Veterinary Clinical Sciences - Research Publications
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ItemSevere pericardial effusion in a cat with peritoneopericardial diaphragmatic hernia and incarcerated hepatic sarcoma.(SAGE Publications, 2022)CASE SUMMARY: A 4-year-old female neutered domestic longhair cat was presented at a referral hospital for dyspnoea with a history of suspected pleural effusion. Thoracic ultrasonography demonstrated a large-volume pericardial effusion causing cardiac tamponade and a cystic mass within the pericardium. CT revealed a peritoneopericardial diaphragmatic hernia (PPDH) caused by a defect of the ventral diaphragm. Herniated contents consisted of the right lateral and caudate liver lobes, and an associated cystic hepatic mass. Ventral midline coeliotomy was performed for herniorrhaphy and partial pericardiectomy, together with lobectomy of the incarcerated liver mass. Histopathology and immunohistochemistry diagnosed a poorly differentiated hepatic sarcoma with inflammation and remodelling in the adjacent incarcerated liver parenchyma. The patient developed metastatic sarcoma 2 months after surgery and was euthanased as a result. RELEVANCE AND NOVEL INFORMATION: Pericardial effusion causing cardiac tamponade is a previously unreported sequelae to PPDH in cats. Reports on the presence of malignancy in incarcerated liver are scarce and the location is not typical for a sarcoma in this species.
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ItemSeropositivity to Campylobacter and association with abortion and lamb mortality in maiden ewes from Western Australia, South Australia and Victoria(WILEY, 2022-06-05)This case-control study investigated associations between Campylobacter fetus or Campylobacter jejuni titre and reproductive outcomes in 22 flocks of Merino and non-Merino maiden ewes aged 1-2 years old. Campylobacter titres were also determined for multiparous ewes aged 3 years or older on the same farms. C. fetus 'positivity' (titre ≥1:80) was detected for 12% (57/462; 95% confidence interval [95% CI] 9.6 to 15.6) of maiden ewes and 31% (65/210; 95% CI 25.0 to 37.4) of mature ewes. The odds for failing to rear a lamb in C. fetus-'exposed' maiden ewes (titre ≥1:10) was 2.01 times that of seronegative ewes (95% CI 1.09 to 3.77; P = 0.027), but there was no association between C. fetus-'positivity' (titre ≥1:80) and failure to rise (OR 1.69; 95% CI 0.77 to 3.76; P = 0.191). C. fetus abortions were confirmed with microbial culture in one maiden ewe flock. In this flock, C. fetus titres fluctuated and often waned by lamb marking, highlighting the value of necropsies during abortion investigations. C. jejuni-'positivity' (titre ≥1:80) was detected for 44% (204/462; 95% CI 39.7 to 48.7) maiden ewes, but odds of failing to rear were decreased for C. jejuni-'positive' ewes (OR 0.52; 95% CI 0.32 to 0.83; P = 0.007). The association between Campylobacter serology and the reproductive outcome was inconsistent in these flocks. Serology should be considered in the context of other risk factors and used in conjunction with other strategies to investigate the impact of Campylobacter exposure on ewe reproductive performance such as monitoring for abortions and lamb necropsies to determine aetiological diagnosis, and vaccination trials.
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ItemLean body weight-adjusted intravenous iodinated contrast dose for abdominal CT in dogs reduces interpatient enhancement variability while providing diagnostic quality organ enhancement(WILEY, 2022-06-10)Contrast-enhanced computed tomography (CECT) is increasingly used to screen for abdominal pathology in dogs, and the contrast dose used is commonly calculated as a linear function of total body weight (TBW). Body fat is not metabolically active and contributes little to dispersing or diluting contrast medium (CM) in the blood. This prospective, analytic, cross-section design pilot study aimed to establish the feasibility of intravenous CM dosed according to lean body weight (LBW) for abdominal CECT in dogs compared to TBW. We hypothesized that when dosing intravenous CM according to LBW, studies will remain at diagnostic quality, there will be a reduced interindividual contrast enhancement (CE) variability, and there will be less change to heart rate and blood pressure in dogs compared to when administering CM calculated on TBW. Twelve dogs had two CECT studies with contrast doses according to TBW and LBW at least 8 weeks apart. Interindividual organ and vessel CE variability, diagnostic quality of the studies, and changes in physiological status were compared between protocols. The LBW-based protocol provided less variability in the CE of most organs and vessels (except the aorta). When dosed according to LBW, liver enhancement was positively associated with grams of iodine per kg TBW during the portal venous phase (P = 0.046). There was no significant difference in physiological parameters after CM administration between dosing protocols. Our conclusion is that a CM dose based on LBW for abdominal CECT lowers interindividual CE variability and is effective at maintaining studies of diagnostic quality.
