Veterinary Clinical Sciences - Research Publications

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    Circus and zoo animal welfare in Sweden: an epidemiological analysis of data from regulatory inspections by the official competent authorities
    Hitchens, PL ; Hultgren, J ; Frossling, J ; Emanuelson, U ; Keeling, LJ (UNIV FEDERATION ANIMAL WELFARE, 2017-11)
    Abstract Good animal welfare is crucial for the success of circuses and zoos. Epidemiological studies of animal welfare that investigate associations between animal-based measures (ABMs) and resource- and management-based measures are needed. However, due to the relatively low numbers of animals within each species kept at individual facilities, such investigations can be difficult to carry out. In this paper, we report the analysis of a multi-facility epidemiological study using data from all regulatory inspections of circus and zoo animals in Sweden for 2010 to 2014. Information from 42 inspections of 38 circuses, and 318 inspections of 179 zoos was analysed. For ABMs assessed during routine inspections of circuses (n = 14) and zoos (n = 61), 9.1 and 14.3% did not comply with requirements for general care of hooves/claws and coat, 10.0 and 8.6% for body condition, and 0 and 1.7% for animal cleanliness, respectively. In addition, the zoo checklist assessed whether animals were kept in appropriate groups, finding non-compliance in 17.0% of inspections. The most frequent non-compliant resource- and management-based measures at routine inspections of circuses were for space (41.7%) and exercise requirements (38.5%). For zoos, 29.4% did not comply with space followed by 28.8% for enrichment requirements. In multivariable logistic regression analyses, zoos that had inadequate or unsafe housing and space design, inadequate bedding, or failed to meet nutritional requirements, were more likely to be non-compliant with at least one ABM. The checklists should be improved to better assess welfare status by including more ABMs; benchmarking of risks and trends over time is also recommended.
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    Changes in Thoroughbred speed and stride characteristics over successive race starts and their association with musculoskeletal injury
    Wong, ASM ; Morrice-West, A ; Whitton, RC ; Hitchens, PL (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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    Prevalence and Factors Associated with Working Equid Lameness in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis
    Merridale-Punter, MS ; Wiethoelter, AK ; El-Hage, CM ; Hitchens, PL (MDPI, 2022-11)
    Lameness is an important concern in working equids of low- and middle-income communities (LMICs) with significant One Welfare implications. This study aims to determine the prevalence and influencing factors of lameness in working equids of LMICs. A systematic review and meta-analysis were performed to investigate pooled outcome prevalence using a random intercept regression model. Subgroup and sensitivity analysis were performed through meta-regression. A meta-analysis of study factors for lameness prevalence was performed. Sixty-four studies were included in the review. The pooled prevalence of lameness was 29.9% (n = 42, 95% CI 17-47%), while the pooled prevalence of gait abnormality was 62.9% (n = 12; 95% CI 31-87%). When considering both outcomes together, the pooled prevalence was 38.4% (n = 46; 95% CI 23-57%) with a significant (p = 0.02) difference between lameness (29.5%; 95% CI 16-48%) and gait abnormality (78.8%; 95% CI 40-95%). Species, country income level, gait assessed, and risk of bias did not significantly affect the pooled prevalence. Lower body condition scores, unresponsive attitudes, and old age were the most frequently reported factors positively associated with lameness-related outcomes. Working 7 days per week was positively associated with lameness. The standardization of outcome terminology, grading systems, and study factor categorization is recommended to enable more accurate interpretation and comparison between studies.
