Abstract
This study was aimed to provide a complete picture of dynamics of selected hematological and serum biochemical parameters in dairy cows from late pregnancy to early postpartum period, giving new and useful information about the guidelines for the management strategies during different physiological phases. This study was carried out on thirty clinically healthy Holstein Friesian dairy cows; in good nutritional condition. Blood samples were collected two weeks before the expected parturition , during the 1st post-partum week and during the 3rd week after parturition. Cows under investigation were clinically examined including body temperature, pulse, respiration, mucous membranes and ruminal movement. Two blood samples were collected: whole blood samples for hematological picture, while serum samples for biochemical analysis which included total proteins, albumin , globulin , AST, ALT, glucose, Creatinine, Blood urea nitrogen (BUN), Total cholesterol, Beta hydroxy butyrate (βHBA), triglycerides, Nitric Oxide (No), Malondialdehyde (MDA), total antioxidant capacity (TAC), serum calcium, magnesium, sodium, potassium, chloride and phosphorus. Significant changes between pre and post-partum period were observed in values of hemogram and biochemical parameters including RBCs, PCV%, hemoglobin, MCV, MCHC, MCH, WBCS count and differential leucocytic count, total proteins, albumin, globulin, glucose, BUN, Total cholesterol, triglycerides, calcium, phosphorus, magnesium, sodium, chloride, No, MDA and TAC, while non-significant changes were observed in AST, ALT, Potassium ,Creatinine and βHBA levels. It can be concluded that late pregnancy and the onset of lactation were accompanied by marked changes in hemato-biochemical and oxidative stress markers which have great impact on dairy cow`s health, immunity and disease susceptibility.

Key words: Transition period, dairy cattle, hemato-biochemical, antioxidants.