Milk production of cows exposed to industrial fluoride pollution

Milk sales records for a dairy herd showed that milk production did not decrease during the first 4 yr of exposure of cows to fluoride pollution from an aluminum plant. During the next 3 yr milk production decreased, but not significantly. From yr 8 of exposure there was a significant decrease, which persisted through yr 19, when the dairy operation was terminated. From yr 15 through yr 19, the milk yield averaged less than 60% of the expected value.