Here’s what you need to know. TREES That Are TOXIC To HORSES. The rather recent discovery of box elder trees across the United States and Canada as the cause of a deadly muscle disease in horses coincides with the discovery of European sycamore trees in Southern and Central Europe as the cause of a similar disease there. While some horse enthusiasts feel that leaves and acorns from oak trees are safe in small amounts, it’s advisable to protect your horse from any potential source of toxicity. Pigweed and its relative lamb's quarters can cause kidney failure. | Photo: iStock. If good-quality forage is plentiful, horses will avoid most poisonous plants because they are unpalatable and have a bitter taste and/or smell. There is a clear seasonality that coincides with ripe seeds, Valberg notes. The golden chain tree (Laburnum anagryroides) and night blooming jessamine (Cestrum nocturnum) also contain alkaloids harmful for horses. DON’T CHOOSE THE WRONG PLANT: Species such as yew, laurel and privet are poisonous to horses. Following birth, the colt may present symptoms of overgrown hooves, poorly developed muscles and premature eruption of baby teeth. This website uses cookies to improve your experience while you navigate through the website. She also had the pasture vacuumed to remove any seeds. With rapid and labored breathing, fast heart rate, and rapidly progressive muscle weakness and stiffness, death occurs in most cases within 72 hours of the onset of signs. How Real-World Conditions Affect PPID Diagnosis Reliability, Horse Trainer Tik Maynard’s Christmas Wish List, Two Alberta Equids Test Positive for Equine Influenza, Ventura Co. Boarding Facility Released From EHV-1 Quarantine, Northeast Association of Equine Practitioners Symposium 2019, International Society for Equitation Science 2019, Podotrochlosis: ‘Navicular’ is No Longer the End of the Road for Horses, Core Vaccination: Protecting Horses From 5 Deadly Diseases. Horses are herbivores that will consume or at least sample almost all forms of greenery available to them. Thriving in full sunlight to partial shade, American beeches prefer moist, well-drained soil and attract wildlife like birds due to their production of small nuts. The inhibition process is as a result of pyrrolizidine alkaloids’ presence in the plant. Most trees are just fine to have around horses, and others pose horrible risks that can end in much suffering, laminitis, and worse. We also use third-party cookies that help us analyze and understand how you use this website. Death can occur within a few days. Some are respiratory, some cardiac, some neurologic, and some gastrointestinal, says Carey Williams, PhD, associate professor at Rutgers’ Equine Science Center, in New Brunswick, New Jersey. Boxelder trees are toxic to horses Tom Guthrie, Michigan State University Extension - September 25, 2017 The seeds of the boxelder tree (Acer negundo) containing the toxin hypoglycin A have been associated with Seasonal Pasture Myopathy in horses. Lilium spp. While toxic levels vary, the toxicity level in ragwort is scary. About maples. Clinical signs begin as soon as one hour after consumption and include paralysis, abdominal pain, diarrhea, and abnormal heart rate and/or rhythm. Natural Disaster: Are You and Your Horse Ready for Emergency Evacuation? Boxwood shrubs This dense evergreen plant comes in several varieties, but all types and parts are toxic. The irony is horses are easily attracted to toxic and foreign pastures, which are most likely poisonous. Stephanie Valberg, PhD, DVM, director of the University of Minnesota Equine Center, who led a team of collaborators to discover seasonal pasture myopathy, proposes the name be changed to hypoglycin A myopathy (H-AM). New leaves and young acorns, especially when green, are the most dangerous parts. The effects of Black Walnut poisoning happen incredibly quickly, usually within 24 hours after your horse has been exposed. An endophyte fungus, Acremonium coenephialum, is found on tall fescue grass (Festuca spp.) The disruption in muscle cells causes the horse’s postural and respiratory muscles to deteriorate. Also called groundsel, tansy ragwort weed has leaves that produce small yellow flowers. Nut trees that contain toxins harmful for horses include aesculin, found in the yellow (Aesculus octandra) and Ohio buckeye (Aesculus glabra) trees. Prevention is the best way to keep your horses safe from toxic poisoning. Are Your Horses Ready for You to be Quarantined? Boxelder trees are toxic to horses. There is no need to remove any pre-existing oaks, one of our most valuable species, but beware that the acorns can also be poisonous to your equine friends, to rake them up and remove them or consider temporary fencing when they fall in the autumn. Once the leaves die, they are neither as toxic nor as palatable to horses. Without fencing, horses might strip the bark off trees in pastures or paddocks. But