“UNITED WE STAND”: COMBINING REPRODUCTIVE TRACT ULTRASONOGRAPHY AND VAGINAL CYTOLOGY TO DETERMINE OVARIAN CYCLE STAGE IN WILD FELIDS.

Abstract

BACKGROUND-AIM Despite current conservation efforts, most non-domestic felids are threatened with extinction. Reproduction is key to species survival. However, many wild and captive felids reproduce poorly. Thus, a deeper understanding of their reproductive physiology is needed to implementing assisted reproduction (ART) into these species conservation. This study aimed to compare vaginal cytology and female reproductive tract ultrasonography (US) in six species of captive non-domestic felids (Panthera leo, n=20; P. pardus kotiya, n=1; P. pardus tulliana, n=1; P. uncia, n=1; Catopuma temminckii, n=6; Neofelis nebulosa, n=1; and Acinonyx jubatus, n=1) for assessing the reproductive cycle. METHODS Transrectal US and vaginal smears were performed during routine anesthetic procedures over a period of three years. The ovarian cycle stage was determined separately by assessing the presence and size of ovarian follicles and corpora lutea (CL), and the percentage of cornified vaginal epithelial cells. Where possible, samples from the same animal were then compared and the ovarian cycle stage corrected when necessary. RESULTS Assessed US and cytologies revealed many commonalities between species. Overall, pro-estrus was characterized by small ovarian follicles and 60-90% cornification, while big follicles and >90% cornification were observed in estrus. Females in diestrus presented CL and 10-60% cornification. Quiescence ovaries and <10% cornification were detected in anestrus. Transrectal US proved to be a finer tool, enabling determination of the cycle stage in 71% of the animals assessed, compared to the 67.7% predicted with vaginal cytology alone. The combination of both techniques allowed a more accurate cycle stage prediction (87.1%). This was supported by a positive correlation between the size of the biggest follicle and percentage of epithelial cornification in P. leo (n=8; r=.76; p=0.030), and Catopuma temminckii (n=5; r=.89; p=0.042). CONCLUSIONS Besides being practical tools to routinely assess the reproductive cycle, these two techniques in combination may also be used for further research into the normal reproductive cycle of wild felids, which may be used to improve ART success rates, and in turn the conservation breeding programs of these endangered species.