants known to accumulate nitrates include redroot pigweed, lambsquarters, kochia, curly dock, Russian thistle, nightshades, and Johnsongrass. Grazed crop or cover crop species known to accumulate nitrates include barley, oats, millet, rye, sorghum-sudangrass, wheat, corn, alfalfa, sugar beet, rape, radish, and turnip.

Contact your local Extension or Department of Agriculture office for assistance testing forage for nitrate content. In Montana, MSU Extension offers an in-office test to

rapidly assess the presence of high forage Photo: M. Lavin, MSU nitrates. In Wyoming, the Department of Kochia (Bassia scoparia) has green or reddish stems, Agriculture offers feed and forage analyses linear leaves, and is often covered with silver or rusty for nutrients and toxic constituents. hairs. Kochia and other members of the goosefoot family (Chenopodiaceae) have been associated with oxalate and nitrate poisoning, although occurrences are uncommon.

- 17 - Saponins Saponins are naturally occurring glycosides in plants Plants containing selenium: that have soap-like compounds. Saponins increase the Plants with more than 5 ppm selenium are potentially permeability of membranes and may cause hemolysis toxic. Primary selenium accumulator or indicator plants of red blood-cells, thus releasing hemoglobin. may accumulate up to several thousand ppm selenium. Obligate accumulator species, including milkvetch and Symptoms: princesplume, can cause acute poisoning but are rarely Plants containing saponins may act as a diuretic causing consumed due to poor palatability. Secondary selenium diarrhea. Other symptoms include biliary obstruction, accumulator plants may contain up to several hundred bloat in ruminants, photosensitivity, salivation, acute ppm selenium, but lesser amounts are much more hepatopathy, and death. Some saponin containing common. This group includes aster species, milkvetch, plants (e.g. oats) are beneficial when consumed, saltbush, Indian paintbrush, curlycup gumweed, and increasing and accelerating the ability to absorb snakeweed. The low-accumulator group, including compounds such as calcium and silicon that assist in alfalfa, corn, and grains, rarely accumulate more digestion. than 50 ppm selenium and usually only 5 to 12 ppm. Plants containing saponins include snakeweed, However, it is the low-accumulator plants that cause puncturevine, kochia, and bouncingbet. the most toxicity problems because they are commonly grazed by livestock and can lead to chronic selenium Selenium poisoning. Selenium is an essential nutrient for animals, but it accumulates in certain plants to levels that are toxic to livestock when those plants are growing in selenium- rich soils. For example, some species of saltbush provide good forage on soils with low selenium levels but are poisonous when growing on soil high in selenium. Selenium-rich soils are derived from cretaceous shales and glacial deposits and are generally found in semi- arid areas. Plant uptake is variable and depends on Photo: USDA-NRCS the chemical form of selenium, soil pH, temperature, moisture, plant species, and stage of plant growth.

Symptoms: Selenium intoxication can occur as acute or chronic poisoning. Signs of acute selenium poisoning, occurring when animals ingest more than 50 parts per million (ppm), include abnormal posture, unsteady gait, abdominal pain, increased pulse and respiration rate, Photo: USDA-NRCS and sudden death. Chronic selenium poisoning is more Milkvetch species (Astragalus spp.) have pinnately compound common, with symptoms including rough coat (bob- leaves and pea-shaped flowers and are primary selenium accumulators. To prevent animals from eating excessive amounts tail, roached-mane), hair loss, hoof lesions, lameness, of selenium, identify areas of high selenium soil and develop a defective hoof growth, and reduction in fertility. grazing or forage-production plan.

- 18 - Other Forage Problems and Disorders Bloat Symptoms: Bloat is caused by the entrapment of fermentation The injury may result in sores and inflammation on gases in the rumen. Bloat usually occurs when livestock the tongue, gums, eyes, nose, and skin. Sores can lead consume lush legumes such as alfalfa or white clover. to localized skin infections or a general infection from Soluble proteins in forages and other small particles bacteria entering the circulatory system. Additional within the cells of the plant are rapidly released once injuries include plant fibers that may lodge in the they reach the rumen. These proteins and particles are stomach or intestines and fibers imbedded in eyelids attacked by slime-producing rumen microbes, which causing lesions to the eyeball. Animals suffering cause a buildup of stable foam. The foam, often due mechanical injury may stop eating and develop a poor to the presence of saponins, decreases the animal’s condition. ability to expel rumen gases that are created from Plants causing mechanical injuries include bristle- fermentation of plant material. These gases begin grass, cheatgrass, needlegrasses, foxtail barley, rye, to accumulate, causing pressure on the diaphragm, wild oats, burdock, and . leading to bloat.

Symptoms: Livestock suffering from bloat will begin to swell rapidly on the left side. Kicking at their sides or stomping their feet are other signs the animal is experiencing discomfort. Breathing may be labored, and urination and defecation frequent. In severe cases, the rumen can become distended, and death may occur. Plants causing bloat include alfalfa, clovers, brassi- cas, cultivated grains, and sweetclovers.

Photo: M. Lavin, MSU Some plant species, although not poisonous, can cause injury to animals resulting in discomfort, inflammation, or poor condition. Mechanical injuries can be caused by native or non-native species with long awns such as foxtail barley (Hordeum jubatum), needle- and-thread, or cheatgrass.

Mycotoxins Mycotoxins are toxins produced by mold (fungi). The host plant itself may not be toxic (e.g. alsike clover, sweetclover), but toxicity problems can occur with Photo: USDA-NRCS improper feed (seeds, hay, silage) harvest and storage. Alfalfa (Medicago sativa) is an important forage species with Some fungi cause toxicity problems in specific plant trifoliate leaves and purple or blue, occasionally yellow, flowers. species (e.g. perennial ryegrass, tall fescue, lupine). Risk of poisoning from alfalfa and other forage legumes Major classes of mycotoxins include aflatoxins, depends on the amount and rate of consumption, composition of the animal’s diet, the plant’s accumulation of toxic chemicals trichothecenes, fumonisins, zearalenone, ochratoxin, (e.g. selenium, nitrate), and how the crop was managed, and ergot alkaloids (e.g. endophyte-infested fescue, harvested, or stored. swainsonine). Mechanical Injuries Symptoms: Mechanical injuries are physical issues caused by Symptoms will vary depending on the mold involved. spines, sharp seeds, burs, and awns. The plant may Mycotoxins in lupine can cause severe liver, kidney not be poisonous, but the injuries can cause symptoms and muscle disease. Ergot alkaloids in tall fescue cause that resemble a toxin effect. vasoconstriction at the extremities, elevated respiration

- 19 - rate, convulsions, lameness and tenderness of the legs, Plants causing photosensitization: poor hair condition, loss of extremities (hooves, ears, Plants associated with primary photosensitization tails), decrease in milk production, difficult births, and are buckwheat, St. Johnswort, and cow . abortion. Plants associated with liver damage leading to Plants commonly containing mycotoxins include photosensitization include horsebrush, tansy ragwort, alsike clover, red clover, corn, sweetclovers, perennial groundsel, fiddleneck, houndstongue, and blueweed. ryegrass, tall fescue, and lupine. In addition, moldy plants and blue-green algae can cause liver damage from Photosensitization photosensitization. Photosensitization can be caused from consuming plant species containing light-sensitive compounds that, once absorbed in the , circulate in the blood. In primary photosensitization, photodynamic compounds accumulate in blood vessels at the skin surface, particularly in non-pigmented Photo: T. Nelson, USDA-NRCS skin, and ultraviolet light transforms compounds into toxins. As a result, skin becomes abnormally sensitive to sunlight causing severe inflammation and damage. Secondary photosensitization, which is more common than primary photosensitization, is caused by a variety of plant toxins that cause liver damage or liver disease. The damaged liver cannot excrete phylloerythrin (a bacterial breakdown of chlorophyll), and it accumulates in the bloodstream. As phylloerythrin circulates and is Photo: T. Nelson, USDA-NRCS exposed to ultraviolet light, it causes oxidative injury St. Johnswort (Hypericum perforatum), identified by the five- to blood vessels and skin tissue. Animals do not readily petaled yellow flowers with black glands on the petal margins, can form dense patches in mountains, foothills, rangelands and eat plants containing liver-damaging substances disturbed areas. Animals that eat St. Johnswort and are exposed to (e.g. pyrrolizidine alkaloids) unless they lack quality direct sunlight develop photosensitization in the white areas of the forage or are exposed to plants in hay. Since ingesting body. Affected animals should be moved out of direct sunlight and provided free access to fresh water and feed. damaging substances is cumulative, liver disease and associated photosensitization may take many months Volatile Oils to appear. Volatile oils are organic compounds that readily Symptoms: vaporize or evaporate. They are responsible for a plant’s Signs of primary photosensitization include severe skin odor and a bitter taste, and, in some plants, are part of irritation, photophobia (e.g. seeking shade), rubbing and the plant’s defense to herbivory and insects. Toxicity shaking the head, excessive eye tearing and discharge, varies with plant species. redness of non-pigmented skin, increased sensitivity Symptoms: of skin, and swelling around ears, eyelids, lips, and nose. Skin can ooze serum, form crusts, lose hair, and Livestock exposed to plants with volatile oils may have slough white skin. Lameness can occur from impacts dermatitis or skin and mucous membrane irritation. to hooves. Secondary photosensitization, in addition When ingested, volatile oils may cause digestive tract to symptoms of primary photosensitization, includes irritation, , reduced rumen activity, damage to signs of liver failure such as weight loss, neurologic the mucous lining of the digestive tract, nervousness, signs (e.g. yawning, drowsiness, aimless wandering, altered milk taste, and diarrhea. head pressing, increased licking, and coma), jaundice, Plants containing volatile oils include sagebrush, abdominal distention, and diarrhea. sagewort, buttercup, and horseweed.