opting out of some of these cookies may affect your browsing experience. Clinical signs after ingestion can include digestive upset or colic, leading to tremors or seizures in severe cases, says Williams. The distance you fence around the tree is primarily based on what part of the plant is problematic, says Stringer. Ash trees are commonly found in horse pastures because they are considered to be safe for horses. Planted forages can be toxic. Ragwort; Foxgloves; Buttercups; Yew; Oak; Rhododendron; Ragwort poisoning. Some are very dangerous because of their potency. Wild cherry This tree’s leaves, seeds, and bark are all toxic. Holly tree or shrub The American holly, recognized by its evergreen prickly leaves and red berries, is moderately toxic to horses. Horses are tied up outside of their normal pasture (such as wash racks, trailers or hitching posts), and they can reach these toxic trees and shrubs. So, what trees and shrubs are toxic, and what do they do to a horse? | Photo: Thinkstock. At a Glance | The Good Drink: Keeping Horses Hydrated, incredible pony gelding for your christmas, who led a team of collaborators to discover seasonal pasture myopathy, http://labos.ulg.ac.be/myopathie-atypique/declare-case-owners, webpages.uidaho.edu/range/toxicplants_horses/Toxic%20Plant%20Database.html, Equine Innovators: Feeding Horses With Dr. Laurie Lawrence, Recipes for Success: Formulating Equine Diets, Dynamic Endoscopy to Assess Airway Function. Poisoning is difficult to catch in time to treat because signs come on so rapidly. Just eight ounces of the leaves or bark can kill a 1,000-pound horse. There are some fruit trees that are toxic to horses that you need to avoid—those of the prunus family. The acorns’ tannic acid can cause portions of the intestinal lining to slough, says Williams. It’s a bit of a mystery, but these trees might have been growing in some horse farms’ pastures for years without causing problems. Large limbs weakened by rubbing, storm damage, or poor pruning develop weak spots that might give way under pressure from wind or ice. There are two black walnut trees and one english walnut tree in the pasture. Oleander: Highly poisonous, as it can cause the horse to suffer … Cytosine toxins irritate horses’ gastric systems and cause respiratory distress. The plant’s toxic alkaloids (taxine A and B) are extremely fast acting and horses have been found dead with the leaves of the tree still in their mouths. It … Try as he might, he never rose again. “When those three-lobed leaves wilt, they become very sweet but also very toxic, so horses will crave them even if they have other grass available. Other potentially lethal trees and shrubs include the golden chain tree (, Horses Burned in Australian Bushfires Recover, How Scientists Count Equine Parasites With a Cell Phone. If possible, affected horses should be hospitalized and treated for muscle damage right away, says Valberg. Rhododendron. She explains that the toxin hypoglycin A is present in seeds obtained in the autumn from box elder (Acer negundo) and sycamore maples (Acer pseudoplatanus) and is the likely cause of the problem, she says. Acorns: Only poisonous for horses in large amounts, but they can cause cramps, constipation, abdominal pain and kidney damage. Most horses will avoid eating this plant; however, it can contaminate hay. This tree’s leaves, seeds, and bark are all toxic. By keeping horses from under the drip line, you help ensure that they can’t easily access broken limbs that hold wilting leaves. The normal length of gestation for horses is 10 months, but may increase up to 13 months -- if abortion does not occur -- with exposure to the endophyte fungus. Shortly after arrival and admission, her beloved Pico, whom she had owned since he was born, went down in the stall. Harmful trees are be-still and lucky nut tree (Thevetia thevetiodes), red buckeye tree (Aesculus pavia) and elderberry (Sambucus canadensis). New leaves and young acorns, especially when green, are the most dangerous parts. Department of Animal Science - Plants Poisonous to Livestock. In severe cases, oak poisoning can be fatal. 15 Common Poisonous Plants For Horses (Common in the U.S.) There is no perfect pasture, perfect in this case means without toxic plants. The top five trees poisonous to large animals are the RED MAPLE, OAK, BOX ELDER, CHOKECHERRY and BLACK WALNUT.Careful attention must be paid to animals pastured close to these trees, and every effort must be made to prevent access. It doesn't take much to cause a problem. These trees are moderately toxic. Valberg has discovered that horses particularly at risk for H-AM are those that are young or new to overgrazed pastures with Acer trees, are turned out more than 12 hours a day, and receive little supplemental feed. Even if the horse will be euthanized, the veterinarian might want to save blood and urine for testing at a specialized metabolic laboratory