Differences in the occurrence of selenium, copper and zinc deficiencies in dairy cows, calves, heifers and bulls

Abstract

This study was conducted to evaluate the mineral status of various bovine categories reared on the same farm, and to monitor the quality of their mineral nutrition in this way. Blood samples were collected on 20 farms in various regions of the CzechRepublicto diagnose the selenium (Se), copper (Cu) and zinc (Zn) status of dairy cows, calves, heifers and bulls. Blood samples were collected from 5 dairy cows and their calves, 5 heifers and, whenever possible, also from 5 bullocks (10 farms). To assess the Cu and Zn status of the cattle, blood serum concentrations of the elements were determined by flame AAS. The Se status assessment was based on the glutathione peroxidase (GSH-Px) activity in whole blood. Dairy cows and calves showed the higher GSH-Px activity in comparison with heifers and bulls (P < 0.001). Overall mean GSH-Px activity in the blood of dairy cows, calves, heifers and bulls was 720.47 ± 174.47 µkat/l, 688.34 ± 204.12 µkat/l, 555.69 ± 318.36 µkat/l and 516.17 ± 214.70 µkat/l, respectively. Se deficiency was diagnosed in 23% of the examined dairy cows (20% herds), 31% calves (25% herds), 51% heifers (50% herds) and in 58% of bulls (50% herds). Dairy cows showed lower Zn and higher Cu concentrations in comparison with the other categories (P < 0.001). Mean Zn concentrations in blood serum of dairy cows, calves, heifers and bulls were 12.21 ± 3.19 µmol/l, 18.91 ± 5.78 µmol/l, 17.80 ± 2.76 µmol/l and 16.69 ± 3.08 µmol/l, respectively. Zn deficiency was diagnosed in 41% of the examined dairy cows (45% herds) and 13% of bulls (10% herds). None of the calf or heifer herds was classified as Zn deficient when Zn deficiency was found in only 9% of calves and 1% of the examined heifers. Mean Cu concentrations in blood serum of dairy cows, calves, heifers and bulls were 13.62 ± 2.62 µmol/l, 10.18 ± 3.22 µmol/l, 10.96 ± 2.52 µmol/l and 11.18 ± 2.40 µmol/l, respectively. Cu deficiency was diagnosed in 28% of the examined dairy cows (20% herds), 70% of calves (80% herds), 65% of heifers (75% herds) and 70% of bulls (60% herds). Deficiency of at least one of the microelements monitored was diagnosed on all investigated farms.