RAGWORT ALARM

Sir — It alarmed me to learn about a reader’s friend finding ragwort in her horse’s hay (10 August). Her horses were blood tested, only to find they were all suffering liver damage. It distresses me even further to read a column in a local farming magazine appearing to encourage landowners to ignore ragwort — even suggesting it’s not a problem plant and that it’s beneficial to wildlife.

My husband and I keep our fields clean and our horses safe, but suggesting ragwort is beneficial will surely mean that more of it will be found in hay. C Wendes

Newport, Isle of Wight

H&H vet Karen Coumbe MRCVS replies: “Although there is limited hard evidence to confirm how many horses are actually affected by ragwort, it is undoubtedly harmful to horses.

“It is well recognised that horses who ingest plants containing the topic pyrrolizidine alkaloids, found in ragwort, will develop liver disease and potentially liver failure if they eat enough of it. These plants are generally unpalatable to horses unless withered — following pasture topping or within hay — or they may eat them if grazing is restricted.

“It is considered a ‘hit and run’ poison, in that there is a delayed onset of chronic progressive liver failure after eating ragwort. It does not have an immediate damaging effect and the onset of clinical signs may not show until weeks to months following ingestion. Also, not all horses that eat a limited amount develop signs, as not all horses will eat the same quantity and some will have more robust livers than others.

“A tiny amount is unlikely to be fatal, but regular ingestion of ragwort is damaging to a horse, especially if they also have a high worm burden or poor diet.

“Although it is not an offence to have ragwort growing on your land, you must enforce certain management guidelines — see bhs.org.uk/ragwort and gov.uk/guidance/prevent-thespread-of-harmful-invasiveand-non-native-plants”