Top 13 Toxic trees to Horses

 

 Toxic plants & Trees and your horse

 

Thankfully, horses usually avoid toxic plants. After all, most poisonous plants are distasteful. Horses are also much larger than dogs, cats, and humans. So where a nibble of some plants may instantly poison you or your other pets, horses have a little leeway. In other words, your horse would have to consume a significant amount of certain less toxic plants to feel any effects.  Although it may not consume large quantities at any given time, the build-up from months of consumption can make the animal sick or may even be fatal.

However, extremely hungry horses have been known to eat poisonous plants despite their horrid taste. In addition, high levels of stress and vitamin or nutrient deficiencies could cause your horse to sample toxic plants. For that reason, ensure your horse has quality forage and feed.

 But beyond that, accidents do happen. Well-intentioned neighbors have dumped grass clippings over pasture fences as a horse treat, unaware that the yew clippings mixed with the grass are extremely toxic to animals.

 
Unfortunately, people are often unaware of the fact that certain plants may be poisonous to horses as well.  There are many different types of poisonous plants and they often affect horses differently and at different rates.

Buttercups

 Horses that suffer from malnutrition or that have access to overgrazed and poor quality pastures may have little choice but to graze on plant life that is toxic.

Some toxic plants may even be strong enough that a few nibbles are enough to harm the horse. To avoid the threat of toxic weeds, trees and plants, people with horses must educate themselves on which plants are toxic to horses and have the potential to harm their equine friends. This knowledge will prevent them from planting these plants anywhere near the horses, and will make them aware of what dangerous plants are already within the animal's reach.

Plants may be toxic to horses in a variety of ways. While most poisonous plants are a danger when consumed, some can have a harmful effect with simple contact. While there are numerous plants that are poisonous to horses there are some that are more commonly found near horse pastures than others. Buttercups, for example, are a type of plant that is toxic to horses when the fresh flowers and leaves are ingested. This is one of the types of plants that horses often find unpalatable, but will eat if necessary. Mild to moderate cases of buttercup ingestion results in digestive disturbances such as diarrhea and colic. When a horse has been severely poisoned by the plant it may suffer from convulsions and eventual death.

Plant poisoning symptoms

 

The type and amount of plant eaten dictates the symptoms. Plants can affect the respiratory, gastrointestinal, nervous, or cardiovascular systems or the liver, blood and/or kidneys. Oftentimes it is difficult to diagnose plant poisoning in a horse because many of the symptoms mimic those of other conditions.Other potential warning signs that are associated with toxic plants and should be considered an emergency include changes in heart rate and respiratory rate, a horse that goes into a sudden frenzy, colic, and a horse that collapses.

However, many plant poisonings are serious and potentially fatal. If you suspect your horse has consumed a toxic plant, contact your equine veterinarian immediately.

Some symptoms to watch for include

• Disorientation
• Unprovoked Frenzy
• Tremors
• Muscle Spasms
• Difficulty Swallowing
• Colic  
• Fluctuating Heart and Respiratory Rates
• Excessive Salivation
• Collapse
• Abnormal Amounts or Colors of Urine

Poisonous plants to avoid

Some toxic plants pose a serious threat to your horse. Just a few bites of certain plants can greatly sicken or even kill your horse. Other plant toxins have the ability to build up over time and slowly poison your horse. As such, it is very important to understand which plants to steer clear from on the riding trail and eradicate from your pasture.

The following are the most common poisonous plants to your horse. However, just because a plant is not listed does not mean it is safe for your horse to eat. If you have any questions consult your equine veterinarian.

