Abstract: REASONS FOR PERFORMING STUDY: A device is needed to safely and wirelessly evaluate accelerations experienced by the horse hoof under a variety of surface conditions with the horse exercising at training or racing speeds. OBJECTIVES: To develop a miniaturised wireless data acquisition system (WDAS) which reliably records hoof accelerations and the times over which they occur in a minimally invasive manner in the exercising Thoroughbred. METHODS: The following criteria were set for device development: production of a lightweight and minimally invasive system, which provides an adequate acceleration range, appropriate frequency response to capture high speed events, and compatibility with a low power wireless telemetry system. Following device development, the WDAS was calibrated, and tested in 6 Thoroughbred horses over a variety of surfaces. RESULTS: Collection of acceleration in seven trials using 6 horses over a variety of surfaces resulted in repeatable acceleration data with respect to the overall characteristic shape of the impact profile. Impact accelerations varied with surface, ranging 34.8-191.7 g. Accelerations on take off were in a similar range, although higher in some trials. Peak impact accelerations tended to larger over the grass paddock surface, than either the indoor arena or the dirt track. During dirt track trials, accelerations on take-off were often comparably larger than those observed on impact within the same footfall. CONCLUSIONS: This study reports the development of a wireless system that successfully measures hoof acceleration in a minimally invasive manner over a variety of surface and exercise conditions. POTENTIAL RELEVANCE: The WDAS will be used in further studies to evaluate various components of the horse-racetrack interface, in an attempt to identify risk factors for musculoskeletal injury in the Thoroughbred racehorse.

Abstract: Reasons for performing study: Assessing back movement is an important part of clinical examination in the horse and objective assessment tools allow for evaluating success of treatment. Objectives: Accuracy and consistency of inertial sensor measurements for quantification of back movement and movement symmetry during over ground locomotion were assessed; sensor measurements were compared to optical motion capture (mocap) and consistency of measurements focusing on movement symmetry was measured. Methods: Six nonlame horses were trotted in hand with synchronised mocap and inertial sensor data collection (landmarks: T6, T10, T13, L1 and S3). Inertial sensor data were processed using published methods and symmetry of dorsoventral displacement was assessed based on energy ratio, a Fourier based symmetry measure. Limits of agreement were calculated and visualised to compare mocap and sensor data. Consistency of sensor measurements was assessed using Pearson correlation coefficients and linear regression to investigate the effect of speed on movement symmetry. Results: Dorsoventral and mediolateral sensor displacement was observed to lie within ± 4–5 mm (± 2 s.d., 9–28% of movement amplitude) and energy ratio to lie within ± 0.03 of mocap data. High levels of correlation were found between strides and trials (0.86–1.0) for each horse and each sensor and variability of symmetry was lowest for T13 followed by T10, T6, L1 and S3 with no significant effect of speed at T6, T10 and T13. Conclusions: Inertial sensor displacement and symmetry data showed acceptable accuracy and good levels of consistency for back movement. The small mediolateral movement amplitude means that changes of <25% in mediolateral amplitude (also unlikely to be detected by visual assessment) may go undetected. New sensor generations with improved sensor sensitivity and ease of use of equipment indicate good potential for use in a field situation.

Abstract: REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212<W<0.505, P < 0.001). CONCLUSIONS: Correlations between behavioural and heart rate variables in the behavioural tests revealed that horses with a high level of locomotion or much restlessness behaviour exhibited high mean heart rate and low heart rate variability. In particular, heart rate variables in the behavioural tests were found to correlate with riders' rating scores. Furthermore, the underlying components of the handling test, retrieved with a principal component analysis (PCA) correlated with riders' rating scores while the underlying components of the novel object test did not. POTENTIAL CLINICAL RELEVANCE: It is concluded that it is possible for a large panel of assessors to agree upon a horse's temperament and that objective measures from behavioural tests correlate significantly with temperamental traits assessed by a panel of assessors.

Abstract: REASONS FOR PERFORMING STUDY: Clinical history and examination are important features in diagnosis of equine back dysfunction. However, interpretation is subjective and therefore may vary substantially. OBJECTIVES: To establish a clinical tool to objectively evaluate the function of the equine back, in the form of a database on the kinematics of the back at the walk and trot in fully functioning riding horses. METHODS: Thirty-three fully functioning riding horses walked and trotted on a treadmill. Morphometrics and kinematics were tested for correlations to age, height, weight and stride length, and differences between gender (geldings and mares) and use (dressage and showjumping). RESULTS: A database for range of movement and symmetry of movement for extension and flexion, lateral bending, lateral excursion and axial rotation was presented. Symmetry values were very high for all variables. Significant differences were observed in use and gender. Age was negatively correlated to extension and flexion of the thoracolumbar junction. CONCLUSIONS: Interrelationships between use, gender and age to conformation and movement were established. POTENTIAL RELEVANCE: The database provides a basis for objective reference for diagnosis, therapy and rehabilitation of clinical cases of back dysfunction.

Abstract: Reasons for performing study: Crib-biting is an equine stereotypy that may result in diseases such as colic. Certain breeds and management factors have been associated.
Objectives: To determine: breed prevalence of crib-biting in US horses; the likelihood that one horse learns to crib-bite from another; and owner perceptions of causal factors.
Methods: An initial postal survey queried the number and breed of crib-biting horses and if a horse began after being exposed to a horse with this habit. In a follow-up survey, a volunteer subset of owners was asked the number of affected and nonaffected horses of each breed and the extent of conspecific contact. The likelihood of crib-biting given breed and extent of contact was quantified using odds ratio (OR) and significance of the association was assessed using the Chi-squared test.
Results: Overall prevalence was 4.4%. Thoroughbreds were the breed most affected (13.3%). Approximately half of owners believed environmental factors predominantly cause the condition (54.4%) and crib-biting is learned by observation (48.8%). However, only 1.0% of horses became affected after being exposed to a crib-biter. The majority (86%) of horses was turned out in the same pasture with other horses and extent of contact with conspecifics was not statistically related to risk.
Conclusion: This is the first study to report breed prevalence for crib-biting in US horses. Thoroughbreds were the breed more likely to be affected. More owners believed either environmental conditions were a predominant cause or a combination of genetic and environmental factors contributes to the behaviour. Only a small number of horses reportedly began to crib-bite after being exposed to an affected individual, but approximately half of owners considered it to be a learned behaviour; most owners did not isolate affected horses.
Potential relevance: Genetic predisposition, not just intensive management conditions and surroundings, may be a factor in the high crib-biting prevalence in some breeds, and warrants further investigation. Little evidence exists to suggest horses learn the behaviour from other horses, and isolation may cause unnecessary stress.