Incidence and risk factors of heat-related illness in dogs from New South Wales, Australia (1997-2017).

Heat Related Illness (HRI) in dogs is expected to increase as heatwaves surge due to global warming. The most severe form of HRI, heat stroke, is potentially fatal in dogs. The current study investigated the incidence and risk factors for HRI in dogs in NSW, Australia, from 1997 to 2017. We identified 119 HRI cases during this period, with a fatality rate of 23%. Dog breeds at elevated risk of HRI were Australian Stumpy Tail Cattle Dog, British Bulldog, French Bulldog, Maremma Sheepdog, Italian Greyhound, Chow Chow, Airedale Terrier, Pug, Samoyed, English Springer Spaniel, Labrador Retriever, Golden Retriever, Cavalier King Charles Spaniel, Border Collie, Staffordshire Bull Terrier, and pooled non-Australian National Kennel Council breeds (which included the American and Australian Bulldog) when compared with cross breeds (i.e., the reference variable). As expected, HRI cases were more likely in December and January, during the Australian summer and during hotter years (e.g., 2016). There were no differences in the risk of HRI between males and females nor between desexed or un-desexed dogs; but older dogs were at increased risk of HRI. These findings underscore the need for data collection that will enable the incidence of HRI in dogs to be monitored and to better understand canine risk factors particularly as temperatures will continue to rise due to global warming. The risk of mortality from HRI underpins the need for education programs focussed on prevention and early identification of HRI so that owners present affected dogs to their veterinarian as promptly as possible.

Associations of body condition score with health conditions related to overweight and obesity in cats.

OBJECTIVES: To explore the associations of cat body condition score with various health conditions, such as diabetes mellitus, dermatological conditions and hypertension, that have been shown to relate to overweight and/or obesity in cats, dogs or humans. MATERIALS AND METHODS: Electronic patient records between January 3, 2005 and June 21, 2015 were obtained from a cat-focused primary accession clinic in metropolitan Sydney where the body condition score of cats was routinely evaluated. Binomial logistic regression modelling was conducted to investigate the associations, after adjusting for age, sex and breed, between 21 health conditions and body condition score recorded on a 9-point scale. RESULTS: Fourteen of the 21 health conditions examined showed significant associations with an increased body condition score, particularly those of 7 and above. These were dermatological conditions, atopic dermatitis, musculoskeletal conditions, arthritis, hypertension, respiratory conditions, asthma, oral conditions, diarrhoea, general and lower urinary tract conditions, ophthalmic conditions, diabetes mellitus and allergic conditions. Additionally, cats with body condition score of 8 or 9 had significantly higher odds for gastrointestinal conditions and upper urinary tract conditions when compared with cats with body condition score of 5. CLINICAL SIGNIFICANCE: As far as we know, this is the first study reporting positive associations of high body condition score with atopic dermatitis, hypertension, asthma, diarrhoea, ophthalmic conditions and allergic conditions in cats. A large number of positive associations between health conditions and high body condition score indicates that excess fat mass should be given a greater emphasis in preventive health care for cats.

Critical review of dog detection and the influences of physiology, training, and analytical methodologies.

Detection dogs serve a plethora of roles within modern society, and are relied upon to identify threats such as explosives and narcotics. Despite their importance, research and training regarding detection dogs has involved ambiguity. This is partially due to the fact that the assessment of effectiveness regarding detection dogs continues to be entrenched within a traditional, non-scientific understanding. Furthermore, the capabilities of detection dogs are also based on their olfactory physiology and training methodologies, both of which are hampered by knowledge gaps. Additionally, the future of detection dogs is strongly influenced by welfare and social implications. Most importantly however, is the emergence of progressively inexpensive and efficacious analytical methodologies including gas chromatography related techniques, "e-noses", and capillary electrophoresis. These analytical methodologies provide both an alternative and assistor for the detection dog industry, however the interrelationship between these two detection paradigms requires clarification. These factors, when considering their relative contributions, illustrate a need to address research gaps, formalise the detection dog industry and research process, as well as take into consideration analytical methodologies and their influence on the future status of detection dogs. This review offers an integrated assessment of the factors involved in order to determine the current and future status of detection dogs.