Toxic Plants

• Bracken Fern is a perennial fern with triangular leaves and black horizontal roots. It can grow up to three feet high. It is usually found in clumps in woodland areas and moist open areas across the United States. Signs of consumption include weight loss, depression, lack of coordination, muscle twitching, and a weak and fast pulse.
  Bracken Fern is a perennial herb that when ingested depletes thiamine, also known as Vitamin B1. All parts of the plant are poisonous and when eaten in large quantities it may cause the horse to lose its appetite and as a result suffer from weight loss. Horses poisoned by this plant may become depressed, uncoordinated and may suffer from paralysis and a slow heartbeat. Like buttercups, most horses will not eat bracken fern unless their food supply is lacking.

• Poison Hemlock is a perennial weed with toothed, fern-like leaves and clusters of small white flowers in late summer. A single plant has many stems. It has a large white parsnip-like root and is found along roadsides and in open, uncultivated areas across North America. Signs of consumption include nervousness, tremors, and a lack of coordination, that progress to depression, a weakened heart and respiratory rate, and possibly colic.Poison Hemlock is a perennial weed that has leaves similar to the leaves of a fern. In the late summer months, it will also have white, small flowers. All parts of the plant, including the root is poisonous. This plant can be lethal for horses when the animal ingests four pounds or more. A horse that has ingested this plant and become poisoned by it will become nervous and have tremors. Colic and a weakened pulse rate are also signs. Another perennial weed is the water hemlock. This weed is, in fact, one of the most poisonous of plants. It can be identified by the purple spots on its jointed stems, the umbrella-shaped clusters of white flowers, and serrated leaves. It is found across the U.S., primarily in waterways and areas that are moist. The roots, as well as the leaves and flowers of this weed, are poisonous, which makes it poisonous year-round. Water hemlock is much more toxic than poison hemlock as death may occur after eating as little as eight ounces of the plant. When poisoned, the central nervous system of the horse is affected. Water hemlock may result in violent behavior from the horse, convulsions, muscle and heart function loss, and excess salivation and dilated pupils.

• Johnsongrass/Sudan grass are both coarse-stemmed grasses with broad, veined leaves that can grow to six feet in height. Johnsongrass is predominant in southern climates, while Sudan grass is cultivated across North America as a forage plant. Sudan grass can cause cystitis (inflammation of the urinary bladder). Signs of poisoning may include bladder paralysis that causes dribbling or bloody urine and may progress to paralysis of the hind limbs.Johnson Grass and Sudan Grass are grasses that can cause bloody urine, paralysis of the bladder and even hind limb paralysis. Sudan Grass is found throughout North America while Johnson Grass is generally in the south. These grasses can reach heights of six feet and are characterized by leaves that are veined and broad. Locoweed poisoning often does not occur until a horse has ingested large amounts of the plant for no less than two weeks. This is a plant that horses find palatable, which means that they will often return to it if it is present. It has short stems, leaves that grow on tufts, and when in bloom, there are flowers of white or purple. These plants may be found in the southwestern and western parts of the country. Depression, staggering, abnormal head bobbing and weight loss are signs of poisoning from this plant.
  Another toxic weed is Yellow Star Thistle. It is an annual weed that can result in a brain disease that is not only irreversible, but also fatal. It is found in Northern California and Colorado. Cotton-like hair covers the leaves of the plant and there are yellow disc-like flowers. Signs of poisoning may not appear until weeks of consuming the plant in either its dry or fresh form. Because the taste is not offensive to horses, some may be attracted to the weed and prefer it to other plants. Poison signs include impaired mastication, hypertonicity of facial muscles, frothing of the mouth and severe weight loss due to an inability to eat. Death is often the result of pneumonia or starvation.

• Locoweed is a perennial weed with short stems and multiple leaves that grow in tufts. Some have silvery hairs. The stalks on which the white or purple flowers bloom have no leaves. They are found throughout the western and southwestern United States. Signs of consumption include strange behaviors such as excessive head bobs, exaggerated gaits, or staggering that progresses to a horse's collapse. Horses may also become depressed, lose weight, and mares may abort their foal.

