With its bright, sunshine yellow flowers ragwort is as attractive as weeds get — but it’s deadly for your horse. The plant takes advantage of bare patches of ground and areas of poor grass cover and germinates. Unfortunately, horses expose soil in areas where they roll; where they are short of grazing, they will eat the grass down close to the ground and they can cut up a field, especially in wet conditions, with their hooves, particularly those that are shod — all of which create opportunities for ragwort to thrive.
Insects, such as bees and butterflies benefit from ragwort, so there is never going to be a wholesale poisoning of it sanctioned, so what can you do when faced with it on your land?
Ragwort tends to be quite high — generally up to knee height — with a straight, thick stem and a cluster of bright yellow flowers at the top that look not unlike large daisies. Horses generally won’t eat it out of choice because when alive it tastes bitter — although it does become more palatable as it wilts. Therefore be aware that dried ragwort in hay could also be eaten because the horse is likely to be unaware of its presence.
If you spot ragwort growing in your horse’s pasture, don’t just pull it up, but dig out all the roots before it seeds, so that there is no chance of it spreading. Wear gloves while doing so and afterwards burn the plant (see bhs.org.uk for more information on how to remove and dispose of the weed). In extreme cases you may need to use a herbicide, but avoid this if possible as it may make patches of your paddock toxic for a period.
Horses who are hungry, with a shortage of grass in their paddocks, are the most likely to eat ragwort, so always ensure that yours has plenty to eat, as well as pulling up any ragwort you spot. By doing so, your horse will stay safe from this poisonous weed.
Most horses can eat a bite of ragwort and suffer no lasting ill effects, although a few liver cells are damaged every time. Regular consumption of large quantities of ragwort’s toxic compounds (pyrrolizidine alkaloids), though, can cause liver failure as the organ loses its ability to regenerate cells. The result of this will be death.
Sometimes there are no signs of poisoning, which is why ragwort is called the ‘silent killer’. On occasions, it shares the same signs with other causes of liver disease, and because few post mortems are carried out, many horse owners never find out what prompted their horse’s death. When signs of ragwort poisoning are apparent, they include a loss of weight as well as loss of sparkle, appetite and shiny coat. As his condition worsens the horse may exhibit colic, diarrhoea or jaundice, with yellowing of the skin, whites of his eyes and gums. He may also suffer from depressive behaviour, circling, aggressive tendencies or seizures.
Your vet will be able to arrange for your horse to have a blood test or ultrasound scan, which will show if his liver is damaged, but not if ragwort is the cause. If your horse has liver failure — or 70% of the liver is damaged — the prognosis is generally poor as cell damage cannot be reversed.