- 20 - Symptoms Sudden death, increased salivation, heavy breathing salivation, increased death, Sudden Death, abortions, lameness, diarrhea, swollen lower legs, joint stiffness, laminitis, increased foottemperature Irritation to the mouth and gastrointestinal tract, colic, diarrhea, salivation, bitter milk when lactating Death, bloat, congestion goiter, of rumen and abomasum, diarrhea, blindness, red-coloredhypothyroidism, urine, pulmonaryand hemolytic emphysema, pulmonary anemia, staggering, blindness, depression, emphysema, reduced weight gain Death, blindness, hemorrhages, depression, nasal and rectal bleeding, bloody urine, loss anemia, of appetite, high fever, difficulty breathing,excessive salivation (cattle, sheep); convulsions, , weight loss, incoordination, fast pulse, crouching stance, weakness (horses) Decreased rumen activity, colic, anorexia, excessive salivation, toxicity diarrhea, liver Death (ruminants), bloat,Death (ruminants), overgrown hooves, reproduction problems, labored breathing, frequent urination and defecation, photosensitivity Death, abortions, lameness, diarrhea, swollen lower legs, joint stiffness, laminitis, increased foottemperature cherry-red pupils, diluted convulsions, cyanosis, death, Sudden blood and tissue, increased salivation, rapid heart rate, abnormal anxiousness weakness, heavy breathing, and Intestinal stasis, convulsions, ataxia, colic, bloat, diarrhea, decreased salivation, dilated pupils, increased heart rate Severe weight loss, muscle photosensitivity, atrophy, jaundice, incoordination, depression, aimless wandering, head pressing, tearingeye Affected Organ or System all systems integumentary, musculoskeletal gastrointestinal cardiovascular, gastrointestinal, musculoskeletal, nervous, respiratory cardiovascular, cardiovascular, nervous, ocular, renal gastrointestinal, liver gastrointestinal, gastrointestinal, gastrointestinal, integumentary, reproductive, respiratory gastrointestinal, musculoskeletal, reproductive blood, all systems gastrointestinal, gastrointestinal, musculoskeletal, nervous integumentary, liver, musculoskeletal, nervous, ocular Toxin or DisorderToxin nitrate, cyanogenic glycoside (HCN) selenium glycoside bloat, nitrate, cyanogenic glycoside (HCN), mycotoxin glycoside, glycoside, thiaminase saponin bloat, nitrate, selenium, photosensitization unknown cyanogenic glycoside (HCN) alkaloid alkaloid, photosensitization 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table all no data summer fall summer, summer, fall, and hay in summer, summer, fall all all spring no data no data 2 2 Part Plant all all stem all; berry all; tops all seeds stem, leaves all all; seedsall; all X X X X X X X X Horse R 1 X Goat X X X X X X X Sheep X X Affected Livestock Livestock X X X X X X X X X Cattle X ) ) ) ) ) ) ) ) ) ) )

Plant Species glabriusculaXylorhiza Actaea rubra Hyoscyamus niger Lotus corniculatus Pteridium aquilinum Beta vulgaris Medicago sativa Berteroa incana maritima,Triglochin Echium vulgare Saponaria officinalis Black henbane ( Baneberry ( sugar Beet, ( trefoil Birdsfoot ( Brackenfern* ( Alyssum, hoary ( Arrowgrass* ( palustris T. woody Aster, ( Blueweed ( Bouncingbet ( Alfalfa* ( X = known affects, R = rarely affects, S = suspected to affect Table 1. Signs 1. poisoning of andTable conditions under which plant species can be dangerous livestock. to Symptoms listed each for plant are those most likely be to observed. allNot symptoms will be seen in all toxicities, and signs poisoning of may vary greatly depending dosage and on the time taken consume to the dose. Also, individual animals respond differentlyto specific toxins. 1 - 21 - Symptoms Photosensitivity Death, congestion of rumen and abomasum, muddy cyanotic mucus membranes, , cyanosis, staggering, chocolate-brown blood, acidosis, watering reduced eyes, milk reducedflow, weight gain, abortion, infertility Photosensitivity, tearing Abdominal pain, irritation of digestive tract, reddening of oral mucous salivation membranes, diarrhea, excessive Sudden death, coma, convulsions, muscular spasms, difficulty breathing, bloat, mucous membranes appear pink/red, venous blood is cherry red, nervousness, weakness, staggering, excessive salivation Bloat (ruminants), enlargedBloat weight loss, (ruminants), liver, photosensitivity, jaundice, depression, aimless wandering, walking in circles, head pressing, yawning excessiveBloat salivation, (ruminants), dehydration, reproduction problems photosensitivity, muscularBloat (ruminants), tremors, increased respiratory rate, weakness, drowsiness, photosensitivity, staggering, recumbency, reproduction problems Sudden death, coma, liver damage, convulsions, ataxia, incoordination, loss appetite, abdominal vomiting, of pain, depression, weakness Death, bloat, congestion goiter, of rumen and abomasum, hypothyroidism, blindness, diarrhea, red-colored urine, and staggering, hemolytic blindness, pulmonary anemia, emphysema, depression, gain reduced weight diarrhea vomiting, cramps, stomach , Affected tegumentary, liver, Organ or System integumentary cardiovascular, cardiovascular, gastrointestinal, reproductive, respiratory integumentary, ocular gastrointestinal gastrointestinal, cardiovascular, all respiratory, organs in nervous gastrointestinal, integumentary, reproductive gastrointestinal, integumentary, musculoskeletal, reproductive, respiratory gastrointestinal, nervous, renal, liver cardiovascular, cardiovascular, gastrointestinal, musculoskeletal, nervous, respiratory gastrointestinal oat, mycotoxin, Toxin or DisorderToxin furanocoumarin, photosensitization mycotoxin, nitrate, selenium fragopyrin, fragopyrin, photosensitization glycoside, oils volatile cyanogenic glycoside (HCN) nitrate, photosensitization alkaloid, bloat, mycotoxin, nitrate, photosensitization bloat, glycoside, nitrate, photosensitization glycoside bl bloat, nitrate, cyanogenic glycoside (HCN), mycotoxin glycoside 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table summer, summer, fall summer, summer, fall summer, summer, fall, and hay in all spring, summer all all spring, summer all fall spring, summer, fall 2 2 Part Plant flowers, seeds stems all all youngall; stems & leaves, seeds all all all sprouts, seeds fruit, leaves all; tops X X X X X X R R Horse R 1 X X X X X X X Goat X X X X X X X X X X

vestock vestock Sheep Affected Li X X X X X X X X X S Cattle X ) ) ) ) ) ) ) P. Brassica Raphanus

) ) ( ) ) ) Plant Species Ceratocephala Xanthium strumarium,Xanthium Zea mays Zea Heracleum maximum Prunus virginiana Trifolium hybridum Trifolium Trifolium repens Trifolium Ranunculus spp. Fagopyrum esculentum Fagopyrum Rhamnus catharticaRhamnus Cow parsnip ( Buttercup ( and testiculata Chokecherry* ( alsike Clover, ( and Pin cherry ( pensylvanica Clover, red ( Clover, white ( Cocklebur* ( X. spinosum Corn* ( Buckthorn ( Buckwheat ( Brassicas – canola, kale, radish, turnip ( spp.), radish spp.), sativus X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 22 - Symptoms Birth abortion, defects, coma, convulsions, irregular heartbeat, prostration, difficult respiration, vomiting,excessive salivation, weakness, irregular gait Sudden death, coma, cyanosis, irregular heartbeat, rapid pulse, colorationblue mucous of membranes, vomiting, abdominal pain, diarrhea, pupils of weakness, dilation Sudden death, abortions, increased heart rate, increased respiratory rate, panting, open mouth breathing, extreme difficulty breathing, venous blood is cherry red, mucous membranes bright red, excitement Sudden death, coma, convulsions, ataxia, prostration, vomiting, staggering, lowered temperature, excessive salivation, tremors, labored breathing, weakness Sudden death, coma, muscle tremors, , abdominal incoordination,pain, depression, salivation, weakness, reluctance to move Heart liver failure, atrophy, lameness, bone and joint performance, reproduction reduced of loss anemia, degeneration, long hairs of the main and tail (horses, cattle); reduction in fertility (sheep) Gangrene in extremitiesGangrene in (‘fescue reproduction impaired foot’), and milk production, heat stress, failure to shed winter coat (cattle); (horses) reproduction poor Rectal prolapse, red urine, edema of the legs, photosensitivity, photophobia, jaundice, weight loss, severe depression, aimless walking, diarrhea, incessant licking of objects, head pressing (cattle, weight horses); loss, appetite loss goats) (sheep, Colic Death, profuse swelling of the fore stomach, colic, bloody diarrhea, milk tainted Sudden death, cyanosis, cherry-red venous blood, difficulty breathing, excessive salivation, nervousness, weakness Blindness, severe photosensitivity, difficulty chewing and swallowing, weight loss, head pressing Affected Organ or System gastrointestinal, gastrointestinal, nervous, reproductive cardiovascular, cardiovascular, gastrointestinal, ocular cardiovascular, nervous, reproductive, respiratory gastrointestinal, gastrointestinal, musculoskeletal, nervous musculoskeletal, gastrointestinal, renal integumentary, musculoskeletal cardiovascular Gastrointestinal, musculoskeletal, nervous, ocular, systems all renal, gastrointestinal gastrointestinal cardiovascular, respiratory gastrointestinal, integumentary, musculoskeletal, nervous, ocular Toxin or DisorderToxin alkaloid cardiac glycoside cyanogenic glycoside (HCN) alkaloid nitrateoxalate, selenium alkaloid, mycotoxin, nitrate alkaloid (pyrrolizidine), photosensitization alkaloid (tropane) glycoside cyanogenic glycoside (HCN) unknown, photosensitization 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table spring, summer, fall all; hay all; fall, spring all; spring no data no data summer, summer, and in hay no data no data no data no data spring 2 2 Part Plant aves, all; leaves, roots leaves all all; bulb, all; mature leaves all; leaves, stem leaves le seeds seeds all; seeds all; all youngall; plants all X X X X X X X R Horse R 1 X X X X X Goat R X X X X X S X X R

vestock vestock Sheep Affected Li X X X X X X X X X Cattle X ) ) ) ) ) ) ) ) ) ) . Plant Species Apocynum cannabinum, A. androsaemifolium Amsinckia menziesii, A. lycopsoides Zigadenus spp.)Zigadenus Veratrum spp.) Linum spp Linum Rumex crispusRumex Thlaspi arvense Thlaspi Descurainia sophia Schedonorus Sambucus racemosaSambucus Convolvulus arvensisConvolvulus Grindelia squarrosa Fescue, tall Fescue, ( Elderberry, red* Elderberry, ( hellebore* False ( Dock, curly* ( Dogbane* ( ( Deathcamas* ( Fiddleneck* ( ( bindweed Field ( pennycress Field ( Flax ( Flixweed ( arundinaceus Curlycup gumweed ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 23 - Symptoms Death, rectal prolapse, hemolysis, red urine, anemia, redness and skinincoordination, to swelling photosensitivity, diarrhea, jaundice, depression, circling, aimless eyes, around wandering, head pressing, excessive tearing, weakness, weight and appetite loss Death, abortions, liver swelling and failure, rapid weak pulse, difficulty breathing, prostration, twitching, secondary photosensitivity, redness and edema of the tissues of the head, swelling of head incoordination, lips, (ears, face), anorexia, depression, lagging herd behind in Death, coma, kidney failure, recumbency, muscle tremors, tetany, loss of appetite, slow pulse, weakness, collapse, incoordination, depression, reluctance drooling to move, Sweating, salivation, labored breathing, pupil dilation Sweating, salivation, labored breathing, pupil dilation Death, coma, intoxication, vomiting, salivation, muscle tremors, ataxia Death, ataxia, weakness, unable to stand Death, congestion bloat (ruminants), of rumen and abomasum, shortnesstetany, of breath, cyanosis, staggering, chocolate- brown blood, watering reduced eyes, weight gain, abortion, rapid infertilitypulse, Sudden death, abortions, coma, respiratory paralysis, birth defects, ataxia, muscle tremors, cyanosis, rapid weak pulse, incoordination, nervousness, abdominal pain, weakness, salivation, frequent urination and defecation, dilated pupils convulsions, respiratory coma, severe death, Sudden paralysis, rapid pulse and breathing, muscle degeneration, excessive salivation, vigorous chewing, teeth grinding, dilated pupils Affected Organ or System All systems, liver hepatic, integumentary musculoskeletal, musculoskeletal, renal respiratory respiratory gastrointestinal, gastrointestinal, musculoskeletal musculoskeletal cardiovascular, gastrointestinal, reproductive, respiratory all systems musculoskeletal, cardiovascular, nervous, respiratory Toxin or DisorderToxin alkaloid (pyrrolizidine), photosensitization tetradymol, tetradymol, photosensitization oxalate oils volatile oils volatile cannabinoid alkaloid bloat, nitrate, mycotoxin, selenium alkaloid 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table all spring spring, fall, winter spring, and in hay spring, and in hay no data all; hay all; spring, fall all; spring spring 2 2 Part Plant l; seeds l; all all all leaves, buds all no data stems all; seedall; pods all; rootsall; al X X S X X X S X Horse X 1 X X X X Goat R X X X X X R

vestock vestock Sheep Affected Li X X X X X X Cattle R ) ) ) ) ) ) ) )