• Tansy Ragwort is a multi-stem weed with alternating leaves that produce clusters of small, daisy-like yellow flowers. It grows primarily in the coastal northwest United States and New England. Signs of toxicity may not appear until 6 or more months after the plant is consumed. These signs may include lethargy, photosensitization, and digestive disorders. Signs may not be evident until signs of liver failure occur, including loss of appetite, weight loss, and jaundice.
  
  Tansy Ragwort is a weed that is found in the coastal northwest United States. Horses that consume this plant will generally not display signs of poisoning until six months or longer have passed from the initial ingestion. When signs do appear, it may be in the form of appetite loss, weight loss, liver failure, jaundice, photo-sensitivity, and lethargy. People can recognize this weed by its multiple stems and flowers that are similar in appearance to daisies.
  
  These are just a few of the plants that are toxic to horses. There are many more across the country that people must be aware of. In some instances plants may be native to one part of the U.S. and not found in other areas. Because some plants are potentially poisonous, horse owners and caregivers should recognize not only the signs that are specific to certain plants, but also the basic signs of poisoning. If a horse ever displays symptoms such as disorientation, difficulty swallowing, tremors, increased salivation, a noticeable change in urine color or muscle spasms, an equine veterinarian should be contacted immediately. Although horses are larger than smaller pets, they require the same care and consideration to keep them safe. Horse owners that are aware of the potential threat of poisonous plants can take the precautions necessary to protect their animals. Ensuring that horses have a healthy place to graze and learning to recognize dangerous vegetation are important steps to take.

• Water Hemlock is one of the most poisonous plants. It is a perennial weed with jointed stems (often with purple spots), multiple toothed leaflets, and small, white flowers that grow in umbrella-shaped clumps at the end of erect, hairless, clustered stems. It is common in marshy areas of meadows and along waterways across the United States. Most poisonings occur in the spring before the flowers or even leaves appear, since the roots are also poisonous. Signs of consumption include excessive salivation, dilated pupils, and nervousness that progress to difficulty breathing, loss of heart and muscle function, or convulsions and seizures.

• Yellow Star Thistle is an annual weed that forms a spherical plant up to three feet tall. It has round, yellow flowers surrounded by stiff spines up to 3/4" long. They are predominant across the western United States along roadsides and in cultivated fields and pastures. Signs of consumption include tensed facial muscles and an inability to drink or bite or chew food that leads to weight loss and possibly death.

 

Toxic TREES:   

 

Trees provide shelter, shade and wind breaks for large animals but may also be a contributing cause of illness. Typically, animals with adequate nutrition will not browse foliage or ingest leaves or seeds, but drought, storms resulting in fallen branches, curiosity or boredom may result in their consumption. 

The following trees have no place in horsekeeping areas because of their toxicity or potential for causing digestive distress. They are listed in order of the risk they pose to horses, starting with the most hazardous:

 

1.) Yew is a woody evergreen shrub with closely spaced, flat, needlelike leaves. It has yellow or bright red berries that are soft and juicy with a hole in the end where dark seeds are visible. They are common ornamental plants across North America. Consumption usually results in sudden death. However, animals found alive are usually trembling, colicky, have difficulty breathing, and have a diminished heart rate.   Horses often find these leaves desirable and ingesting only a mouthful can cause cardiac collapse, respiratory failure, and death in as little as thirty minutes.

 2.)   Oleander is another ornamental shrub that can potentially kill a horse within a short period. Oleander can be recognized by its large pink, white or deep red flowers. The shrub ranges in size from five feet tall to nearly as tall as a tree at twenty-five feet. It can be found in the western part of the U.S. and in the southwest. The entire part of the plant is poisonous to horses and horses need not ingest large amounts to become fatally poisoned. A poisoned horse may display tremors and twitching of its muscles, pain, an abnormal heartbeat, labored breathing and symptoms similar to colic.Signs of consumption include colic, difficulty breathing, tremors, irregular heart rate, and either an elevated or slowed pulse. Death can result from heart failure.  This shrub is poisonous to small animals, dogs and cats also. Horses may also have diarrhea that is at times bloody. A horse that is fatally poisoned by this shrub can die of heart failure in as little as twelve hours.

