Serum levels of minerals in beef heifers and cows in the cloudforest of Salta, Argentina

Abstract

Mineral deficiencies are a problem of great productive impact worldwide. In the Argentine Northwest (NOA) extensive breeding is one of the most important economic activities and it is in frank growth. In the NOA, studies on deficiency diseases are scarce and partial. The present work aims to describe seasonal variations of serum levels of calcium, phosphorus, magnesium, copper and zinc in beef cows and rearing calves. In a farm, 20 cows and 20 weaned heifer calves were selected, which were maintained under grazing conditions and without external supplementation. Blood samples were taken at intervals of 3 months for one year. Serum levels of calcium, magnesium, copper and zinc were determined by atomic absorption spectrophotometry and phosphorus by UV-visible spectrophotometry. The results indicate the existence of moderated hypocupremia in the calves (48.6 ± 11μg / dl) during all sampled periods. Cows presented normal values (66 ± 3.5 μg / dl) but close to the lower limit during some sampling. Subnormal levels of phosphorus were observed during the summer (December and March) in both categories. This work confirms that copper and phosphorus can behave as limiting factors in the evaluated conditions.