Abstract
Background:
Postpartum involution of the reproductive organs strongly impacts the fertility of cows. The key features include bacterial contamination of the uterus followed by uterine clearance as well as macroscopic and microscopic involution. Close monitoring is essential during the puerperium, as physiological inflammation may progress to a persistent infection.

Aim:
This study used exfoliative cytology to assess endometrial and lochia cell composition in 44 puerperal cows following various obstetrical interventions to determine their value as indicators of pathological processes during the early puerperium.

Methods:
Uterine involution was monitored by transrectal and vaginal examinations every 2 days. Animals were grouped according to obstetrical management (cesarean section, fetotomy, and manual traction), fetal membrane retention, and puerperal development (sound or disturbed). Endometrial cytology (ec) samples were obtained using a CytoBrush®. Lochia secretions were collected manually using a sterile glove. The retrieval of lochia secretion was limited depending on the postpartum reformation of the cervix. The slides were stained using an eosin-thiazine staining kit (Hemacolor®).

Results:
A total of 96 endometrial samples and 37 lochia smears were analyzed using light microscopy. Evaluation of the cellular composition included endometrial cells, neutrophil granulocytes, and erythrocytes. The incidence and quantity of each cell type were recorded. After cesarean section, the concentration of neutrophil granulocytes was consistently high for six days [p = 0.046]. Overall, none of the other parameters had a significant influence on the numbers of neutrophil granulocytes during the first six days after parturition (obstetrical management [p = 0.82], retention of fetal membranes [p = 0.75], and disturbed puerperium [p = 0.065]).

Conclusion:
According to our results, endometrial exfoliative cytology and lochia samples are not suitable for monitoring the early puerperium in cows.

Key words: Cow; Cytology; Granulocyte; Puerperium; Uterus.