Plant Species Halogeton glomeratus Halogeton Physalis longifoliaPhysalis Thermopsis montana Conium maculatum Conium sativa Cannabis Senecio spp.) Sarcobatus Sarcobatus Glechoma hederacea Halogeton* ( Hemlock, poison* ( Ground ivy ( longleaf Groundcherry, ( Groundsel* ( Grains, cultivated rye, barley, (oats, wheat) triticale, Greasewood* ( vermiculatus Goldenbanner ( Hemlock, water* ( Hemp ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 24 - Symptoms Lameness, long hairs of the main and tail break Death from starvation, muscle tremors, facial paralysis, unable to take hold of and chew food inhalation (chewing disease), pneumonia, severe weight loss, incoordination, dehydration, salivation depression, excessive Photosensitivity Sudden death, convulsions, abortions or limb deformities, cherry-red membranes, mucous cyanosis, blood and venous increased salivation, difficult breathing, nervousness, weakness, urinary incontinence, ataxia, leg hind weakness Death, rectal prolapse, red urine, edema of legs, photosensitivity, circles, in loss, walking diarrhea, weight jaundice, depression, excessive yawning incoordination, irregular heartbeat, recumbency, Convulsions, , colic, vomiting, depression Colic, abdominal pain, burning sensation of mouth and throat, vomiting, diarrhea, irritated skin Abdominal pain, vomiting, diarrhea, irritated skin Colic, rumen stasis, muscular twitching, paralysis, respiratory paralysis, incoordination, excessive thirst, loss of appetite, bloat increased(ruminants), heart rate, dilated pupils, impaired vision, subnormal temperature, dry muzzle, decreased salivation Death, abortions, liver swelling and failure, rapid weak pulse, difficulty breathing, prostration, twitching, secondary photosensitivity, redness and edema of the tissues of the head, swelling of head incoordination, lips, (ears, face), anorexia, depression, lagging herd behind in Death,coma, convulsions, seizures, weakness and incoordination of the hind legs, recumbency, weight loss, depression, appear blind and difficulty have seeing, diarrhea Irritated skin, mucous membranes, and nostrils Affected egumentary Organ or System integumentary, musculoskeletal gastrointestinal, gastrointestinal, nervousrespiratory, integumentary all systems integumentary, nervous, liver, musculoskeletal cardiovascular, gastrointestinal gastrointestinal, gastrointestinal, gastrointestinal, integumentary cardiovascular, gastrointestinal, ocular int hepatic, integumentary gastrointestinal, nervous integumentary Toxin or DisorderToxin selenium DDMP photosensitization cyanogenic cyanogenic glycoside (HCN), nitrate alkaloid (pyrrolizidine), photosensitization neurotoxic diterpenoid irisin glycoside alkaloid (tropane) tetradymol, tetradymol, photosensitization thiaminase volatile oils, tannic acid, gallic acid 2 ata Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table no data no data no data all; wilted, regrowth all; hay all; spring, fall no data no data; hay no d spring hay all; no data 2 2 Part Plant stem all; green green all; plants seeds all all all no data seeds all; all all all all X X X X X X X X Horse R 1 X X X X S Goat R X X X X X R R

vestock vestock Sheep Affected Li X X X X X X X X S Cattle R ) ) ) ) ) ) )

) ) . ) . ) spp Plant Species Acroptilon repens Pediomelum Pediomelum Menziesia ferruginea Menziesia Datura stramonium Equisetum canescens Tetradymia Iris missouriensis Iris pseudacorus Castilleja spp Conyza canadensis Conyza Cynoglossumofficinale Sorghum halepense Iris, Rocky Mountain ( Indian paintbrushIndian ( Knapweed, Russian* Knapweed, ( , false Huckleberry, ( Indian breadroot, silverleaf ( argophyllum Iris, yellowflag ( Jimsonweed* ( Johnsongrass* ( Horsetail* ( Horseweed, Canadian ( Houndstongue* ( Horsebrush* ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 25 - Symptoms Convulsions, incoordination, recumbency, irregular heartbeat, incoordination,Convulsions, recumbency, hypotension, colic, vomiting, depression Sudden death, acute , abortion Death, muscular or respiratory paralysis, tremors, incoordination, stiffness, staggering, falling, muscle tremors, collapse, bloat, weakness, nervousness, salivation regurgitation, vomiting, irregular heartbeat, incoordination,Convulsions, recumbency, hypotension, colic, vomiting, depression Colic, vomiting, reddening and swelling or blistering of the skin, irritation,eye weight loss when exclusively fed leafy spurge, salivation diarrhea, excessive Sudden death, blindness, kidney failure, liver disease, brown colored mucous membranes and blood, severe difficulty breathing, gastrointestinal inflammation, incoordination, photosensitivity, depression, depressed appetite, dehydration, swollen eyelids, crusty muzzle, weight loss Death, convulsions, vomiting, diarrhea, excitement Death, abortions, birth defects, brain hemorrhages, respiratory collapsed lung, disease), (roaring breathing load distress, decreased male fertility, blindness, weakness, loss of control of hind limbs, prostration, collapse, decreased body condition, lameness, abnormal loss behavior, of direction, knocking of hocks and feet when walking, breaking of long hairs of the mane and depressed, nervousness movements, jaw spastic tail, Birth defects, abortions and fetal death, decreased fertility, congestive heart failure, liver damage, incoordination, stiff aggressiveness, loss of irregularand abnormal gait, behavior, loss, depression, weakness, staring, weight direction, excitability, difficulty eating, exaggerated mouthmovement, dull coat Death, respiratory failure, coma, birth defects (crooked legs, cleft abortion,palate), convulsions, incoordination, difficult breathing, muscle twitching, loss of muscle control, head lethargy, pressing, drydepression, nervousness, salivation, coat excessive Staggering, lameness Affected Organ or System gastrointestinal reproductive, respiratory musculoskeletal, gastrointestinal, nervous respiratory, all systems gastrointestinal, integumentary all systems; kidney, all systems; kidney, liver gastrointestinal, gastrointestinal, nervous integumentary, musculoskeletal, nervous, reproductive gastrointestinal, gastrointestinal, reproductive, congenital, nervous, cells, liver musculoskeletal, nervous, hepatic, reproductive, respiratory musculoskeletal, nervous wainsonine) Toxin or DisorderToxin neurotoxic diterpenoid nitrate, oxalate, sulfate alkaloid (diterpene), bloat neurotoxic diterpenoid diterpene esters nitrate, oxalate, thiaminase, sulfate, alkaloid, saponin, photosensitization alkaloid (s alkaloid (solanaceous) alkaloid (swainsonine), selenium, nitrotoxin alkaloids, mycotoxin nitrateoxalate, 2 Time Year ll; hay ll; plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table all; winter no data spring (low), summer (tall) spring, fall no data all; hay all; no data all; spring, summer all; hay all; no data a 2 2 Part Plant ll all new all; growth, seeds all all sap all all no data leaves, seed all; seeds all; a X X X X S X R Horse R 1 X X X X S X R Goat R X X X X X X X X X R R

vestock vestock Sheep Affected Li X X X X X X X X X Cattle X ) ) ) ) ) ) . ) ) ) . ) . ) . ) spp Plant Species Astragalus spp Ledum glandulosumLedum Lupinus barbarum Lycium Delphinium spp Delphinium Kalmia polifolia Euphorbia esula Bassia scoparia Malva neglecta Chenopodium album Chenopodium Oxytropis spp Lambsquarters* ( Larkspur* ( Laurel ( Leafy spurge ( Locoweed* ( Labrador tea ( Milkvetch* ( A.(not cicer Lupine* ( common Mallow, ( Matrimony vine ( Kochia* ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 26 - Symptoms Death, coma, shock, bloat (ruminants), kidney failure, muscle tremors, irregular heart rate, weak pulse, incoordination, colic, weakness, diarrhea, jaundice, labored breathing, drowsiness, pupils depression, dilated drowsiness, salivation, excess Possible death, recumbency, fast weak pulse, collapse, increased respiratory rate, anemia, red-brown urine, pale mucous membranes, weakness, staggering Sudden death, abortions, difficulty breathing (open-mouth respiratorybreathing), failure, collapse, mucous membranes cherry-red in venous color, blood cherry red, nervousness, weakness, excitement, excessive salivation Death, lameness, sloughing of the hoof circular (horses), ridges in all feet, loss of long hairs of the mane and tail Lameness, biliary stasis, photosensitivity, jaundice; swelling of (sheep) head the Sudden death, recumbency, increased respiratory rate, difficulty breathing, muscle weakness, staggering gait, bloating, excessive salivation Abortion, congenital defects, persistently retained placenta, renal incoordination,failure, aimless wandering Death, convulsions, seizures, respiratory paralysis, recumbency, respiratory convulsions, seizures, Death, recumbency, paralysis, rapid weak pulse, difficult breathing with grunting sounds, abdominal pain, colic, diarrhea bloat (ruminants), staggering, weakness, muscle tremors, reluctance incoordination, stand, to deep depression, elevated temperature, dilation of pupils Death, congestion of rumen and abomasum, muddy cyanotic mucus membranes, shortness of breath, cyanosis, staggering, chocolate-brown blood, watering reduced eyes, milk flow, abortionreduced gain, weight infertility and Sudden death, erratic heartbeat, colic, decreased gut motility, diarrhea, vomiting Lameness circular (horses), ridges in all feet, loss of long hairs of mane and tail Affected Organ or System all systems cardiovascular, renal respiratory, all systems integumentary, musculoskeletal hepatic, integumentary, musculoskeletal cardiovascular, cardiovascular, gastrointestinal, musculoskeletal, respiratory renal, reproductive renal, cardiovascular, cardiovascular, gastrointestinal, musculoskeletal, nervous, respiratory cardiovascular, gastrointestinal, reproductive, respiratory cardiovascular, cardiovascular, gastrointestinal integumentary, musculoskeletal Toxin or DisorderToxin alkaloid, nitrate sulfide alkaloid, cyanogenic cyanogenic glycoside (HCN) selenium saponin, nitrate, photosensitization alkaloids isocupressic acid cardiac glycoside, cardiac glycoside, selenium nitrate glycoside selenium 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table all spring, summer no data no data no data summer all; winter, spring all; actively growing, hay fall no data no data 2 2 Part Plant all; fruit,all; leaves leaves all leaves leaves, stems all; seeds,all; roots needles, needles, bark stems all leaves, flowers leaves X X X X X X Horse R 1 X X X X X R Goat R X X X X X X R R R Sheep R Affected Livestock Livestock X X X X X X X X R R Cattle R ) ) ) ) ) )

