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

Abstract

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♂:2♀) 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-17β 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 0.2 mg/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-17β 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-17β 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.