Selenium and iodine status relationship in calves and heifers from selenium and iodine deficient areas in Serbia

Abstract

The selenium and iodine status was determined in calves (3, 6 and 9 months old) and heifers (12 months) on two farms (A-Kovin, and B-Vrbas) in iodine and selenium deficient areas of Serbia. Selenium concentrations in feedstuffs on the territories surrounding farm A and B were lower than 0.1 ppm in more than 90% of the samples and lower than 0.05 ppm in more than 67% of the samples. Plasma selenium concentrations in calves and heifers from both farms were very low, ranging from 1.58 to 9.42 µg/L. Plasma GSH-Px activity was very low in 3 month old calves: 8.4 ± 5.2 and 16.1 ± 4.3 µkat/L on farm A and B, respectively, and significantly higher in 12 month old heifers: 39.0 ± 6.2 and 40.8 ± 9.8 µkat/L on farm A and B, respectively. Mean plasma T4 levels in all groups of calves and heifers were relatively high, ranging between 57.1 and 102.9 nmol/L. Mean plasma T3 levels in calves and heifers from both farms ranged from 2.72 to 3.51 nmol/L, and did not vary significantly, except for the 3-month-old calves on farm B, where the level was significantly higher than in the other groups. A significant correlation was found between plasma GSH-Px activity and T3:T4 ratio in the 6- month-old calves from farm A (r2 = 0.80), as well as in the combined groups of 6-and 9-month old calves from farm B (r2 = 0.68)