Do Not Toss Yard Waste Over the Horse Fence

Yard waste “trimmings” can be toxic to livestock.

The weather is warming up and it is the time of year when people prefer yard work to house or barn work. Horse owners may not be aware that various yard waste “trimmings” can be toxic to horses and other livestock. In urban areas, neighboring homeowners toss yard vegetative plants over the fence, not realizing these can be deadly when consumed by horses. It is always a good idea to establish a good acquaintance with your neighbors and educate them to the toxic affect yard waste may have on horses and other livestock.

During this time of year, the greatest risk can come from those who need a place to discard their yew bush trimmings. As little as ½ lb. of yew trimmings can be fatal when consumed by a horse. Death can occur within 24 hours, though occasionally death may be precluded by respiratory difficulty, shaking or muscle weakness. Unfortunately, there is no known antidote for yew poisoning.

Other ornamental plants common to our landscape are the Rhododendrons and Azaleas. All parts of these plants, but especially the foliage, contain poison, and two or three leaves may produce a severe toxic reaction. Rhododendrons are more likely to retain green leaves year round than most other plants, and most toxicoses occur in the early spring, when other green forage is unavailable.

Prevention is critical to assure that your horse stays healthy. As summer arrives and new plants begin growing, other plants with the potential to harm horses are also leafing out. For more info on plant toxicity, see the following below

  • Rhododendron – Vomiting, diarrhea, hypersalivation, weakness, coma, hypotension, CNS depression, cardiovascular collapse and death.
  • Azalea – Vomiting, diarrhea, hypersalivation, weakness, coma, hypotension, CNS   depression, cardiovascular collapse and death.
  • Morning Glory – can cause hallucinations– Symptoms: Gastrointestinal upset, agitation, tremors, disorientation, ataxia, anorexia, hallucinations.
  • Oleander is pretty, and poisonous–can severely affects cats, dogs, and even horses. All parts contain a highly toxic cardiac glycoside and can cause a number of problems. Symptoms: Colic, diarrhea (possibly bloody), sweating, incoordination, shallow/difficult breathing, muscle tremors, recumbence, and possibly death from cardiac failure.
  • Ivy (California, Branching, Glacier, Needlepoint, Sweetheart, English Ivy) – Ivy foliage is more toxic than its berries. Symptoms: Vomiting, abdominal pain, hypersalivation, diarrhea.
  • Sago Palm – a very popular landscaping plant. They are apparently very tasty to animals, and unfortunately highly toxic–all parts are poisonous, but especially the seeds. Symptoms: Vomiting, melena, icterus, increased thirst, hemorrhagic gastroenteritis, bruising, coagulopathy, liver damage, liver failure, death.
  • Tomato Plant- Although it won’t prove lethal for your pet, they can provide a good dose of discomfort. Symptoms: Hypersalivation, inappetence, severe gastrointestinal upset, diarrhea, drowsiness, Central nerves system depression, confusion, behavioral change, weakness, dilated pupils, slow heart rate.
  • Lily-of-the-Valley – Causes excessive salivation, watery eyes, sweating, abdominal pain, weakness, convulsions and death. This plant is largely an ornamental plant, but may grow wild near old home sites. The plant is highly toxic to all animals.
  • Yew – The bark and leaves of this very popular evergreen provided the basis for the cancer-treatment drug, paclitaxel–but general ingestion of any part of the tree (except the flesh of the berry) can be very dangerous to animals. Horses have an especially low tolerance to yew. Symptoms: Central nervous system effects such as trembling, incoordination, and difficulty breathing. It can also cause significant gastrointestinal irritation and cardiac failure, which can result in death.

Courtesy of Penn State College of Agricultural Sciences