PARIS (Bloomberg) — The French government said it discovered four new cases of so-called mad cow disease, bringing the total number of cases detected this year in France to 125.

The infected cows were slaughtered and burned along with the herds they had been in contact with, in accordance with health regulations, the agriculture ministry said.

Current cases of the disease were probably caused by contaminated animal-based feeds, according to two government groups formed to monitor bovine spongiform encephalopathy, or BSE, better known as mad cow disease.

The number of cases detected in France since 1991 now stands at 172, more than two-thirds of the total in this year alone.

Monday, the European Union imposed a six-month ban on the use of ground-up bones and other animal remains in livestock feed, to help halt the spread of mad cow disease and allay consumer fears of contracting the human form of the illness.

Creutzfeldt-Jakob, the human variant of BSE, has claimed more than 80 lives in the UK and two in France. Scientists believe it is spread through infected beef.