Oestrous cycle of the common wombat, Vombatus ursinus, in Victoria, Australia

Abstract

Wild-caught female common wombats from Victoria, Australia, were studied in captivity to investigate the oestrous cycle by assessing vaginal cytology and peripheral plasma progesterone concentrations. Eight wombats, five adults (21–29 kg) and three subadults (19–23 kg), which were held for between 2 weeks and 11 months did not cycle in captivity. Their progesterone concentrations were consistently low (≤6.9 nmol L–1) and vaginal smears contained predominantly superficial epithelial cells. Three wombats (21–27 kg), held in captivity for >1 year, regularly cycled (when bodyweights exceeded 23.5 kg). Information gathered from four consecutive cycles in each of these three wombats revealed a follicular phase with low progesterone concentrations (≤6.9 nmol L–1) and vaginal smears with a high percentage of superficial epithelial cells alternating with periods of high progesterone concentrations (range 41.6–123.8 nmol L–1) and smears in which parabasal–intermediate epithelial cells predominated. The average length of the monitored oestrous cycles was 47.2 days (35–60 days). The follicular phase lasted ~19 days and the luteal phase lasted ~28 days. In conclusion, wombats can cycle regularly in captivity even under conditions of intensive monitoring.