Veterinary Science Collected Works - Theses
Permanent URI for this collection
Search Results
1 - 3 of 3
-
ItemStudies of Exercise induced pulmonary haemorrhage in Thoroughbred and Standardbred Racehorses( 2022)Exercise induced pulmonary haemorrhage (EIPH) or ‘bleeding’ is an important disease of exercising horses. Though it is a disease commonly identified by equine veterinary practitioners, there is a lack of information regarding the impact of an episode of EIPH to career after examination or whether occurrence of EIPH is predictive of a horse’s lifetime athletic potential. There also exists a lack of consensus as whether the commonly used treatment, frusemide (a loop diuretic) is an effective medication to reduce or prevent EIPH. This research project addresses these two questions, with the aim of producing high quality information which can be used to underpin evidence based clinical recommendations for EIPH in horses.
-
ItemAn investigation of training and racing workloads in Thoroughbred racehorses in Australia and their relationship to performance and bone fatigue( 2020)Bone and joint injuries in Thoroughbred racehorses typically originate in areas of intense loading and are attributable to fatigue damage accumulated under repetitive cyclical loading. This thesis will focus on an epidemiological understanding of the bone fatigue process as it relates to Thoroughbred training and racing. Factors investigated include workload, stride parameters, speed and distance worked. Specifically, this included an investigation of racehorse management, training and rest compared to previously published risk factors and how they relate to performance, stride characteristics of galloping horses during racing and how varying strides and race factors influence the estimated accumulation of bone damage over race starts. It was hypothesised that (i) there would be a large variation between trainers in the training and rest practices; (ii) greater workloads in training would not be associated with superior race performance; (iii) speed would be correlated with stride parameters, increasing proportionally more with stride duration than the number of strides (and therefore stride length) at higher speeds; (iv) stride parameters would differ by horse-and race-level factors; and (v) a higher percentage of bone fatigue life would be used for longer distance races, firmer track surfaces and higher classed races. These hypotheses were investigated by conducting a semi-structured in-person interview of 66 registered Thoroughbred trainers in Victoria, Australia; by analysing GPS and accelerometer data including speed and stride data from 25,245 Thoroughbred race starts in Tasmania, Australia; and by generating a mathematical model of bone fatigue accumulation using information from the stride parameter data. Australian Thoroughbred training programs include high volumes of galloping with more than half exceeding previously reported risk levels for fracture. Older age and longer intended race distances were associated with higher galloping workloads, and there was a large degree of variation between trainers in workloads, rest practices and surfaces used in training. Trainers who utilised the lowest and highest galloping workloads (at speeds of >13.3 or 13.3-14.3 m/s) as horses prepared for racing had fewer wins and places. There was substantial inter-horse variation in stride parameters, with speed predicting half or less of this variation. Male sex, greater race distance, better finishing position, and firmer track surfaces were associated with fewer strides per 200 m and longer stride durations. Females, older age, longer race distances, firmer track surfaces, and greater weights carried for high-classed races were associated with greater percentage fatigue life accumulated over each race start. There was a wide variety of strategies implemented by trainers in preparing and maintaining horses for racing and managing them between racing campaigns, yet this variation did not translate to how well horses performed. Variation was identified for stride parameters of horses galloping in races under different conditions, but further variation existed based on innate qualities of the individual horse, therefore future studies assessing risk for individual horses would benefit from the inclusion of stride characteristics. The future goal is to establish appropriate racehorse training and racing programs which allow for appropriate bone adaptation to withstand load whilst avoiding fatigue failure.
-
ItemUse of behavioural signs for riskbased prevention of catastrophic breakdown in racehorses( 2020)Bone and joint injuries in Thoroughbred racehorses typically originate in areas of intense loading. Despite the increasing understanding regarding the pathogenesis of bone fatigue, early detection prior to fatigue fracture is difficult. This thesis focuses on understanding equine behaviour and its potential to reflect orthopaedic pain to assist in the early identification of horses at risk of injury. Previous research suggests an association between facial expression and the presence of equine lameness. In cattle, motion sensors have been validated to record recumbency behaviour used to detect disease without the need for continuous observation. This thesis aimed to investigate monitoring of behavioural patterns as predictors of injury in racehorses. In the first study, Thoroughbred racehorses were monitored at rest with motion sensors placed on forelimbs. Sensor data was collected, and an algorithm developed to identify certain behaviours. Algorithms were validated through video observation and calculation of algorithm sensitivity and specificity. There was excellent agreement for standing, lying, and for stepping behaviour patterns suggesting potential for long term, objective, remote monitoring of horses in the stable environments. In the second study, previously validated facial grimace scales were used to score pain from photographs of Thoroughbreds, captured from video recordings during trot up examinations. This method demonstrated horses with moderate mouth strain (HGS) and tense and extended upper lip (FEReq) were associated with horses less likely to be lame. Exposed sclera was associated with lameness in hand, at the trot. Cohen's kappa was used to measure the proportion of agreement between raters, with behaviours scored to more than two categories the kappa was ordinal weighted. Mean inter observer agreement was moderate, and the sum of facial scores showed no difference between lame and sound horses. There were few associations between lameness status and facial predictors, limiting the potential use of facial expression for prediction of orthopaedic pain during pre-race lameness examinations. In conclusion, motion sensors are sensitive to detect horse movements and have potential use in longitudinal monitoring of horse behaviour. Future research in this area includes prediction of behavioural indicators of musculoskeletal pain in racehorses that could contribute to the development of a risk-based injury prevention model. The facial grimace scales had limited ability to differentiate lame from ‘sound’ horses in this cohort of racehorses. External factors associated with racehorse management, including environmental stress, may be one reason facial grimace scales are not effective for the recognition of subtle lameness in this cohort.