horse eating a poisonous plant

Which Plants are Poisonous for Horses?

Expert Advice: Kim Lina Pethahn, an independent feed consultant, wrote this article.

Common Symptoms and What to Avoid

Poisonous plants can be found all over the world and sadly horses do not always know that what they’re eating might be dangerous or even fatal. 

 

Humans are responsible to keep poisonous plants out of the fields and away from the stables. But errors can occur or the horse eats something while out on a hack and starts displaying unusual behaviour. Even in these stressful situations it is important to keep calm for the sake of the horse and to help as best as you can.

All About Poisonous Plants

What Happens to the Horse's Body when Consuming Poisonous Plants?

Poisonous plants contain ingredients that are toxic when eaten. The level of toxicity of a plant depends on various factors. Here, the dose makes the poison. The dose of toxins present in the plant depends on fertilization, season and weather, among other factors. 

 

The toxins contained in a poisonous plant can be divided into different groups of substances. In toxic plants there are alkaloids and enzymes, as well as hormones, nitrates, oxalic acids, proteins, saponins, terpenes and terpene derivatives.

 

These substances are characterized by a bitter taste. They can be found in various forms in plants and can cause poisoning when consumed in higher doses. However, they can be used as medicines in the right quantity.

 

In every organism, enzymes are essential for the metabolism. They influence the functions of the body through biochemical reactions and thus keep it running. But in the body an increased dose can lead to poisoning as well. For example, the enzyme thiaminase leads to the destruction of vitamin B1, which is essential for the metabolism.

Infamous, Poisonous Plants

Different plants carry different outcomes, some might only create mild symptoms other can result in death.

 

Careful! Even hay can hide poisonous plants, while most horses avoid bitter tasting poisonous plants, the dried hay hides it. 

 

10 common and poisonous plants:

 

  1. Hellebores – Toxicity: extremely – 60g is fatal
  1. Belladonna – Toxicity: extreme – 120g is fatal
  1. Henbane – Toxicity: extreme – 125g is fatal
  1. Foxglove – Toxicity: extremely – 200g of fresh leaves or 25g of dried leaves are fatal
  1. Aconite – Toxicity: extreme – 300g is fatal
  1. Azalea – Toxicity: high – 450 to 900g can be fatal
  1. Sycamore – Toxicity: extreme – Atypical Myopathy follows and results in fatality 70% of the time
  1. Wormwood – Toxicity: high – 500g can cause miscarriages in pregnant mares
  1. Milkweed – Toxicity: high – fatal in high dosis, severity depending on species
  1. Buckeye – Toxicity: moderate to high – rarely fatal but can lead to colic

Common Symptoms

The symptoms caused by poisoning with a poisonous plant are as varied as the number of plants themselves. We have compiled the most important ones for you here:

 

– Shortness of breath

 

– Unusual salivation up to foaming at the mouth

 

– Trembling up to convulsions

 

– Dilated pupils


– Colic


– Diarrhea

How To Act

Most importantly, keep calm and don’t cause unnessecary stress for your horse.

 

Is there a suspicion of poisoning through a poisonous plant? If so, the veterinarian should be notified immediately. It is best to keep the plant suspected of causing the poisoning. You should show it to the veterinarian. Until the vet arrives, the horse should stop eating if possible but drink as much as possible. To reduce the risk of injury from possible seizures caused by a poisonous plant, it is beneficial to pad the stall with bedding or bring the horse to a more open space with soft ground.

How to Prevent Horse's From Eating Poisonous Plants

An important contribution to prevention can be made by regularly refreshing your knowledge about poisonous plants. If this is too boring for you alone, you can simply grab friends from the stable and repeat the poisonous plants with them – in this way, you not only gain something from it yourself, but also make people sensitive to this topic.

 

Another important point of prevention is to regularly search the paddocks and the stable area for poisonous plants and to immediately remove any plants found together with their roots. The more riders in the stable know, the safer the stable grounds will be.

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