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ItemBrain magnetic resonance imaging and histopathology findings in a dog with global brain ischaemia following cardiopulmonary arrest(WILEY, 2022-06-02)BACKGROUND: Global brain ischaemia following cardiopulmonary arrest is uncommonly reported in veterinary medicine yet neurologic injury after arrest is a known morbidity. CASE REPORT: An 18-week-old male entire Cavalier King Charles Spaniel-Poodle was referred following 3 days of neurologic abnormalities after cardiopulmonary arrest. After resuscitation, the animal had decerebrate rigidity, a stuporous mentation and intermittent episodes of vocalisation and apnoea. A brain magnetic resonance imaging (MRI) was undertaken 4 days after cardiopulmonary arrest, with standard sequences (T1-weighted, T2-weighted and fluid-attenuated inversion recovery) as well as diffusion-weighted imaging to better discern ischaemic injury and cytotoxic oedema for prognostic reasons. MRI findings were consistent with global brain ischaemia affecting the hippocampus, cerebellum and substantia nigra, the latter two not previously identified in canine cases of global brain ischaemia. The patient was euthanased on day eight post-cardiopulmonary arrest due to a lack of neurological improvement and developing sepsis as a complication. Ante-mortem identification of affected areas of the brain was confirmed on histological examination, with evidence of ischaemic injury seen in the cerebrum, hippocampus, cerebellum, basal nuclei and thalamus. CONCLUSION: This report describes ante-mortem MRI and postmortem findings in a dog with global brain ischaemia following cardiopulmonary arrest. A multimodal approach to neuroprognostication in patients recovering from cardiopulmonary arrest is recommended.
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ItemChanges in Thoroughbred speed and stride characteristics over successive race starts and their association with musculoskeletal injury(WILEY, 2023-03)BACKGROUND: Certain stride characteristics have been shown to affect changes in biomechanical factors that are associated with injuries in human athletes. Determining the relationship between stride characteristics and musculoskeletal injury (MSI) may be key in limiting injury occurrence in the racehorse. OBJECTIVES: This study aimed to determine whether changes in race day speed and stride characteristics over career race starts are associated with an increased risk of MSI in racehorses. STUDY DESIGN: Case-control study. METHODS: Speed, stride length, and stride frequency data were obtained from the final 200 m sectional of n = 5660 race starts by n = 584 horses (case n = 146, control n = 438). Multivariable joint models, combining longitudinal and survival (time to injury) analysis, were generated. Hazard ratios and their 95% confidence intervals (CI) are presented. RESULTS: The risk of MSI increased by 1.18 (95% CI 1.09, 1.28; P < 0.001) for each 0.1 m/s decrease in speed and by 1.11 (95% CI 1.02, 1.21; P = 0.01) for each 10 cm decrease in stride length over time (career race starts). A more marked rate of decline in speed and stride length was observed approximately 6 races prior to injury. Risk of MSI was highest early in the horse's racing career. MAIN LIMITATIONS: Only final sectional stride characteristics were assessed in the model. The model did not account for time between race starts. CONCLUSIONS: Decreasing speed and stride length over multiple races is associated with MSI in racehorses. Monitoring stride characteristics over time may be beneficial for the early detection of MSI.
