Alkaline bone phosphatase activity as related to fluoride ingestion by dairy cattle.

Abstract

Alkaline phosphatase prepared from bone and studied in vitro in relation to the effect of fluoride was relatively insensitive to fluoride. Concentrations of fluoride in excess of 10/sup -2/ M were required for inhibition. Experiments with dairy heifers and cows indicated a close correlation between fluoride ingested, fluoride content of the bone, osseous abnormalities, and alkaline bone phosphatase activity. Fluorosis occurred in heifers fed rations containing 66 and 68 ppm of fluoride in contaminated hay and NaF respectively, for a period of 20 months. Additions of about 69 ppm of CaF/sub 2/ to the rations for 20 months caused no detrimental effect to the dairy animals. In an experiment lasting seven years and 108 days, dairy cattle were fed rations containing 12, 27, 49, and 93 ppm of sodium fluoride. When the rations contained 49 or 93 ppm of NaF, osseous abnormalities, excessively high accumulation of fluoride in the bone, and significant increases in alkaline bone phosphatase activity occurred. Results indicated that alkaline bone phosphatase activity was related to abnormal formation.