with Phil Rennie
Many common plants, often found in gardens or in the wild, are lethal to livestock. In the second part of a series we look at the main, potentially deadly plants.
Acorns/Oak: (Quercus spp.) Fallen acorns and branches are sources of toxin, and are most poisonous when green. Cattle and sheep are vulnerable, with young stock more susceptible than adults. Affected individuals show lethargy, anorexia and wasting, with frequent urination.
Bracken Fern: (Pteridium esculentum) Toxicity occurs with grazing scrubby areas and rough pasture sward. Cattle, goats and horses can be affected. Various forms of disease can develop including bladder bleeding with discoloured urine, bowel tumour growths and neurological staggers.
Nightshade: (Solanum nigrum) Plants are found in patches under areas of shade such as hedgerows. Toxicity has been noted in goats and cattle, with calves mainly affected. Alkaloid and cyanide toxins produce neurological signs and death from asphyxia and heart failure.
Ngaio: (Myoporum laetum) Access is by grazing scrubby or bush areas and fallen
Oleander: (Nerium oleander) Found in gardens as an ornamental shrub, just a few leaves or pruning waste thrown over the fence is enough to be lethal. Affected species include cattle, sheep, horses and camelids. Toxicity results from several cardiac glycosides, notably oleandrin and nerine. Affected stock show evidence of gut pain and difficulty breathing associated with profound heart and lung disease.
Ragwort: (Senecio jacobaea) Occurs at times of feed shortage, heavy pasture infestation and intake of contaminated hay. Cattle, sheep, horses and pigs are vulnerable. The main finding is chronic wasting, mainly through severe liver damage.
Redroot: (Amaranthus retroflexus) Sourced from weed overgrowth in yards and failed crop paddocks. Cattle, sheep and pigs are affected. Signs include lethargy, anorexia, wasting with frequent urination.
Rhododendron: (Azalea and Rhododendron spp) All parts are toxic, especially the leaves from this common garden shrub. Sheep, goats, horses and cattle are commonly affected. Signs include spectacular vomiting and intense abdominal pain, slowing heart rate, convulsions and coma before death.
Tutu: (Coriaria arborea) Occurs near bush blocks when grazing scrubby or bush areas and transporting stock along roadsides. Cattle, sheep and horses are affected. Sudden death results with lung congestion the main finding.
Yew: (Taxus spp.) Garden waste access may occur or stock grazing near trees or clippings. Cattle, sheep, horses and camelids are susceptible. All parts of this tree are poisonous. Profound breathing difficulty and sudden death result.
If you have any questions about possible toxins on your property, contact your local vet, before running the risk of exposing stock to the source. Vets are well placed to investigate any suspicious cases and help to prevent future poisonings.