Gastric dilation-volvulus in dogs attending UK emergency-care veterinary practices: prevalence, risk factors and survival.

OBJECTIVE: To report prevalence, risk factors and clinical outcomes for presumptive gastric dilation-volvulus diagnosed among an emergency-care population of UK dogs. METHODS: The study used a cross-sectional design using emergency-care veterinary clinical records from the VetCompass Programme spanning September 1, 2012 to February 28, 2014 and risk factor analysis using multivariable logistic regression modelling. RESULTS: The study population comprised 77,088 dogs attending 50 Vets Now clinics. Overall, 492 dogs had presumptive gastric dilation-volvulus diagnoses, giving a prevalence of 0·64% (95% Confidence interval: 0·58 to 0·70%). Compared with cross-bred dogs, breeds with the highest odds ratios for the diagnosis of presumptive gastric dilation-volvulus were the great Dane (odds ratio: 114·3, 95% Confidence interval 55·1 to 237·1, P<0·001), akita (odds ratio: 84·4, 95% Confidence interval 33·6 to 211·9, P<0·001) and dogue de Bordeaux (odds ratio: 82·9, 95% Confidence interval 39·0 to 176·3, P<0·001). Odds increased as dogs aged up to 12 years and neutered male dogs had 1·3 (95% Confidence interval 1·0 to 1·8, P=0·041) times the odds compared with entire females. Of the cases that were presented alive, 49·7% survived to discharge overall, but 79·3% of surgical cases survived to discharge. CLINICAL SIGNIFICANCE: Approximately 80% of surgically managed cases survived to discharge. Certain large breeds were highly predisposed.

Dogs attending primary-care practice in England with clinical signs suggestive of Chiari-like malformation/syringomyelia.

Chiari-like malformation/syringomyelia (CM/SM) in dogs describes a developmental disorder that can cause pain and reduced quality of life. This retrospective study aimed to report the period prevalence, clinical signs and risk factors for diagnosis of symptomatic CM/SM in the veterinary primary-care setting using a cross-sectional design. The study population included all dogs within the VetCompass Programme (September 1, 2009-June 13, 2014). Overall, the period prevalence of symptomatic CM/SM was 0.05 per cent (95 per cent CI 0.04 per cent to 0.06 per cent) for all breeds. The period prevalence in the Cavalier King Charles Spaniel (CKCS) was 1.6 per cent (95 per cent CI 1.2 to 2.06). Other breeds at increased odds included the King Charles Spaniel (KCS), Affenpinscher, Chihuahua and Pomeranian. Insured dogs had 4.6 times the odds (95 per cent CI 2.95 to 7.17) of having a diagnosis of CM/SM compared with uninsured dogs. Pain was the most commonly associated clinical sign (67 dogs, 72 per cent). Analgesics were prescribed to 72 (77.4 per cent) of the symptomatic dogs. Despite its low overall period prevalence, the high proportion of affected dogs identified with chronic pain suggests a significant welfare issue. Financial implications could impede the diagnostic process and lead to underestimation of the true prevalence. This study may help to inform clinicians about the clinical relevance and the need for improved awareness of clinical signs, particularly in high-risk breeds, to optimise the management of CM/SM in primary-care practice.

Epidemiology of hyperadrenocorticism among 210,824 dogs attending primary-care veterinary practices in the UK from 2009 to 2014.

