Summary. An oestrous cycle length of 33 days (N = 4, range 32–34) was obtained for the common wombat from a number of parameters including vaginal smears, vaginal biopsies, changes in pouch morphology and behavioural observation. All but one of the successive periods of oestrus occurred during winter. Hourly measurements of body temperature by telemetry showed a rhythm typical of nocturnal species. Superimposed on this diurnal rhythm was another rhythm which could be correlated with the oestrous cycle.
D. G. Peters and R. W. Rose
S. L. Bryant and R. W. Rose
Summary. The growth cycle of the corpus luteum (CL) of the potoroo is similar to that of other macropodids. During delayed gestation, the post-partum CL remains quiescent until it is reactivated by removal of the sucking pouch young. The CL then undergoes a period of growth, rapid from Day 6 until Day 12, followed by a gradual decline from Day 21 to Day 27.
Excision of the CL before Day 6 of pregnancy either inhibited embryonic development or failed to support it. Excision of the CL between 6 and 21 days after removal of pouch young did not prevent embryos developing to full term but interfered with parturition. Excision on Day 25 after removal of pouch young allowed birth but impaired lactation, neonates dying within 2 days. By Day 27, the CL appeared to be no longer essential for embryonic development, birth or neonate survival. It is suggested that the CL of the potoroo is required for a slightly greater proportion of pregnancy than in most larger kangaroos because the birth canal must be prepared before each parturition.
R. W. Rose and S. M. Jones
Basal body temperature, quantitative changes in vaginal smears and plasma concentrations of progesterone were measured during a number of oestrous cycles in Tasmanian bettongs (Bettongia gaimardi). These methods of monitoring the reproductive cycle were compared in an attempt to find a technique that allowed non-stressful assessment of the reproductive condition of the bettongs. Telemetric measurement of basal body temperature showed that there was a diurnal variation of 1.3°C, typical of a nocturnal animal. During the oestrous cycle, there was a small, but not significant, peak in basal body temperature at oestrus (day 0) followed by a significant trough on day 2. There was a significant increase on day 3 and the temperature remained raised until day 10, during which time plasma progesterone concentrations are also high; the temperature then fell 2 days before oestrus. This fall corresponds to a decrease in concentration of plasma progesterone and in the numbers of leucocytes in vaginal smears. Telemetric measurement of body temperature may be useful as a non-stressful method of monitoring the oestrous cycle in bettongs.