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    Predicting the potential for zoonotic transmission and host associations for novel viruses
    Pandit, PS ; Anthony, SJ ; Goldstein, T ; Olival, KJ ; Doyle, MM ; Gardner, NR ; Bird, B ; Smith, WA ; Wolking, D ; Gilardi, K ; Monagin, C ; Kelly, T ; Uhart, M ; Epstein, JH ; Machalaba, C ; Rostal, MK ; Dawson, P ; Hagan, E ; Sullivan, A ; Li, H ; Chmura, AA ; Latinne, A ; Lange, C ; O'Rourke, T ; Olson, SH ; Keatts, L ; Mendoza, AP ; Perez, A ; de Paula, CD ; Zimmerman, D ; Valitutto, M ; LeBreton, M ; McIver, D ; Islam, A ; Duong, V ; Mouiche, M ; Shi, Z ; Mulembakani, P ; Kumakamba, C ; Ali, M ; Kebede, N ; Tamoufe, U ; Bel-Nono, S ; Camara, A ; Pamungkas, J ; Coulibaly, K ; Abu-Basha, E ; Kamau, J ; Silithammavong, S ; Desmond, J ; Hughes, T ; Shiilegdamba, E ; Aung, O ; Karmacharya, D ; Nziza, J ; Ndiaye, D ; Gbakima, A ; Sijali, Z ; Wacharapluesadee, S ; Robles, EA ; Ssebide, B ; Suzan, G ; Aguirre, LF ; Solorio, MR ; Dhole, TN ; Nga, NTT ; Hitchens, PL ; Joly, DO ; Saylors, K ; Fine, A ; Murray, S ; Karesh, W ; Daszak, P ; Mazet, JAK ; Johnson, CK (NATURE PORTFOLIO, 2022-08-19)
    Host-virus associations have co-evolved under ecological and evolutionary selection pressures that shape cross-species transmission and spillover to humans. Observed virus-host associations provide relevant context for newly discovered wildlife viruses to assess knowledge gaps in host-range and estimate pathways for potential human infection. Using models to predict virus-host networks, we predicted the likelihood of humans as hosts for 513 newly discovered viruses detected by large-scale wildlife surveillance at high-risk animal-human interfaces in Africa, Asia, and Latin America. Predictions indicated that novel coronaviruses are likely to infect a greater number of host species than viruses from other families. Our models further characterize novel viruses through prioritization scores and directly inform surveillance targets to identify host ranges for newly discovered viruses.
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    Relationship between Thoroughbred workloads in racing and the fatigue life of equine subchondral bone
    Morrice-West, A ; Hitchens, PL ; Walmsley, EA ; Tasker, K ; Lim, SL ; Smith, AD ; Whitton, RC (NATURE PORTFOLIO, 2022-07-07)
    Fatigue life (FL) is the number of cycles of load sustained by a material before failure, and is dependent on the load magnitude. For athletes, 'cycles' translates to number of strides, with load proportional to speed. To improve previous investigations estimating workload from distance, we used speed (m/s, x) per stride collected using 5 Hz GPS/800 Hz accelerometer sensors as a proxy for limb load to investigate factors associated with FL in a Thoroughbred race start model over 25,234 race starts, using a combination of mathematical and regression modelling. Fore-limb vertical force (NKg-1) was estimated using a published equation: Vertical force = 2.778 + 2.1376x - 0.0535x2. Joint load (σ) was estimated based on the vertical force, scaled according to the maximum speed and defined experimental loads for the expected variation in load distribution across a joint surface (54-90 MPa). Percentage FL (%FL) was estimated using a published equation for cycles to failure (Nf) summed across each race start: Nf = 10(σ-134.2)/-14.1. Multivariable mixed-effects linear regression models were generated on %FL, adjusting for horse-level clustering, presented as coefficients; 95%CI. Scaled to the highest joint load, individual starts accrued a mean of 9.34%FL (sd. 1.64). Older age (coef. 0.03; 0.002-0.04), longer race-distances (non-linear power transformed), and firmer track surfaces (ref. Heavy 10: Good 3 coef. 2.37; 2.26-2.48) were associated with greater %FL, and males accrued less than females (p < 0.01). Most variables associated with %FL are reported risk factors for injury. Monitoring strides in racehorses may therefore allow identification of horses at risk, enabling early detection of injury.
