Effect of Transvaginal Aspiration of Oocytes on Blood And Peritoneal Fluid Parameters in Mares

Transvaginal aspiration of oocytes (TVA) is a commonly used clinical procedure to obtain oocytes for in vitro production of embryos in horses. The goal of this study was to evaluate the effect of the TVA procedure on blood and peritoneal parameters, and to investigate the association of these findings with variables such as use of antibiotics, number of ovarian punctures, and length of the procedure. Physical examination was performed and blood and peritoneal fluid were obtained from 14 mares before they underwent TVA and the same parameters were assessed 24 hours after the procedure. On examination, 13/14 mares remained clinically healthy after the procedure. One mare developed low-grade fever, transient anorexia and mild colic that resolved within 12 hours post-TVA. The use of antibiotics, length of procedure and number of ovarian punctures did not have an effect on the measured parameters. All the mares presented significant changes in the leukogram, but these mostly remained within normal reference range values. The peritoneal parameters were also consistently affected after TVA. A significant post-TVA increase in lactate, total protein, and peritoneal neutrophil count was observed in peritoneal fluid. Peritoneal lactate level was elevated above baseline physiological levels in more than 50% of the mares. Results from this study indicate that there is an expected degree of inflammation after TVA procedures and peritoneal fluid parameters could be successfully used to monitor inflammation in the early stages.