Prepartal platelet count and fibrinogen concentration in dairy cows with and without retained placenta

Abstract

Although extensive data are available on leukocyte changes in prepartal period in cows with and without retained placenta, there is no data describing changes in platelet count. The aim of this study was to define changes in platelet count in cows, with and without retained placenta, three weeks before and one day after calving. Using fibrinogen level as a general reference to cow's health, we also tested the hypothesis that cows, that develop placenta retention in prepartal period, have a subclinical systemic inflammatory reaction. Blood samples taken from 14 Holstein cows were analyzed, three times in a week interval before and 24 hours after calving. After calving, cows were retrospectively divided, in the group without (n=9) and the group with retained placenta (n=5). Clauss method was used for determination of fibrinogen concentration and blood smear examination for assessment of platelet count. The results have shown that retained placenta is associated with increase in platelet count seven days before calving and decrease in platelet count 24 hours after calving comparing to precalving values. The week before calving group of cows, that developed retained placenta had platelet count significantly higher, comparing to control group of cows. Fibrinogen level was not significantly different between groups. The recorded increase in platelet count, one week before calving can be related to unidentified stress factors, and decrease of platelet count 24 hours after calving, can be explained by their increased consumption, due to activation of haemostatic mechanisms after placenta abruption.