OBJECTIVES: To estimate prevalence and risk factors for diagnosis with hyperadrenocorticism in dogs attending primary-care veterinary practices in the UK from 2009 to 2014. METHODS: Cases were identified by searching the de-identified electronic patient records from UK primary-care veterinary practices participating in the VetCompass Programme. RESULTS: The estimated prevalence for hyperadrenocorticism diagnosis in dogs was 0·28% (95% confidence interval: 0·25 to 0·31). Multivariable logistic regression analysis revealed four associated risk factors: breed, breed-relative bodyweight, age and insurance status. The bichon frise had 6·5 times the odds (95% CI: 3·5 to 12·1, P<0·001) of hyperadrenocorticism compared with crossbreds. Dogs weighing more than or equal to their breed mean had 1·7 times the odds (95% CI: 1·3 to 2·3, P<0·001) of hyperadrenocorticism compared with dogs weighing less than the breed mean. Dogs aged 12·0 years and above showed 5·7 times the odds (95% CI: 3·7 to 8·7, P<0·001) of hyperadrenocorticism compared with dogs aged 6·0 to 8·9 years. Insured dogs had 4·0 times the odds (95% CI: 2·8 to 5·6, P<0·001) of hyperadrenocorticism compared with non-insured dogs. CLINICAL SIGNIFICANCE: This is the first epidemiological report of a non-referral hospital population of dogs diagnosed with hyperadrenocorticism in the UK and describes important breed, age and bodyweight associations with this disorder which may improve diagnosis and enhance understanding of the underlying pathophysiology.

Degenerative mitral valve disease: Survival of dogs attending primary-care practice in England.

This study aimed to evaluate survival of dogs with degenerative mitral valve disease (DMVD). A retrospective cohort study of dogs with DMVD attending primary-care practices in England was undertaken. Cases of DMVD were identified within the electronic patient records (EPRs) of practices sharing data with VetCompass. Kaplan-Meier curves were used to explore survival and Cox regression models identified factors associated with hazard of death. The EPRs from 111,967 dogs, attending 93 veterinary practices between January 2010 and December 2011 identified 405 cases diagnosed with DMVD giving a prevalence of diagnosed DMVD of 0.36% (95% CI: 0.29-0.45%). A further 3557 dogs were classified as possible cases (heart murmurs consistent with DMVD). Overall, a total of 3962 dogs were classified as heart murmur cases (possible and diagnosed DMVD), giving a prevalence of 3.54% (95% CI: 3.26-3.84%). One hundred and sixteen (28.6%) of the diagnosed DMVD cases were incident, newly diagnosed with DMVD. The mean age at diagnosis was 9.52 years (95% CI: 8.98-10.14 years). Fifty-eight (50.0%) of the incident cases died during the study period. The median survival time (MST) for all-cause mortality was 25.4 months (95% CI: 20.4-34.4 months) after disease detection for DMVD cases. For possible cases, 121 (29.7%) from a random sample of 407 possible DMVD cases were incident cases (newly detected heart murmur consistent with DMVD during the study period). The mean age at which a heart murmur was first recorded in possible cases was 9.73 years (95% CI: 9.02-10.44 years). Forty-nine (40.5%) possible cases died during the study period. The MST for all-cause mortality was 33.8 months (95% CI: 23.7-43.1 months) after a heart murmur was initially detected. In the multivariable survival analysis for possible and diagnosed cases, Cavalier King Charles Spaniels (CKCSs) and other purebreds had higher hazards of death than crossbreds. Dogs weighing ≥20.0kg and older dogs had an increased hazard of death compared with those <20.0kg and younger dogs, respectively. The study highlights poorer survival for all-cause mortality in CKCSs and larger dogs. The reported survival characteristics could aid veterinary surgeons' advice on the prognosis for dogs with DMVD and help the assessment of the impact of the condition at a population level.

Prevalence of and risk factors for degenerative mitral valve disease in dogs attending primary-care veterinary practices in England.

