Hundreds of cattle and pig farms are under investigation following the discovery of a banned antibiotic in animal feed in the Netherlands.

Dutch authorities discovered the prohibited antibiotic furazolidone during routine tests on animal feed.

The Dutch Food Safety Authority (NVWA) has traced the banned substance in batches of feed supplied by Van Kats Food & Feed, based in Lopik.

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Officials said the contaminated protein ingredient was found in feed supplied by the company to a number of veal and dairy farms.

NVWA said the tainted feed was sold to at least 97 pig farms and five veal farms in Holland and 11 farms in Germany. Some of the veal has been exported to France, Germany, Italy and Belgium.

The authorities fear the contaminated feed has already been fed to thousands of animals because the batch was sold to farms between March and April this year.

Therefore, a widespread cull may be necessary, pending the outcome of tests. Local reports have suggested that as many as 12,700 calves and cattle and 50,000 pigs may have to be culled.

NVWA has suspended the activities of Van Kats Food & Feed while a full investigation is carried out.

The use of furazolidone in food-producing animals has been prohibited in Europe since 1995 due to concerns about side effects and an increased risk of cancer.