Fruits are more toxic than the foliage. Apart from black nightshade, other Solanaceae perils are horse nettle (Solanum carolinense), Jerusalem cherry (Solanum pseudocapsicum) and buffalo bur (Solanum rostratum), just to start. Once the central nervous system is affected, your horse may experience permanent side effects. Cultivated hybrids of Sudan grass typically contain less cyanide, if any. Another factor that protects horses is their size—a 1,000-pound animal has to consume significantly higher quantities of most toxins than a smaller animal does to feel any effects. Horses are most frequently poisoned when they are bedded with black walnut shavings; as little as 20% of the shavings need to be from this tree for toxicity to result. Thiamin is necessary to nerve function, and deficiencies can lead to neurological impairment. ID: A woody evergreen shrub with closely spaced, flat, needlelike leaves a half-inch to one inch long. Russian knapweed spreads via a creeping root system; its erect, stiff stems grow two to three feet high and are covered with gray hairs, and its thistlelike flowers range from purple to white; Russian knapweed has no spines or prickles.Range: Both plants appear throughout the Western United States, approximately from Missouri to California, and from Mexico northward, almost to Canada. (Read about one horse's recovery in Red Maple Leaf Poisoning Scare. She may also want to run some lab work to check how your horse’s organs are functioning. ID: A medium-sized tree with leaves that are green in the spring and summer, with shallow notches, bright red stems and a whitish underside; in fall, the leaves turn bright red. The fruit of the horsenettle are round yellow berries when mature. The symptoms your horse is experiencing will determine the course of supportive treatment the veterinarian will recommend. Depression / Diarrhea / Separation Anxiety / Seperation Anxiety, Central nervous system symptom (pupil dilation, loss of muscular coordination, depression, hallucinations, convulsions), Gastrointestinal symptoms (diarrhea, decreased appetite, colic). Some manifestations of toxicity are subtle. Stinging nettle rash presents as raised bumps or hives that are often light in color and up to a centimeter in diameter. It does well in disturbed habitats, and many people consider it a weed. The pulse may be either slowed or accelerated.What to do: Horses can survive if treated early with supportive care, such as the administration of activated charcoal to inhibit further toxin absorption and the use of anti-arrhythmic drugs to stabilize the heart. If you’re not already receiving the EQUUS newsletter, click here to sign up. "I defy anyone to tell me they have a pasture with zero poisonous plants," says Jeffery Hall, DVM, PhD, a toxicologist at Utah State University. Because horses are trickle feeders and graze for the majority of the time they are awake, on rare occasions they can eat something poisonous. Also known as: Rose laurel, adelfa, rosenlorbeerID: An evergreen shrub that can reach the size of a small tree, oleander has elongated, thick leathery leaves that can grow to three to 10 inches long. U. dioica generally grows in moist, nitrogen-rich areas, preferring open, rich forests and disturbed sites. The first indication is rapid breathing, which progresses to tremors, frequent urination and defecation, gasping and convulsions.What to do: Supportive drug therapy can offset the effects of less severe cyanide poisoning. Some species may be covered with silvery hairs. Carolina horsenettle is commonly found in the southeastern United States. The stems have purple spots, which are most evident near the base of the plant.Range: Grows wild along roadsides and other open uncultivated areas throughout North America.The danger: Hemlock leaves, stems and seeds contain several potent neurotoxins that affect both the central and peripheral nervous systems. Most animals will avoid the plant.Signs: Signs appear within an hour or two of consumption, starting with nervousness, tremors and incoordination, progressing to depression and diminished heart and respiratory rates and possibly colic. Most animals will avoid the plant.Signs: The toxins affect neurons primarily within the brain, causing various signs, including excessive salivation, dilated pupils and nervousness, progressing rapidly to difficult breathing, degeneration of the heart and skeletal muscles, seizures and convulsions; death usually results from respiratory paralysis. EQUUS thanks Anthony Knight, BVSc, MRCVS, and Jill Richardson, DVM, for their assistance in the preparation of this article. As little as a pound or two of leaves can be fatal.Signs: Depending on how many leaves were eaten, signs can appear within a few hours or as long as four or five days after consumption. Prevention of ingestion is the ideal form of treatment. The yellow fruits, borne in clusters and strongly resembling tomatoes are very toxic. This guide looks at the types of poisoning a horse can suffer from, spotting the signs of poisoning and what to do if you think your horse may have been poisoned. Also known as: Barnaby's thistleID: Yellow star thistle is an annual weed that branches out from a single base stem to form a spherical plant up to three feet tall; its round yellow flowers