Use pesticides selectively and carefully and follow recommended procedures for the safe storage and disposal of surplus pesticides and containers. Supportive therapy may aid horses in combating the neurotoxicity symptoms. What Common Milkweed Looks Like Common milkweed produces clusters of pink to mauve-white flowers which bloom June to August. For more information on identifying milkweed varieties, consult your local county Extension agent (http://aces.nmsu.edu/county/) or NMSU Extension Circular 678, Poisonous Plants of New Mexico Rangelands (http://aces.nmsu.edu/pubs/_circulars/CR678/welcome.html). The risk of poisoning increases when pastures or rangelands are overgrazed and horses have no other suitable forage to eat. Milkweed (Asclepias spp.). Horsetail milkweed (Asclepias subverticillata) is one of the more toxic species of milkweed plants. Several species of milkweed, a well-known perennial plant, cause poisoning in horses and other livestock, usually when more palatable plants are not available. Milkweeds contain various toxic cardenolides (cardiac glycosides) that have cardiotoxic effects. Milkweed poisoning occurs frequently in sheep and cattle and occasionally in horses. 2014. While monarch butterflies require milkweed to complete their life cycle, horses are best served by ignoring the ubiquitous plant. Milkweed | ASPCA … The plant itself stands around 3 to 4 feet tall and leaks a milky sap when the stem is broken. Milkweed (Asclepias spp.) Be sure to use adjuvants described on herbicide labels. Cottonweed, Silkweed, Virginia Silk, Wild Cotton. Bracken fern. Consuming even as little as 0.1%-0.5% bodyweight of the fresh plant can be toxic to a horse. Unlike the neurotoxicity described below, poisoning due to cardiac glycosides rarely results in convulsions, so death usually occurs without signs of struggle. In addition to sound grazing management, herbicides can be an important component of a comprehensive weed management plan. It is not common for livestock or horses to consume milkweed as it is highly unpalatable. is an erect-stemmed, herbaceous perennial plant that grows from 3 to 4 feet tall (Figure 1). Control requires multiple herbicide applications. "Poisonous" does not mean deadly. Some of the signs of poisoning include twitching lips, open mouth and involuntary chewing movements; it’s often been called “chewing disease”. Allison, C.A, J.L. Chemical weed and brush control for New Mexico rangelands [Circular 597]. Scientific Name Common Name(s) Species Most Often Affected Parts Poisonous Primary Poison(s) Aconitum spp. Most poisonous plants will not kill an animal. Common milkweed produces cardiac-glycosides that are toxic to horses and might cause depression, irregular heartbeat, diarrhea, overall … However, consuming milkweed can lead to death in less than 24 hours. Plant poisoning of horses. Cherry (Black, Pin, Choke) Black Cherry. Ames: Iowa State University Press. Instead, animals will suffer from chronic toxicity, which is caused by repeat expos… http://aces.nmsu.edu/pubs/_b/B713/welcome.html. Jackson, WY: Tenton NewMedia. To find more resources for your business, home, or family, visit the College of Agricultural, Consumer and Environmental Sciences on the World Wide Web at aces.nmsu.edu/pubs/. The cardiac glycosides are found in the majority of milkweed species, while the neurotoxin is specific to the whorled-leaf types such as horsetail milkweed. And, as disquieting as it may be to contemplate, the chances are pretty good that at least some are toxic to horses. The quantity of narrow-leaved milkweed necessary to cause severe poisoning and death of a 1,000-pound horse is approximately two to three pounds of the green plant. Authors: Respectively, Professor/Extension Horse Specialist and Extension Brush and Weed Specialist, Department of Extension Animal Sciences and Natural Resources, New Mexico State University. Carpenter, and J.C. Reagor. Monkshood, Aconite, Wolfsbane: humans, cattle, goats (Print Friendly PDF). Hundreds of poisonous plants grow in North America, and many are extremely common. The plants are characterized by the thick, milky sap that seeps out when the plant stem is broken. Retrieved July 12, 2017, from https://www.ars.usda.gov/pacific-west-area/logan-ut/poisonous-plant-research/docs/milkweed-asclepias-spp/, B-710: Russian Knapweed and Yellow Star-thistle Poisoning of Horses Milkweeds are found throughout North America. 486–489). Therefore, horse owners should take appropriate measures to rid their pastures of milkweed and ensure that the hay they provide their horses is safe and free of milkweed. is Associate Professor and Extension Horse Specialist. Figure 1. Affects all livestock, most dangerous to ruminants. These plants grow in a range of soil and moisture conditions, from roadsides and ditches to pastures and rangelands. This plant is easily controlled with proper management. Other information: Monarch butterfly caterpillars feed on the foliage of common milkweed. Milkweed is popular with monarch butterflies as a place to lay their eggs—in fact, it’s the only place monarch butterflies lay eggs. These chemical compounds attack the tissues and muscles around the heart, leading to slow and labored breathing. 