Metabolismo energético e proteico e perfil bioquímico hepático em vacas mestiças leiteiras submetidas ao uso diário de ocitocina durante a lactação

Abstract

Oxytocin has been used for the purpose of facilitating milking and increase milk production. Sharing the needle can serve pathogens and lead to phlebitis beyond the discomfort in the application. In dairy cows have not been described metabolic implications related to the continued use of oxytocin. Thus, we sought to evaluate the effects of oxytocin throughout the lactation period of Holstein x Gir cows, with an emphasis on energy, protein and liver biochemical profile metabolism. The study was conducted on a property in the municipality of Resende, south of Rio de Janeiro. We selected 12 crossbred cows (Gir x Holstein) aged four to seven, with seven to 15 days calved with no signs of disease, good condition (ECC 3.0 to 3.5), randomly divided into two groups treatment set according to the application form of OT on the property: OT group (GOT) - 0.3 ml (3 IU) intravenously at the beginning and middle of each milking; control group (GCT) - no OT. Blood samples were collected at intervals of 15 days, from 15 to 150 days postpartum and the last collection of thirty days interval (180 days postpartum, DPP). Serum was determined values of the total protein, albumin, urea, total and direct bilirubin, glucose, cholesterol, and HDL cholesterol, triglyceride, non-esterified fatty acids and beta-hydroxybutyrate, using commercial kits according to the manufacturer's specification. The concentrations of total protein in both groups, GOT and GCT were lifted from 15-105 DPP and DPD 150 the GCT. Albumin concentrations were normal in both groups in early lactation, lower 30 and 105-135 DPP the GOT. Urea was below the reference value (23 mg/dL) in GOT to 15 DPP and GCT at 15, 30 and 105 DPP. There were smaller concentrations GCT compared to GOT at all times, except at 90 DPP and statistical difference at 30, 75 and 105 DPP. Serum activity of AST and ALT enzymes there was no significant difference between treatments and AST, the GOT was normal when compared to reference and high in GCT to 15 DPP and 135 DPP. Serum concentrations of total direct and indirect bilirubin levels remained within normal limits throughout the period. Glycemia presented with progressive and steady decrease DPP between 15 to 120 in both groups. There was no effect of OT on blood glucose as the behavior was similar and no significant difference between treatments (p <0.5). The non-esterified fatty acids presented above with 0.40 mmol / L concentrations (Kaneko et al., 2008), at 45 and 135 to 180 of the DPD 135 of GOT and 180 days in GCT. The beta-hydroxybutyrate concentrations were elevated in both GOT and in GCT at all times (Kaneko et al., 2008). Cholesterol values were high and rising in GCT (126 ± 63 to 190 ± 34 mg / dL) and GOT (205 ± 45 to 243 ± 61 mg / dL) with statistical difference between the groups 15 to 90 and 120, 150 and 180 PPD. In the GOT in no time triglycerides were below the reference values and the lowest level was observed in GCT to 30 DPP. Exogenous oxytocin daily during milking crossbred cows milk production positively influenced and changed the indicators of energy and protein profile, confirming the catabolic action of oxytocin without, however, alter liver function and without causing clinical changes in animals.