BACKGROUND: To date, epidemiological studies on degenerative mitral valve disease (DMVD) in dogs have largely reported referral caseloads or been limited to predisposed breeds. Analysis of primary-care data to identify factors associated with DMVD would help clinicians identify high-risk individuals and improve understanding. OBJECTIVES: To estimate the prevalence of and identify risk factors for DMVD in dogs attending primary-care veterinary practices in England. ANIMALS: Cases were identified within the electronic patient records of 111,967 dogs attending 93 practices. Four hundred and 5 dogs were diagnosed with DMVD (diagnosed cases) and a further 3,557 dogs had a heart murmur (HM) consistent with DMVD (possible cases). METHODS: Retrospective cross-sectional study design. Prevalence was adjusted for the sampling approach. Mixed effects logistic regression models identified factors associated with DMVD. RESULTS: Prevalence estimates of diagnosed DMVD and HMs consistent with DMVD (both diagnosed and possible cases) were 0.36% (95% confidence interval [CI]: 0.29-0.45) and 3.54% (95% CI: 3.26-3.84) respectively. In the multivariable analysis, males had higher odds of diagnosed DMVD than did females (odds ratio [OR] 1.40, 95% CI: 1.12-1.74). Insured dogs had increased odds of DMVD compared with noninsured dogs (OR 3.56, 95% CI: 2.79-4.55) and dogs ≥20 kg had approximately half the odds of DMVD diagnosis compared with dogs <20 kg (OR 0.51, 95% CI: 0.36-0.74). Strong associations between a DMVD diagnosis and individual breeds and age were identified. CONCLUSIONS AND CLINICAL IMPORTANCE: Degenerative mitral valve disease was a common disorder in practice-attending dogs. Knowledge of identified risk factors for DMVD could improve clinical diagnosis and direct future research.

Prevalence of disorders recorded in cats attending primary-care veterinary practices in England.

Improved understanding of absolute and relative prevalence values for common feline disorders could support clinicians when listing differential diagnoses and also assist prioritisation of breeding, research and health control strategies. This study aimed to analyse primary-care veterinary clinical data within the VetCompass project to estimate the prevalence of the most common disorders recorded in cats in England and to evaluate associations with purebred status. It was hypothesised that common disorders would be more prevalent in purebred than in crossbred cats. From a study population of 142,576 cats attending 91 clinics across Central and South-East England from 1 September 2009 to 15 January 2014, a random sample of 3584 was selected for detailed clinical review to extract information on all disorders recorded. The most prevalent diagnosis-level disorders were periodontal disease (n = 499; prevalence, 13.9%, 95% confidence intervals [CI], 12.5-15.4), flea infestation (n = 285; prevalence, 8.0%; 95% CI, 7.0-8.9) and obesity (n = 239; prevalence, 6.7%; 95% CI, 5.7-7.6). The most prevalent disorder groups recorded were dental conditions (n = 540; prevalence, 15.1%, 95% CI, 13.6-16.6), traumatic injury (n = 463; prevalence, 12.9%; 95% CI, 11.6-14.3) and dermatological disorders (n = 373; prevalence, 10.4%; 95% CI, 9.2-11.7). Crossbred cats had a higher prevalence of abscesses (excluding cat bite abscesses) (P = 0.009) and hyperthyroidism (P = 0.002) among the 20 most common disorders recorded. Purebreds had a higher prevalence for coat disorders (P <0.001). Veterinarians could use these results to focus their diagnostic and prophylactic efforts towards the most prevalent feline disorders. The study did not show an increased prevalence of common disorders in purebred cats compared with crossbred cats. Primary-care veterinary clinical data were versatile and useful for demographic and clinical feline studies.

Feline hyperthyroidism reported in primary-care veterinary practices in England: prevalence, associated factors and spatial distribution.