1995. Most livestock losses are a result of hungry animals being concentrated around milkweed-infested corrals, bed grounds, and driveways. and Ph.D. studies concentrated on equine reproduction, health, and management. If you think that your animal is ill or may have ingested a poisonous substance, contact your local veterinarian or our 24-hour emergency poison hotline directly at 1-888-426-4435. The greatest incidence of milkweed poisoning in horses occurs when milkweed species have been baled along with the normal hay crop. Table 1. One essential part of a sheep’s day is that of grazing. Apply Roundup with AMS at 8.5 lb/100 gallons of water. If you believe that your horse may have been exposed to milkweed toxins, remove the suspect feed immediately and call your veterinarian. Further control recommendations can be found in NMSU Extension Circular 597, Chemical Weed and Brush Control for New Mexico Rangelands (http://aces.nmsu.edu/pubs/_circulars/CR597/welcome.html.) Hart, C.R., T. Garland, A.C. Barr, B.B. His M.S. College Station: Texas Cooperative Extension Service. The milky white sap is sticky and has a bitter taste but livestock eat the topmost, tender leaves if good forage isn't abundant. Oleander is a beautiful but poisonous plant that’s native to California. While the fresh, green plant material is the most toxic, dried plants present in pastures or hay retain their toxicity. As is the case with many plant poisonings, preventing consumption of the plant is the only guaranteed means of avoiding toxicity and potential death. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard. Therefore, horse owners should take appropriate measures to rid their pastures of milkweed and ensure that the hay they provide their horses is safe and free of milkweed. Other less common plants causing livestock poisonings are water hemlock, poison hemlock, brackenfern and the nightshades. Philadelphia: Williams and Wilkins. For a 1,000-pound horse, this toxic dose could be between 0.5 and 20 pounds of plant matter. The soil around my old property is largely sand and gravel. Dosages of whorled milkweed as low as 0.1 % - 0.5% of the animal's body weight may cause toxicosis and, possibly, death. How It Affects Livestock Normal ensilage fermentation safely eliminates the poisonous principle. http://aces.nmsu.edu/pubs/_b/B712/welcome.html, B-713: Locoweed Poisoning of Horses Symptoms of poisoning in horses include a weak, rapid pulse, dilated pupils, dry mouth, incoordination, diarrhea, convulsions, coma, and sometimes death. Small vines, broad-leafed weeds, some wildflowers you recognize—some you don't. NMSU and the U.S. Department of Agriculture cooperating. Jason L. Turner Toxic and Non-Toxic Plant List - Horse Plants Toxic to Horses Adam-and-Eve (Arum, Lord-and-Ladies, Wake Robin, Starch Root, Bobbins, Cuckoo Plant) | Scientific Names: Arum maculatum | Family: Araceae All parts of the jimsonweed plant are poisonous to horses and humans; toxicity is caused by tropane alkaloids. http://aces.nmsu.edu/pubs/_b/B710/welcome.html, B-712: Oleander Poisoning of Horses But, young animals may eat these plants out of curiosity, and older animals may graze on these undesirable plants under the following conditions: 1. These toxins usually make the plants smell or taste bad, and animals generally avoid them. Asclepiadaceae R.Br. Common milkweed is potentially poisonous to some livestock. The toxic nature of milkweed is due to one of two agents: cardiac glycosides (cardenolides) or an unidentified neurotoxin. Signs of milkweed poisoning due to cardiac glycosides include depression and reluctance to stand, irregular heartbeat, colic, dilated pupils, muscular weakness or tremors and uncoordinated gait, and labored breathing, with death following within 24 hours. The toxic Whorled milkweed is shown to the right. Jason was active in 4-H and FFA while growing up in Northeastern Oklahoma. 2012. ©2020 HorseDVM™, LLC. 2012. New Mexico State University is an equal opportunity/affirmative action employer and educator. Learn more about our mission and programs. Occasional browsing on milkweed is not likely to cause any significant problem. Owners give them bad food or forage that contains poisonous plants. Oleander. Western Whorled Milkweed Poisoning in Livestock Colorado State University Veterinary Diagnostic Laboratories. Brand names appearing in publications are for product identification purposes only. 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