title: Postpartum endometrial cytology in beef cows.
abstract: The objectives were to characterize postpartum endometrial cytology and to determine the prevalence of subclinical endometrial inflammation and its impact on reproduction in beef cows. Samples for endometrial cytology (low-volume uterine lavage) were obtained from 135 of 137 Angus cows (2-87d postpartum) in northern Minnesota, 26d before breeding started. Agreement between examiners for subjective inflammation scores was very high (kappa=0.971); the correlation between these scores and PMN counts was high (r=0.83; P<0.001), validating subjective categorization. The proportion of PMN and large mononuclear cells (principally macrophages) declined with postpartum interval (P<0.001), whereas small mononuclear cells were consistently present (and not significantly affected by postpartum interval). Pregnancy rate to fixed-time AI was 29% and overall pregnancy rate was 89%. There was no association between cell type and ultimate pregnancy status or day of conception (P>0.10). Although inflammation later in the postpartum period apparently impaired subsequent reproduction in dairy cows, in cows >50 d postpartum at sample collection in the present study, no cytological parameter significantly predicted final pregnancy status or day of conception. Previous twinning increased the risk of subclinical endometritis (P=0.02), but not the probability of becoming pregnant (P=0.14). In conclusion, we inferred that beef cows had the ability to clear uterine inflammation after resumption of ovarian cyclicity.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
authors.forename: N R
authors.initials: NR
authors.lastname: Santos
authors.forename: G C
authors.initials: GC
authors.lastname: Lamb
authors.forename: D R
authors.initials: DR
authors.lastname: Brown
authors.forename: R O
authors.initials: RO
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000473:pathology*; D004716:Endometritis / Q000473:pathology*; D004717:Endometrium / Q000473:pathology*; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D009504:Neutrophils / Q000473:pathology; D011247:Pregnancy; D011644:Puerperal Disorders / Q000473:pathology / Q000662:veterinary*; D007507:Therapeutic Irrigation / Q000662:veterinary