Endometritis in the mare: A comparison between reproductive history and uterine biopsy as techniques for predicting susceptibility of mares to uterine infection

Thirty mares with no clinical signs of endometritis were categorized as being susceptible or resistant to uterine infection depending on whether or not they had a history of recurrent endometritis. The same mares were then independently classified as susceptible or resistant on the basis of their uterine biopsies; those with significant endometrial degeneration were considered to be susceptible to endometritis. The mares then received an intrauterine inoculation of pathogenic Streptococcus zooepidemicus . Those mares which eliminated bacteria by 10 d after inoculation were considered truly resistant to endometritis, whereas those still infected at 10 d were considered susceptible. The original classifications based on history or biopsy were compared to the inoculation results. A history of recurrent endometritis provided a more sensitive (0.90) and specific (0.95) indication of susceptibility to uterine infection than a uterine biopsy with significant endometrial degeneration (sensitivity 0.5, specificity 0.75).