Chronic fluorosis in cattle due to the ingestion of a commercial lick.

A year after introduction of a lick known to contain a commercial phosphorous source intended for agronomical purposes, approximately 2% adult cattle, from a herd numbering 120 animals, were observed to show signs of lameness. Four years later, this prevalence had increased to 5%, but teeth abnormalities were evident in 70-80% of animals. The average fluoride concentration of 5 coccygeal bone samples from 4-year-old animals was 6.94 x 10(3) mg kg-1. A lick sample had a fluoride concentration of 1.4 x 10(3) mg kg-1. A water and pasture sample contained 0.03 ppm and 0.3 ppm fluoride respectively. These values suggested that the lick was responsible for the clinical signs of chronic fluororis in the herd.