Biochemical profile of Mangalarga Marchador mares during the last third of pregnancy, foaling and lactation

ABSTRACT: Adaptive changes in metabolism may occur under specific physiological conditions, being necessary the knowledge of the biochemical constituents that can undergo variations during the sixty days before foaling, until the first sixty days of lactation. The present study aimed to identify and evaluate the biochemical profile of Mangalarga Marchador mares during the last third of pregnancy, foaling and lactation. For this, 48 mares were used, which formed a maintenance group (MG), composed of non-pregnant mares and an experimental group, called the transition group (TG), formed by pregnant mares. Blood samples were collected at the following times: MG was evaluated in a single time (beginning of all collections); TG was evaluated in seven times [T-60, T-30, T-15 (days before foaling), T0 (first six hours after foaling), T15, T30, T60 (days after foaling)]. All animals were submitted to biochemical analysis, in which the concentrations of total calcium, chloride, phosphorus, magnesium, sodium, potassium, uric acid, creatinine, and urea were measured. The two groups differed significantly (P<0.05) in calcium, magnesium, sodium, potassium, creatinine, uric acid and urea concentration. Variation between times was also observed for these compounds. However, chloride and phosphorus did not differ between MG and TG. It was concluded that the last third of pregnancy, foaling and lactation exerts major influence on the biochemical constituents of blood through adjustments to maintain homeostasis in mares.