Livestock-Poisoning Plants of California
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Making a Difference for California University of California Agriculture and Natural Resources http://anrcatalog.ucdavis.edu Publication 8398 | January 2011 Livestock-Poisoning Plants of California LARRY FORERO, University of California Cooperative Extension Livestock Advisor, Shasta and Trinity Counties; GLENN NADER, University of California Cooperative Extension Livestock and Natural Resources Advisor, Sutter-Yuba and Butte Counties; ARTHUR CRAIGMILL, University of California Cooperative Extension Environmental Toxicology Specialist, Sierra Foothill Research and Extension Center; JOSEPH M. DITOMASO, University of California Cooperative Extension Weed Specialist, Department of Plant Sciences, UC Davis; BIRGIT PUSCHNER, Professor of Veterinary Toxicology, California Animal Health and Food Safety Laboratory; and JOHN MAAS, University of California Cooperative Extension Veterinarian, School of Veterinary Medicine, UC Davis. Poisonous plants cause significant losses of livestock With few exceptions, livestock will not eat every year. A successful livestock operator must know poisonous plants unless forced to by hunger. The which poisonous plants occur on a given range or single most important way to prevent poisoning is to pasture and how they can be controlled or avoided. use proper range and pasture management practices This publication shows which plants are poisonous, to provide ample forage, encouraging consumption tells how they affect stock, and suggests ways to of nontoxic plants. Areas infested with poisonous reduce losses from poisoning. plants should be avoided when trailing, holding, or Undesirable effects may result from a single unloading animals. Supplemental feed may protect ingestion of a large amount of a poisonous plant, but stock if these conditions cannot be avoided, but some plants are so toxic that very small amounts may there are circumstances (for example, herbicide result in severe disease or death. Other plants cause applications) that may change palatability or increase chronic poisoning only after ingestion over weeks or toxicity in some plants. If toxic weeds are embedded months. The later situation may result in clinical signs in alfalfa cubes or included in total mixed rations, long after the exposure to the toxic plant material, and animals may not be able to avoid ingestion of them. treatment may no longer be possible. Many poisonous plants may be controlled with herbicides. Often, however, the uneven distribution Livestock-Poisoning Plants of California ANR Publication 8398 2 Diagnosing a plant poisoning can be difficult and Livestock Poisoning by Plants Possible poisonous plant in hay or feed: must be done quickly. In many cases, clinical signs in California What to do are nonspecific (such as diarrhea), and postmortem The California Animal Health and Food Safety • Work with your veterinarian to determine lesions are not characteristic. The assistance of your whether the animals’ clinical sign may be a result (CAHFS) Laboratory System toxicology laboratory veterinarian is crucial. This is especially important of plant exposure. investigated numerous cases of suspected plant in insurance or legal investigations. Producers • Collect the whole plant (if practical) or poisonings from 1990 to 2007. CAHFS veterinary and farm managers, along with veterinarians representative parts of the plant, including toxicologists have diagnosed plants as the cause of leaves, flowers, stems, roots, and fruit, and and diagnosticians, play important roles, and all toxicosis in more than 600 submitted cases, most of have it identified by a trained individual (local contribute information that may be important to these in livestock. The largest number of submissions nursery, county agricultural commissioner, UC diagnose a poisoning case. Once all the information Cooperative Extension Advisor, veterinarian, was for cattle, followed by horses, pigs, goats, and is available, all evidence is collected, and proper diagnostic laboratory, etc.). sheep. sampling of specimens has occurred, a summary • Save suspect plant material or feed for possible The most commonly diagnosed cause of plant of findings will be instrumental in preventing future evaluation. poisoning is ornamental oleander, a nonnative species recurrences. • Once plants are identified, ask your veterinarian (fig. 1). The data from CAFHS are from submitted to contact a veterinary toxicologist for detailed Accurate plant identification is critical if you samples, so they do not necessarily represent the consultation. suspect that a particular plant is causing problems overall occurrence of plant poisonings in California. • If the animal dies, submit it to a veterinary for your livestock. Producers can be