Effects of Chronic Fluorosis on Thyroxine, Triiodothyronine, and Protein-Bound Iodine in Cows

Abstract

This study was conducted to evaluate the effects of chronic fluorosis in cows on their blood serum levels of thyroxine (T-4), triiodothyronine (TA and protein-bound iodine (PBI). Data collected from twenty cows with chronic fluorosis in the Tendurek Mountain region (altitude about 2000 m) in East Anatolia, Turkey, were compared with data from ten healthy cows from the Van region (altitude 1700 m). Statistically significant differences (p < 0.05) between the serum values in the fluorotic cows and the controls were found: 5.7 +/- 0.48 vs 3.7 +/- 0.45 mu g/dL for T-4, 1.53 +/- 0.038 vs 0.97 +/- 0.051 ng/mL for T-3, and 3.8 +/- 0.29 vs 2.6 +/- 0.23 mu g/dL for PBI. Hypothyroidism was therefore evident in the cows with chronic fluorosis.