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    Biomechanical and Microstructural Properties of Subchondral Bone From Three Metacarpophalangeal Joint Sites in Thoroughbred Racehorses
    Pearce, DJ ; Hitchens, PL ; Malekipour, F ; Ayodele, B ; Lee, PVS ; Whitton, RC (FRONTIERS MEDIA SA, 2022-06-28)
    Fatigue-induced subchondral bone (SCB) injury is common in racehorses. Understanding how subchondral microstructure and microdamage influence mechanical properties is important for developing injury prevention strategies. Mechanical properties of the disto-palmar third metacarpal condyle (MCIII) correlate poorly with microstructure, and it is unknown whether the properties of other sites within the metacarpophalangeal (fetlock) joint are similarly complex. We aimed to investigate the mechanical and structural properties of equine SCB from specimens with minimal evidence of macroscopic disease. Three sites within the metacarpophalangeal joint were examined: the disto-palmar MCIII, disto-dorsal MCIII, and proximal sesamoid bone. Two regions of interest within the SCB were compared, a 2 mm superficial and an underlying 2 mm deep layer. Cartilage-bone specimens underwent micro-computed tomography, then cyclic compression for 100 cycles at 2 Hz. Disto-dorsal MCIII specimens were loaded to 30 MPa (n = 10), while disto-palmar MCIII (n = 10) and proximal sesamoid (n = 10) specimens were loaded to 40 MPa. Digital image correlation determined local strains. Specimens were stained with lead-uranyl acetate for volumetric microdamage quantification. The dorsal MCIII SCB had lower bone volume fraction (BVTV), bone mineral density (BMD), and stiffness compared to the palmar MCIII and sesamoid bone (p < 0.05). Superficial SCB had higher BVTV and lower BMD than deeper SCB (p < 0.05), except at the palmar MCIII site where there was no difference in BVTV between depths (p = 0.419). At all sites, the deep bone was stiffer (p < 0.001), although the superficial to deep gradient was smaller in the dorsal MCIII. Hysteresis (energy loss) was greater superficially in palmar MCIII and sesamoid (p < 0.001), but not dorsal MCIII specimens (p = 0.118). The stiffness increased with cyclic loading in total cartilage-bone specimens (p < 0.001), but not in superficial and deep layers of the bone, whereas hysteresis decreased with the cycle for all sites and layers (p < 0.001). Superficial equine SCB is uniformly less stiff than deeper bone despite non-uniform differences in bone density and damage levels. The more compliant superficial layer has an important role in energy dissipation, but whether this is a specific adaptation or a result of microdamage accumulation is not clear.
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    Association of Thoroughbred Racehorse Workloads and Rest Practices with Trainer Success
    Morrice-West, AV ; Hitchens, PL ; Walmsley, EA ; Wong, ASM ; Whitton, RC (MDPI, 2021-11)
    Understanding the relationship between the training practices of Thoroughbred racehorses and race performance is important to ensure advice given to trainers for injury prevention or management is practical and consistent. We assessed associations between intended volume and speed of gallop training (i.e., typical workloads for horses free of injury or other performance limiting conditions) and rest practices on official trainer career and previous season success rates (rate of wins and places, prizemoney per start). Sixty-six Australian Thoroughbred trainers were surveyed. Multivariable negative binomial regression models were employed for the outcomes career and previous season wins and places, and linear regression models for prizemoney per start. Intended training workload was not associated with prizemoney. Pre-trial total galloping distances (≥13.3 m/s) between 7500 m and 15,000 m were associated with a higher rate of career wins, and previous season wins and places per start (p < 0.05). Slow-speed (13.3-14.3 m/s) galloping distance to trial between 5000 m to 12,500 m was associated with higher rate of career placings per start, with reduced performance over 12,500 m (p = 0.003). Greater time between race starts was associated with a greater rate of previous season wins and prizemoney per start until three weeks between starts, with decline in performance thereafter (p < 0.05). Greater frequency of rest breaks was associated with greater prizemoney per start earnt in the previous season (p ≤ 0.01). These results suggest that modifications to training programs aimed at injury prevention, such as avoiding long galloping distances, should not adversely affect trainer success.
