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Murray Logan - One of the best experts on this subject based on the ideXlab platform.

  • The effect of tooth wear on the feeding behaviour of free‐ranging koalas (Phascolarctos cinereus, Goldfuss)
    Journal of Zoology, 2006
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging feeding behaviours of five adult koalas Phascolarctos cinereus with varying degrees of tooth wear were investigated using acoustically sensitive radio telemetry. An increase in tooth wear was found to be associated with a significant increase in the average amount of time spent feeding, average number of leaves consumed and the average number of daily chews. This suggests that koalas compensate for tooth wear by increasing food intake. Furthermore, there was a significant increase in the average number of chews per leaf and average chew rate, suggesting a greater investment in processing each leaf.

  • the effect of tooth wear on the feeding behaviour of free ranging koalas Phascolarctos cinereus goldfuss
    Journal of Zoology, 2006
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging feeding behaviours of five adult koalas Phascolarctos cinereus with varying degrees of tooth wear were investigated using acoustically sensitive radio telemetry. An increase in tooth wear was found to be associated with a significant increase in the average amount of time spent feeding, average number of leaves consumed and the average number of daily chews. This suggests that koalas compensate for tooth wear by increasing food intake. Furthermore, there was a significant increase in the average number of chews per leaf and average chew rate, suggesting a greater investment in processing each leaf.

  • EFFECT OF TOOTH WEAR ON THE RUMINATION-LIKE BEHAVIOR, OR MERYCISM, OF FREE-RANGING KOALAS (Phascolarctos cinereus)
    Journal of Mammalogy, 2003
    Co-Authors: Murray Logan
    Abstract:

    Rumination-like behavior, or merycism, of 5 adult male koalas (Phascolarctos cinereus) with various degrees of tooth wear was investigated using acoustically sensitive radio telemetry. Increased tooth wear was associated with a significant increase in mean rate of merycism mastication, mean number of merycism mastications per bout per 24 h, and mean number of mastications per 24 h. The ratio of mean number of ingestive mastications to mean number of merycism mastications per 24 h remained approximately 17:1 with increasing tooth wear. These results suggest that in contrast to true rumination, alterations in merycism behavior may be important in compensating for reduced molar effectiveness.

  • the effects of tooth wear on the activity patterns of free ranging koalas Phascolarctos cinereus goldfuss
    Australian Journal of Zoology, 2002
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging activity patterns of five adult males and one sub-adult male koala (Phascolarctos cinereus) with varying degrees of tooth wear were investigated using acoustically sensitive radio-telemetry. Increased tooth wear was found to be associated with a significant decrease in the amount of time spent sleeping and being inactive. Furthermore, compared with individuals with low degrees of tooth wear, individuals with high tooth wear were found to spend considerably less time moving within and between trees, and had home ranges an order of magnitude smaller. Hence, feeding compensations were found to come at the expense of other activities such as sociality and therefore have important consequences for reproductive output. Individuals with high tooth wear also spent longer feeding per bout, and spaced feeding bouts out more evenly throughout a 24-h period, thereby exhibiting reduced degrees of nocturnality. The sub-adult was found to range over a disproportionately large area and spend a relatively large amount of time moving between trees, indicative of a dispersing individual. Moreover, the activity patterns of this individual were found to differ slightly from the adult trends and were perhaps affected by the extra energetic demands associated with dispersal.

  • The association of tooth wear with sociality of free-ranging male koalas (Phascolarctos cinereus Goldfuss)
    Australian Journal of Zoology, 2002
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The sociality (as measured by the degree of bellowing and amount of tree use) of five adult male koalas and one sub-adult male koala (Phascolarctos cinereus), with varying degrees of tooth wear, were investigated using acoustically sensitive radio-telemetry. Initial increases in tooth wear that coincide with an increase in age to maturity were associated with an increase in reproductive effort. Advanced tooth wear was found to be associated with a decrease in reproductive effort. This trend in reproductive effort is consistent with life-history predictions, and suggests that tooth wear has the potential to impose limitations on the reproductive longevity and fecundity of free-ranging male koalas.

Peter Timms - One of the best experts on this subject based on the ideXlab platform.

Gordon Drummond Sanson - One of the best experts on this subject based on the ideXlab platform.

