Recumbency decreases mare and foal survival following in-hospital dystocia management.

Background: Mare and foal survival are increased with prompt dystocia management. Data regarding mortality outcomes in mares and foals, when mares are recumbent at admission for dystocia resolution, are scarce.

Objectives: To evaluate recumbency at hospital admission as a risk factor for survival of mares and foals following dystocia management. Subsequent mare fertility was also evaluated.

Study Design: Retrospective cohort.

Methods: Data were obtained from medical records at Rood and Riddle Equine Hospital of mares with dystocia between 1995 and 2018. Mare signalment, ambulation status, survival data and foaling records were collected. The proportion of mare survival and mare fertility were analysed using chi-squared tests. Foal survival was analysed using Fisher's exact test. Odds ratios were calculated using multivariable logistic regression.

Results: There were 1038 ambulatory mares and 41 recumbent mares included in the analysis. Survival rates after dystocia resolution were 90.5% (977/1079) in mares and 37.3% (402/1079) in foals. Ambulatory mares had higher odds of survival (OR 6.93, 95% CI: 3.25-14.78, p < 0.001) than recumbent mares. Foals delivered from ambulatory mares had higher odds of survival (OR 22.7, 95% CI: 3.11-165.44, p = 0.002) compared with foals delivered from recumbent mares. Fertility was not statistically different for surviving Thoroughbred mares within 3 years following dystocia resolution between ambulatory and recumbent mares.

Main Limitations: Retrospective study design and small case number of recumbent mares.

Conclusions: Mare and foal survival was significantly decreased when mares with dystocia were recumbent at hospital admission. Subsequent fertility, as defined for this study, of surviving mares was not affected by ambulation status at the time of dystocia resolution.