) . ) . ) Plant Species Allium spp.) Aconitum columbianum Aconitum Adonis aestivalis Asclepias spp Penstemon spp Tribulus terrestrisTribulus Pennisetum glaucum Pinus ponderosa Pinus Cercocarpus ledifolius, Solanum spp.) Stanleya pinnata Onion* ( Penstemon ( Nightshade* ( Puncturevine ( Mountain mahogany, Mountain mahogany, curl-leaf true and ( C. montanus Princesplume ( Millet ( Monkshood* ( Pine, ponderosa* Pine, ( Pheasant’s eye* ( Milkweed* ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 27 - Symptoms Death, abortions Death, Skin irritation, reduced rumen activity, vomiting, diarrhea Ataxia (front forequarters), falling down, abnormal behavior, unpredictable excitable, circling, Colic, muscle weakness, diarrhea Incoordination, collapse, muscle staggering spasms, (ryegrass staggers), head shaking, photosensitivity, grass tetany Death, weakness, increased stagger, respiratory rate, increased water intake, reduced animal performance, diarrhea grass tetany, Death, renal failure, fluid around kidneys, ataxia, bloat muscle weakness tremors, and recumbency, (ruminants), knuckling at the fetlock joints, decreased rumen activity Congenital malformations, muscle degeneration, muscle tremors, salivation excessive anorexia, colic, incoordination, convulsions, restlessness, death, Sudden twitching facial of muscles Sudden death, abortions, coma, convulsions, collapse, staggering, difficulty breathing, mucous membranes appear pink/red, venous blood is cherry red, excessive salivation, nervousness, excitement male decreased degeneration, and necrosis Abortions, liver fertility, sloughing of nasal mucosa, weight loss, stomach pains, diarrhea followed constipation by Death, coma, kidney failure, muscle tremors, recumbency, tetany, weakness, depression, reluctance move to Lameness, cracked or deformed hooves, loss of long hairs of the mane and tail Affected Organ or System gastrointestinal, gastrointestinal, nervous gastrointestinal, integumentary gastrointestinal, gastrointestinal, nervous gastrointestinal, gastrointestinal, musculoskeletal integumentary, nervous musculoskeletal, musculoskeletal, nervous, respiratory gastrointestinal, gastrointestinal, musculoskeletal, renal gastrointestinal, gastrointestinal, musculoskeletal nervous all systems gastrointestinal, musculoskeletal liver reproductive, musculoskeletal, musculoskeletal, renal integumentary, musculoskeletal Toxin or DisorderToxin lactone, volatile oils volatile lactone, oils volatile lactone, monoterpene, oils volatile nitrate alkaloid, alkaloid, mycotoxin, nitrate, photosensitization alkaloid, nitrate, selenium oxalate, nitrateoxalate, alkaloid alkaloid cyanogenic glycoside (HCN) saponin, selenium oxalate selenium 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table all no data fall, winter hay no data fall all no data no data spring, summer spring no data no data 2 2 Part Plant leaves leaves leaves stem leaves leaves all no data no data notall; berries all all leaves X X X X X X X X Horse R 1 X X X Goat R S X X X X X X X X R Sheep R Affected Livestock Livestock X X X X X X X X X R Cattle R ) ) ) ) ) )

) ) ) ) )

) spp.) Plant Species Artemisia dracunculus, Atriplex Artemisia filifolia, Amelanchier alnifolia Amelanchier Amaranthusretroflexus Lolium perenne Phalaris arundinacea Portulaca oleracea Corydalis aurea Salvia reflexa Cytisus scoparius Gutierrezia sarothrae Sagewort, green and white ( A. ludoviciana Saltbush ( Sagebrush, big* ( Sage, and fringed and sand Sage, ( A. frigida Sage, lanceleafSage, ( Ryegrass, perennial perennial Ryegrass, ( Reed canarygrass Reed ( Scrambled eggs eggs Scrambled ( Serviceberry* ( Snakeweed* ( Redroot pigweed* Redroot ( Scotch broom ( Purslane ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 28 - Symptoms Blindness, difficulty eating (tongue appears paralyzed),severe wandering aimless pressing, head loss, weight photosensitivity, Death, abortion, collapse, pink or red mucous membranes, cherry-red blood, difficulty breathing, nervousness,excitement, excessive salivation, weakness Death, congestion of rumen and abomasum, muddy cyanotic mucus membranes, shortness of breath, cyanosis, staggering, Death, acidosis, congestion of rumen and abomasum, muddy or red cyanotic mucus membranes, shortness of breath, cyanosis, staggering, chocolate-brown blood, watering reduced eyes, milk reducedflow, weight gain, abortion and infertility Death, coma, kidney recumbency, muscle failure, tetany, tremors, weakness, depression, reluctance to move Abortions, convulsions, rapid weak pulse, stomach pain, salivating Photosensitivity, reddening and edema, severe itching, blistering, sloughing of white skin, scratching head; convulsions, rapid respiration and pulse, loss of condition, elevated temperature, crouching, restlessness Death, rumen stasis, ataxia, liver degeneration, inhalation become loss, lambs weight bloat, irregularpneumonia, pulse, stiff andwasted, muscle tremors, decreased appetite,vomiting, dehydration, depression, weakness, teeth grinding, frothing at coughing mouth, chocolate-brown blood, watering reduced eyes, milk flow, abortion,reduced gain, weight infertility Anticoagulant effects; death, (ruminants), lameness, bloat internal and external hemorrhaging during nose, chamber, eye (e.g. birthing), large swellings protuberant over body areas, anemia, bloody and black feces, weakness Lameness Affected Organ or System gastrointestinal, gastrointestinal, integumentary, nervous, ocular cardiovascular, cardiovascular, gastrointestinal, nervous, respiratory reproductive cardiovascular, gastrointestinal, reproductive, respiratory cardiovascular, cardiovascular, gastrointestinal, reproductive, respiratory musculoskeletal, renal cardiovascular, cardiovascular, gastrointestinal integumentary gastrointestinal, gastrointestinal, musculoskeletal respiratory all systems musculoskeletal Toxin or DisorderToxin unknown, photosensitization cyanogenic cyanogenic glycoside (HCN) nitrate nitrate, cyanogenic glycoside (HCN) oxalate alkaloid, volatile oils hypericin, hypericin, photosensitization sesquiterpene lactone dicoumarol, dicoumarol, mycotoxin, bloat unknown 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table spring, summer summer no data summer, summer, fall no data no data all; spring, hay summer, summer, hay fall, hay no data 2 2 Part Plant all all stems all no data leaves leaves, flowers all moldy moldy feed no data S X X X R R Horse R 1 X X S R Goat R X X X X X R Sheep R Affected Livestock Livestock X X X X S X X R Cattle R ) ) ) ) ) ) ) ) . ) .

Plant Species . sudanenese. spp Hypericum perforatumHypericum Lathyrus spp.)Lathyrus Descurainia pinnata hoopesii Hymenoxys Melilotus officinalis Melilotus vulgare Tanacetum Oxalis spp Suckleya suckleyana Suckleya Sorghum bicolor, S. x Sunflower ( Sorrel ( St. Johnswort* ( Tansy mustard Tansy ( Suckleya, poison Suckleya, ( Sorghums*, forage, grain, grain, forage, Sorghums*, sorghum-sudangrass, sudangrass ( drummondii, S. bicolor var Sweetclover, yellow and and yellow Sweetclover, white* ( Sweetpea ( common Tansy, ( Sneezeweed* ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 29 - Symptoms Death, convulsions, hyperproteinemia, excessive bleeding, bloat thickening(cattle), of skin, photosensitivity, swollen lymph nodes, abnormal difficulty behavior, standing,itching and rubbing of infected areas, diarrhea, poor appetite, hair loss Abortions, fetal death, recumbency, increased heart rate, increased respiratory rate, difficulty breathing, brown colored mucous membranes, staggering gait Birth defects, abortion, coma, convulsions, paralysis of the muscles of the respiratory and cardiovascular system, muscle tremors, staggering, incoordination, diarrhea, excessive salivation Death, congestion of rumen and abomasum, muddy cyanotic mucus membranes, shortness of breath, cyanosis, staggering, chocolate-brown blood, watering reduced eyes, milk flow, abortion,reduced gain, weight infertility Death, congestion of rumen and abomasum, muddy cyanotic mucus membranes, shortness of breath, cyanosis, staggering, chocolate-brown blood, watering reduced eyes, milk flow, abortionreduced gain, weight infertility and Death from starvation, brain necrosis, muscle tremors, facial unable facial paralysis, muscles hypertonic expression), (wooden to chew food or drink mouth (chewing disease), held open, tongue protrudes, inhalation pneumonia, severe weight loss, incoordination, dehydration, depression, excessive salivation Sudden death, coma, circulatory failure, convulsions, slow heart rate, gastric distress, muscle trembling, vomiting, difficulty breathing, incoordination, diarrhea, nervousness, fatigue, dilated pupils Rectal straining, liver cirrhosis, fluid buildup in abdomen, bile duct proliferation, red urine, photosensitivity, swelling and redness to skin around diarrhea, eyes, stomach pain, aimless wandering, head pressing, excessive tearing, weakness, lethargy, anemia, incoordination, dragging rear feet, weight loss, appetite loss, depression Anti-thyroid symptoms Anti-thyroid Affected Organ or System cardiovascular, cardiovascular, gastrointestinal, integumentary, nervous cardiovascular, cardiovascular, musculoskeletal, reproductive gastrointestinal, musculoskeletal, nervous, reproductive cardiovascular, cardiovascular, gastrointestinal, reproductive, respiratory cardiovascular, cardiovascular, gastrointestinal, reproductive, respiratory gastrointestinal, gastrointestinal, nervousrespiratory, cardiovascular, gastrointestinal, musculoskeletal, nervousrespiratory, all systems endocrine Toxin or DisorderToxin nitrate, photosensitization nitrate alkaloid (nicotine) nitrate nitrate DDMP alkaloid (taxine) alkaloid (pyrrolizidine), photosensitization glucosinolates 2 Time Year plant part or time of year; most susceptible plant part or most dangerous time of year * toxic dose information available for species 2 in Table fall no data no data no data fall all all; winter spring, summer, hay fall 2 2 Part Plant leaves, all; seeds all; stems green all; growth stems stems all; leaves all all seeds X X X X Horse X 1 S X X X Goat X S X X X Sheep X Affected Livestock Livestock S X X X X X X Cattle R ) ) ) ) ) ) ) ) ) Plant Species

