September 24, 2023

Poisoning of Livestock

Written by Dr Phil Rennie of Tauranga Te Puna Katikati Papamoa Village Vets

Sporadically during most years’ vets are called to investigate sudden illnesses and unexpected deaths in otherwise healthy animals. While they can occur at any time of year, summertime is not uncommon as feed supplies shrink and hunger may lend to fewer discerning diets! Often where no obvious sign of infection or trauma has occurred, we need to look at intoxication as the cause of the symptoms.

While not exhaustive below are some of the main plants and metal contaminants that are known to be lethal to livestock.

  • Oleander: Often found in gardens as an ornamental shrub, just a few leaves thrown over the fence into a paddock can be lethal to stock.
  • Yew: All parts of this tree are poisonous; prevent stock from grazing near trees or clippings.
  • Acorns: Most poisonous when green; young stock are more susceptible to toxicity
  • Foxglove: Although very bitter in taste and therefore not very palatable, ingestion can cause heart failure due to cardiac glycosides. Other plants like lilies can also have these toxins.
  • Rhododendron: Leaves are toxic to sheep and cattle, watch out for the pet lamb nibbling leaves in the garden!
  • Avocado: All parts are toxic; goats and horses appear to be most sensitive to the toxin and lactating animals can develop a sterile mastitis.
  • Tutu: Known for killing a circus elephant! This toxic native plant is found mainly in bush blocks. Keep stock away from areas where it is known to grow or border onto.
  • Other plants like Bracken Fern, Ragwort, Hemlock and various members of the Nightshade family can also cause illness and death in livestock.
  • Lead: Lead poisoning of stock has been known to be caused by old car batteries and from animals licking and chewing at lead paint.
  • Arsenic: Stock have died after eating the ash left after burning tanalised wood, also old sheep dip contains arsenic

If you have any questions about possible toxins on your farm, please contact your local vet. Vets can investigate any suspicious cases and help to prevent poisonings from occurring.