  • the effect of tooth wear on the feeding behaviour of free ranging koalas Phascolarctos cinereus goldfuss
    Journal of Zoology, 2006
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging feeding behaviours of five adult koalas Phascolarctos cinereus with varying degrees of tooth wear were investigated using acoustically sensitive radio telemetry. An increase in tooth wear was found to be associated with a significant increase in the average amount of time spent feeding, average number of leaves consumed and the average number of daily chews. This suggests that koalas compensate for tooth wear by increasing food intake. Furthermore, there was a significant increase in the average number of chews per leaf and average chew rate, suggesting a greater investment in processing each leaf.

  • The effect of tooth wear on the feeding behaviour of free‐ranging koalas (Phascolarctos cinereus, Goldfuss)
    Journal of Zoology, 2006
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging feeding behaviours of five adult koalas Phascolarctos cinereus with varying degrees of tooth wear were investigated using acoustically sensitive radio telemetry. An increase in tooth wear was found to be associated with a significant increase in the average amount of time spent feeding, average number of leaves consumed and the average number of daily chews. This suggests that koalas compensate for tooth wear by increasing food intake. Furthermore, there was a significant increase in the average number of chews per leaf and average chew rate, suggesting a greater investment in processing each leaf.

  • the effects of tooth wear on the activity patterns of free ranging koalas Phascolarctos cinereus goldfuss
    Australian Journal of Zoology, 2002
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The free-ranging activity patterns of five adult males and one sub-adult male koala (Phascolarctos cinereus) with varying degrees of tooth wear were investigated using acoustically sensitive radio-telemetry. Increased tooth wear was found to be associated with a significant decrease in the amount of time spent sleeping and being inactive. Furthermore, compared with individuals with low degrees of tooth wear, individuals with high tooth wear were found to spend considerably less time moving within and between trees, and had home ranges an order of magnitude smaller. Hence, feeding compensations were found to come at the expense of other activities such as sociality and therefore have important consequences for reproductive output. Individuals with high tooth wear also spent longer feeding per bout, and spaced feeding bouts out more evenly throughout a 24-h period, thereby exhibiting reduced degrees of nocturnality. The sub-adult was found to range over a disproportionately large area and spend a relatively large amount of time moving between trees, indicative of a dispersing individual. Moreover, the activity patterns of this individual were found to differ slightly from the adult trends and were perhaps affected by the extra energetic demands associated with dispersal.

  • The association of tooth wear with sociality of free-ranging male koalas (Phascolarctos cinereus Goldfuss)
    Australian Journal of Zoology, 2002
    Co-Authors: Murray Logan, Gordon Drummond Sanson
    Abstract:

    The sociality (as measured by the degree of bellowing and amount of tree use) of five adult male koalas and one sub-adult male koala (Phascolarctos cinereus), with varying degrees of tooth wear, were investigated using acoustically sensitive radio-telemetry. Initial increases in tooth wear that coincide with an increase in age to maturity were associated with an increase in reproductive effort. Advanced tooth wear was found to be associated with a decrease in reproductive effort. This trend in reproductive effort is consistent with life-history predictions, and suggests that tooth wear has the potential to impose limitations on the reproductive longevity and fecundity of free-ranging male koalas.

Geoffrey W. Pye - One of the best experts on this subject based on the ideXlab platform.

  • STRECK CELL PRESERVATIVE STABILIZES KOALA (Phascolarctos cinereus) WHOLE BLOOD FOR COMPLETE BLOOD COUNTS
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2018
    Co-Authors: Christine M. Molter, Laura Keener, Kendal E. Harr, Mollie Zaback, Philip H. Kass, Geoffrey W. Pye
    Abstract:

    Abstract Wildlife health assessments at remote sites may lead to delayed testing of whole blood for complete blood counts (CBC) resulting in artifacts affecting clinical interpretation. Streck Cell Preservative (SCP) is a proprietary liquid stabilization reagent designed to preserve human leukocytes and may be applicable to wildlife health assessments when immediate processing of blood is not possible. The purpose of this study was to determine if SCP adequately preserved EDTA-anticoagulated whole blood from koalas (Phascolarctos cinereus) for up to 14 days. Blood from 12 captive adult koalas was collected and combined with SCP in a 1 : 1 ratio and refrigerated. Paired samples of SCP treated and untreated blood had CBCs performed at five time-points over 14 days. Streck Cell Preservative extended koala EDTA-anticoagulated whole blood viability to 14 days by decreasing cellular lysis. Species- and method-specific reference intervals for SCP should be generated to avoid clinical misinterpretation, especiall...

