Minimally Invasive Monitoring of the Estrous Cycle Based on Changes in Plasma Progesterone Concentration and Vaginal Cytology in a Captive Female Lion (Panthera leo)

Abstract

　We measured the plasma progesterone concentration, and examined changes in the vaginal smear and secretion of genital mucus in a female Lion (Panthera leo) by behavioral restraint using husbandry training. Plasma progesterone concentrations and the cytology of the vaginal smear demonstrated cyclic changes. When anuclear superficial cells were dominant in the vaginal smear, the plasma progesterone concentration was almost at the basal level and a large amount of genital mucus was observed. Duration of estrous cycle, proestrus, estrus, and metestrus to diestrus of Lion were assumed to be 52.6±5.0, 8.3±1.5, 6.2±2.7, and 37.2±4.6 days, respectively.