Endometritis is a uterine disease of dairy cows causing substantial negative effects on reproductive performance and inflicting considerable economic losses. It is typically diagnosed by endometrial cytology evaluation and commonly named cytological endometritis (CEM). In most previous studies, cows were defined as CEM positive if the proportion of polymorphonuclear cells (%PMN) in their endometrial cytology was above a pre-set threshold. Thresholds were established based on CEM diagnosis in association with reproductive performance, typically analyzed by a single reproductive parameter and calculated for all cows together. Our objective was to examine whether primiparous and multiparous cows should optimally be diagnosed for CEM by different %PMN thresholds and sampling timings, using a combination of several reproductive performance parameters. Two endometrial cytobrush cytology samples were collected from Holstein-Friesian dairy cows (n = 415; 269 multiparous; 146 primiparous), at 30–40 d in milk (DIM) and 60–70 DIM, and %PMN were evaluated microscopically (blindly; Diff-Quick stain, Medi-Market). The %PMN thresholds were set at ≥1% to ≥10%, ≥15%, and ≥20%, and accordingly, for each of the thresholds, several reproductive performance parameters were compared between CEM-positive versus CEM-negative cows. Upon application of several analytic approaches, our results indicated that optimal CEM diagnosis should be performed by different criteria in primiparous and multiparous cows: in primiparous cows at 30–40 DIM, using a threshold of ≥7%PMN, and in multiparous cows at 60–70 DIM, using a threshold of ≥4%PMN. Such a diagnostic approach provides a comprehensive view of the reproductive prognosis of CEM-positive primiparous and multiparous cows, which is pertinent information for researchers, veterinarians, and farmers.
Bibliographical noteFunding Information:
The authors thank all farmers for allowing us to conduct the research in their farm, and Nathalie Weizmann (Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel) for technical help and editing. This study was supported by The Israel Dairy Board Fund (Yehud, Israel; grant no. 705-0064-14) and by the Hebrew University (Jerusalem, Israel). The authors have not stated any conflicts of interest.
© 2022 American Dairy Science Association
© 2022, The Authors. Published by Elsevier Inc. and Fass Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
- dairy cows
- polymorphonuclear cells
- Cattle Diseases/diagnosis