Glucose infusion response to some biochemical parameters in dairy cows during the transition period

The aim of this study was to evaluate the effect of pre-partum versus post-partum periods on the biochemical profile in dairy cows. The effect of glucose tolerance test (GTT) on glucose (Gluon-farm) and β-Hydroxybutyrate (BHBon-farm) levels was also assessed. 42 Holstein cows from two different farms (farm A and farm B) were enrolled in the study. Body Condition Score (BCS) was determined for both groups. The GTT was carried out 7±5 days pre-partum and 7±5 days post-partum. In both periods blood samples were taken at T0 (pre-glucose administration), at T10 and T80 (10 and 80 minutes post-glucose administration). All samples were analysed for total protein, albumin, globulin, glucose, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium (Ca), phosphorus (P), sodium (Na), chloride (Cl), potassium (K), magnesium (Mg) and BHBon-farm. Two- way ANOVA was applied to determine significant effects of the transition period (pre-partum vs. post-partum) and farm (A vs. B) on the studied parameters as well as the effect of time before and after the GTT on Gluon-farm. The average values of BCS, glucose, urea, Ca, Cl and K are significantly lower in the post-partum when compared to the pre-partum period (P<0.05). The increase in AST concentrations during the post-partum period (P<0.05) is considered a suitable indicator of hepatic steatosis. The glucose tended to increase significantly at T10 (P<0.05) and returned to pre-infusion concentrations at T80. These results confirm that the transition period is an important metabolic challenge to high-yielding dairy cows. Therefore, this study provides useful information in order to prevent the outset of nutritional imbalance that typically occurs in high production dairy cows.