Agreement between postmortem endometrial cytology, biopsy and bacteriology in culled dairy cows

Abstract

The objectives of this study were to determine: a) the agreement between postmortem endometrial cytology, uterine biopsy and presence of intrauterine fluid in apparently normal genital tracts collected from culled dairy cows; b) the agreement between results obtained from paired uterine horns using the different diagnosis methods; and c) the microorganisms isolated from uteri with cytological endometritis. One hundred grossly normal genital tracts from Holstein cows were collected at a local slaughterhouse. Samples for cytology, histopathology and bacteriology were obtained from both uterine horns, and presence of any intrauterine content was determined after opening the tracts. Cut-off values used for positive cytology were ≥5% PMN (polymorphonuclear neutrophils). Data were analyzed by ROC curve analysis, Cohen's Kappa method and Chi-square tests. Presence of inflammatory infiltrate and its endometrial distribution were the only histological parameters significantly correlated with cytology results (AUC: 0.780 and 0.694, respectively). Agreement between histology and cytology was moderately high for presence of infiltrate (kappa = 0.55) and low for infiltrate distribution (kappa = 0.33). Other histological parameters (status of endometrial epithelium, endometrial glands or fibrosis), intrauterine content or bacteriology were not correlated with cytology. Presence of intrauterine content was significantly (P = 0.036) related with biopsy results. Moderately high agreement was observed between paired uterine horns for cytology (kappa = 0.65) and biopsy (kappa = 0.74). Bacteriology was not related with cytology or biopsy, but different bacteria were isolated from cytology negative or positive uteri. It was concluded that endometrial cytology, although less sensitive than biopsy, is a useful tool for diagnosing subclinical endometrial inflammation.

Subclinical Endometritis in Dairy Cattle

“…are commonly isolated from the uterus [17]. In the case of SE, in contrast, several studies [7][8][9] showed that bacterial populations isolated from the uterus of cows diagnosed with SE did not differ from those of healthy cows. Prunner et al [18] found that presence of Trueperella pyogenes in the uterus postpartum was a risk factor for development of clinical endometritis, but neither Trueperella pyogenes nor E. coli were associated with SE.…”

“…Subclinical endometritis is the inflammation of the endometrium without clinical signs and often without evidence of infection [7][8][9]. Alteration of the inflammatory response postpartum could be at the origin of this condition.…”

“…Presence of intrauterine fluid and a thick uterine mucosa may be normal findings in physiological situations such as estrus or early postpartum [48], and perhaps the evaluation of fluid characteristics could improve the sensitivity of ultrasound diagnosis [49]. Mariño et al [9] found a significant relationship between presence of abnormal intrauterine fluid and SE diagnosed by biopsy but not by cytology.…”

“…Cytology samples can be obtained from the uterine body or from one of the uterine horns. Mariño et al [9] compared cytology and biopsy findings between the two horns of 100 bovine uteri collected postmortem and observed that samples collected from the left horn were more representative of both uterine horns than those collected from the right one.…”

“…During the follicular phase of the estrous cycle, there is an increased infiltration of PMN in the endometrium elicited under estrogenic influence [65]. Several studies [9,52,57] have found that the PMN% in cytological samples taken with cytobrush was not affected by the stage of the estrous cycle. However, when the SE diagnosis was done by biopsy, a higher degree of inflammatory infiltration could be observed in the follicular phase of the cycle [9].…”