Perfil metabólico de bovinos confinados com dietas de diferentes densidades energéticas

Abstract

The aim of this study was to determine the main metabolic alterations I calves that underwent two different diets, one using a 36.96% starch in dry matter composition and another using 16.81%. Sixteen Hollsteiner calves were used, initially weighting an average of 250 + 25,5 Kg, evaluated along a 91-day confinement period. Evaluations were made comparing between experimental days and different sampling moments within the day, at 0, 4, 6, 8 and 10 hours, using as reference the first serving of the day. Animals were distributed in groups of eight components each, according to their weight. Ruminal parameters such as pH of ruminal fluid and blue methylene reduction time were evaluated, as well as blood parameters such as blood glucose, lactate, albumin, magnesium, chloride, phosphorus, calcium, iron, beta-hydroxybutyrate (B-HBO), nonesterified fatty acids, insulin, IGF-1, pCo2, acid glycoprotein, alpha-2-macroglobulin, apolipoprotein A1, apolipoprotein A4, IgG, ceruloplasmin, haptoglobin and transferrin. Evaluating both metabolic and ruminal profile, it was observed that inclusion of higher percentages of starch in diets are able to cause metabolic responses. Animals that have undergone a higher starch-composed diet presented more severe acidosis compensations when compared to the other experimental group. Both experimental groups were in anabolic gain weight of 0,89 e 1,79kg/day for the 36.96% starch-group and 18.81% starch-group, respectively. The higher the starch concentration in the diet, the higher the glucose values obtained. The inclusion of energy in diet, specially coming from starch addition, is becoming increasingly used in calves’ diet in order to increase productivity rates and zootechnic and financial efficiency in both beef and dairy cattle. However, exceedingly higher starch concentrations may cause metabolic disturbances to calves.