title: Cytological endometritis at artificial insemination in dairy cows: Prevalence and effect on pregnancy outcome.
abstract: The aims of our field study in dairy cows were (1) to consolidate cytotape (CT) as a valid technique to diagnose cytological endometritis (CYTO) during artificial insemination (AI); (2) to establish a cutoff point concerning the polymorphonuclear cells (PMN) proportion to diagnose CYTO at AI; (3) to assess the prevalence of CYTO at AI; and (4) to evaluate the effect of CYTO on the pregnancy outcome of that AI. The investigation was performed using 1,625 AI-CT samples harvested from 873 Holstein-Friesian cows from 18 dairy farms in the Flemish region of Belgium. The CT device consisted of adapting a 1.5-cm piece of paper tape on the top of a conventional AI catheter covered with a double guard sheet, allowing an endometrial cytology sample to be taken when performing an AI. A receiving operator characteristic curve was built to assess the threshold level above which the PMN proportion significantly affected the AI success. Multilevel generalized mixed-effect models were built to identify factors affecting the pregnancy outcome of the AI under investigation. Only 7 samples (0.4%) harvested in 5 cows were discarded because of low-quality parameters. The cutoff point for CYTO at AI was set at ≥1% PMN (sensitivity=33.8%, specificity=88.6%). Prevalence of CYTO at AI was 27.8%. The conception rate for CYTO-positive samples was 32.7%, whereas it was 47% for CYTO-negative samples. A CYTO-negative AI had 1.8 [odds ratio (OR)] more chances to become pregnant than a CYTO-positive one. Other factors identified as detrimental for the pregnancy outcome were body condition score ≤1.5 (OR=0.6), relative 305-d milk yield (OR=0.9), dystocia (OR=0.3), parity ≥2 (OR=0.7), and warm months of the year. In conclusion, CT is a consolidated technique to diagnose CYTO at AI, PMN 1% is the threshold level to diagnose CYTO at AI, around one-quarter of inseminated uteri suffer from CYTO, and affected uteri having a significantly lower chance to become pregnant from that insemination.
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke 9820, Belgium. Electronic address: osvaldo.bogado@ugent.be.
authors.forename: O
authors.initials: O
authors.lastname: Bogado Pascottini
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke 9820, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Hostens
authors.affiliation: CRV Holding BV, Van Thorenburghlaan 14, Oosterzele 9860, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Sys
authors.affiliation: CRV Holding BV, Van Thorenburghlaan 14, Oosterzele 9860, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Vercauteren
authors.affiliation: Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke 9820, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Opsomer
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology; D004716:Endometritis / Q000662:veterinary*; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence
keywords: artificial insemination; cytotape; dairy cow; subclinical endometritis