3) Red maple trees  is one such tree whose leaves are harmless most of the year until wind damage or seasonal change causes them to fall from the tree and wilt.   It's the wilted leaves that produce Cyanide.  Cyanide suffocates animals by blocking oxygen transport via the red blood cells. Poisoning of a thousand pound horse typically occurs after it has ingested one and a half pounds of maple leaves.   Signs of poisoning include lethargy, elevated heart rate, refusal to eat, dark or discolored (red, brown, or black) urine, discolored or darkened gums and mucous membranes, increased respiratory rate, rapid heart rate, and dehydration. It may also cause a pregnant mare to abort.   They are found across North America. 

4.) Cherry trees, plum trees, peach trees and relatives.   Equally toxic are cherry (black cherry, chokecherry, and fire cherry) peach and plum trees, all members of the Prunus species. These leaves also produce cyanide when wilted, affecting horses within a few hours of ingestion. To be safe, remove these deadly trees or relocate horses away from pastures or paddocks bordered by or containing them.

5.) Black Walnut  is another tree that is poisonous to horses. Unlike the red maple tree, it is the bark, nuts, roots, and woods that are toxic. Contact with black walnut, typically in bedding that has shavings from the tree, can cause increased temperature, lethargy, hoof temperature, swelling of the lower limbs, and depression. With the exception of laminitis, most of the symptoms resolve on their own when the horse is no longer exposed to tree's shavings.

6.) Black Locust 

7.) Red Maple -  Cut this tree down if it’s in or near your pasture.Other varieties of maple trees are NOT toxic unless they have hybridized with red maple.

8.) Oak - You don’t need to cut these trees down – provide plenty of palatable hay or grass and, most likely, your horses won’t eat the oak leaves. Fence the tree out so that the horses can’t eat the bark and have less access to acorns and leaves.

Black Walnut - The trees themselves, including the leaves, shouldn’t pose problems to your horses unless they are eating the entire tree. It is recommended not to cut down this tree if it’s in your horse pasture because that will actually increase the likelihood of toxicity as horses will then be walking through walnut sawdust. If you are still concerned, be sure to fence off the area once you’ve cut the trees in order to cut down on horse traffic through the sawdust.

11.) Oak trees,

12.) acorns

13.)  Russian olive, also known as oleaster 

 

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. Pastures should be examined, especially after storms, and fallen limbs, branches and leaves should be removed. The black walnut tree itself is not toxic, but shavings made from it are and should not be used as horse bedding.

The following trees are GOOD choices for shade trees in horse pastures;

Hickory, Shagbark – mature height of 60-80 feet. Best along woodedges, bark peels off making the tree “dirty.” Shagbark is one of the fastest growing hickories, but it is slower than most other hardwoods such as oak. Slow growth.

Beech, American - Mature height of 50-70 feet. This tree is huge and does best with lots of space (width is almost the same as height!). Prefers sun. Slow-medium growth.

Hemlock, Eastern/Canadian - Mature height of 40-70 feet. Evergreen hedge when planted 2’ apart, used for windbreaks. Slow-medium growth.

Cedar, Eastern Red - Mature height of 40-50 feet. Good windbreak when planted in rows. Medium growth.

Birch, Yellow or River - Mature height of 40-75 feet, depending on variety. Medium-fast growth.

Hackberry, Common - Mature height of 40-60 feet. Tolerates many growing conditions. Medium-fast growth.

Ash, Green or White - Mature height of 50-80 feet, depending on variety. Green Ash has a fast growth rate, White is medium.

Honeylocust, Common - Mature height of 30-70 feet. Adaptable tree that tolerates pollution, salty soil and drought. Fast growth.

Poplar, Tulip - Mature height of 70-90 feet. Prefers full sun and lots of space. Fast growth.