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ItemPrevalence of failure of passive immunity transfer in Australian non-replacement dairy calves(WILEY, 2022-03-30)Failure of passive immunity transfer (FPIT) increases the risk of morbidity and mortality in dairy calves. The prevalence of FPIT in dairy calves has generally been reported to be high, with FPIT estimated to occur in 38%-42% of Australian dairy calves. However, the focus of previous studies has been on replacement heifer calves. Our aim was to assess the prevalence of FPIT in Victorian bobby calves (non-replacement dairy calves). We collected blood samples from 3608 bobby calves at three abattoirs at exsanguination, and measured serum total protein as an indicator of passive transfer. We found that 36% of bobby calves showed evidence of FPIT (serum total protein ≤52 g/L), and 50% of calves had poor or fair passive transfer (<58 g/L). When a subset of calves (from farms with more than five calves in the dataset) was analysed using a linear mixed model, Jersey calves and crossbred/other calves had an estimated 5.3 g/L and 5.1 g/L higher serum total protein concentration, respectively, than Holstein-Friesian calves (P < 0.001). Our results suggest that the prevalence of FPIT in bobby calves at abattoirs is similar to that reported in dairy heifer calves sampled on farms. A high prevalence of FPIT has implications for bobby calf morbidity and mortality, as well as calf viability and profitability for dairy-beef production.
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ItemCross-species emotional political ecology in rural Pakistan(Elsevier, 2023-02-01)This article engages cross-species intersectionality and emotional political ecology to evaluate a dairy extension service that ran in Punjab and Sindh, Pakistan, between 2012 and 2017. The project aimed to mitigate potential negative impacts of implementation, such as the exacerbation of pre-existing social inequality, by applying principles of women’s agency and empowerment in project design. Evidence from the two case study villages reveals how social difference (caste and class) shape women’s access to extension meetings and the resources to implement practices. The evidence also reveals that through cattle work woman cultivate an emotional bond with their animals, given the multiple instrumental and sociocultural values they represent for households. Singh (2013) provides a definition of the agentic potential of this emotional bond as the ‘ability to affect and be affected.’ The higher socioeconomic classes that had good access to the extension service were able to improve animal welfare and milk production through which they cultivated satisfaction, pride and independence. Alternatively, women expressed feelings of longing or boredom in the absence of this invaluable resource in their lives. This article confirms the importance of intersectionality for designing interventions that are sensitive to inter and intra household dynamics and that cross-species relations form pivotal axes for social difference. These cross-species relations cultivate emotions/affect during engagement with the extension service.
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ItemObservations on the effects of non-maternal adult contact on the behavioural patterns of pre-weaned dairy heifers(CSIRO Publishing, 2023)Context. Dairy calves are often separated from their dams following birth, despite the beneficial effects of early life adult contact on behavioural development across species. Cow–calf contact systems are rare and often difficult to implement in the modern dairy industry. The development of alternative systems offering some of the benefits of adult social contact during early life, such as contact with non-maternal adults, has been limited. Aims. This study explored the behavioural patterns of grouped pre-weaned calves reared with or without non-maternal adult contact, and is the first in a series of studies following the social and behavioural development of experimental calves from the age of 2 weeks to 2 years. Methods. Four groups of 10 calves housed at pasture were studied from 2 to 12 weeks of age. Two groups were housed with three non-maternal dry cows each (+S). Calf behaviour in these groups was compared with that of calves in the remaining two groups, housed without adult contact (−S). Observations were conducted on behaviours including grazing, locomotion and lying, using 5-min scan sampling between morning (0930 hours) and afternoon (1600 hours) milk-feeding on 1 day every second week of the experiment (x¯ = 5.9 h of data ± 0.4 h/group.day). Key results. Few behavioural differences were found between groups. All groups performed mostly lying behaviour in the middle of the day and spent the most time grazing in the afternoon before the evening milk feed. Conclusions. Our results indicated that calves housed at pasture behave according to innate diurnal patterns previously observed in studies of calves housed with the dam, and choose to spend the majority of daylight hours lying or grazing. Being housed with non-maternal adults has few effects on these observed behavioural patterns. Implications. Our study suggests that non-maternal adult contact does not affect the immediate behavioural development of calves housed at pasture. Future research needs to explore longitudinal effects of this contact.
