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Cassiat, G., Pourcelot, P., Tavernier, L., Geiger, D., Denoix, J. M., & Degueurce, D. (2004). Influence of individual competition level on back kinematics of horses jumping a vertical fence. Equine Vet J, 36(8), 748–753.
Abstract: REASONS FOR PERFORMING STUDY: The costs and investments required for the purchase and training of showjumpers justify the need to find selection means for jumping horses. Use of objective kinematic criteria correlated to jumping ability could be helpful for this assessment. OBJECTIVES: To compare back kinematics between 2 groups of horses of different competition levels (Group 1, competing at high level; Group 2 competing at low level) while free jumping over a 1 m vertical fence. METHODS: Three-dimensional recordings were performed using 2 panning cameras. Kinematic parameters of the withers and tuber sacrale (vertical displacement, vertical and horizontal velocities), backline inclination and flexion-extension motion of the 3 main dorsal segments (thoracic, thoracolumbar and lumbosacral) were analysed. RESULTS: Group 2 horses had a lower displacement of their withers and tuber sacrale from the end of the last approach stride until the first departure stride (P<0.05). As a result, they increased the flexion of their thoracolumbar and lumbosacral junctions during the hindlimb swing phase before take-off (P<0.05). However, withers and tuber sacrale velocities were slightly modified. Group 1 horses pitched their backline less forward during the forelimb stance phase before take-off and straightened it more after landing (P<0.05), probably indicating a more efficient strutting action of their forelimbs. CONCLUSIONS AND POTENTIAL RELEVANCE: Because significant differences in back motion were found between good and poor jumpers when jumping a 1 m high fence, criteria based on certain back kinematics can be developed that may help in the selection of talented showjumpers.
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Fruehwirth, B., Peham, C., Scheidl, M., & Schobesberger, H. (2004). Evaluation of pressure distribution under an English saddle at walk, trot and canter. Equine Vet J, 36(8), 754–757.
Abstract: REASONS FOR PERFORMING STUDY: Basic information about the influence of a rider on the equine back is currently lacking. HYPOTHESIS: That pressure distribution under a saddle is different between the walk, trot and canter. METHODS: Twelve horses without clinical signs of back pain were ridden. At least 6 motion cycles at walk, trot and canter were measured kinematically. Using a saddle pad, the pressure distribution was recorded. The maximum overall force (MOF) and centre of pressure (COP) were calculated. The range of back movement was determined from a marker placed on the withers. RESULTS: MOF and COP showed a consistent time pattern in each gait. MOF was 12.1 +/- 1.2 and 243 +/- 4.6 N/kg at walk and trot, respectively, in the ridden horse. In the unridden horse MOF was 172.7 +/- 11.8 N (walk) and 302.4 +/- 33.9 N (trot). At ridden canter, MOF was 27.2 +/- 4.4 N/kg. The range of motion of the back of the ridden horse was significantly lower compared to the unridden, saddled horse. CONCLUSIONS AND POTENTIAL RELEVANCE: Analyses may help quantitative and objective evaluation of the interaction between rider and horse as mediated through the saddle. The information presented is therefore of importance to riders, saddlers and equine clinicians. With the technique used in this study, style, skill and training level of different riders can be quantified, which would give the opportunity to detect potentially harmful influences and create opportunities for improvement.
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Perkins, N. R., Reid, S. W. J., & Morris, R. S. (2004). Effect of training location and time period on racehorse performance in New Zealand. 1. Descriptive analysis. N Z Vet J, 52(5), 236–242.