Vicia villosa Nicotiana attenuata Taxus brevifolia Taxus Eragrostis tef Cardaria draba Cirsium arvense Salsola tragus Salsola Centaurea solstitialis Senecio jacobaea Whitetop ( Tobacco, * Tobacco, ( hairyVetch, ( Thistle, Russian* Thistle, ( Thistle, CanadaThistle, ( Yew* ( Teff ( Yellow starthistle*Yellow ( Tansy ragwort*Tansy ( X = known affects, R = rarely affects, S = suspected to affect Table 1, (cont.) Table 1 - 30 - Comments Dosage is for leaves and stems, but the roots times are 5 to 10 more poisonous. Poisonous at all growth stages. Dosage is for consumption 2 weeks over resulting in liver disease. Clinical signs notmay appear for 2 to 8 months after consumption. if eaten quicklyToxic or when a major component of livestock diet. Losses occur when eating large quantities of leaves that fallen have to the ground in the fall and winter or new growth in spring. Increases in toxicity as growing season containing oxalate to forage adapted are animals advances. if valuable be Can plants and consumed with non-toxic forage. Ingestion of wilted leaves can cause death in 1 hour or less. New growth and re-growth toxic. also are Toxic dose dependsToxic on rate of consumption and digestion. Death occur may 6 to hours after12 consumption. Dried plants remain toxic. Consumption of green plant risk can be greatest lethal.early at Toxic vegetative growth stages followed the by flower and pod stages. Signs can occur within 5 hours of consumption of green plant, and death follows Allwithin parts a day. of the plant are toxic. Many factors affect toxicity, but generally0.05% bw is minimum lethal dose. Consumption 0.1 to 0.6% bw of leavesConsumption depending on growth 0.1 stage or 0.24% freshbw twigs (lethal). bruised, Fresh, wilted or (drought and frost), dry leaves are poisonous. leaves more toxic than Young mature leaves. Seed stones are poisonous. Consumption of fresh green sprouts (cotyledon and seeds stage) Toxicity (burs). is not present in mature plants. Selenium accumulated in the leaves. Nitrate levels are higher in lower stalks and stems. Flowering spikes contain twice the amount of toxin and require half the dosage. Plants lose toxicity with Plants more drying hay). toxic when stressed (e.g. from frost. or drought Consumption for at least 30 Live days. and dried plants are toxic. Roots and young shoots with highest toxicity. Consumption within of 1 – 5% can a few days be lethal. Chronic poisoning caused accumulative by consumption of a total intake bw over of 25 to 150% several months. Becomes more toxic as growing season advances. Peak toxicity at maturity. dependsToxicity on other forage availability. Horses Toxic DosageToxic (bw = body weight; n/a = not applicable) n/a bw 0.1% No data n/a 0.03 - 0.05% bw No data No data 0.5 - 1.5% nitrate0.5 - 1.5% Rarely affected Rarely No data 22 ppm (selenium) 22 ppm affected Rarely bw 3 - 5% 1 - 7% (acute) bw Rarely affected Rarely Sheep/Goats Rarely affected Rarely bw - 5% 1.5 6 - 12 oz 6 - 12 0.25% bw 0.03 - 0.06% bw No data 0.5 - 2.5% bw 0.5 - 1.5% nitrate0.5 - 1.5% 0.75 – 3.0% bw 0.75 0.1 - 0.4% bw - 0.4% 0.1 0.1 – 5.0% bw 0.1 No data 10,000 ppm (nitrate) 200 – 300% bw (chronic) 0.3 - 1.5% bw 0.3 - 1.5% Cattle 1 - 5% bw (acute) bw 1 - 5% 0.1% bw 0.1% bw - 5% 1.5 No data 0.25% bw 0.03 - 0.05% bw 10 – 20 lbs/day 10 1% bw 1% 0.5 - 1.5% nitrate0.5 - 1.5% 0.75 – 3.0% bw 0.75 0.1 - 0.6% bw 0.1 0.1 - 1.5% bw - 1.5% 0.1 No data 22 ppm (selenium) 22 ppm (selenium) 10,000 ppm (nitrate) 0.3 - 1.5% bw 0.3 - 1.5% ) ) ) ) ) ) ) ) Plant Species Amsinckia spp.)Amsinckia Xanthium spp.)Xanthium Apocynum spp.)Apocynum Veratrum spp. Veratrum Zigadenus spp.)Zigadenus Zea mays Zea Rumex crispusRumex Pteridium aquilinum Prunus virginiana Halogeton glomeratus Halogeton Triglochin spp.)Triglochin Medicago sativa Sarcobatus vermiculatus Senecio spp.) Sambucus racemosaSambucus Fiddleneck ( Greasewood ( Groundsel ( False hellebore False ( Elderberry, red Elderberry, ( Dock, curly ( Dogbane ( Deathcamas ( Cocklebur ( Corn ( Arrowgrass ( Brackenfern ( Chokecherry ( Halogeton ( Alfalfa ( Table 2. Toxic doses for commonly diagnosed plant poisonings in Montana and Wyoming. Symptoms of livestock poisoning may not be evident be evident not may poisoning livestock of Symptoms Wyoming. and in diagnosed poisonings Montana commonly plant doses for 2. Toxic Table is reached. threshold until a toxic - 31 - Comments ). Consumption 1 to 3 months. over variesToxicity with growth stage. More problems associated with mature, droughty plants. Animals impacted after consuming nitrates. plants with >1% Highly palatable and highly toxic to cattle. for both Toxicity low and tall larkspur is most prevalent at flowering stage and decreases afterToxicity seed drop. declines growing over season. or Fresh dried plants toxic. Seeds remain toxic. Toxicity of theToxicity leaves and fruit is present in all growth stages. Higher toxicity in fall than spring and in berries than leaves. Dried plants remain toxic. Ingestion in the form of wilted leaves can result in death in an hour or less. Symptoms appear 2 to 9 weeks after consumption. Species vary in toxicity substances levels. Toxic throughout plant and concentrated plants in seeds. more Younger toxic than mature plants. Seed stage especially toxic. Smaller doses poisonous if cattle eat lupine daily for 3 to 7 days. All parts are toxic with roots, seeds and pre-flowering leaves highest in concentration. Horses that consume around 1 plant per for day 2 weeks show symptoms. Lethal for cattle when eating or 5% more of their total daily diet of mature plants for periods days. exceeding 15 present in all plantToxins parts, increasing with maturity and remain after drying. Seeds highest have concentration. Species vary in toxicity levels. Narrow leaf species are the most toxic and broad-leaf species relatively non-toxic. risk Toxicity when plant is actively growing. Risks decrease with drying but plant remains toxic. Toxic dose dependsToxic on rate of consumption and digestion. All plant parts and growth stages are toxic, fresh or dried, but toxicity decreases as plant matures and dries. Less dangerous after seed dispersal. Consumption of green plant (lethal). Seeds, especially when immature, are more are especially Seeds, when immature, (lethal). plant green Consumption of toxic than other plant parts. Remains toxic when dried. Sheep are mainly affectedby this plant when eaten in conjunction with black sagebrush ( Symptoms appear 2 to 5 weeks after consumption. and Fresh dry plants are toxic. Horses Toxic DosageToxic (bw = body weight; n/a = not applicable) 86 - 200% bw >50% of diet n/a affected Rarely 0.1 - 0.3% bw 0.1 0.25% bw lbsin 6 weeks4 - 81 affected Rarely 0.075% bw 0.075% 2% of dry matter intake/day 0.5% of bw seeds days for 10 0.05 – 2.0% bw No data 0.1 – 1.0% bw – 1.0% 0.1 n/a containing Feed horsetail.>20% Sheep/Goats n/a >50% of diet nitrates >1% Rarely affected bw – 21%) (3 0.1 - 0.3% bw 0.1 No data bw 0.5 - 1.5% 0.25% bw No data No data Rarely affected Rarely 0.05 – 2.0% bw 8 oz 0.1 – 1.0% bw – 1.0% 0.1 affected. Rarely 0.5 - 1.25% Cattle n/a >50% of diet nitrates >1% 0.5 - 3.5% bw 0.1 - 0. 3% bw 3% - 0. 0.1 30 - 50% in bw dry weight bw - 1.5% 0.1 0.2 - 0.8% bw 0.25% bw No data 1 – 5% bw of seeds1 – 5% 5 - 10% bw 5 - 10% 0.05 – 2.0% bw 0.1 – 1.0% bw – 1.0% 0.1 containing Feed horsetail.>20% n/a ) ) ) ) ) ) ) ) ) ) . ) spp.)

spp.) Plant Species Acroptilon repens Astragalus spp.) Aconitum columbianum Aconitum Asclepias spp.) Bassia scoparia Lupinus spp.)Lupinus Delphinium spp.)Delphinium Datura stramonium Tetradymia canescens Tetradymia Equisetum Chenopodium album Chenopodium Oxytropis spp Conium maculatum Conium Cynoglossumofficinale Solanum Sorghum halepense Kochia ( Lambsquarters ( Larkspur ( Locoweed ( Knapweed, RussianKnapweed, ( Lupine ( Milkvetch ( A.(not cicer Nightshade ( Jimsonweed ( Johnsongrass ( ( Monkshood Milkweed ( Hemlock, poison ( Horsebrush ( Horsetail ( Houndstongue ( Table 2, (cont.) Table - 32 - Comments Total intake of 25 to 50% several bw over months.Total Hay retains toxicity for months. Consumption 2 weeks over is lethal. Cattle abort after eating 20 lbs green weight. Green and dry plants toxic. increases Toxicity on sandy soils. Consumption daily is days lethal. for 10 Many factors affect toxicity, but generally0.05% bw is minimum lethal dose. are found in moldyToxins feed and not in a pasture setting. Sweetclover hay can remain toxic for 3 to 4 years and can be used if diluted with uncontaminated (1:3). feed Occasionally toxic to sheep. Found to be lethal in experiments. most For species, sagebrush is a useful forage plant. to 0.6% bw of leavesConsumption depending on stage 0.1 of growth or 0.24% freshbw twigs (lethal). Wilted leaves more toxic than fresh leaves. concentrationsToxic vary plant by phenology and location. at all growth Toxic stages. Many factors affect toxicity, generally0.05% bw is minimum lethal dose for nitrate accumulation. Oxalate levels remain high in dry plants. Consumption of plant green weight several over weeks causes impacts. Young susceptible. horses most Consumption of green or dry foliage, bark, seeds, and aril surrounding seeds are all toxic. Foliage is readily eaten livestock. by Cattle appear to eat needles when stressed such as during winter snowstorms or shortage of forage. Consumption per for day more than (abortion). 3 days Cattle in last trimester are most susceptible. Consumption of 2% fresh bw plant is lethal. Many factors affect toxicity, but generally0.05% bw is minimum lethal dose. Dosage is fatal to sheep. Toxicity increasesToxicity with the pungency of onion. Horses Toxic DosageToxic (bw = body weight; n/a = not applicable) 3 - 7% bw No data affected Rarely nitrate0.5 - 1.5% – 20 mg/kg10 of days); feed (100 60 mg/kg – 70 of days) feed (21 n/a n/a No data 0.5 - 1.5% nitrate0.5 - 1.5% 86 - 200% bw bw 0.1% n/a No data n/a No data No data Sheep/Goats No data 5% bw 5% Rarely affected Rarely 10 - 20% bw 10 2 lbs green leaves nitrate0.5 - 1.5% 0.1 - 0.4% bw - 0.4% 0.1 bw 4% 0.75 lbs for 1 – 3 0.75 days 0.5 - 1.5% nitrate0.5 - 1.5% 0.5% bw n/a Rarely affected Rarely No data 16 oz green oz 16 weight Rarely affected Rarely Cattle 0.5 - 1.5% nitrate0.5 - 1.5% 5 - 10% bw 5 - 10% 10 – 20 mg/kg10 of days); feed (100 60 mg/kg – 70 of days feed (21 10 - 20% bw 10 affected Rarely nitrate0.5 - 1.5% 0.1 - 0.6% bw 0.1 bw 1% n/a 0.5 - 1.5% nitrate0.5 - 1.5% 0.5% bw n/a 4.8 - 6 lbs dry or green needles or bark 2% bw Rarely affected Rarely 25% of diet25% ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) . Plant Species Amelanchier alnifolia Amelanchier Artemisia tridentata Amaranthusretroflexus Allium spp Adonis aestivalis Hymenoxys perforatumHypericum Descurainia pinnata Melilotus officinalis Melilotus Taxus brevifolia Taxus Pinus ponderosa Pinus Nicotiana attenuata Salsola tragus Salsola Sorghum spp Centaurea solstitialis Gutierrezia sarothrae Thistle, RussianThistle, ( Sneezeweed ( Sorghum-sudangrass, and sudangrass ( St. Johnswort ( ragwortTansy ( Serviceberry ( Snakeweed ( and yellow Sweetclover, white ( Sagebrush, big ( Yew ( Redroot pigweed Redroot ( Yellow starthistleYellow ( Tobacco, coyote Tobacco, ( Pine, ponderosa ( Onion ( Pheasant’s eye ( Table 2, (cont.) Table - 33 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Damp, wet, marshy areas, irrigated pastures, saline and soils alkaline Dry alkaline soils, or bentonitic soil of steppe, forests, along streamsMoist of soils Cultivated Roadsides, fields, pastures Roadsides, fields, pastures Roadsides, fields, meadows, river bars,vacant lot Roadsides, woodlands, pastures Moist forest, to wet woodlands and meadows, thickets within subalpine forested landscapes, to along streams, valleys Cultivated Fields, wooded areas, vacant lots, riparian corridors Cultivated, reported to escape into disturbed soils and roadsides Fields, roadsides Fields, Meadows, pastures, fields, roadsides Moist meadows, grasslands, irrigated fields, hay along roads, lawns Open forest, woodlands, thickets; up to lower subalpine Riparian thickets, forests, pine and ash woodlands, rocky grasslands of soil stony slopes, Moist areas, roadsides, fields, pastures Meadows, fields, lawns, roadsides, streambanks Meadows, moist grasslands, roadsides, fields Streambanks, roadsides, fields, farmyards, pond and reservoir edge Cultivated, rarely escaping Moist soil of avalanche slopes, thickets, open forest, woodlands, often along streams X X X X X X X X Disturbed X X X X X X X X X X X X X Cropland X X X X X X X X X X X Wet Areas X X X X X X X X X X X X X X X X Valleys X X X X X X X X X X X X X Plains X X X X X X Habitat X X Shrubland X X X X X Foothills X X X X X X X X Mountains X X X X

