Utilização de complexos orgânicos de minerais no pré-parto de vacas, e durante o aleitamento de bezerras holandêsas

Abstract

The objectives of this experiment were to evaluate the effect of complexed minerals use during prepartum as well as the performance and necessity or not of mineral supplementation during those cows rearing. In the first part of experiment 128 multiparous Holstein dairy cows were used and randomly assigned into two groups: MI-65 cows groups (cows consuming ionic mineral) and MC-63 groups (Cows consuming complexed mineral). Serum concentrations of Zn, Cu and Co were determined throughout atomic absorption spectrophotometry. Incidence of placental retention as well as colostrum quality were analyzed using the Qui-square test (5%). In order to test the differences between means of mineral concentrations and serum IgG Fischer and Duncan tests were respectively used (5%). There was no difference neither for colostrum quality amongst groups nor for placenta retention incidence or metrits or serum IgG (P>0.05). IgG concentrations were different in sampling times (P>0.05) showing a decrease two weeks before parturition. Serum Zn and Cu concentrations were not different between groups (P>0,05). In the second part of the experiment the supplementation of complexed minerals to dairy calves until 60 days of age was evaluated. It was a completely randomized split-plot design. Parcel was formed by 6 combined treatment in a factorial 2 x 6 design, considering as treatments the two types of minerals supplemented to cows (ionic or complexed) and three treatments at the calves barn ( no mineral, complexed mineral and ionic mineral). Concentrate, mineral mixture and water intakes as well as calves weight was evaluated. Serum concentrations of Zn, Cu and Co were also determined throughout atomic absorption spectrophotometry. IgG concentration was evaluated by radial immunodiffusion and total serum protein by biuret technique. In order to test the difference between means of concentrate and water intake as well as for serum IgG concentration and total protein the statistic test used was Fischer (5%). There were no differences (P>0.05) in total protein and IgG concentrations in the different treatment groups. Although there was a difference between sampling days (P<0.05) as well as group x day interaction. All groups showed higher IgG concentration after colostrum intake. Concentrate and water intake showed a group x day interaction (P<0.05). All groups presented an increasingly intake along the experimental period. There were no differences for calves body weight in the evaluated days (7,14,21,28,35,42,49,56 and 60) (P>0.05). There was a linear weigh increase of 0,580 g/day. Serum Cu and Zn concentrations did not differ between groups. There was neither a group x sampling day interaction. The use of complexed or ionic minerals for rearing dairy calves did not affect neither the intake rates nor the weight gains, which makes unnecessary the supplement of minerals during this particular age.