Is Ragwort harmful to horses

Wednesday, 7th August 2013

Ragwort- The killer hiding in verges and pasturesRAGWORT—AN UPDATE

Our article on Ragwort has produced much interest and comment and several misconceptions have been aired. The point has been made by horse owners that the plant should be exterminated and by naturalists that it should be encouraged as an important host for the cinnabar moth.

Ragwort is one of the wild flowers planted in the Olympic Park.

1). It is not practical to eradicate ragwort nationally but it should be removed from any areas where

animals graze. The most efficient method is to spray the “rosette” stage (eg) with Barrier H Ragwort Killer

The mature plant may need two applications to kill it and dead plants should be removed and burned.

If the plant is dug up (eg with a ragwort fork) all traces of root must be removed to prevent re-growth.

The plant should never be allowed to set seed as the thousands produced are spread by wind and remain viable for long periods.

2). Ragwort is poisonous to all animals but more rapidly lethal to horses deer and cattle than sheep or goats. There are a number of species of the plant which may vary in toxicity although in general plants growing in sunny conditions are likely to have higher levels of poisonous alkaloids.

3).Horses do not generally eat green flowering ragwort but some do particularly during droughts. Owners have reported that horses (and cattle) sometimes seem to develop a taste for ragwort and seek it out again once eaten. Sheep appear to need about 20 times more than horses or cattle to poison them but three quarters of sheep fed small amounts of ragwort for two weeks die in the next 6 months.

In all species young growing animals are most susceptible.

4). The pyrrolizidine alkaloids in ragwort not only damage the liver but prevent it from regenerating.

The effect is cumulative so there may be no symptoms from small amounts eaten over long periods until animals may appear blind and paralysed after liver failure.

Q.- How many horses die each year from Ragwort poisoning ?

A-There are no reliable figures as often post-mortems are not carried out and a horse exposed to

poisoning may change hands at least once before symptoms develop.

However ragwort poisoning of cattle is officially stated to cause greater economic losses than all other

poisonous plants combined