3 M M M Noxious W I I I I I I I I I I 2 I I I I I N N N N N N N N Native N, N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F F F F F F F F F F F F F F S S S G Lifeform G Plant Family Ranunculaceae Chenopodiaceae Fabaceae Solanaceae Boraginaceae Caryophyllaceae Polypodiaceae Brassicaceae Rhamnaceae Polygonaceae Ranunculaceae Fabaceae Brassicaceae Juncaginaceae Rosaceae Rosaceae Fabaceae Fabaceae Fabaceae Asteraceae Poaceae , Scientific Name(s) Scientific Xylorhiza glabriusculaXylorhiza Actaea rubra Beta vulgaris Lotus corniculatus Hyoscyamus niger Echium vulgare Saponaria officinalis Pteridium aquilinum Brassica spp. Raphanus sativus Raphanus catharticaRhamnus Fagopyrum esculentum Ranunculus spp. and Ceratocephala testiculata Medicago sativa Berteroa incana maritima,Triglochin palustris T. Prunus pensylvanica Prunus Prunus virginiana hybridum Trifolium pratense Trifolium repens Trifolium strumarium,Xanthium X. spinosum Mays Zea Heracleum maximum Plant Species Aster, woody Aster, Baneberry sugar Beet, trefoil Birdsfoot Black henbane Blueweed Bouncingbet Brackenfern Brassicas Buckthorn Buckwheat Buttercup Alfalfa Alyssum, hoary Arrowgrass Cherry, pin Chokecherry alsike Clover, Clover, red Clover, white Cocklebur Corn Cow parsnip G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3. Plant family, native status, noxious weed designation, and habitat descriptions for poisonous plant species in Montana and Wyoming. and species in Montana plant poisonous for descriptions habitat and weed designation, status, native noxious family, 3. Plant Table 1 - 34 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Grasslands, sagebrush woodlands, badlands, steppe, meadows, fellfields, roadsides Disturbed soils of fields, roadsides, pastures Moist meadows, thickets, woodlands, sagebrush steppe, pastures forest, along stream, Cultivated Saline soil of stream terraces, badlands, dry alkaline soils streambanks pastures, and farmyards of soil moist Shaded, Dry soils of grasslands, fields, roadsides Margins of wetlands, streambanks, roadsides, streambanks, disturbedMargins wetlands, of sites, vernally moist Many species in MT and WY that vary in habitat; Meadows, calcareous ridges, stony open forest, soil, along streams, grasslands, and sagebrush steppe; up to subalpine Moist to wet, disturbed sites, ditches, roads, streams, wetlands Rocky soil, along streams, forest openings, open wooded roadsides meadows, areas, Moist open forest and woodlands, thickets, avalanche subalpine to valleys slopes, along streams; riparianWet meadows, thickets, moist forest openings, subalpine to slopes; up avalanche Moist meadows, pastures, ditch banks and irrigated fields Dry soils, cultivated areas, roadsides, lawns, pastures Fields, pastures, vacant lots, roadsides Hay fields, roadsides, farmyards,waste areas Barren areas, saline soil of arid areas, disturbed steppe in arid valleys, dry lakebeds, abandoned dry farm fields Moist, disturbed soil along streams, ditches, cool open slopes X X X X X X X X X X Disturbed X X X X X X Cropland X X X X X X X X X X X Wet Areas X X X X X X X X X X X X X X Valleys X X X X X X X X X X X X X Plains X X Habitat X X X X X X Shrubland X X X X X Foothills X X X X X X Mountains X X X X X

3 Noxious B I I I I I I I I I 2 I N N N N N N N N N N, Native N, N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F F F F F F F F F F F S S G Lifeform G Plant Family Brassicaceae Fabaceae Poaceae Chenopodiaceae Lamiaceae Solanaceae Asteraceae Asteraceae Linaceae Liliaceae Polygonaceae Apocynaceae Caprifoliaceae Liliaceae Poaceae Boraginaceae Convolvulaceae Chenopodiaceae Apiaceae . spp. spp spp. Scientific Name(s) Scientific Descurainia sophia Thermopsis montana, rhombifolia T. Sarcobatus vermiculatus Glechoma hederacea longifoliaPhysalis Senecio spp. Grindelia squarrosa Zigadenus crispusRumex Apocynum cannabinum, A. androsaemifolium Sambucus Veratrum spp. Schedonorus arundinaceus Amsinckia menziesii, A. lycopsoides arvensisConvolvulus Linum Halogeton glomeratus Halogeton maculatum Conium Plant Species Flixweed Goldenbanner Grains, cultivated Greasewood Ground ivy Groundcherry, longleaf Groundsel Curlycup gumweed Deathcamas Dock, curly Dogbane Elderberry hellebore False Fescue, tall Fiddleneck bindweed Field Flax Halogeton Hemlock, poison G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3, (cont.) Table 1 - 35 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Moist meadows, to wet thickets, woodland margins Marshes, meadows, wet wetlands, stream banks, irrigation ditches farmyards, Disturbed rights-of-way, roadsides, railroad soils, cultivated areas Moist soils of disturbed sites, roadsides, ditches, waste areas, alluvial bottom land, cultivated fields, pastures Fields, grasslands, meadows, roadsides, stream terraces farmyards, rangeland, Disturbed roadsides, pastures, of soil cultivated fields, tolerant of saline soil Moist forests to wet and meadows; valleys to subalpine Wet meadows, marshes, wetlands along meadows, streams, Wet roadsides Fields, dryGrasslands, grasslands and sagebrush steppe Moist soil to wet meadows, pastures, forests, streambanks, shoreslake at all elevations Disturbed rangelands, meadows, grasslands, roadsides Disturbed ground of pastures, fields, roadsides, grasslands, woodlands,meadows, forests, riparian areas Cool, moist, upland slopes in coniferous forests, forming dense thickets on north slopes; valleys to subalpine Dry grasslands, sagebrush steppe, desert shrubland, roadsides, and woodlands; often in sandy soils Moist grasslands, sagebrush steppe, moist meadows, to wet thickets, forest openings, near streams; up to alpine Disturbed soils of roadsides, fields, rangeland, pastures Grasslands, sagebrush steppe, open forest or woodland, rocky ridges Deep, moist soils, mountain meadows, stands, along springs and seeps around or streams X X X X X X X Disturbed X X X X X X X Cropland X X X X X X X X Wet Areas X X X X X X X X X X X X X X X X X Valleys X X X X X X X X X X X Plains X X Habitat X X X X X Shrubland X X X X X X X X X X Foothills X X X X X X X X X Mountains X

3 B B Noxious M I I I I I I I 2 I N N N N N N N N N N N Native N, N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F F F F F F F F F F F S S S Lifeform G Plant Family Iridaceae Solanaceae Poaceae Asteraceae Chenopodiaceae Ericaceae Chenopodiaceae Apiaceae Cannabaceae Asteraceae Equisetaceae Asteraceae Boraginaceae Ericaceae Fabaceae Scrophulariaceae Iridaceae Ranunculaceae Ranunculaceae spp. Scientific Name(s) Scientific Iris pseudacorus Datura stramonium Sorghum halepense Acroptilon repens Bassia scoparia glandulosumLedum album Chenopodium Cicuta douglasii Cannabis sativa Cannabis canescens Tetradymia Equisetum canadensis Conyza Cynoglossumofficinale ferruginea Menziesia Pediomelum argophyllum Castilleja spp. Iris missouriensis Delphinium bicolor, D. D. bicolor, Delphinium nuttallianum, geyeri,D. and others Delphinium barbeyi, occidentale,D. D glaucum, and others Plant Species Iris, yellowflag Jimsonweed Johnsongrass Knapweed, Russian Kochia Labrador tea Lambsquarters Hemlock, water Hemp Horsebrush Horsetail Horseweed, Canadian Houndstongue false Huckleberry, Indian breadroot, silverleaf paintbrushIndian Iris, Rocky Mountain Larkspur, low Larkspur, tall Larkspur, G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3, (cont.) Table 1 - 36 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Cultivated Moist meadows, to wet open moist forest, along streams; up subalpineto Stony slopes, cliffs, rock outcrops, on limestone or , open pine forest Moist meadows and forests, bogs, around up to lakes; alpine Grasslands, woodlands, meadows, riparian forest, pastures and Grasslands with well-drained rangeland, soil, sagebrush steppe, dry woodlands, pastures, and exposed ridges at all elevations Many species of lupine in MT and not WY; all are for cited commonly most are Species listed poisonous; toxins; varied habitat from sandy dry, soil of grasslands, sagebrush steppe, streambanks, moist meadows, open dry, forest, woodlands; all elevations areas waste Disturbed barnyards, pastures, Fields, roadsides, farmsteads, waste areas Many species in MT and WY vary in habitat and toxicity; moist soilStony, of grasslands, sagebrush steppe, alkaline meadows, gravel bars, thickets, near wetlands or streams, open forest, limestone-derived soil, clay soil; all elevations Meadows, grasslands, pine streambanks, badlands, woodlands, fields, roadsides, ditches, marshes, potholes Riparian forests, grasslands, woodlands, thickets, pastures, roadsides, fences, disturbed ditches, along streams, soils, farmyards, cultivated field edge Many species in MT and WY that vary in habitat; grasslands, sagebrush steppe, open forest, meadows, woodlands, thickets, riparian areas, rock outcrops; all elevations X X X X Disturbed X X X X X Cropland X X X X X X X Wet Areas X X X X X X X X X Valleys X X X X X X X Plains X X Habitat X X X X X Shrubland X X X X X X X Foothills X X X X X X Mountains X

