Understanding Ragwort poisoning in horses
May 4, 2022
The ingestion of Ragwort, Senecio jacobea, is one of the most common causes of poisoning in horses in the UK, so it’s worth understanding what it looks like and how best to try and stop it from getting into your horse. In this short article, Holly Gimmler, one of our equine vets covers all the basics you need to know about Ragwort poisoning.
Ragwort is a tall daisy like plant with yellow petals. It is a weed that commonly grows on road verges and some pastures. It contains a toxin, pyrrolizidine alkaloid which makes Ragwort one of the most common causes of poisoning in horses in the UK due to its widespread nature.
The plant tastes bitter so horses will generally avoid eating Ragwort if it is in their pasture unless the pasture is of poor quality, where there is little else to eat, or if the plant is disguised in hay and therefore less noticeable. There have been welfare case incidents where ragwort toxicity has occurred on particularly barren pasture.
How do I know if my horse has ragwort poisoning?
Clinical signs or Ragwort poisoning are observed when a large volume of Ragwort has been consumed over a long period of time, resulting in liver damage.
Signs of liver disease include:
- Inappetence (lack of appetite)
- Lethargy
- Weight loss
- Abdominal pain (colic)
- Photosensitisation, which presents as sunburn, especially on unpigmented (pink) skin
- Jaundice
- Compulsive walking, head pressing or convulsions are signs of hepatic encephalopathy where the brain is affected by rising levels of toxic substances in the blood, resulting in neurological signs
Our vets can test for signs of liver damage by taking a blood sample, which we run in our lab. This looks at specific liver enzymes which usually show elevated levels in affected cases. However, this does not prove the cause of poisoning and a liver biopsy and subsequent analysis of the liver cells under a microscope is the most definitive way of diagnosing the condition and the extent to which the liver is damaged.
How do we treat ragwort poisoning?
Unfortunately, there is no definitive cure. Treatment is therefore based around supportive care. It can take a long time for horses to recover and in severe cases the damage may be irreversible.
Our vets may recommend liver supplements, including vitamin B12 and milk thistle, which can be given in feed. Re-sampling of blood is often recommended in order to ascertain whether liver enzymes are decreasing which indicates that your horse is responding to treatment.
Sadly, in severe or advanced cases, once neurological signs are seen, the chances of survival are grave.
To help your horse avoid Ragwort, follow these simple steps
- Pasture management is key in preventing Ragwort poisoning. So, regularly check your pasture (and the area around your pasture) for Ragwort and if you find it,
- Pull the plant out of the ground, whole if possible, including the roots. This is best done in early Summer before flower heads mature and when the ground is wet.
- Also remove the younger “rosette” stages.
- Avoid cutting the stem as this can encourage growth, or spread seeds.
- Make sure you wear gloves when doing this.
- Do not dispose of the plants onto muck heaps or leave in horse’s pasture as the plant can re-seed
- Be sure to check that there are no Ragwort flowers present in hay
- Ensure your horse is in good health all year round
- See the BHS toolkit guide for more information
If you suspect your horse has ingested Ragwort, then please contact our vets immediately on 01327 811007
Holly Gimmler BVSc MRCVS
Holly joined our equine veterinary team in July 2021 having just graduated from the University of Liverpool. During her studies she gained valuable experience treating equine emergencies and caring for inpatients under the guidance of top specialists at the Philip Leverhulme Equine Hospital. She enjoys all aspects of equine veterinary work and has gained particular interests in anaesthesia, medicine and reproduction.
References
Bhs.org.uk. 2022. Identifying Common Ragwort in England | The BHS. [online] Available at: <https://www.bhs.org.uk/our-work/welfare/our-campaigns/ragwort-toolkit/toolkit-dealing-with-ragwort-england/identifying-ragwort> [Accessed 27 February 2022].
