Influência das concentrações de cálcio sanguíneo de cabras leiteiras no período de transição sobre o perfil energético-proteico, mineral e hormonal

Abstract

Hypocalcemia in dairy cows has been studied around the world, mainly due to its impact on animal production and productivity, will be related to various diseases. However, few studies have been conducted on this disease in small ruminants, especially in dairy goats. Therefore , the aim of this study was to determine the concentrations of calcium during the transition period in dairy goats in order to differentiate groups of hypocalcemic animals (G1) and normal calcium (G2), in order to infer the influence of subclinical hypocalcemia in profile metabolic thereof. For this, 35 goats, otherwise healthy, pregnant, primiparous and multiparous, crossbred or purebred dairy breeds used. Blood samples were collected by jugular venipuncture before delivery [30 , 20 and 10 days before parturition (dap)] , on the day of partum and post -partum [10,20,30,40,50 and 60 days later parturition (dpp)]. The variables measured were: glucose, non-esterified fatty acids (NEFA), β - hydroxybutyrate (BHB), cholesterol, triglycerides, amylase, total protein (TP), albumin, urea, creatinine, aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), creatine kinase (CK), total calcium, phosphorus (P), magnesium (Mg), chlorides, hormones cortisol and insulin, as well as ions Ca++, Na+ and K+. Were considered to have subclinical hypocalcemia goats showed that Ca++≤ 0.72mmol/L. The statistical model used for analysis was ANOVA . In G1 concentrations of Ca++ remained below that of G2 and the biggest difference ( P < 0.001 ) occurred at parturition . The highest concentrations of NEFA were observed at birth in both groups, but were higher in G1 (P< 0.03) than the G2 at delivery and during the pre -partum. The BHB had a slight growth from beginning to 40dpp in both the G1 and G2 and there were no differences between them. The behavior of amylase was increased in antepartum reaching their highest values to 10dpp and remained stable postpartum in both groups, did not return to their initial values. A decrease in the values of triglycerides 20dap until 10dpp and differences (P<0.05) were found between the pre-and postpartum in both groups occurred. Cholesterol remained slight growth in postpartum, a little more evident in G2 than in G1, however these did not differ. Reduction in the concentration of insulin to 10dap in both groups, but in this G1 was greater (P˂0.001) that some times postpartum. The highest values of cortisol and glucose occurred at delivery and there were no differences between groups. The PT values were rising delivery to 30dpp not returning to baseline values in both G1 and G2. Albumin fell to 20dap and grew from birth up to 30dpp when returned to its initial value in both groups. The lower (P<0.05) values of total calcium is given at birth and the G1 was lower than G2 in almost the entire period. It is concluded that in subclinically goats hypocalcemic serum concentrations of Ca++ fall before the normocalcêmicas goats and remain lower throughout the transition period and that some variables of the metabolic profile as NEFA, glucose, insulin and total calcium are strongly influenced by the Ca++. Furthermore, the lower food intake by goats with subclinical hypocalcemia is one of the main factors affecting the metabolic profile and probably the productivity of these animals. However, other studies should be conducted to measure the effects of this disease in its subclinical form , the production rates and the emergence of other diseases in the transition period in dairy goats.