Toxic Range Plants

Poisonous plants represent one of the greatest hazards to livestock ranching in Eddy County and on western rangelands. In addition to direct losses by death, there are those due to weight loss, poor reproductive performance, and poor health. Through scientific reports and practical experience, ranch managers have learned to recognize poisonous plants and keep livestock losses to a minimum. When we receive abnormal weather there are plants germination that we may not have seen for a long time. Some of the things that can be done to prevent problems with poisonous plants are: 1. Know the poisonous plants. This is the first line of defense against toxic plants. Most of us know what is normal but if you see plants you have not seen before it would be good to find out what they are. 2. Practice good range management. To a limited degree, poisonous plants will always be present on rangelands, but the real danger is when the plants are eaten. Livestock poisoning is more often the result of poor range feed condition and difficult management situations than the presence of poisonous plants. When there is good precipitation after an extended drought there may be more toxic plants available than normal. Most poisonous plants are unpalatable and will be eaten only if other good quality forage is not available, or when they are the first to green up, or sticking out of the snow. 3. Feed adequate balanced mineral and vitamin A supplements. Livestock with a mineral health imbalance are more susceptible to many toxins than are healthy animals, and they seek out plants that may contain a mineral but are in a toxic form. 4. Provide adequate forage, especially during early spring or drought periods. Livestock after winter are seeking green feed, so consider using hay instead of pelleted forms of supplement. Most producer put out tubs, or sweet lick, these stimulate the consumption of forage, but when toxic plants are the green forage this may not be what you want to do. 5. Avoid driving livestock through infested or poor feed condition range. Hungry animals lose their selectivity, and poor rangelands contain far more poisonous plants than those in good condition. 6. Use control measures herbicides, grubbing, etc. on heavy infestations of toxic plants. The most common toxins in New Mexico poisonous plants are alkaloids, glycosides, minerals, nitrogenous compounds, oxalates and other organic acids, compounds causing photosensitivity, and resins or resinoids Alkaloids, these are the most powerful poisons and produce strong physiological reactions, generally affecting the nervous system. The alkaloid is usually distributed throughout the plant and is active whether it is fresh or dry. There are no antidotes for alkaloid poisoning. Some of the common alkaloid containing range plants in Eddy County are locoweeds (Astragalus spp.), Rayless goldenrod (Haplopappus heterophyllus), rosea, or jimmy weed, larkspur (Delphinium spp.), mostly in the Queen area and groundsel (Senecio spp.). Lupines (Lupinus spp.) are found a higher altitudes and just North, and West of Eddy County. If caught early some animals will survive by giving them good feed. Animals will be Nervous system, liver damage, locoism, trembling, abortion, depression, paralysis, vomiting, loss of coordination, coma, and death. Glycosides are compounds composed of a toxic agent combined with a sugar. The toxic agent is harmful when released from the glycosides. Cyanide (HCN, prussic acid) is the most common toxin in the glycosides. Glycoside levels in the plant are often related to environmental factors such as freezing, wilting, drought, and crushing. Cyanide is generally not retained in plant tissues after drying. Catclaw (Acacia greggii), chokecherry (Prunus virginiana), and johnsongrass (Sorghum halepense) are potential cyanide producers. Sudden death is the most common symptom. Animals will show Excitement, gasping, staggering, paralysis, prostration, convulsions, emphysema, blindness, coma, and death. Minerals, excessive absorption of certain minerals may be dangerous to livestock. Selenium is possibly the most important poisonous mineral in New Mexico. It may be found in some species of locoweed (Astragalus spp.), fourwing saltbush (Atriplex canescens), snakeweed (Gutierrezia sarothrae), and asters (Aster spp.). Prince’s plume (Stanleya pinnata) grows only on seleniferous soils. Symptoms of mineral toxicity include birth defects, loss of appetite, depression, labored breathing, excessive urination, coma, and death through respiratory and myocardial failure. Nitrogenous compounds. Both range and crop plants may contain potentially toxic levels of nitrogenous compounds. Care must be taken during drought or after fertilizer or herbicide application. Nitrates are also toxic in dry material and silage. Nitrogenous compounds are often found in many species of the amaranth (Amaranthaceae), sunflower (Asteraceae), mustard (Brassicaceae), and goosefoot (Chenopodiaceae) families. Excessive Nitrogen the blood will be dark cholate brown, cause abortion, depression of lactation, discolored urine, vitamin A deficiency, brown blood, trembling, weakness, labored breathing, hemorrhages, coma, and death. Oxalates and organic acids, many plants contain oxalates, but few species in Eddy County and New Mexico contain enough to be considered dangerous. Halogeton (Halogeton glomeratus) and dock (Rumex spp.) possess soluble oxalates that are corrosive to animal tissue. Non-ruminants are more susceptible to oxalate poisoning than ruminants because the large rumen capacity enables the animal to detoxify small amounts of soluble oxalates. Most cases of ruminant poisoning occur on poor feed condition rangelands. Affect the nervous system, reduced coagulability of blood, acute kidney inflammation, dullness, colic, depression, labored breathing, prostration, weakness, coma, and death. Compounds that cause photosensitivity, on certain occasions, animals become hypersensitive to light. Photodynamic pigments contained in horse brush (Tetradymia spp.), lechuguilla (Agave lechuguilla), sacahuista (Nolina spp.), and puncture-vine (Tribulus terrestris) react with light to produce swelling about the head, blistering, and a sunburned appearance. Damage may be so severe that the lips, ears, and eyelids may be lost. Bacterial infection may also set in. In some cases in the winter this is a problem on horses and cattle with any white pigment skin on Alfalfa, (Medicago sativa). In addition to photosensitivity liver damage, inflammation of skin, itching, necrosis of skin, restlessness, leakage of serum through skin or blistering; death does not occur directly from the photodynamic action, but as a result of kidney failure. Resins or resinoids, these are highly complex organic compounds that are present in a number of plants. Resins are found in milkweeds (Asclepias spp.), marijuana (Cannabis sativa), water hemlock (Cicuta maculata), and chinaberry tree (Melia azedarach). Sumptoms of animals affected include direct irritation of the nervous and muscular tissue, depression, weakness, staggering, labored breathing, elevated temperature, and dilation of pupils, degeneration of kidneys, coma, and death. Several noxious plants contain no poisonous compounds, and instead cause injury through mechanical means if grazed. This is often by long awns or bristles (Aristida spp., Hordeum jubatum, Stipa spp.) or by stinging hairs (Urtiea spp.). There are at least 270 poisonous plants known to occur in New Mexico. Many of these do not pose a threat except in exceptional circumstances. There are few very common poisonous ornamentals or garden plants that may occasionally escape. For a complete list see An Annotated checklist of Poisonous or Injurious range Plants of New Mexico, Extension Circular 636 by Dr. Kelly W. Allred. Subscribe to Eddy County Ag news at: http://nmsueddyag.blogspot.com/ Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.