3 Noxious B I I I I 2 I N N N N N N N N Native N, N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F F F F F S S S Lifeform G Plant Family Poaceae Ranunculaceae Rosaceae Solanaceae Ericaceae Euphorbiaceae Fabaceae Fabaceae Malvaceae Solanaceae Fabaceae Asclepiadaceae Liliaceae

. spp Scientific Name(s) Scientific Aconitum columbianum Aconitum Cercocarpus ledifolius, C. montanus Solanum spp. Kalmia polifolia, polifolia, Kalmia K. microphylla Euphorbia esula Oxytropis sericea, lambertii,O. and others Lupinus sericeus, L. caudatus, L. leucophyllus, L. argenteus, L. plattensis, L. polyphyllus, L. pusillus, and others Malva neglecta barbarum Lycium Astragalus spp. A.(not cicer) Asclepias spp. Pennisetum glaucum Allium Plant Species Monkshood Mountain curl- mahogany, true and leaf Nightshade Laurel Leafy spurge Locoweed Lupine common Mallow, Matrimony vine Milkvetch Milkweed Millet Onion G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3, (cont.) Table 1 - 37 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Many species in MT and WY that vary in habitat; Stony or sandy soils of grasslands, sagebrush steppe, open coniferousmeadows, woodlands Deep soils of sagebrush steppe, steep open slopes, dry subalpine to valleys hillsides; and plains Grasslands, sagebrush meadows, streambanks, steppe, slopes talus roadsides, Usually on alkaline or saline soil of sagebrush steppe, grasslands, badlands Moist roadsides Moist, open forests, disturbed areas; valleys to subalpine Moist to dry forests, grasslands, meadows, woodlands, subalpine lower to slopes; valleys avalanche streambanks, Sagebrush steppe, grasslands, juniper woodlands, subalpine to valleys pastures; badlands, Sandy, rocky or well-drained soil; grasslands, sagebrush sagebrush grasslands, rocky well-drained soil; or Sandy, steppe, rock outcrops, open forest and woodlands, roadcuts, meadows; all elevations Escaped ornamental plant, weed in cultivated fields, roadsides pastures, Drier forests, rocky exposures associated with grasslands Clay soil and selenium-rich dry, soil on open slopes, barren hills and flats, streambanks, badlands Dry, sandy or gravelly soil of streambanks, pastures, areas roadsides, waste Rich disturbed soil of farmyards, waste areas, cultivated fields Cultivated fields, roadsides, streambanks,waste areas Streambanks, ditch banks, wetlands, mostly at lower to middle elevations. Disturbed sites, roadsides, sides, and newly planted lawns Disturbed areas, roadsides, fields, pastures, andwaste areas X X X Disturbed X X X X X X

Cropland X X X X X X X X Wet Areas X X X X X X X X X X X X Valleys X X X X X X X X X X X X X Plains X X X X X X Habitat X X X X X X X Shrubland X X X X X X X X X Foothills X X X X X X X X Mountains X

3 Noxious M I 2 I I I I I N N N N N N N Native N N N N N N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F T F F F F F S S S S S Lifeform G G Plant Family Asteraceae Asteraceae Chenopodiaceae Fabaceae Fumariaceae Rosaceae Asteraceae Scrophulariaceae Ranunculaceae Pinaceae Brassicaceae Zygophyllaceae Portulacaceae Chenopodiaceae Poaceae Poaceae Lamiaceae Asteraceae spp. Scientific Name(s) Scientific Artemisia tridentata Artemisia dracunculus, A. ludoviciana Atriplex spp. Cytisus scoparius Corydalis aurea alnifolia Amelanchier Gutierrezia sarothrae Penstemon Adonis aestivalis Pinus ponderosa Pinus Stanleya pinnata terrestrisTribulus Portulaca oleracea Amaranthusretroflexus Phalaris arundinacea Lolium perenne Salvia reflexa Artemisia filifolia, A. frigida Plant Species Sagebrush, big Sagewort, green and white Saltbush Scotch broom eggs Scrambled Serviceberry Snakeweed Penstemon Pheasant’s eye Pine, ponderosa Pine, Princesplume Puncturevine Purslane pigweed Redroot canarygrass Reed Ryegrass, perennial lanceleafSage, Sage, sand and fringed sage G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3, (cont.) Table 1 - 38 - Habitat Description Habitat State-listed noxious weed in Montana (M), Wyoming (W), or both (B). 3 Grasslands, cultivated fields, roadsides,waste areas Disturbed soil of open forest, meadows, pastures, often associated with timber harvest or fire Cultivated, rarely escaping Moistdisturbed soils fields,of meadows, thickets, roadsides, woodlands, open forest, wetlands streambanks, Dry disturbed soils of roadsides, cultivated fields, dry lake beds, waste areas Sandy or gravelly soil of streambanks, hills, railroad right-of- waste areas way, Roadsides, cultivated fields, grasslands roadsides,Fields, streambanks areas disturbed roadsides, grasslands, Fields, forest,Wet humid environments, usually on acid soils Moist slopes and well-drained meadows; up to subalpine Cultivated, rarely escaping Open forests, prairies, fields, streambanks,waste areas Grassland, open forest, pastures, meadows, roadsides, disturbed areas Sparselyvegetated soil recedingof lakes and ponds or flood areas, cultivated fields Disturbed soil of fields, grasslands, rangeland, streambanks, streambanks, rangeland, grasslands, fields, of soil Disturbed meadows,wet thickets, roadsides, cultivated fields Roadsides, fields, streambanks, grasslands, rangeland, open slopes badlands in Roadsides, fields, thickets, meadows, moist areas, open aspen or pine forest Moist disturbed meadows, along streams and ditches X X X X X X X X X X Disturbed X X X X X X X X X X X X X X Cropland X X X X X X X X Wet Areas X X X X X X X X X X X X X X Valleys X X X X X X X X X X X Plains X X X Habitat

Shrubland X X X X X X X X X Foothills X X X X X X X X Mountains X X

3 B B B B B Noxious M I I I I I I I I I I 2 I I I N N N N N N N, Native N, N = Native, I = Introduced to Montana and Wyoming 1 2 F F F F F F F F F F F F F F F F S G Lifeform G Plant Family Asteraceae Poaceae Asteraceae Asteraceae Solanaceae Fabaceae Brassicaceae Asteraceae Taxaceae Asteraceae Poaceae Oxalidaceae Clusiaceae Chenopodiaceae Asteraceae Fabaceae Fabaceae Asteraceae Brassicaceae

