The influence of postpartum period on the leucogram of Holstein cows

Abstract

With the purpose to evaluate the influence of postpartum period on the values of the leucogram of Holstein cows, 142 blood samples were collected from cows during the first 90 days after parturition. Blood samples were collected from clinically healthy cows that were non-reactive to the antigen of bovine leukosis virus (GP 51). These animals were divided into 9 experimental groups based on the time of the postpartum sample collection. In the blood samples the following tests were done: counting of the total and differential number of leukocytes. During the entire study period, the leukocyte profile was predominantly lymphocytic, having a physiologic leukocytosis due to neutrophilia associated with a left regenerative shift, lymphocytosis, and eosinophilia during the first 24 h after parturition. During the first week after parturition, there was a gradual decrease in the number of leukocytes due to an absolute reduction in the total number of neutrophils and lymphocytes. An exception was observed with the absolute number of eosinophils from the samples collected between 6 - 8 days postpartum, the values of these variables were similar to those animals that had already completed puerperium. During the first week of puerperium the values reference range between 18,977 ± 5,644 and 12,247 ± 5,058 leukocytes/mm³; 8,453 ± 2,956 and 4,376 ± 4,139 neutrophils/mm³ (532 ± 547 and 88 ± 174 band neutrophils/mm³; 7,920 ± 2,689 and 4,289 ± 4,039 segmented neutrophils /mm³); 334 ± 387 and 225 ± 298 eosinophils/mm³; 50 ± 128 and 23 ± 45 basophils/mm³; 10,004 ± 4,901 and 7,595 ± 3,127 lymphocytes/mm³; 121 ± 178 and 21 ± 85 monocytes/mm³.