Equine Metritis Study Guide

Overview and Clinical Importance

Metritis in mares encompasses inflammation of all uterine layers (endometrium, myometrium, and perimetrium) and represents a significant cause of reproductive failure. This study guide covers two primary forms: contagious equine metritis (CEM) and postpartum metritis, both critical topics for the NAVLE examination.

Contagious Equine Metritis (CEM)

Definition and Etiology

CEM is an acute, highly contagious venereal disease caused by Taylorella equigenitalis, a gram-negative, microaerophilic coccobacillus. First identified in 1977 in the United Kingdom, CEM has since been reported worldwide but is considered eradicated from the United States.

Organism Characteristics

Taylorella equigenitalis is fastidious and slow-growing, requiring 3-7 days on specialized chocolate blood agar under microaerophilic conditions. Two biotypes exist: streptomycin-sensitive and streptomycin-resistant. The organism is cytochrome oxidase and catalase positive but otherwise biochemically unreactive.