Dynamic of metabolic indicators, insulin like-growth factor I (IGF-I) and cortisol in holstein cows during the transition period

ABSTRACT

Background: Physiological events occur in the transition period marked by negative energetic balance, where the energetic demand is higher due to fetal nutrition and lactogenesis and intensified by the decrease of the dry matter intake in the pre-partum period. The adaptation of cows is dependent of homeostatic and homeorhetic mechanisms regulated by catecholamine, cortisol, GH, IGF-I, insulin and glucagon but the priorization of homeorhetic mechanisms could result in metabolic diseases. Considering the scarce longitudinal studies about the Brazilian conditions the aim of this project was to evaluate the influence of transition period on metabolic indicators, cortisol and IGF-I in Holstein cows.Materials, Methods & Results: Thirteen cows, from 2nd to 4th lactation were evaluated weakly from week -2 to week +3 in relation to calving to determine the body condition score (BCS), metabolic and endocrine profile. The BCS decreased between week -2 (BCS = 4.0) and +1 (BCS = 3.0), followed by and slight increase on weeks +2 and +3 (P = 0.000). The most of metabolic indicators and hormones have changed during the transition period (P ≤ 0.05), especially around calving. It was possible to detect the peak of cortisol, glucose, non-esterified fatty acids (NEFA), ß-hydroxibutyrate (BHB), and aspartate aminotransferase (AST) on delivery and week +1. On the other hand, total calcium, triglycerides (TG) and cholesterol (CHOL) decreased was observed around parturition. Insulin like growth factor type I (IGF-I) showed marked reduction between pre and postpartum, and the lowest value was observed in the week +1. TP and GLOB had the lowest value on calving and globulin has a gradual increase from delivery to week +3.[...]