  • Retrovirus-related disease in zoo-based koalas (Phascolarctos cinereus) in North America
    Technical Reports of the Australian Museum Online, 2014
    Co-Authors: Geoffrey W. Pye, Hao Qiang Zheng, William M. Switzer
    Abstract:

    Koala retrovirus (KoRV)-related disease is a major suspected cause of death in koalas (Phascolarctos cinereus) in zoos in North America. There are currently eleven zoos exhibiting koalas in North America. A mortality survey of these institutions indicated that mortalities directly related to KoRV (e.g., lymphoma, leukemia, anemia, bone marrow hypoplasia, osteochondromatosis) and mortalities suspected to be KoRV-related (e.g., immunosuppression, unusual opportunistic infections (e.g., Coccidioidomycosis), potentially other neoplasia) account for 41% of deaths. Testing of the living North American koala population for a recently reported, exogenous koala retrovirus variant (KoRV-B) identified four KoRV-B-positive individuals in a population of 54 koalas (7.4%).

  • GASTROINTESTINAL TORSIONS AND INTUSSUSCEPTION IN NORTHERN KOALAS (Phascolarctos cinereus) AT SAN DIEGO ZOO (1976–2012)
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2014
    Co-Authors: Nicole M. Joyce-zuniga, Jennifer Roesler, Chris Hamlin Andrus, Meg Sutherland-smith, Bruce A. Rideout, Geoffrey W. Pye
    Abstract:

    Abstract: The recent classification as threatened status of the northern koala (Phascolarctos cinereus) by the Australian Government highlights the importance of the conservation and health management of this iconic Australian marsupial. This case series describes gastrointestinal torsion and intussusception in six northern koalas (three males, three females, 2–11 yr old) at the San Diego Zoo from 1976 to 2012. Two koalas died shortly after presentation. Diagnoses of ileocecal intussusception, resulting from enteritis in one case and cecal torsion in the other, were made at postmortem examination. One koala died 4 days after an exploratory laparotomy, with negative findings, and an acute double colonic intussusception was diagnosed at postmortem examination. Two small intestinal mesenteric torsion and one proximal colon mesenteric torsion cases were successfully corrected surgically. In the case of colonic mesenteric torsion, the koala had recurrent clinical signs 2 wk later, and a second surgery requirin...

  • FAT-SOLUBLE VITAMIN AND MINERAL COMPARISONS BETWEEN ZOO-BASED AND FREE-RANGING KOALAS (Phascolarctos cinereus)
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2013
    Co-Authors: Debra A. Schmidt, Geoffrey W. Pye, William Ellis, Chris C. Hamlin-andrus, Mark R. Ellersieck, Tai C. Chen, Michael F. Holick
    Abstract:

    Abstract: As part of a health investigation on koalas at San Diego Zoo, serum samples were analyzed from 18 free-ranging and 22 zoo-based koalas, Phascolarctos cinereus. Serum concentrations of calcium, chloride, cobalt, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc, and vitamins A, E, and 25(OH)D3 were quantified. Calcium, chloride, molybdenum, selenium, and vitamin E concentrations were significantly higher in zoo-based koalas than in free-ranging koalas, whereas magnesium, manganese, phosphorus, and zinc concentrations were significantly higher in the free-ranging koalas. No significant differences were found between genders. The results from this study will help to establish a starting point for determining target circulating nutrient concentrations in koalas.

  • SERUM VITAMIN D LEVELS IN FREE-RANGING KOALAS (Phascolarctos cinereus)
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2013
    Co-Authors: Geoffrey W. Pye, William Ellis, Sean Fitzgibbon, Brian Opitz, Laura Keener, Bruce W. Hollis
    Abstract:

    Abstract:  Dueto climatic conditions in Northern America and Europe, koalas (Phascolarctos cinereus) are often housed indoors. Koala joeys raised in these environments are susceptible to the development of metabolic bone disease due to a lack of exposure to solar ultraviolet radiation to themselves and their dam. As an initial step toward describing vitamin D sufficiency and adequately measuring responses to supplementation, vitamin D values were calculated by using serum collected from 20 free-ranging koalas on St. Bees Island, Queensland, Australia. Vitamin D values ranged from 8.1 to 30.4 pg/ml (18.4 ± 5.5 pg/ml) for 1, 25-hydroxyvitamin D, and from 1 to 14 nM/L (7.4 ± 3.0 nM/L) for 25-hydroxyvitamin D. These koala serum vitamin D values are unusually low when compared with eutherian mammals. Although this study was limited in numbers and in the geographically range of the koalas sampled, it does suggest that the koala's requirement for vitamin D is low. Therefore, supplementation to prevent disease ma...

Adam Polkinghorne - One of the best experts on this subject based on the ideXlab platform.

