Good prognosis for survival to hospital discharge in a group of horses with uterine prolapse treated at a veterinary medical teaching hospital.

OBJECTIVE: To describe uterine prolapse, predispositions, and outcomes in mares treated between 1988 and 2019. ANIMALS: 24 mares with uterine prolapse. PROCEDURES: Clinical records were retrospectively reviewed, and follow-up information was gathered. The Mann-Whitney U test and Fisher exact test were used to analyze results for history and outcome variables for potential association with mare survival to hospital discharge. The χ2 test was used to compare breed distribution. RESULTS: Age was known in 23 mares (median, 11.1 years). For 15 mares with exact known parity, the median parity was 3 births (range, 1 to 13 births). For 22 mares, the maiden status was known (7 [32%] maiden; 15 [68%] multiparous). Breed distribution differed significantly between mares with uterine prolapse and all mares treated at the Veterinary Medical Teaching Hospital. Arabians were overrepresented in the uterine prolapse group (7/24 [29%]), compared with all mares treated (4,174/44,474 [9%]). Uterine prolapse occurred within 2 hours after parturition for 10 of 11 mares with known foaling times, after dystocia for 7 mares, and after abortion for 4 mares. Seventeen of 23 (74%) mares survived to hospital discharge. Acute hemorrhage was the most frequent cause of death. There were no correlations between mare survival to hospital discharge and mare parity or age, foal sex, retained fetal membranes, sepsis, or maiden status. Colts were overrepresented in foals with a known sex (12/17). CLINICAL RELEVANCE: Results indicated a breed predisposition to uterine prolapse, with Arabian mares overrepresented among affected mares. No characteristics correlated with mare survival to hospital discharge.

Effects from disruption of mitochondrial electron transport chain function on bull sperm motility.

Sperm mitochondrial function is essential for normal physiology and fertility, but the importance of mitochondrial activity to support specific sperm functions, such as motility, varies between species. It was previously believed that mitochondrial function was not necessary for bull sperm motility [1]; however, this theory is contradicted by recently reported findings that the upper fraction of bull sperm swim-up preparations had both high motility and elevated mitochondrial oxygen consumption rates [2]. The objective of this study was to investigate the relationship between mitochondrial function and motility in bull sperm. We hypothesized that sperm motility would be positively correlated with mitochondrial oxygen consumption (MITOX) but unaffected by pharmacological inhibition of electron transport chain (ETC) activity. This was accomplished by monitoring both mitochondrial oxygen consumption and motility parameters in the presence of mitochondrial effector drug treatments. Duplicate ejaculates were collected by electroejaculation from Black Angus bulls (n = 4). Oxygen consumption, as % air saturation (pO2; oxygen partial pressure), over time was monitored in the presence of 5 drug treatments: vehicle control, FCCP, Antimycin (ANTI), Oligomycin (Oligo), and FCCP + Oligomycin (FCCP + OLIGO). Duplicate aliquots were prepared for concurrent motility assessment by computer-assisted sperm analysis (CASA) at 6 and 30 min post-treatment (t6 and t30). The impact of treatments on pO2 (in % air saturation) over time were assessed by generalized linear mixed effects modeling (GLMM) which was also used to test for differences in average motility across treatment conditions and time points (t6 and t30). Pearson product-moment correlation was used to investigate relationships between oxygen consumption and motility parameters. Overall, pO2 differed over time between treatment conditions (p < 0.0001). When compared to the vehicle treatment, ANTI and OLIGO significantly inhibited oxygen consumption (p < 0.05, adjusted), and FCCP stimulated a marked increase in oxygen consumption. No significant differences in motility over time were observed between treatments, so comparison of motility parameters between treatment conditions was performed with pooled timepoints. Motility parameters were only observed to differ significantly from the vehicle with ANTI Treatment, for which significant decreases in numerous parameters, including total motility (p = 0.007), progressive motility (p = 0.01), DAP (p = 0.01), VAP (p = 0.01) and VSL (p = 0.02) were identified. For the vehicle treatment, correlational analysis did not reveal any significant correlations between pO2 and any motility parameters at t6; however, several significant correlations were identified at t30. Mean pO2 was negatively correlated with local motility (p < 0.01) and positively correlated with DCL, DAP, and VCL (p < 0.05). Results from this study suggest that bovine sperm motility is impacted by mitochondrial functionality, with ETC inhibition by ANTI causing significant reduction in motility parameters. This study also demonstrates the use of a new technology for the assessment of bovine sperm mitochondrial function. This modality for evaluation of bull sperm mitochondrial function will inform future efforts to understand bull sperm function and fertility and aid investigations into toxicological agents.