In autumn, most trees take on beautiful colors which can make for beautiful pictures. By winter, deciduous trees and shrubs lose their leaves and/or seeds. Also, when an autumn storm passes by, large amounts of leaves can already be shed. If horses are in a pasture or paddock surrounded by trees and shrubs, it is important to know which leaves can be toxic if eaten. In this article we will cover the trees that are a potential danger to your horse, especially during the fall.
What trees and shrubs are poisonous?
Not all trees and shrubs are equally toxic to horses. The amount to which the materials are toxic can also vary greatly. Normally, a horse will not readily eat from trees or shrubs on its own accord because many poisonous trees have an unpleasant taste. Especially in the fall, when grass often becomes less, horses will be more likely to eat other plant materials. Also, when leaves or seeds lie on the grass, they can be eaten unnoticed while grazing because dry leaves lose their pungent taste making the horse less likely to leave them.
The following are the most common trees and shrubs that are toxic to horses:
Beech
Beech comes in red and green varieties and can be either a tree or a shrub. The beech nuts fall from the trees in the fall; these are poisonous to horses. Beech bushes can also produce beechnuts, but there are usually not many because hedges are often pruned when the shrub flowers. When your horse ingests a few beechnuts, there is usually nothing wrong, but a few hundred grams can cause poisoning symptoms of which gastrointestinal problems and colic are often characteristic.
Oak
In oak trees, both leaves and the green acorns are toxic to horses. The acorns which are still green in color and the leaves contain tanine. Tanin is harmful to horses, but often causes problems only at higher intakes. These problems can lead to serious consequences and even death. So keep a close eye on your horse when there are oak trees nearby and, if necessary, cordon off the part of the pasture or paddock where there are many acorns.
Maple
In recent years there has been increasing research into a muscle disease for horses called Atypical Myopathy. So far it is known that at least the seeds, leaves and germs of the Common Maple contain poison which may cause the disease. Of the Feather Maple, only the seeds are thought to contain the poison. The seeds of a maple are also described as “helicopters” and fall from the trees in the fall, especially when there is wind. Because of their shape, the seeds can be blown very far away, causing them to end up in a large area around the tree.
It is important to know which trees are in the vicinity of the pasture and to check regularly to see what material from trees has entered the pasture. Symptoms linked to atypical myopathy include fever, muscle tremors, stiffness and muscle weakness. Horses that have been poisoned will often lie down and have an increased heart rate. The urine of these horses may be coffee-colored. When atypical myopathy is suspected, it is important to call the veterinarian as soon as possible and remove any other horses from the same pasture.
Chestnut
A very recognizable tree in autumn is the chestnut. In autumn, large quantities of chestnuts fall from these trees with prickly husks. Several materials of the chestnut tree are poisonous, including the bark, leaves, immature chestnuts and the green husks. The immature chestnuts can fall off the tree as early as late summer and, like green acorns, contain tanine. Should there be a chestnut tree in your horse’s pasture, it may be helpful to temporarily fence off the area around the tree from the horses. Regularly cleaning up the chestnuts also reduces the risk of your horse eating them.
Buxus
Buxus is widely used for hedges or as an ornamental shrub, but many people do not know that this shrub is very toxic to horses. Because buxus is hardy, it stays green in the fall and winter. Horses will not eat this shrub easily, but when there is little vegetation left in the winter, horses may still take a bite of the shrub. The buxus is extremely poisonous horses and just a few branches can be deadly. It is therefore important to keep the horse calm and contact the veterinarian immediately if your horse has eaten buxus.
Taxus
Many horse people know that the taxus is poisonous. The buxus can be recognized by its branches with needles and its red berries. This tree also stays green in the winter. The toxin the tree contains causes heart failure in the horse. For a horse, just one twig can be deadly. So be very careful when this tree is in your yard!
Besides the poisonous trees and plants in this article, there are other species that are not healthy for your horse. It is wise to check your pasture and paddock to see what trees and/or shrubs are around. If you do this once each season, you will also notice vegetation that blooms in other seasons. Always consult a veterinarian if you suspect that your horse has ingested toxic plant material.
