Prince Charles has told an international gathering of scientists and officials in London that he treats his own cows and sheep with homeopathy to reduce the use of antibiotics. The future monarch told delegates from 20 nations and organisations that the remedies helped keep his farming operation organic.

He said: "It was one of the reasons I converted my farming operation to an organic – or agro-ecological – system over 30 years ago and why we have been successfully using homeopathic – yes, homeopathic – treatments for my cattle and sheep as part of a programme to reduce the use of antibiotics," the Guardian reported.

Among those present were the government's chief medical officer, Dame Sally Davies, who had dismissed homeopathy in humans as "rubbish", although the prince's criticism of the over-use of antibiotics in farming and in humans will be universally welcomed.

The British Veterinary Association, the leading representative body for vets in the UK, dismissed homeopathy and said that it could not endorse any treatment that was not proven to work.

It said the consequences of such treatment "could be serious animal health and welfare detriment because of the lack of therapeutic effect, which would be counterproductive to best animal health and welfare,"John Blackwell, its senior vice president told the Guardian.

Clarence House said that homeopathy was used on a case-by-case basis at Home Farm, in combination with more conventional medicine, to minimise dependence on antibiotics. The prince's support in homeopathic medicines for humans has led to conflict with doctors and scientists including his belief that treatment should be available on the NHS.

There are 500 farmers trained in homeopathy and 38 homeopathic vets, according to the Department for Environment, Food and Rural Affairs.