Uterine bacteriology, histology, resumption of ovarian activity and granulocyte function of the postpartum cow in different milking frequencies

The postpartum uterine bacteriology, histology, resumption of ovarian activ ity and polymorphonuclear granulocyte (PMN) number and function in 18 Swedi sh dairy cows were studied. Cows were milked either 2x (n = 9) or 3x per da y (n = 9). Endometrial biopsy samples for bacteriological and histological investigations were collected during 8 weeks postpartum, starting within on e week after calving. Milk samples for progesterone determination were coll ected twice a week until the cows had shown normal reproductive cyclicity. Blood samples for granulocyte function (phagocytic capacity and total numbe r) were collected from each animal on the same days as when the biopsies we re obtained. All animals in both groups were free from bacteria at the late st after 6 weeks port portum and there was no difference regarding bacteria l elimination and bacterial species between milking groups. No difference r egarding uterine histology between milking groups was seen. In both groups, 8 cows had normal to slight infiltration of leukocytes in the endometrium at the end of sample collection. No changes in granulocyte function could b e seen in the 2 milking groups. Resumption of ovarian activity was detected on day 45.6 +/- 9.3 (mean +/- SD) postpartum in the 2x milking group and 3 6.6 +/- 9.0 (mean +/- SD) post-partum in the 3x milking group (p = 0.05). B ased on our findings, an increased milking frequency from 2 to 3 times a da y did not influence the uterine function postpartum.