Feline hyperthyroidism is a commonly diagnosed endocrinopathy that can have a substantial deleterious impact on the welfare of affected cats. This study aimed to estimate the prevalence, associated factors and geographical distribution for feline hyperthyroidism in England, using primary-care veterinary practice clinical data from the VetCompass Animal Surveillance Project. Prevalence was estimated from the overall cat cohort. Associated factor analysis used an age-matched, nested, case-control design with multivariable logistic regression. There were 2,276 cases of feline hyperthyroidism identified from 95,629 cats attending 84 practices from September 2009 to December 2011. Cases were aged 6-25 years. 3.7 per cent of cases and 9.9 per cent of controls were purebred, 56.4 per cent of cases and 56.5 per cent of controls were female, and 88.1 per cent of cases and 86.0 per cent of controls were neutered. The apparent prevalence was 2.4 per cent (95% CI 2.3 to 2.5 per cent) overall, and 8.7 per cent (95% CI 8.3 to 9.0 per cent) in cats aged 10 years or above. Burmese (OR 0.15, 95% CI 0.07 to 0.32, P<0.0001), Persian (OR 0.17, 95% CI 0.08 to 0.33, P<0.0001), Siamese (OR 0.4, 95% CI 0.21 to 0.75, P=0.004) and purebred cats overall (OR 0.33, 95% CI 0.25 to 0.42, P< 0.0001) had lower odds of feline hyperthyroidism than non-purebred cats. Insured cats had increased odds (OR 1.78, 95% CI 1.56 to 2.03, P< 0.001). There was little evidence of spatial variation. This study highlights feline hyperthyroidism as a high-prevalence disease in England, and reports reduced odds of diagnosis in certain breeds and purebred cats overall.

Number, causes and destinations of horses leaving the Australian Thoroughbred and Standardbred racing industries.

OBJECTIVE: Significant proportions of horses leave the Australian Thoroughbred and Standardbred racing industries, which has ramifications for both the economic sustainability and the public perception of racing. The aim of this study was to quantify potential horse wastage, describe the destinations of exiting horses and identify risk factors for horses going to these destinations. METHODS: Questionnaires were sent to 1258 selected Thoroughbred and 981 Standardbred trainers, with response rates of 30% and 32%, respectively. The survey investigated the role of various risk factors for wastage, including horse age, sex and number of years in training. The destination of departing horses was also examined in relation to these risk factors. RESULTS: Total horse exit rates for the 2002-03 official race year were 39.7% and 38.7% for the Thoroughbred and Standardbred racing industries, respectively. Reasons for leaving included 'poor performance/slow' (36.5% Thoroughbreds, 35.2% Standardbreds), 'illness/injury' (31.0%, 27.1%), 'to breed' (9.4%, 10.1%), 'unsuitable temperament/behaviour' (6.4%, 6.4%) and 'other' (16.8%, 21.2%). Statistically significant (P < 0.001) risk factors influencing the destinations of both Thoroughbred and Standardbred racing horses included whether the trainer owned the horses, sex, age and reasons for leaving. In addition, some factors were specific to one breed or the other. CONCLUSIONS: Improved behaviour training and early identification of the causes of poor performance could assist in reducing wastage.

An epidemiological study of diabetes mellitus in dogs attending first opinion practice in the UK.

This study aimed to estimate the prevalence of canine diabetes mellitus (DM) in primary-care clinics in England, to identify risk factors associated with DM and to describe the survival of affected dogs. Cases of DM were identified within the electronic patient records of 89 small-animal practices. A nested case-control study identified risk factors for the diagnosis of DM using logistic regression models. Cox proportional hazards models were used to analyse variables associated with survival. Four-hundred and thirty-nine canine DM cases were identified, giving an apparent prevalence of 0.34% (95% CI 0.31% to 0.37%). Neutered males were at an increased risk of diabetes compared with entire males, whereas neutering was not associated with DM in females. When compared with crossbred dogs, Yorkshire terriers had increased odds, whereas German shepherd dogs and golden retrievers had lower odds of DM. Being classified as overweight and having a diagnosis of pancreatitis, hyperadrenocorticism or a urinary tract infection were positively associated with DM. Older dogs and those diagnosed with pancreatitis had a higher hazard of death, whereas insured and neutered dogs had a lower hazard. This study provides an objective assessment of canine DM using primary-care veterinary practice data and is a valuable benchmark against which future epidemiological trends in DM can be assessed and improvements in the management of DM in primary-care practice can be judged.