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    Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats
    Saylors, K ; Wolking, DJ ; Hagan, E ; Martinez, S ; Francisco, L ; Euren, J ; Olson, SH ; Miller, M ; Fine, AE ; Nga, NTT ; Phuc, TM ; Kalengkongan, JD ; Consortium, P ; Kusumaningrum, T ; Latinne, A ; Pamungkas, J ; Safari, D ; Saputro, S ; Bamba, D ; Coulibaly, KJ ; Dosso, M ; Laudisoit, A ; Jean, KMN ; Dutta, S ; Islam, A ; Shano, S ; Mwanzalila, M ; Trupin, IP ; Gbakima, A ; Bangura, J ; Yondah, ST ; Karmacharya, D ; Shrestha, RD ; Kamta, MAM ; Mouiche, MMM ; Ndolo, HM ; Niama, FR ; Onikrotin, D ; Daszak, P ; Johnson, CK ; Mazet, JAK (BMC, 2021-05-14)
    In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development's (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security.
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    Training practices, speed and distances undertaken by Thoroughbred racehorses in Victoria, Australia
    Morrice-West, A ; Hitchens, PL ; Walmsley, EA ; Stevenson, MA ; Whitton, RC (WILEY, 2020-03)
    BACKGROUND: Musculoskeletal injuries (MSI) in racehorses are commonly due to bone fatigue, a function of the number of cycles (strides) and the magnitude of load applied to the limb. These parameters can be estimated using speed and distance, with greater than 6000 m/month at a gallop (>14 m/s), in combination with canter distances greater than 44,000 m/month, reported to increase fracture risk. Despite their importance, there are limited data on the distances and speeds horses are exposed to during training. OBJECTIVES: Estimate training volume at different speeds undertaken by Australian Thoroughbred racehorses. STUDY DESIGN: Cross-sectional study. METHODS: Registered trainers (n = 66) in Victoria, Australia were surveyed. Questions were designed to assess the full training workload from initial pre-training to training performed to achieve and maintain race fitness, as well as information on rest periods. Descriptive analyses were stratified by trainer- and horse-level factors, with assessment of variance within and between groups. Cluster analyses were used to identify similar workload intensity groups. RESULTS: Horse-level factors (age, targeted race distance) were associated with workload (younger
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    Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses
    Steel, CM ; Collins, VL ; Hance, SR ; Adkins, AR ; Hitchens, PL (Wiley, 2019-04-01)
    Background Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance of weanling and yearling Thoroughbreds. We investigated the prevalence and radiographic appearance of slab fractures of the third (T3) and central tarsal (Tc) bones. Methods Weanling and yearling horses with complete or incomplete T3 or Tc fracture were identified by searching a database of radiographs. The prevalence and radiographic appearance at initial diagnosis and after continued pasture turnout, as well as prognosis for racing, of fractures of T3 and Tc were determined. Results Fractures were identified in 186 tarsi (184 T3 fracture only, 1 Tc fracture only, 1 Tc and T3 fracture) of 157 horses (126 unilateral T3, 29 bilateral T3, 1 contralateral Tc and T3, 1 unilateral Tc and T3) from 7676 examinations. The prevalence of T3 and Tc fractures was 2.40 (95% CI 2.07, 2.76) and 0.04 (95% CI 0.01, 0.11) per 100 radiographic examinations respectively. Fractures were identified on the D556–65°MPlLO view and occurred by survey examination at 11.1 ± 1.3 months in 85.7% horses. At initial diagnosis, 84.3% of T3 fractures appeared incomplete and involved the distal articular surface. Fracture score improved (P < 0.001), and dorsal modelling (P < 0.001) and osteoarthritis score increased in the distal intertarsal joint (P < 0.001), but not the tarsometatarsal joint, between survey and repository examinations. Fractures healed by repository examination in 71.9% of tarsi if there was > 6 months between examinations. There was no difference in sale price, and horses with T3 fractures had fewer trials when 2 and 3 years old (P = 0.023), yet no difference in other parameters of racing success when 2 or 3 years old compared with controls. Conclusion Tarsal slab fractures can occur in juvenile Thoroughbreds and most heal with continued pasture turnout of > 6 months. Further investigation is required to determine risk factors and before making firm conclusions regarding the optimal management, prognosis for racing and long‐term soundness.