Non-invasive methods of oestrus detection in captive southern hairy-nosed wombats (Lasiorhinus latifrons).

In order to develop a reliable method of oestrus detection in captive southern hairy-nosed (SHN) wombats, the reproductive behaviour of four groups of adult animals (1 male:2 female) was monitored using video surveillance and activity using movement-sensitive radio transmitters for a period of 12 months. During this time faecal samples were collected every 3 days and subsequently analysed for progesterone and oestradiol-17beta metabolites. In an attempt to induce and characterise oestrus-specific behaviour, each female was administered a subcutaneous injection of either 0.01 (n=2), 0.1 (n=4) or 0.2mg/kg (n=2) of oestradiol benzoate in one of two hormone trials. Remote video surveillance was an effective tool for detecting the reproductive behaviour of the captive SHN wombat. Courtship (n=426) and mating (n=46) was observed in five wombats and consisted of 13 distinctive behaviours in six consecutive phases: (1) investigation, (2) attraction, (3) chase, (4) restraint, (5) copulation and (6) recovery. Female sexual receptivity occurred at night and lasted for approximately only 13-h. Faecal progesterone metabolite analysis proved to be a reliable method for mapping oestrous cycle activity, but was not useful for the prediction of oestrus. Six out of the eight female wombats displayed periods of elevated progesterone secretion, corresponding to a mean (+/-SE) luteal phase of 20.9+/-1.1 days (n=23). Oestrous cycle length, defined as the interval between two successive luteal phases separated by a follicular phase was 31.8+/-1.1 days (n=12) and consisted of a follicular phase of 11.6+/-0.6 days (n=12). Changes in the secretion of faecal oestradiol-17beta metabolites provided little instructive information on oestrous cycle activity and were not associated with oestrus. Administration of oestradiol benzoate resulted in a spike of oestradiol-17beta metabolites in the faeces 3-4 days later, but was not dose dependent nor did it facilitate reproductive behaviour in either sex. Activity was not linked to key events in the oestrous cycle and appears not to be suitable as a method for detecting oestrus in the SHN wombat. We therefore recommend the use of 24-h video surveillance as the most reliable method for oestrus detection in captive SHN wombats.

Monitoring male southern hairy-nosed wombat (Lasiorhinus latifrons) reproductive function and seasonality in a captive population.

This study reports on the development and application of techniques used to assess the reproductive status of captive male southern hairy-nosed wombats (n=4) at Rockhampton Zoo. Initially, a GnRH agonist was used to establish a method for determining a reliable index of plasma and faecal testosterone secretion. Intra-muscular injection of buserelin (4 microg) resulted in an increase (P<0.05) in plasma and faecal testosterone concentration 90 min and 3 days after administration, respectively. Seasonal changes in faecal androgen, sperm production (spermatorrhoea) and testicular, prostatic and bulbourethral gland size were examined over a 18-month period, with prostate and bulbourethral gland cross-sectional areas being assessed by ultrasonography. Plasma testosterone secretion increased from early late winter and then decreased in spring (P<0.001); no seasonal variation (P=0.22) in faecal testosterone metabolite concentrations was apparent. Testicular volume showed no significant variation (P=0.29) over the sampling period. While there was no seasonal change (P=0.197, n=54) in prostate size, bulbourethral gland size increased in late-autumn, peaked in mid-winter and declined in early summer (P= or <0.001, n=55). Spermatozoa were found in the urine throughout the year. While, the captive population of SHN wombats at Rockhampton Zoo demonstrated significant changes in reproductive function, the extent of seasonality was less pronounced than that previously reported for wild populations in Southern Australia.