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ItemAre children and dogs best friends? A scoping review to explore the positive and negative effects of child-dog interactions(PEERJ INC, 2022-12-19)Personal wellbeing is greatly influenced by our childhood and adolescence, and the relationships formed during those phases of our development. The human-dog bond represents a significant relationship that started thousands of years ago. There is a higher prevalence of dog ownership around the world, especially in households including children. This has resulted in a growing number of researchers studying our interactions with dogs and an expanding evidence base from the exploration of child-dog interactions. We review the potential effects of child-dog interactions on the physical, mental, and social wellbeing of both species. A search of the SCOPUS database identified documents published between January 1980 and April 2022. Filtering for key inclusion criteria, duplicate removals, and inspecting the references of these documents for additional sources, we reviewed a total of 393 documents, 88% of which were scientific articles. We were able to define the numerous ways in which children and dogs interact, be it neutral (e.g., sharing a common area), positive (e.g., petting), or negative (e.g., biting). Then, we found evidence for an association between childhood interaction with dogs and an array of benefits such as increased physical activities, a reduction of stress, and the development of empathy. Nonetheless, several detrimental outcomes have also been identified for both humans and dogs. Children are the most at-risk population regarding dog bites and dog-borne zoonoses, which may lead to injuries/illness, a subsequent fear of dogs, or even death. Moreover, pet bereavement is generally inevitable when living with a canine companion and should not be trivialized. With a canine focus, children sometimes take part in caretaking behaviors toward them, such as feeding or going for walks. These represent opportunities for dogs to relieve themselves outside, but also to exercise and socialize. By contrast, a lack of physical activity can lead to the onset of obesity in both dogs and children. Dogs may present greater levels of stress when in the presence of children. Finally, the welfare of assistance, therapy, and free-roaming dogs who may interact with children remains underexplored. Overall, it appears that the benefits of child-dog interactions outweigh the risks for children but not for dogs; determination of the effects on both species, positive as well as negative, still requires further development. We call for longitudinal studies and cross-cultural research in the future to better understand the impact of child-dog interactions. Our review is important for people in and outside of the scientific community, to pediatricians, veterinarians, and current or future dog owners seeking to extend their knowledge, and to inform future research of scientists studying dogs and human-animal interactions.
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ItemCharacterising a unique recreational hunting method: hound hunting of sambar deer (Cervus unicolor) in Victoria, Australia(CSIRO Publishing, 2022)Context: Scent-trailing dogs (‘hounds’) are used to hunt introduced sambar deer (Cervus unicolor) in south-eastern Australia, but little is known about this recreational hunting technique. Aim: The aim of this study was to characterise hound hunting of sambar deer in Victoria, Australia. Our study had three objectives as follows: (1) to report the hunting success of the technique; (2) to estimate pursuit times and distances; and (3) to investigate the landscape features associated with kill sites. Methods: Data were collected from four hound-hunting crews during 2020–2021. GPS data from collars fitted to hounds were used to quantify hunt duration (min) and hunt distance (m). Logistic regression was used to estimate the effects of deer sex and hound pack size on the probability of hunting success. We used a Bayesian multinomial regression resource selection function (RSF) to identify the characteristics of sites where deer were killed (elevation, aspect, and distances to water and roads). Key results: The four hunting teams ranged in size from 2 to 10 people and from one to eight hounds. Of 136 hunts, most (88%) harvested a deer, with pursued deer escaping on the other 12% of occasions. Pursuit times and distances were highly variable, with pursuit time >60 min for 46% of hunts and pursuit distance >5 km for 30% of hunts. The probability of killing a pursued male and female deer were similar, and there was not a positive relationship between pack size and hunt success. The RSF showed that both male and female deer were more likely to be killed on steeper slopes and closer to roads. Conclusions: Successful hound hunting of sambar deer involves pursuits of considerable duration and requires a network of roads, with geographical features associated with deer kills sites being related to hunter access. Implications: Hound hunting may be a useful wildlife management tool for land managers, but further studies are needed to assess its efficacy for achieving management goals.