Abstract: AIM: To describe characteristics of Thoroughbred training stables in Matamata and in all other locations in New Zealand combined, over two 19-month time periods in 1996-1997 and 1998-1999, representing equal length periods immediately prior to and after the construction of a new training surface at the Matamata Racing Club. METHODS: Retrospective records covering all horses training and racing in New Zealand during two 19-month time periods (1996-1997 and 1998-1999), covering 161 locations, were obtained from New Zealand Thoroughbred Racing (NZTR). Outcome variables included whether a horse was raced again in the 6 months following any start in the first 13 months of either time period, number of race starts for every horse, and finishing position. Summary measures with confidence intervals (CI) and unadjusted odds ratios (OR), measuring strength of associations for various factors, were computed. RESULTS: The datasets contained information on 45,446 horses, 11,336 races, 5,110 trials and a total of 110,643 race starts. Horses trained at Matamata represented 8% (3,715) of the total horse datasets, and accounted for 11,977 race starts (10.8%). They were more likely to start in a race or trial in either time period and were 1.4 and 1.3 times as likely to finish first, second or third compared with horses trained at other locations in 1996-1997 and 1998-1999, respectively. A 6-month no-race period occurred for 9,306/12,584 (74%) horses that started at least once in the first 13 months of either time period. Horses trained at Matamata were less likely to have a 6-month no-race period than horses trained at other locations in both time periods. There was no effect of time period within each location on the probability of either a horse having a 6-month no-race period or of a race start being followed by a 6-month no-race period, but there was an overall effect of time and more 6-month no-race periods were observed in 1998-1999 relative to 1996-1997. CONCLUSION: Summary statistics are presented for Thoroughbred racing in New Zealand over two 19-month time periods. Differences between the populations of horses trained in Matamata compared with those trained at other locations were attributed, in part, to the fact that many of the more successful racehorse trainers in the country have stables at Matamata. As a result, the population of horses in Matamata may not be representative of the racehorse population in New Zealand. Although more likely to win or place in both time periods, the magnitude of the advantage to horses in Matamata was reduced in 1998-1999 relative to 1996-1997, and this could be due, in part, to effects of the new track surface at Matamata. There was no evidence of a rise in risk of a 6-month no-race period following any race start in those horses trained in Matamata in 1998-1999 relative to either horses trained at other locations or to horses trained in Matamata during the earlier time period.
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Perkins, N. R., Reid, S. W. J., & Morris, R. S. (2004). Effect of training location and time period on racehorse performance in New Zealand. 2. Multivariable analysis. N Z Vet J, 52(5), 243–249.
Abstract: AIM: To investigate training location (horses trained in Matamata vs those trained at all other venues in New Zealand), and time period (1996-1997 and 1998-1999), while controlling for other horse- and race- or trial-related factors, as a means of assessing the possible impact of construction of a new training surface at the Matamata Racing Club on indirect measures of racehorse performance (number of starts, and failure to race within 6 months of any start). METHODS: Multivariable logistic regression and poisson analysis were used to analyse data derived using a retrospective cohort approach. Multivariable logistic regression was also used to analyse a case-control study. All data were derived from New Zealand Thoroughbred Racing (NZTR), records of race and trial results for racehorses trained in Matamata and other venues in New Zealand, covering two 19-month time periods (1996- 1997 and 1998-1999). Outcome variables included whether a horse started again in the 6 months following any start that occurred in the first 13 months of either time period, and a count of the total starts for every horse. RESULTS: Factors associated with increased risk of a start being followed by a 6-month no-race period included training location other than Matamata in comparison to horses trained in Matamata in the 1996-1997 time period, increasing age, 1998- 1999 over 1996-1997, starting in a trial rather than a race, placing fourth or worse in a start, softer track conditions, summer vs autumn, increasing cumulative exercise intensity in the 60 days prior to a start, and increasing race distance. Factors associated with an increase in the total number of starts included horses trained at Matamata in 1996-1997 compared with other time period-location combinations, younger age of horses at the time of a start, longer race distance, and an increasing proportion of starts in stakes races. CONCLUSIONS: Official race and trial results data provided a valuable resource for epidemiological studies of factors influencing racehorse performance. Results of analyses performed here provided little evidence of any adverse impact of a new training surface at the Matamata Racing Club on indirect measures of racehorse performance.
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Murray, J. K., Singer, E. R., Morgan, K. L., Proudman, C. J., & French, N. P. (2004). Memory decay and performance-related information bias in the reporting of scores by event riders. Preventive Veterinary Medicine, 63(3-4), 173–182.