to determine the cause, as a standard post-mortem exam might not provide a specific diagnosis, says Valberg. These parts increase in toxicity as the plant matures, especially with seeds, and decrease as the plant dies. In addition, many owners of small animals typically take care when planting vegetation around their yard or when walking their pets outdoors in parks or while camping. There are a vast number of plants located throughout Canada that are toxic to horses in some respect. As they also eat so they should be away from the toxic tress as they cannot distinguish what is toxic and what is not. However, some poisonous plants are palatable to horses and some need only be consumed in very small amounts to cause poisoning. Trees belonging to the Prunus species also contain cyanogenic toxins and include peach, plum, apricot and cherry. Privet pollen is known to cause asthma and eczema in sufferers. The American holly, recognized by its evergreen prickly leaves and red berries, is moderately toxic to horses. Oak These trees are moderately toxic. Shavings with as little as 20% black walnut content are toxic to your horse. Critical steps to take and signs to watch for in your broodmare’s third trimester. Plants toxic to horses: Botanical name: Symptoms: Common name: Abrus precatorius: Severe vomiting and diarrhea (sometimes bloody), tremors, high heart rate, fever, shock, and death. Grasses containing alkaloids include reed canary grass (Phalaris arundinacea), staggerygrass (Amanthium muscaetoxicum) and those from the Eleusine species. If an animal consumes a large enough amount of this toxin, he will basically suffocate. Clinical signs of oak toxicity include poor appetite, weight loss, and impaction, followed by diarrhea, kidney failure, and edema. If you don’t fence off your trees, then check their condition regularly or have an arborist evaluate them. Some manifestations of toxicity are subtle. Another plant that is toxic to horses are bracken ferns. The fall season appears to be when horses are at the highest risk of being affected by SPM with fewer horses affected in the spring and summer. Slaframine is produced by “black patch fungus," Rhizoctonia, which grows on clover during periods of stress. Clinical signs usually appear in a matter of hours, and it only takes a few shavings and a short exposure time to cause the toxicity. The toxin behind the slobbers, slaframine, is produced by a fungus that afflicts clovers, which stimulates the salivary glands and causes horses to drool. The black walnut tree (Juglans nigra) contains an unknown toxin that is poisonous for horses, causing weakness, laminitis and dermatitis. texensis (Texas redbud) Fence horses out of areas with a lot of wilted maple leaves and keep maple branches out of reach from the horses. Other toxicities cause problems that don’t lead to death. This group includes familiar fruit trees like cherries, apricots, peaches, plums, and others. Signs. Horses have the plant material baled into their hay, and they eat it that way. Poisoning is more common in spring due to early sprouting, and clinical signs of poisoning include gastrointestinal irritation and neurologic signs. However, any adventurous eater can be affected, she notes. They may also have a large frame, but appear to be immature compared to their size. There is no way your horse will go to the bitter pasture when there is sweet and fresh grass around it. Choose plants for your horse’s safety: There are several species that are poisonous to horses such as yew, laurel and privet. Maple Trees: Maple leaves are highly toxic, particularly when they are in a stressed state prior to dying (e.g. Their seeds are said to resemble a buck’s eye, and their leaves are green in summer, turning golden and orange in the fall. Common Plants and Trees That Are Poisonous to Horses. Their seeds are said to resemble a buck’s eye, and their leaves are green in summer, turning golden and orange in the fall. If you need help identifying a tree, bring samples to your local Extension office, or check out this online tree identification tool from Virginia Tech: dendro.cnre.vt.edu/dendrology/idit.htm. Serviceberry trees (Amelanchier alnifolia) contain cyanogenic glycosides, producing symptoms such as difficulty breathing, panting, red mucous membranes, dilated pupils and shock. Unknown toxins in maple trees cause increased anemia in horses. These trees are moderately to highly toxic in horses, says Williams. If the bark is the problem and not the leaves, place the fence four to five feet from the tree trunk. Black walnut shavings are one of these types. I knew that oak trees were toxic, and had many of those removed. “The most important time to watch for problems is after a storm that might have caused a limb of the tree … to fall into the pasture,” she continues. Let’s look at 10, starting with the most poisonous. 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