Avaliação de proteínas de fase aguda, hemograma, marcadores metabólicos energéticos e resistência a insulina no periparto de vacas leiteiras com mudança de condição no pré-parto

Abstract

The aim of this study was to evaluate acute phase proteins concentration,hemogram parameters, energetic metabolic parameters and the response to glucose and insulin tolerance test (GITT) in periparturientdairy cows that changed the body condition score (BCS) during the pre-partum period. For this study 20 pregnant Holstein dairy cows were evaluated, from the day -21 from expected calving date until 30 days postpartum, kept in a semi-extensive system in Southern Rio Grande do Sul, Brazil. Animals were categorized into two groups, cows that gained BCS from the third to the first week before the expected calving date (UP-BCS n = 11) or lost BCS (LO-BCS n = 9) during this period. Blood samples were collected at days 21, 14, 7 and 3 pre-partum, on the calving date and at days 3, 6, 9, 16, 23 and 30 postpartum to evaluate the concentrations of glucose (GLU), non-esterified fatty acids (NEFA), insulin (INS), albumin (ALB),and haptoglobin (HP)andparaoxonase (PON) activity. At days -20 pre-partum and 9 postpartum all cows were subjected to a glucose and insulin tolerance test (GITT), to obtain basal glucose levels, insulin stimulated blood glucose response (ISBGR), area under the curve (AUC) for glucose until 60 and 180 minutes, half-life of glucose until 60’ and 180’ and the clearance rate of glucose until 60' and 180’. The following parameters were evaluated for insulin concentrations: peak insulin, insulin increment and the AUC for insulin at 60 'and 150'. Milk yield was recorded daily, and an average was generated every 5 days, from 16 to 41 days in milk. Weekly hemogram was performed, and the cows were weighted and BCS was evaluated. The UP-BCS cows had higher levels (P<0.05) of PON in postpartum and ALB in the pre and postpartum period (P< 0.05 for both periods), while the LO-BCS group had higher levels of HP in both periods (prepartum: P< 0.04 and postpartum P<0.05). Average milk yield was 3 kg/cow/day higher in the UP-BCS than LO-BCS group (P<0.03; 27,4± 1.4 Kg/d vs. 24.4 ± 1.2 Kg/d).Hemogram hadhighercount of monocytes in the LO-BCS group in the pre (P <0.01) and postpartum periods (P <0.03), and greater number of animals with neutrophil:lymphocyte ratio > 1. The concentrations of GLU, NEFA, INS and GITT were not different(P > 0.05)between groups. We conclude that the pre-partum loss of BCS alters the inflammatory mediators during the peripartum period.