124 Effect of transvaginal oocyte aspiration on equine blood and peritoneal fluid parameters
Authors: Orellana-Guerrero D. , Santos-Villanueva E. , Koshak S. , De La Fuente A. , Dujovne G. 
Published: January 2021

Transvaginal aspiration of oocytes (TVA) in the equine industry has gained more relevance and become a valuable technique to produce offspring from subfertile mares. TVA is a semi-invasive procedure and requires handling the ovaries transrectally to position them closely to an ultrasound probe located in the mare’s vagina. Once the ovary lies in close apposition to the ultrasound probe, a 12G needle is inserted through the needle guide, puncturing, aspirating, and scraping each follicle to recover the oocyte. Potential complications described include rectal tears, puncturing of blood vessels, ovarian abscesses, and peritonitis. Occasionally, problems occur after uneventful procedures, such as colic, peritonitis, pain, and anorexia. However, the source of these complications is not fully known. We hypothesize that blood and peritoneal fluid parameters would differ pre- and post-TVA in mares. A few reports provide some parameters after TVA (e.g. peritoneal protein, neutrophils, nucleated cells) without reference to pre-TVA values. These studies have not identified an effect in peritoneal fluid variables due to multiple abdominocenteses. Therefore, our aim was to analyse blood and peritoneal fluid in mares pre- and post-TVA, and to identify changes in parameters of the procedure (duration, number of pokes, number of follicles) and the mares’ clinical responses. Ten healthy mares were selected to undergo the procedure. Thirty minutes before starting TVA, a blood sample was drawn for complete blood count (CBC) and blood chemistry, and abdominocentesis was performed to obtain abdominal fluid and assess the cytology. This same protocol was repeated 24 hours after TVA. Physical exams were performed pre- and post-TVA. Paired t-tests were used to identify differences between groups (pre- and post-TVA). Spearman correlations (ρ) were used to assess the relationship between variables. There was a significant increase in peritoneal lactate (5.65-fold), peritoneal total protein (2.4-fold), and total nucleated cells (46-fold) between pre- and post-samples. These parameters were not associated with operator, number of times the needle was introduced into the ovaries, or number of aspirated follicles. The remaining parameters evaluated in CBC and blood chemistry did not differ. A positive correlation between total peritoneal protein and blood albumin was found post-TVA (ρ=0.72, P=0.01) but not pre-TVA (ρ=−0.1, P=0.65), suggesting an increase in protein level due to bleeding. Clinically, 9 mares were healthy throughout the study except one that presented signs of pain (facial grimace, anorexia, hyperthermia) the day following TVA. In conclusion, we showed changes in the peritoneal fluid during uneventful TVA procedures. The information provided by this research gives further insight into changes potentially caused by a TVA in abdominal fluid parameters. Further studies are necessary to determine expected standards and the duration of the changes after TVA.