  • Treatment of Chlamydia-associated ocular disease via a recombinant protein based vaccine in the koala (Phascolarctos cinereus)
    Biologicals : journal of the International Association of Biological Standardization, 2016
    Co-Authors: Courtney A. Waugh, Adam Polkinghorne, Ray Austin, Peter Timms
    Abstract:

    Koalas (Phascolarctos cinereus) are affected by debilitating chlamydial disease that can lead to blindness, infertility, and death. The causative agent is the intracellular bacterium Chlamydia pecorum. While antibiotics can be used to treat koala chlamydial infection, they are often ineffective or cause severe dysbiosis to the animal's unique gut flora. Recent work has progressed on the development of a protective vaccine for Chlamydia in the koala. This study demonstrates that the use of a vaccine can have a positive effect in koalas already with clinical signs of ocular disease, suggesting a possible therapeutic effect and an alternative to antibiotic therapy.

  • Serum Antibody Response to Koala Retrovirus Antigens Varies in Free-Ranging Koalas (Phascolarctos cinereus) in Australia: Implications for Vaccine Design
    Journal of wildlife diseases, 2016
    Co-Authors: Courtney A. Waugh, Amber Gillett, Adam Polkinghorne, Peter Timms
    Abstract:

    Abstract Little is known about the immune response in the koala (Phascolarctos cinereus) to its retroviruses. Koala retroviruses (KoRVs) have been linked to neoplasia in wild and captive koalas, but there is no treatment available. We tested the KoRV-specific serum immunoglobulin G antibody response in nonimmunized and immunized koalas.

  • identification characterisation and expression analysis of natural killer receptor genes in chlamydia pecorum infected koalas Phascolarctos cinereus
    BMC Genomics, 2015
    Co-Authors: Katrina M Morris, Peter Timms, Adam Polkinghorne, Marina Mathew, Courtney Waugh, Beata Ujvari
    Abstract:

    Background Koalas (Phascolarctos cinereus), an iconic Australian marsupial, are being heavily impacted by the spread of Chlamydia pecorum, an obligate intracellular bacterial pathogen. Koalas vary in their response to this pathogen, with some showing no symptoms, while others suffer severe symptoms leading to infertility, blindness or death. Little is known about the pathology of this disease and the immune response against it in this host. Studies have demonstrated that natural killer (NK) cells, key components of the innate immune system, are involved in the immune response to chlamydial infections in humans. These cells can directly lyse cells infected by intracellular pathogens and their ability to recognise these infected cells is mediated through NK receptors on their surface. These are encoded in two regions of the genome, the leukocyte receptor complex (LRC) and the natural killer complex (NKC). These two families evolve rapidly and different repertoires of genes, which have evolved by gene duplication, are seen in different species.

  • Conjunctivitis associated with Chlamydia pecorum in three koalas (Phascolarctos cinereus) in the Mount Lofty Ranges, South Australia
    2013
    Co-Authors: Oliver Funnell, Lucy Woolford, Wayne Boardman, Lynley Johnson, Adam Polkinghorne, David J. Mclelland
    Abstract:

    Chlamydiosis is a significant factor contributing to the decline of koala (Phascolarctos cinereus) populations in Australia but has not previously been reported in South Australia. We describe conjunctivitis in three wild koalas from South Australia, with Chlamydia pecorum identified by quantitative PCR.

  • Investigation of the koala (Phascolarctos cinereus) hindgut microbiome via 16S pyrosequencing
    Veterinary Microbiology, 2013
    Co-Authors: Christopher J. Barker, Adam Polkinghorne, Amber Gillett, Peter Timms
    Abstract:

    As a dietary source, the foliage of Eucalyptus spp. is low in available protein and carbohydrate while containing polyphenolic compounds that interfere with enzymatic digestion. To overcome this, the koala (Phascolarctos cinereus) has evolved a range of anatomical and physiological adaptations to assist with digestion and absorption of nutrients from this food source. Microbial fermentation of partially digested eucalyptus leaves is thought to be critical in this process, however, little is known about the composition and diversity of microorganisms that are associated with digestive health in this native species. In this study, we performed 16S rRNA gene pyrosequencing of caecum, colon and faecal pellet samples from two wild, free ranging, Queensland koalas. Our results reveal a highly complex and diverse ecosystem with considerable intra-individual variation. Although samples were dominated by sequences from the Bacteroidetes and Firmicutes phyla there was considerable variation at the genus level. This study is the first non-culture based microbiota analysis, using 454-amplicon pyrosequencing, and provides preliminary data to expand our understanding of the koala hindgut.