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.

Leader of the pack: faecal pellet deposition order impacts PCR amplification in wombats.

DNA sourced from faeces is notoriously less reliable than that from tissue. Hence, understanding whether faecal pellet quality varies within faecal piles may be important for sample selection. We hypothesized that the order in which faecal pellets are deposited may influence microsatellite polymerase chain reaction (PCR) amplification success from sampled faeces, more specifically, that first pellets deposited will have signatures of greater success than later ones. In a first test of the hypothesis, first and later-deposited pellets, as determined from the direction of footprints, were collected from fresh (overnight) faecal piles of northern hairy-nosed wombats (Lasiorhinus krefftii). DNA extracts were typed for seven microsatellite loci. We found that faecal deposition order significantly affected optical density of bands on autoradiographs (a measure of PCR amplification success) when the first faecal pellet was compared with the last one, but not when the first pellet was only distinguishable from later ones. The absence of a difference in amplification rate between first and later pellets is likely a reflection of the overall high amplification success in this study. That first pellets deposited yield more product suggests they contain more intestinal cells. Although further comparisons are needed, these results may inform sample selection in species for which success of microsatellite PCR amplification of faecal DNA is low. Deposition order may have more of an impact on amplification success and genotyping errors as faecal age increases.

Combination of zolazepam and tiletamine as a sedative and anaesthetic for wombats.

OBJECTIVE: To assess the suitability of the combination of zolazepam and tiletamine for routine use as chemical restraint, sedative and anaesthetic in wild wombats. ANIMALS: Sixty common wombats, 25 southern hairy-nosed wombats and 40 northern hairy-nosed wombats. PROCEDURE: Wombats caught in cage-traps in the wild were given injections of the anaesthetic combination either intramuscularly or intraperitoneally. Anaesthesia was maintained for up to 4 h in some cases, and for 12 h in one case. All wombats were released after anaesthesia. RESULTS AND CONCLUSION: This drug combination is effective and apparently safe for the sedation or light anaesthesia of wombats. We did not observe adverse reactions or deaths and the dose range used (4 to 15 mg/kg) demonstrates a wide safety margin. The use of this anaesthetic combination was effective in reducing the stress to wombats from capture and handling.

Relatedness structure detected by microsatellite analysis and attempted pedigree reconstruction in an endangered marsupial, the northern hairy-nosed wombat Lasiorhinus krefftii.

The northern hairy-nosed (NHN) wombat is perhaps Australia's most endangered mammal. Being fossorial and nocturnal as well as rare, NHN wombats are difficult to observe in the wild. Hence little is known of their social biology, such as their mating and dispersal systems. A hypothesis has been advanced that adult females of the species disperse post-breeding, leaving their young to inhabit the natal burrow. Female-biased dispersal is expected to result in higher relatedness amongst males in a burrow cluster than amongst females in a burrow cluster. The usefulness of a panel of microsatellite markers in estimating the relatedness structure, and in reconstructing pedigrees for, the sole known population of NHN wombats was assessed. Microsatellite genotypes at eight or nine loci were obtained from 58 of the 85 known individuals, and used to estimate pairwise individual relatedness using Queller & Goodnight's (1989) RELATEDNESS 4.2. Our analysis gave the unexpected result that both males and females were significantly more closely related to their same-sex burrow cluster mates than random, while opposite-sex animals sharing burrows were only slightly (nonsignificantly) more related than random. This raises the possibility of dispersal patterns which lead to association of same-sex relatives. The observed relatedness structure is not expected to make likely a high incidence of inbred matings, as close relatives of the opposite sex are not significantly associated in space. Parentage analysis was attempted using genetic exclusion and LOD likelihood ratios, but proved difficult because of low genetic variation, incomplete sampling of potential parents, and paucity of ecological data such as known mother/offspring pairs and ages of individuals.