Longevity and mortality of owned dogs in England.

Improved understanding of longevity represents a significant welfare opportunity for the domestic dog, given its unparalleled morphological diversity. Epidemiological research using electronic patient records (EPRs) collected from primary veterinary practices overcomes many inherent limitations of referral clinic, owner questionnaire and pet insurance data. Clinical health data from 102,609 owned dogs attending first opinion veterinary practices (n=86) in central and southeast England were analysed, focusing on 5095 confirmed deaths. Of deceased dogs with information available, 3961 (77.9%) were purebred, 2386 (47.0%) were female, 2528 (49.8%) were neutered and 1105 (21.7%) were insured. The overall median longevity was 12.0 years (IQR 8.9-14.2). The longest-lived breeds were the Miniature poodle, Bearded collie, Border collie and Miniature dachshund, while the shortest-lived were the Dogue de Bordeaux and Great Dane. The most frequently attributed causes of death were neoplastic, musculoskeletal and neurological disorders. The results of multivariable modelling indicated that longevity in crossbred dogs exceeded purebred dogs by 1.2 years (95% confidence interval 0.9-1.4; P<0.001) and that increasing bodyweight was negatively correlated with longevity. The current findings highlight major breed differences for longevity and support the concept of hybrid vigour in dogs.

Chronic kidney disease in dogs in UK veterinary practices: prevalence, risk factors, and survival.

BACKGROUND: The prevalence for chronic kidney disease (CKD) in dogs varies widely (0.05-3.74%). Identified risk factors include advancing age, specific breeds, small body size, and periodontal disease. HYPOTHESIS/OBJECTIVES: To estimate the prevalence and identify risk factors associated with CKD diagnosis and survival in dogs. Purebred dogs were hypothesized to have higher CKD risk and poorer survival characteristics than crossbred dogs. ANIMALS: A merged clinical database of 107,214 dogs attending 89 UK veterinary practices over a 2-year period (January 2010-December 2011). METHODS: A longitudinal study design estimated the apparent prevalence (AP) whereas the true prevalence (TP) was estimated using Bayesian analysis. A nested case-control study design evaluated risk factors. Survival analysis used the Kaplan-Meier survival curve method and multivariable Cox proportional hazards regression modeling. RESULTS: The CKD AP was 0.21% (95% CI: 0.19-0.24%) and TP was 0.37% (95% posterior credibility interval 0.02-1.44%). Significant risk factors included increasing age, being insured, and certain breeds (Cocker Spaniel, Cavalier King Charles Spaniel). Cardiac disease was a significant comorbid disorder. Significant clinical signs included halitosis, weight loss, polyuria/polydipsia, urinary incontinence, vomiting, decreased appetite, lethargy, and diarrhea. The median survival time from diagnosis was 226 days (95% CI 112-326 days). International Renal Interest Society stage and blood urea nitrogen concentration at diagnosis were significantly associated with hazard of death due to CKD. CONCLUSIONS AND CLINICAL IMPORTANCE: Chronic kidney disease compromises dog welfare. Increased awareness of CKD risk factors and association of blood biochemistry results with survival time should facilitate diagnosis and optimize case management to improve animal survival and welfare.

Development and evaluation of electroejaculation techniques in the Tasmanian devil (Sarcophilus harrisii).