Abstract: We used data from a case-control study investigating risk factors for horse falls in the cross-country phase of eventing in Great Britain (GB) to examine evidence for memory decay and information bias. Responses to two questions obtained by telephone for 173 cases and 521 controls were examined for evidence of differential reporting according to the respondent's case-control status and performance in the dressage and cross-country phases of competitions. Information bias was found in the accuracy of reporting dressage penalty scores when analysed as a function of performance level (good/poor). Poor dressage performers were less likely to report accurate dressage scores than good performers. The accuracy of reporting dressage scores decreased as the time between the event and questionnaire completion increased, with no case-control interaction. Competitors who incurred cross-country jumping penalties at the event preceding the selected event reported their cross-country scores with less accuracy when compared with competitors who incurred no penalties. No information bias was found when the reporting of dressage and cross-country scores were analysed as a function of respondent category (case/control).
Keywords: Reporting bias; Memory decay; Risk factors; Horse; Cross-country
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Koenen, E. P. C., Aldridge, L. I., & Philipsson, J. (2004). An overview of breeding objectives for warmblood sport horses. Livestock Production Science, 88(1-2), 77–84.
Abstract: The aim of this paper is to review the current breeding objectives of organisations that run a selection programme for warmblood riding horses in the light of an increasing trend in trade of semen across countries. In a questionnaire, 19 horse breeding organisations provided information on breeding objective traits. Variation both in length and amount of details used to define individual breeding objectives was large, reflecting that many traits in sport horse breeding are not easy to measure, and therefore, have to be defined in a subjective way. The majority of the breeding objectives included conformation, gaits and performance in show jumping and dressage. Some breeding objectives also included behaviour, soundness, health and fertility. However, several organisations did not specify the sport discipline and the level of competition (amateur, national or international level) in the breeding objective. In general, relative weightings of the traits within the verbally presented breeding objectives were not given, but were assessed by the organisations in response to this study. The relevance of more information on expected future production circumstances and on the genetic parameters of the traits of interest are discussed. A further review of the consistency, completeness and the number of traits of the present breeding objectives for sport horses is recommended to optimise the efficiency of selection decisions.
Keywords: Breeding objective; Sport horse; Sport performance; Conformation; Specialisation
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Uzawa, T., Akiyama, S., Kimura, T., Takahashi, S., Ishimori, K., Morishima, I., et al. (2004). Collapse and search dynamics of apomyoglobin folding revealed by submillisecond observations of alpha-helical content and compactness. Proc. Natl. Acad. Sci. U.S.A., 101(5), 1171–1176.
Abstract: The characterization of protein folding dynamics in terms of secondary and tertiary structures is important in elucidating the features of intraprotein interactions that lead to specific folded structures. Apomyoglobin (apoMb), possessing seven helices termed A-E, G, and H in the native state, has a folding intermediate composed of the A, G, and H helices, whose formation in the submillisecond time domain has not been clearly characterized. In this study, we used a rapid-mixing device combined with circular dichroism and small-angle x-ray scattering to observe the submillisecond folding dynamics of apoMb in terms of helical content (f(H)) and radius of gyration (R(g)), respectively. The folding of apoMb from the acid-unfolded state at pH 2.2 was initiated by a pH jump to 6.0. A significant collapse, corresponding to approximately 50% of the overall change in R(g) from the unfolded to native conformation, was observed within 300 micros after the pH jump. The collapsed intermediate has a f(H) of 33% and a globular shape that involves >80% of all its atoms. Subsequently, a stepwise helix formation was detected, which was interpreted to be associated with a conformational search for the correct tertiary contacts. The characterized folding dynamics of apoMb indicates the importance of the initial collapse event, which is suggested to facilitate the subsequent conformational search and the helix formation leading to the native structure.
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Hirota, S., Suzuki, M., & Watanabe, Y. (2004). Hydrophobic effect of trityrosine on heme ligand exchange during folding of cytochrome c. Biochem Biophys Res Commun, 314(2), 452–458.
