Effect of equine transvaginal follicle aspiration on serum concentrations of acute phase proteins and their utility in diagnosis of ovarian abscess

Transvaginal ultrasound-guided follicle aspiration (TVA) is being performed frequently in equine practice, to recover oocytes for in vitro embryo production via intracytoplasmic sperm injection. While complications from TVA are rare, one of the most prevalent major complications is formation of an ovarian abscess, which can result in the necessity for euthanasia. The acute-phase serum proteins, fibrinogen and serum amyloid A (SAA), are markers of inflammation that might be of use in diagnosis of ovarian abscess. However, no information is available on the effect of standard TVA on these acute phase proteins. We evaluated serum fibrinogen and SAA concentrations in mares (n = 8 and 6, respectively) immediately before and on Days 3, 7 and 14 after performance of TVA. Serum amyloid A levels were at baseline on all days. There was no significant difference in mean serum fibrinogen concentrations between D0 and any day after TVA. There was no significant difference in fibrinogen levels between mares that had undergone repeated TVA and a separate group of mares (n = 14) that had never been subjected to TVA. We then describe four cases of mares that had undergone TVA and subsequently presented with signs associated with possible ovarian abscess, in which serum fibrinogen aided in interpretation. We conclude that fibrinogen and SAA are not elevated in mares undergoing TVA, and thus, elevations in mares following TVA should be investigated further and may support early diagnosis of an ovarian abscess.