Electroejaculation (EEJ) has been used successfully to collect samples suitable for genome resource banking from a variety of endangered wildlife species. Ejaculates can also be used to evaluate the reproductive potential of individuals and provide information on seminal characteristics to aid in the development of sperm cryopreservation techniques. Electroejaculation techniques used for marsupial and eutherian species were tested on Tasmanian devils (n=35). Spermic ejaculates were collected in 54% (19/35) of EEJ attempts. Spermic ejaculates were low in volume (3.9±6.5×10(2) µL, range 10-3000 µL) and contained low numbers of spermatozoa (3.3±7.8×10(3) spermatozoa per ejaculate, range 6-33000). The osmolality and pH of presumptive urine-free ejaculates were 389±130 mOsm kg(-1) (range 102-566) and 7.0±0.9 (range 6.0-8.0), respectively. Prostatic bodies were observed in 79% (26/33) of ejaculates. Episodic fluctuations in serum testosterone concentrations were not detected during the EEJ procedure (P>0.05). Increases observed in serum cortisol concentrations during EEJ were less (P<0.05) than those observed after an adrenalcorticotropic hormone challenge and diurnal variation suggested that cortisol concentrations are greater during the day than at night (P<0.05). This information can be used to provide range values for the future examination of basic endocrine responses and the adrenal-pituitary axis of this species. This study also demonstrated that spermatozoa-rich devil electroejaculates are more difficult to obtain and poorer in quality than those of other marsupials.

The effects of season and devil facial tumour disease on the reproductive physiology of the male Tasmanian devil (Sarcophilus harrisii).

Devil facial tumour disease (DFTD) is the cause of the rapid decline of wild Tasmanian devils. Female devils are seasonal breeders with births peaking during autumn (i.e. March) but the degree of reproductive seasonality in male devils is unknown. The objective of this study was to examine the potential effects of season and DFTD on reproductive function in male devils (n=55). Testicular (1.90±0.23 g) and epididymal (0.90±0.06 g) weights were maximal during autumn and spring (P<0.05), whereas prostate (3.71±0.74 g) and Cowper's gland (0.68±0.22; 0.52±0.21 g) weights peaked during autumn (P<0.001). The motility of spermatozoa from the cauda epididymides extracted post-mortem was similar (P>0.05) across season and disease state (31.5±13.1% total motility). Testicular and epididymal weights were no different between animals displaying late or early-stage DTFD signs or disease-free animals (P>0.1). The accessory sex glands were larger in late-stage DFTD animals than in animals with early-stage disease signs or which were disease-free (P<0.01) but effects of season on this result can't be excluded. Serum testosterone concentrations peaked during summer (0.25±0.18 ng mL(-1)) but values were not different from the preceding and subsequent seasons (P>0.05), nor influenced by disease stage (P>0.1). Seasonal and DFTD-related changes in serum cortisol concentrations were not evident (P>0.1). Male devil reproduction does not appear to be restricted by season nor inhibited by DFTD.

Cryopreservation of epididymal sperm collected postmortem in the Tasmanian devil (Sarcophilus harrisii).

Effective sperm cryopreservation protocols are limited to a small number of marsupial species. In this study, postmortem gamete rescue (PMGR) epididymal sperm samples from Tasmanian devils (N=34) euthanized due to the fatal Devil Facial Tumor Disease were used to develop long-term sperm storage techniques for the species. Cryoprotectant toxicity associated with equilibration of sperm samples in a TEST yolk diluent (TEST; 189 mM N-Tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, 85 mM Trizma base [Tris], 11 mM glucose, 20% vol/vol egg yolk; pH 7.1, and 315.0±5.0 mOsm/kg) with a final concentration of 0.06 M trehalose, or 4%, 10%, and 18% vol/vol of either glycerol or dimethyl sulfoxide (DMSO), was examined over 12 h at 15 °C. Trehalose supplementation resulted in an immediate decline (P<0.05) of total motility. After 12 h, total motility was reduced (P<0.05) in treatments containing 18% glycerol, and 10% and 18% dimethyl sulfoxide. The effects of final glycerol concentration (4% and 10%), glycerol equilibration duration (10 min 1 h, or 3 h) prefreeze, freezing rate and the addition of 0.10 M lactose or a combination of 0.10 M lactose and 0.11 M raffinose were assessed during three experiments on the cryopreservation of postmortem gamete rescue samples in TEST. In all experiments, motility and viability were reduced (P<0.01 postthaw). Samples cryopreserved in TEST supplemented with lactose or lactose with raffinose using a fast freezing rate (-8 °C/min from 4 to -40 °C, then -65 °C/min until -165 °C) produced the highest (P<0.05) postthaw motility (18.6±5.5% and 16.9±8.5%, respectively), which represented 35% to 48% retention of prefreeze motility. These results apparently were the best postthaw results of dasyurid sperm reported to date and will help lay the foundations for developing assisted reproductive technologies for marsupial species.

