Oocyte production from naive- and chronically-aspirated mares

摘要

One of the limiting factors using the transvaginal ultrasound-guided aspiration (TUGA) technique is the ability to recover the oocyte from the follicle of the mare. To induce oocyte maturation and improve recovery rates, exogenous hCG is often used to induce the ovulatory process, with aspiration occurring 24-36 h post-hCG administration, prior to ovulation. However, consideration must be given to the number of times a mare is subjected to this procedure, both within a season and over a period of years. Because hCG is a foreign glycoprotein hormone, administration will stimulate the production of antibodies. In the early 1970s, Sullivan et al. [1] proposed that antibody production was responsible for the detrimental effect of repeated hCG administration on ovulation. Subsequent studies have noted a similar reduction in the response of hCG to induce ovulation [2,3], with antibody half-life ranging from 30 days to several months in duration [2]. Furthermore, Duchamp et al. [4] have reported that mares immunized against hCG failed to ovulate within a prescribed time after hCG administration. Limited data are available on the effect of repeated hCG administration on oocyte recovery rates using the TUGA technique. In addition, the effect of repeatedly puncturing the ovary using this technique remains unknown. A retrospective evaluation of oocyte aspiration records from a single season was performed to determine the effect of repeated hCG administration and TUGA procedures on oocyte recovery rates.