The effects of breeding season (late spring to early autumn) on south-east Queensland male koala fertility were examined to improve the efficacy of the AI procedure and to determine the practicality of using free-range animals as semen donors for a genome resource bank. Seasonal changes in male koala reproductive function were assessed in a wild free-range population (n = 14; obtained every 6 weeks from January to November 2005), a necropsied healthy wild population (n = 84; obtained monthly from September 2004 to August 2005) and a captive population (n = 7; obtained monthly from October 2005 to October 2006). Reproductive parameters investigated included bodyweight, coat score, sternal gland area and activity, testosterone secretion, reproductive anatomy volume and semen quality (before and after cryopreservation). Collectively, these findings show that reproduction in male koalas from south-east Queensland changes seasonally and that winter appears to be the optimal season in which to collect semen samples by electroejaculation. While it was possible to repeatedly collect semen from free-range koalas for future genetic management via potential storage in a genome resource bank, the survival of these spermatozoa after cryopreservation was poor and will require further improvement.
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http://dx.doi.org/10.1071/RD09113 | DOI Listing |
Sci Rep
December 2024
Sydney School of Veterinary Science, University of Sydney, Camperdown, NSW, 2006, Australia.
Chlamydiosis is a common infectious disease impacting koalas and is a major cause of population decline due to resulting mortality and infertility. Polymorphisms of major histocompatibility complex (MHC) genes influence chlamydial disease outcomes in several species but koala studies have produced variable results. We aimed to identify the MHC II DAB and DBB repertoire of koalas from Liverpool Plains, NSW, a population heavily impacted by chlamydiosis.
View Article and Find Full Text PDFPLoS One
December 2024
Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales, Australia.
Chlamydiosis is the major infectious disease responsible for significant morbidity and mortality in free-living koalas. Recently, it was reported that 28.5% of koalas infected with chlamydiosis were presented with no overt clinical signs.
View Article and Find Full Text PDFFront Cell Infect Microbiol
November 2024
School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia.
Introduction: This study employs bulk RNA sequencing, PCR, and ELISA assays to analyze the pathological factors affecting the outcomes of ocular infections in koalas. It investigates the immune responses and gene expression profiles associated with various stages of koala ocular chlamydiosis.
Methods: A cohort of 114 koalas from Queensland, Australia were assessed, with 47% displaying clinical signs of ocular disease.
J Atten Disord
January 2025
Department of Epidemiology, Maastricht University Medical Centre+, Care and Public Health Research Institute, Maastricht, The Netherlands.
Objectives: This study investigates the association between dietary intake and ADHD diagnosis and its dimensions in adolescents.
Methods: In the KOALA Birth Cohort Study, 810 adolescents aged 16 to 20 years provided information on ADHD diagnosis and completed a food frequency questionnaire. Dietary patterns were extracted using Principal Component Analysis.
BMC Vet Res
October 2024
Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, 890-0065, Japan.
Background: Koala retrovirus (KoRV), a major pathogen of koalas, exists in both endogenous (KoRV-A) and exogenous forms (KoRV-A to I and K to M) and causes multiple disease phenotypes, including carcinomas and immunosuppression. However, the direct association between the different KoRV subtypes and carcinogenesis remains unknown. Differentially expressed gene (DEG) analysis of peripheral blood mononuclear cells (PBMCs) of koalas carrying both endogenous (KoRV-A) and exogenous (KoRV-A, B, and C) subtypes was performed using a high-throughput RNA-seq approach.
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