The reproductive cycle of the Tasmanian devil (Sarcophilus harrisii) and factors associated with reproductive success in captivity.

Numbers of wild Tasmanian devils are declining as a result of the fatal, transmissible Devil Facial Tumor Disease. A captive insurance population program has been initiated but current captive breeding rates are sub-optimal and therefore the goal of this project was to increase our understanding of the estrous cycle of the devil and elucidate potential causes of failed male-female pairings. Temporal patterns of fecal progestagen and corticosterone metabolite concentrations were examined for females (n=41) in three categories of reproductive status (successful: viable young, n=20 estrous cycles; unsuccessful: paired with a male but no young confirmed, n=44 estrous cycles; non-mated: no access to a male during estrus, n=8 estrous cycles) but substantial differences were not found. Females were more likely to produce pouch young if pairing with the male extended into late proestrus (P<0.05), thereby decreasing the time between pairing and presumed ovulation. The interval between the end of proestrous elevation in progestagen metabolite concentrations and the beginning of the luteal phase was 7.6±2.3 days in successful females. The length of the luteal phase in successful females was 12.5±1.4 days which was not different from unsuccessful or non-mated females (P>0.05). Unsuccessful females had 1-3 estrous cycles within a single year. Successful females were predominantly wild-caught (17/19, 90%) and most produced young following the first estrous cycle of the season (18/20, 90%). Unsuccessful females were predominantly captive born (20/27, 74%) in this study. It is possible that a proportion of females that do not produce pouch young achieve conception but the timing of reproductive failure continues to be elusive in this species.

Characterization and short-term storage of Tasmanian devil sperm collected post-mortem.

The Tasmanian devil is suffering from a severe population decline due to the fatal Devil Facial Tumour Disease (DFTD). The development of assisted reproductive technologies such as AI and long-term sperm storage could facilitate genetic management of captive insurance populations. The aim of this study was to characterise semen samples collected post-mortem, and to develop a suitable diluent for short-term preservation of devil sperm. Low numbers of sperm (1.33 ± 0.85 × 10(6) sperm per male) were extracted from the epididymides of 17 males. Devil sperm sample characteristics such as concentration and morphology were similar to other dasyurids. The most commonly observed morphological abnormalities were midpiece separation, tail curling, and tail twisting (on the axial plane). Changes in motility occurred throughout the regions of the epididymis with (mean ± SD) 29.4 ± 16.8, 46.8 ± 13.6 and 29.4 ± 18.1% of sperm exhibiting motility, and 88.9 ± 11.4, 32.0 ± 24.3 and 0.1 ± 0.2% of motile sperm exhibiting forward progressive motility in the cauda, corpus and caput, respectively. Sperm from the cauda and corpus epididymis maintained 31.7 ± 26.6 and 80.6 ± 85.9%, respectively, of initial motility after 12 h at 15 °C in a TEST yolk buffer diluent. These findings provided new information regarding devil sperm biology and short-term sperm storage; such information is necessary for future development of long-term sperm preservation methods in the Tasmanian devil.