Scientific Name(s) Scientific Senecio jacobaea Eragrostis tef Cirsium arvense tragus Salsola Nicotiana attenuata Vicia villosa Cardaria draba Centaurea solstitialis brevifolia Taxus Hymenoxys hoopesii Hymenoxys Sorghum bicolor, S. x drummondii, S. bicolor var. sudanenese Oxalis spp. Hypericum perforatumHypericum suckleyana Suckleya Helianthus spp. Melilotus officinalis Melilotus spp.Lathyrus vulgare Tanacetum Descurainia pinnata Plant Species Tansy ragwortTansy Teff CanadaThistle, RussianThistle, coyote Tobacco, hairyVetch, Whitetop starthistleYellow Yew Sneezeweed Sorghums, forage, sorghum- grain, sudangrass, sudangrass Sorrel St. Johnswort poison Suckleya, Sunflower Sweetclover, yellow and white Sweetpea common Tansy, mustard Tansy G = grass / graminoid / grass-like, F = forb / broadleaf plant, S = shrub, T = tree Table 3, (cont.) Table 1 - 39 - Resources and References Carlson, M. and B. Anderson. 2013. Cyanide Poisoning, University of Lincoln Extension NebGuide G2184, Lincoln, NE. Available at: http://extensionpubs.unl.edu/ Cornell University. 2007. Brown midrib sorghum sudangrass: successfully growing a high energy grass for dairy cows. Cornell University Cooperative Extension, Agronomy Fact Sheet Series 14, Ithaca, NY. Available at: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet14.pdf Dorn, R.D. 2001. Vascular Plants of Wyoming. Mountain West Publishing, , WY. Drewnoski, M., B. Anderson, P. Kononoff, and B. Reynolds. 2019. Nitrates in Livestock Feeding. University of Nebraska Extension NebGuide G1779, Lincoln, NE. Available at: http://extensionpubs.unl.edu/ Forero, L., G. Nadar, A. Craigmill, J. DiTomaso, B. Puschner, and J. Maas. 2010. Livestock-Poisoning Plants of . University of California Agricultural and Natural Resources Publication 8398, Davis, CA. Available at: https://anrcatalog.ucanr.edu/ Gadberry, S. and J. Jennings. 2016. Nitrate Poisoning in Cattle. University of Division of Agriculture Research and Extension, FSA3024, Little Rock, AR. Available at: https://www.uaex.edu/publications/ Glunk, E., K. Olson-Rutz, M. King, D. Wichman, and C. Jones. 2015. Nitrate Toxicity of Montana Forages. Montana State University Extension MontGuide MT200205AG, Bozeman, MT. Available at: https://store.msuextension.org/ Green, B.T., K.D. Welch, J.A. Pfister, C.G. Chitko-McKown, D.R. Gardner, and K.E. Panter. 2014. Mitigation of larkspur poisoning on rangelands through the selection of cattle. Rangelands 36(1):10-15. Green, B.T., D.R. Gardner, D. Cook, J.A. Pfister, K.D. Welch, and J.W. Keele. 2018. Age-dependent intoxication by larkspur (Delphinium) in Angus steers. Toxicon 152:57-59. James, L.F., D.B. Nielsen, and K.E. Panter. 1992. Impact of poisonous plant on the livestock industry. Journal of Range Management 45(1):3-8. Knight, A.P. and R.G. Walter. 2001. A Guide to Plant Poisoning of Animals in . International Veterinary Information Service, Ithaca, NY. Leininger, W., J. Taylor, and C. Wambolt. 1977. Poisonous Range Plants of Montana. Montana State University Cooperative Extension Service Bulletin 348. Montana State University, Bozeman, MT. Lesica, P. 2012. Manual of Montana Vascular Plants. Brit Press, Fort Worth, TX. Majak, W., B. Brooke, and R. Ogilvie. 2008. Stock-poisoning Plants of Western . Government of Canada, Agriculture Canada. Montana Department of Agriculture. 2019. Montana state-listed noxious weeds. Montana Department of Agriculture, Noxious Weeds Program, Helena, MT. Available at: https://agr.mt.gov/Weeds Montana State University, Schutter Diagnostic Lab, 119 Plant BioScience Building, P.O. Box 173150, Bozeman, MT 59715-3150. (406) 994-5150 [email protected] Website: http://diagnostics.montana.edu/ Panter, K., M.H. Ralphs, J. Pfister, D. Gardner, B. Stegelmeier, S. Lee, K. Welch, B. Green, T. Davis, and D. Cook. 2011. Plants Poisonous to Livestock in the Western States. U.S. Department of Agriculture, Agricultural Research Service, Agriculture Bulletin 415, Logan, UT. Available at: https://www.ars. usda.gov/is/np/PoisonousPlants/PoisonousPlants.pdf Pokorny, M. and J. Mangold. 2020. Montana’s Noxious Weeds. Montana State University Extension Service EB0159, Bozeman, MT. Available at: https://store.msuextension.org/ Sallenave, R. 2016. Water quality for livestock and poultry. New State University Cooperative Extension Service, Guide M-112, Las Cruces, NM. Available at: aces.nmsu.edu/pubs/_m/M112.pdf Smith, M., J. Waggoner, and S. Sims. 2010. Larkspur: Managing grazing to avoid poisoning cattle. University of Wyoming Range Facts MP-111.13, Laramie, WY. Available at: http://www.wyoextension.org/publications/ Stonecipher C.A., D. Cook, K.D. Welch, D.R. Gardner DR, and J.A. Pfister. 2020. Seasonal variation in toxic steroidal alkaloids of foothill deathcamas (Zigadenus paniculatus). Biochemical Systematics and Ecology 90:104044. Stonecipher C.A., K.D. Welch, S.T. Lee, D. Cook, and J.A. Pfister. 2020. Geographical and seasonal variation in water hemlock () toxins. Biochemical Systematics and Ecology 89: 104012. Stubbendieck, J., M. Carlson, C. Dunn, B. Anderson, and D. Redfearn. 2018. Nebraska Plants Toxic to Livestock, Including Bloat-Causing Plants, Rangeland, Pastureland, and Cropland. University of Nebraska Extension EC3037, Lincoln, NE. Available at: https://extensionpubs.unl.edu/ Taylor, J. E. and J. R. Lacey. 2004. Range Plants of Montana. Montana State University Extension Service Bulletin EB 122, Bozeman, MT. Available at: https://store.msuextension.org/ A&M University. 2019. Plants of Texas Rangelands: Virtual Herbarium. Texas A&M AgriLife Extension System, Department of Ecosystem Science and Management, College Station, TX. Available at: https://rangeplants.tamu.edu/common-name-index/ USDA, NRCS. 2020. Cover Crops. Agronomy Technical Note MT-93. USDA-NRCS, Bozeman State Office, Bozeman, MT. Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/mt/home/ USDA, NRCS. 2019. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA. Available at: http://plants.usda.gov Voss, J.L. 2019. Guide to Poisonous Plants. State University, College of Veterinary Medicine and Biomedical Sciences, Fort Collins, CO. Available at: https://csuvth.colostate.edu/poisonous_plants Weathers, Shirley A. 1998. Field Guide to Plants Poisonous to Livestock: Western U.S. Rosebud Press, Fruitland, UT. Whitson, T., L. Burrill, S. Dewey, D. Cudney, B. Nelson, R. Lee, and R. Parker. 2002. Weeds of the West. The Western Society of Weed Science, Newark, CA. Wyoming Department of Agriculture. 2018. Wyoming state designated noxious weeds, Wyoming Department of Agriculture, Weed and Pest Program, Cheyenne, WY. Available at: http://wyagric.state.wy.us/divisions/ts/sections-a-programs/weed-a-pest Glossary Acute poisoning – Adverse effects from a substance Furanocoumarins – Organic chemical compounds resulting either from a single exposure or from associated with photosensitivity through ingestion multiple exposures in a short period of time. and direct contact with the skin. When the Alkaloid – Naturally occurring basic, organic, phytochemicals enter the nucleus of epithelial cells nitrogenous compounds. and form a bond with the DNA, it causes the cells to die resulting in the skin being unable to protect itself Anemia – Deficiency of red blood cells or hemoglobin from sunlight. in the blood. Gallic Acid – A substance, occurring in a free state or Ataxia – Loss of full control of bodily movements. combined as gallotannin, causing skin and mucosal Bloat – A disease in livestock characterized by an irritation. accumulation of gas in the stomach. To make or Glycoside – Any group of organic compounds become swollen with fluid or gas. occurring within plants that produce sugars and Cannabinoids –Psychoactive chemicals, obtained related substances upon hydrolysis. from plants of the Cannabis , that have toxic Hemolysis – Rupture or destruction of red blood cells. effects on the nervous system. Hepatic – Relating to, affecting, associated with, Chronic poisoning – Adverse effects from a supplying or draining the liver. substance result of a long-term exposure when toxins accumulate over time and damage is Hepatopathy – An abnormal or diseased state of the permanent. liver. Cicutoxin – An unsaturated which acts on the Hydrogen cyanide (HCN) – (also known as prussic central nervous stimulant. acid) Extremely toxic, volatile, rapidly acting poison that inactivates cellular respiration by depriving Colic – Severe, often fluctuating pain in the abdomen cells of oxygen. caused by intestinal gas or obstruction in the intestines. Hypericin – A phototoxin contained in pigment glands that fluoresce in the presence of sunlight and causes Congenital – Existing at birth, but not hereditary. acute inflammation and necrosis of cells of the skin Cotyledon – An embryonic leaf in seed-bearing plants, capillaries. Only white or unpigmented skin areas one or more of which are the first leaves to appear are affected. These areas itch and become red, from a germinating seed. swollen, and sore, and the skin may peel or come off in large sheets (photosensitization). Cyanosis – Blue coloring of the lining of the mouth. Hypertonic muscle – Too much muscle tone so that Cystitis – Inflammation of the bladder. areas are stiff and difficult to move. Dicoumarol – Toxic product synthesized from Irisin – A toxin chemical found in Iris rhizomes which coumarin in moldy sweetclover. can cause abdominal pain, burning sensation of the DDMP – A complex compound (2,3-dihydro-3,5- mouth and throat, and vomiting if ingested and mild dihydroxy-6-(H) -pyran-4-) that inhibits the skin irritation upon skin exposure. transporter system of the brain affecting Integumentary – The outer protective layer of cranial nerves. an animal or plant. The integumentary system Edema – Excess of watery fluid collecting in the comprises the skin and its appendages (hair, hooves) cavities or tissues of the body. which protect the body from damage. Endophyte – An organism, often fungi or bacteria, Isocupressic acid –A diterpene acid that interferes living within a plant between living plant cells. The with blood flow to the uterus and can induce relationship with the plant varies from symbiotic to abortion in cattle in the last three months of bordering on pathogenic. pregnancy. Fetal mummification – Shriveling or shrinkage of Jaundice – Yellowing of the skin or whites of the eyes, fetus by absorbing all fluid of fetus and uterus. caused by obstruction of the bile duct, liver disease, or excessive breakdown of red blood cells. Forb – A broad-leaved . Laminitis – Inflammation of the sensitive layers of tissue inside the hoof in horses and other animals. It can cause extreme lameness.

- 42 - Monoterpene – A class of terpenes produced in plants Renal – Relating to the kidneys. that often have a strong odor and may protect the Rumen stasis – Collapse of ruminal function, plants. cessation of normal rhythmic contractions for more Mycotoxin – A toxin produced by a fungus. than two minutes. Major classes of mycotoxins include aflatoxins, Selenium – An essential trace nutrient for animals. trichothecenes, fumonisins, zearalenone, In certain plants it accumulates to levels that are ochratoxin, and ergot alkaloids. toxic to livestock when those plants are growing in Neurotoxic diterpenoid – Toxins, including selenium-rich soils. andromedotoxin and grayanotoxin, present Sesquiterpene lactone – A terpene (sesquiterpene) throughout the plant. Symptoms of poisoning containing a lactone ring. It can cause allergenic include vomiting, depression, hypotension, irregular (irritate eyes, nose, gastrointestinal tracts) or heartbeat, colic, convulsions, inability to coordinate neurotoxic (necrosis or death of neural tissue) voluntary muscles and recumbency. effects. Nitrotoxin – Neurotoxin compounds contained Sulfate – A salt or ester of sulfuric acid. Animals in some milkvetch species that are poisonous consuming plants with high levels of sulfate will to cattle, sheep and horses with cattle being the reduce sulfate to hydrogen sulfide in the rumen most commonly affected. Symptoms of nitrotoxin resulting in degenerative changes in the brain poisoning include weakness (staggered gait, clicking causing depression, blindness or death. of hooves while walking), ataxia, muscle tremors, depression, recumbency and death. Tannic acid – A form of tannin that is a weak acid and a type of polyphenol found in some plants. Oxalate – Poisonous salt of dibasic acid. Tannin – A bitter-tasting organic substance present in Petechial hemorrhage – Tiny pinpoint red mark some galls, barks, and other plant tissue. caused when the body is deprived of oxygen. Teratogen – A chemical or agent (e.g. alkaloid) which Photophobia – Extreme sensitivity to light. crosses the placenta and interferes with embryo or Photosensitivity – Light sensitivity causing abnormal fetus development producing an embryonic or fetal skin reaction to direct sunlight exposure. defect. Extent of the defect depends on the teratogen and the stage of development. Photosensitization – Sensitization of the skin to light. The development of an abnormal capacity to Tetany – A stimulated neuromuscular activity caused react to sunlight typically by edematous swelling by deficiencies of calcium and/or magnesium. and dermatitis. Tetradymol – A sesquiterpene that is a liver toxin. Plains – Plains and valleys are the lowest elevation Thiaminase – An enzyme that produces thiamin habitat in a given area. Plains are influenced by the (vitamin B1) deficiency in livestock by destroying which generally have more growing ingested thiamine after ingestion and reducing season than valleys. thiamine availability. Thiamin deficiency results in Poison – A substance that can cause the illness or retinal degeneration, blindness, depression, weight death of a living organism when introduced or loss, and hemorrhaging syndrome. absorbed. Synonym: toxin; Adjective: poisonous. Thujone – A ketone and monoterpene, which occurs Prostration – Lying stretched out on the ground. naturally, has a menthol odor, and may cause effects resembling epilepsy. Prussic acid – (also known as hydrogen cyanide) Extremely toxic, volatile, rapidly acting poison that Toxin – A substance produced by a living organism that inactivates cellular respiration by depriving cells of is poisonous to another living organism. Synonym: oxygen. poison; Adjective: toxic. Rectal prolapse – Rectal walls have prolapsed to a – Valley and plains are the lowest elevation degree where they protrude out the anus and are habitats in a given area. Valleys are generally in visible outside the body. mountainous areas and rain-shadows. Recumbency – Laying down, unable to walk or remain standing.

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