Evaluation of the metabolic status of Simmental dairy cows in early and mid lactation

Abstract

Fifteen early-lactation cows and 15 mid-lactation cows were chosen for the analysis. Blood samples were collected to measure the beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), triglycerides (TG), glucose (Glu), total protein (TP), albumin (ALB), total bilirubin (TB), urea (U) and the activity of aspartate transaminase (AST) and gamma-glutamyl transferase (GGT). Earlylactation cows showed significantly higher (P<0.05) values of serum BHB and NEFA, and lower of (P<0.05) glycemia levels compared to mid-lactation cows. High lipomobilization (NEFA >0.4 mmol/l) and subclinical ketosis (BHB >1.2 mmol/L) were detected in 6 (40%) and 14 (94.4%) early-lactation cows, respectively, and in none of the mid lactation cows. AST activities above 100 IU/l were detected in two early-lactation and none of the mid-lactation cows. TG concentrations below 0.12 mmol/l were found in 7 (44%) early-lactation and 2 (13.3%) mid-lactation cows. Glucose levels were below 2.5 mmol/l in 10 (66.6%) early-lactation and 5 (33.3%) mid-lactation cows. Early-lactation cows showed lower blood serum concentrations of TG (P>0.05), ALB (P>0.05), TP (P<0.05), U (P>0.05) and GTT (P>0.05) activities and higher concentrations of TB (P>0.05) and AST activities (P<0.05), as compared to mid-lactation cows. These metabolic characteristics were correlated with DMI and energy balance (EB). Blood serum values for glucose, TG, BHB, NEFA and AST showed that earlylactation cows suffered from metabolic disturbances, associated with ketosis, and some degree of hepatic lesions, probably due to fat infiltration. These serum parameters may have a key role in evaluating the metabolic status of dairy cows.