most helpful by diagnostic laboratory. providing a grazing history, carefully observing what plants have been grazed, especially suspicious plants. The best approach is to collect the whole plant (if Possible poisonous plant in pasture: What to do practical) or representative parts of the plant, including 1. Work with your veterinarian to determine of poisonous plants on a range or in a pasture makes leaves, flowers, stems, roots, and fruit, and press whether the animal’s clinical sign may be a large-scale chemical control uneconomical. However, them dry in a folded newspaper between two sheets result of plant exposure. small patches of poisonous plants can and should be of cardboard, or roll them up between the pages of a 2. Determine whether a plant is found in your eradicated to prevent them from spreading to other newspaper or magazine. The plant sample can then be area. Visit the Calflora Web site, http://www. areas. The specifics of chemical control of poisonous taken or sent to your local UC Cooperative Extension calflora.org/. plants are beyond the scope of this publication; advisor or county agricultural commissioner office 3. Walk the field, collecting any unusual or toxic plants, and have them identified. see your county Farm Advisor or a UC Cooperative for identification. Local nurseries may also be a good 4. If you cannot identify a suspect plant, take it to Extension Specialist, or contact a pest control adviser source for plant identification. To determine whether your county agricultural commissioner or UC (PCA) for specific recommendations for your area. a particular plant is found in your area, see the Calflora Cooperative Extension office for identification. Web site, http://www.calflora.org/. 5. If an animal dies, submit it to a veterinary diagnostic lab. Livestock-Poisoning Plants of California ANR Publication 8398 3 Although most of the plants discussed in this treatment. Most important, recognition of poisonous publication are not among those that have confirmed plants in hay or forage may help prevent plant diagnoses, it is important to know that they can be poisonings in animals. poisonous. Awareness of poisonous plants growing in The following tables give summary information a certain geographical region, the season when they about livestock-poisoning plants in California. For full are most available, and their associated clinical signs information on plants listed, refer to the descriptions are instrumental in making a diagnosis and initiating in the text. 600 555 Plant PoisoningPlant Poisoning 1990-2007 1990-2007 500 400 300 200 134 Number of Diagnoses Number Diagnoses of 100 78 49 28 22 14 13 10 9 0 Oleander Nitrate Pyrrolizinine Oxalate Oak Avacado Yew Yellow Lupines Foxtails Accumulators Alkaloid OAK Star YEW Thistle LUPINES OXALATE AVOCADO FOXTAILS FOXTAILS Figure 1. Sources of OLEANDER plant poisoning in livestock, 1990–2007. Source: CAHFS. THISTLE NITRATE ALKALOID YELLOW STAR YELLOW PYRROLIZIDINE ACCUMULATORS Livestock-Poisoning Plants of California ANR Publication 8398 4 Table 1. Livestock-poisoning plants commonly found in selected regions of California Common name Scientific name Common name Scientific name North Coast starthistle Centaurea spp. arrowgrass Triglochin spp. tree tobacco Nicotiana spp. azalea Rhododendron spp. water hemlock Cicuta douglasii, C. maculata chokecherry Prunus virginiana Sierra Foothills dogbane Apocynum spp. cocklebur Xanthium spinosum, X. strumarium fiddleneck Amsinckia spp. deathcamas Zigadenus spp. milkweed Asclepias spp. dogbane Apocynum spp. ragweed or ragwort Senecio spp. foxtail Hordeum spp. and Setaria spp. rhododendrum Rhododendron spp. klamathweed Hypericum perforatum ryegrass, perennial Lolium spp. larkspur (low) Delphinium spp. tansy ragwort Senecio spp. milkweed Asclepias spp. veratrum (false hellebore) Veratrum californicum oak Quercus spp. water hemlock Cicuta douglasii, C. maculata ragweed or ragwort Senecio spp. South Coast toyon Heteromeles arbutifolia arrowgrass Triglochin spp. tree tobacco Nicotiana spp. chokecherry Prunus virginiana western azalea Rhododendron spp. dogbane Apocynum spp. Sierra Nevada Northern Range fiddleneck Amsinckia spp. chokecherry Prunus virginiana locoweed Astragalus spp. dogbane Apocynum spp. milkweed Asclepias spp. lupine Lupinus spp. tree tobacco Nicotiana spp. Ponderosa pine Pinus ponderosa Sacramento Valley Sierra Nevada Central Range cocklebur Xanthium spinosum, X. strumarium chokecherry Prunus virginiana curly dock Rumex crispus deathcamas Zigadenus spp. dogbane Apocynum spp. dogbane Apocynum spp. fiddleneck Amsinckia spp. larkspur (tall) Delphinium spp. foxtail Hordeum spp. and Setaria spp. Ponderosa pine Pinus ponderosa groundsel Senecio spp. ragwort or ragwort Senecio spp. milkweed Asclepias spp. toyon Heteromeles arbutifolia oak Quercus spp.