Deficiência de cobre condicionada a altos teores de zinco, manganês e ferro na região do Médio Paraíba, RJ, Brasil

Abstract

Concentrations of microminerals in the soils, pastures, and sera of adult and young bovines were determined in 7 areas of Middle Paraíba, Rio de Janeiro, Brazil, that showed a history of low reproductive performance, marked weight loss of cows after calving, allotriophagy, and changes in pelage color. The animals were subjected to clinical evaluation, and the main signs were as follows: regular to poor general condition, anemia, alopecia, depigmentation of the pelage in adult animals, discolored pelage (reddish) in dark animals, and thinning and loss of hair around the eyes. Calves showed bad general appearance, retarded development, and rough, dry, and spiked hair. There were other evident signs such as craving and consumption of foreign material such as soil, wood, or bones. After the interview with the owners and on-site evaluation of the herds, soil samples, forages, and blood serum samples were obtained for analysis of macro and micronutrients in 2 different periods: May/June (end of the rainy season–autumn) and October/November (end of dry season–spring). The findings of soil (3.03 ± 1.72/3.13 ± 1.22 mg/ dm3) and forage (11.91 ± 2.92/13.6 ± 5.23 ppm) samples indicated normal and high levels of copper, respectively, in most of the pastures which is contrary to the clinical signs of deficiency observed in the animals. However, the copper levels in serum were lower than normal (0.42 ± 0.14/0.45 ± 0.17 ppm) in majority of the animals, in periods of evaluation and for all properties. Excessively high values of iron, zinc, and manganese were found in soil and pasture samples, which could have probably been acting as antagonists of copper absorption, resulting in a conditioned deficiency.