Determination of ovarian cyclicity and pregnancy using fecal progesterone in forest musk deer (Moschus berezovskii)

Abstract

The forest musk deer (FMD, Moschus berezovskii) is a threatened species in China. Although crucial for its artificial breeding management and thus protection, to date, gonadal steroidogenic activity data are unavailable in this species. Thus, the objectives of the present study were to characterize ovarian activity throughout the estrous cycle, non-pregnant luteal phase, and gestation in female FMD. These goals were accomplished using an enzyme immunoassay to measure fecal concentrations of estradiol (E2) and progesterone. Fecal samples were collected from female FMD (aged 3–4 years) for one year, including during breeding and non-breeding seasons. Non-pregnant estrous cycles were recorded in females, based on fecal progesterone concentrations, their overall estrous cycle length was (mean±SEM) 24.3±0.5 days, with 21.6±0.5 days in the luteal phase and 2.7±0.3 days in the inter-luteal phase. Fecal progesterone and E2 concentrations were also measured in females that became pregnant and gave birth after gestating approximately 6 months. Two weeks after becoming pregnant, the average fecal progesterone concentration was significantly greater than that during non-pregnancy. The average fecal progesterone concentrations during pregnancy increased 3.2-fold above non-pregnant concentrations, decreasing to non-pregnant concentrations only after parturition. By contrast, average fecal E2 concentrations during gestation and after parturition were not different from average non-pregnant concentration. In addition, no difference was observed between progesterone concentration in the first month after pregnancy and the value during the luteal phase. However, progesterone concentration during the second month of pregnancy was significantly higher than the value during the luteal phase. In conclusion, monitoring fecal progesterone is an effective method for assessing ovarian function in FMD and will be a useful tool for breeding management and development of assisted reproductive techniques, such as artificial insemination, in this species.