It seems that ragwort is fast becoming the subject of a nationwide outburst of hysteria similar to that caused by salmonella in eggs (News, July 27). In the hope of calming it, I offer the following thoughts.

Yes, ragwort is poisonous to horses, cattle and sometimes sheep. It can cause acute liver damage in young stock, but this is rare. It is most commonly encountered as chronic liver damage in older animals. But ragwort is distasteful to horses and cattle, and they will eat it only if they are half-starved on a pasture that is bare of almost anything else.

In the agricultural depression of the 1930s and during the Second World War, there was far more ragwort around than there is today. There were no selective weedkillers available, so it had to be controlled either by hand-pulling or by allowing sheep to graze off the young plants, which are less poisonous. There were also many more horses in the country, working on farms or pulling delivery vans. Ragwort poisoning was a recognised disease, but not a major problem.

Any good stockman would not leave his animals on a bare pasture with ragwort. I find it hard to believe that so many of today's horsemen and women leave their horses on bare ragwort-infested pasture that 6,500 of animals succumb to ragwort poisoning annually. I realise that some ragwort could be bought in with hay, but ragwort is easily spotted, is normally rejected by the horse and is in any case easily removed by the groom/ owner. It could be more of a problem to those few horses that are fed silage.

I suggest that if 6,500 horses are dying of "ragwort-like" liver damage each year, it is time to look for other possible toxins. Pesticides added to grain to control weevils and mites are certainly one possibility.

Frances Wolferstan BA, Vet MB, MRCVS, Tamworth, Staffordshire
Re: ...and buy sheep
Date: 3 August 2003
There is a cheap and efficient way to eliminate ragwort from fields and pony paddocks (News, July 27). This consists of simply buying a few sheep! They love ragwort in its early stages of growth and will totally eliminate it for the rest of the year.

I have just driven over Shap Fell, and the verges of the M6 are like a sea of yellow flowers, whereas on the open fell grazed constantly by sheep there is not a single specimen of ragwort to be seen.

Malcolm Kidd, Penrith, Cumbria