are surrounded by stiff spines 1/2 to 3/4 of an inch long. It is estimated that one to 10 pounds of ingested plant material is fatal for horses. Consumption of just a small amount of any part … Nightshade Family: The nightshade family contains many toxic plants, including horse nettle, black nightshade, bittersweet nightshade, some species of groundcherry, and even tomatoes and potatoes. In the summer, U. dioica produces flower clusters which Like some other plants called nettle (Purple dead nettle for example), horse nettle is not actually a nettle. Toxic Plants in Woods Bracken fern, coral ardesia, jasmine and red root. James H. Miller & Ted Bodner, Southern Weed Science Society, Bugwood.org PLEASE NOTE: "Poisonous" does not mean deadly. Scientific Name Common Name(s) Species Most Often Affected Parts Poisonous Primary Poison(s) Apocynum spp. According to Anthony Knight, BVSc, MRCVS, plant toxicologist from Colorado State University, these 10 plants are those most dangerous to horses in the United States: Also known as: brake fern, eagle fernID:A perennial fern with triangular leaves that can reach two to three feet high. This is probably a poisonous plant and despite being very common in poorly cared for fields throughout North America, actual proved cases of poisoning in horses are hard to find. Here are the ones most dangerous to horses in the United States. Euthanasia is recommended if the horse is too debilitated to eat. Items are sold by the retailer, not Wag!. Of the hundreds of toxic plants in North America, only a handful are likely to bring serious harm to horses. It is a member of the nightshade family and causes problems in grass pastures and hay fields. Both species can also accumulate toxic levels of nitrates if overfertilized. Berries are bright red or yellow, soft and juicy with a hole in the end, where the dark seed is visible.Range: Western yew and American yew are native to the West Coast and to the Eastern and central United States, respectively, but these two species along with the Japanese and English yews are commonly planted as ornamentals nationwide.The danger: All parts of the yew plant, except for the fleshy portion of the berries, contain taxine, an alkaloid that causes respiratory and cardiac collapse. In addition, the leaves are not as toxic as the flowers and their buds, so the part of the plant consumed also has a part in what side effects your horse experiences. by Heather Smith Thomas of Salmon, Idaho. Also known as: Spotted water hemlockID: A perennial weed with erect hairless stems that can grow to six feet from clusters of fleshy roots. Walter Chandoha. All parts of the plant are poisonous, but toxicity varies depending on growing conditions. Fruits are more toxic than the foliage. Hundreds of poisonous plants grow in North America, and many are extremely common. Horse nettle is a native perennial with spiny stems and leaves, white to purplish flowers, and toxic fruits that look like tiny yellow tomatoes. For one thing, most of them are unpalatable, and horses who are filling up on quality forage aren't likely to spend a lot of time grazing on the few bitter leaves populating their pasture. If you live in eastern North America, you likely know to watch out for poison ivy’s infamous “leaves of three.” Poison ivy (Toxicodendron radicans) and its close relatives poison sumac (T. vernix) and poison oak (T. diversilobum) all contain a chemical known as urushiol.When touched, nearly all parts of these plants can trigger a severe, itchy, and painful … Symptoms can range from mild, such as mouth pain and diarrhea, to severe, such as convulsions, hallucinations and even death. However, some plants are cause for concern either because even a curious nibble can spell doom or because repeated browsing over weeks or months can lead to serious illness and death. They appear as weeds along roadsides, in cultivated fields and pastures.The danger: Both plants contain a toxic agent that has a neurological effect on the brain that inhibits the nerves and control chewing. Locoweed (Astragalus spp. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard. All parts of the plant are poisonous, but toxicity varies depending on growing conditions. Most plants with toxic substances have unpleasant tastes, which doesn't encourage a horse to browse enough plant material to harm it. If he has been out on pasture, she may ask you to take her out there so she can see what plants he has had access to recently. Hungry horses that lack good forage thanks to droughts or overgrazing, however, can be tempted to eat potentially harmful plants, and in some cases only 2 1/2 pounds of leaves can be toxic to a horse. A single mouthful can be deadly to a horse within minutes.Signs: Sudden death is the most typical sign of yew ingestion. Storey's Barn Guide to Horse Health Care + First Aid, Horse Health Care: A Step-By-Step Photographic Guide to Mastering Over 100 Horsekeeping Skills, Horsekeeping on a Small Acreage: Designing and Managing Your Equine Facilities. The poisoning is chronic in nature; to receive a toxic dose, horses must consume 50 to 200 percent of their body weight over 30 to 90 days.Signs: Affected horses may appear to have tense or clenched facial muscles, and they are unable to bite or chew their food effectively.