Abstract: Effect of a hydrophobic peptide on folding of oxidized cytochrome c (cyt c) is studied with trityrosine. Folding of cyt c was initiated by pH jump from 2.3 (acid-unfolded) to 4.2 (folded). The Soret band of the 2-ms transient absorption spectrum during folding decreased its intensity and red-shifted from 397 to 400 nm by interaction with trityrosine, whereas tyrosinol caused no significant effect. The change in the transient absorption spectrum by interaction with trityrosine was similar to that obtained with 100 mM imidazole, which showed that the population of the intermediate His/His coordinated species increased during folding of cyt c by interaction with trityrosine. The absorption change was biphasic, the fast phase (82+/-9s(-1)) corresponding to the transition from the His/H(2)O to the His/Met coordinated species, whereas the slow phase (24+/-3s(-1)) from His/His to His/Met. By addition of trityrosine, the relative ratio of the slow phase increased, due to increase of the His/His species at the initial stage of folding. According to the resonance Raman spectra of cyt c, the high-spin 6-coordinate and low-spin 6-coordinate species were dominated at pH 2.3 and 4.2, respectively, and these species were not affected by addition of trityrosine. These results demonstrated that the His/His species increased by interaction with trityrosine at the initial stage of cyt c folding, whereas the heme coordination structure was not affected by trityrosine when the protein was completely unfolded or folded. Hydrophobic peptides thus may be useful to study the effects of hydrophobic interactions on protein folding.
Keywords: Amino Acids/chemistry; Animals; Cytochromes c/*chemistry; Heme/*chemistry; Histidine/chemistry; Horses; Hydrogen-Ion Concentration; Kinetics; Ligands; Myocardium/chemistry; Peptides/chemistry; Protein Folding; Spectrophotometry; Spectrum Analysis, Raman; Tyrosine/*analogs & derivatives/*chemistry
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Kasashima, Y., Takahashi, T., Smith, R. K. W., Goodship, A. E., Kuwano, A., Ueno, T., et al. (2004). Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999. Equine Vet J, 36(4), 346–350.
Abstract: REASONS FOR PERFORMING STUDY: Overstrain injuries to the superficial digital flexor tendon (SDFT) and suspensory ligament (SI) are among the most common musculoskeletal injuries which contribute to the considerable wastage of racing Thoroughbreds. Many epidemiological studies have demonstrated the prevalence of and risk factors for tendon injury when racing but have not included those injuries sustained during training. However, since tendon injury during training is seen commonly in clinical practice, it is appropriate to determine the overall prevalence of tendon injury sustained during both training and racing. OBJECTIVE: To determine the prevalence of overstrain injury to the SDFT and SL during training and racing among Thoroughbred flat racehorses in Japan in 1999. METHODS: A retrospective study was performed using a sample population of 10,262 Thoroughbred racehorses. The medical information database of Thoroughbred racehorses registered by the Japan Racing Association (JRA) in 1999 was analysed for SDFT and SL overstrain injury diagnosed by a veterinarian employed by JRA during training and racing. Jump racehorses were excluded from this study. RESULTS: The prevalence of forelimb SDFT tendonitis and SL desmitis was 11.1% (1130 cases) and 3.61% (370 cases) of the population, respectively. In the hindlimb, there were 0.06% (6 cases) and 0.14% (14 cases), respectively. Risks of SDF tendonitis in the forelimb in 3-year-olds or older horses were significantly higher than in 2-year-olds. In contrast, the risk of SL desmitis in the forelimb at age 3 and 4 years was 2.23 and 2.11 times higher, respectively, than in 2-year-olds, but this increased to 5.07 times in those age > or = 5 years. Entire males were at greater risk in comparison to females and geldings. CONCLUSIONS: The results suggest that the prevalence of SDF tendonitis and SL desmitis in the forelimb was associated with the horse's age and sex. The prevalence of SL desmitis increased further with age compared with SDF tendonitis, possibly reflecting a more rapid accumulation of degeneration in this structure. POTENTIAL RELEVANCE: The age-related risk demonstrated in this study provides further support that overstrain injuries are associated with accumulated degeneration. These data provide a valuable resource for further research into the aetiology of tendon injury in the racehorse.
Keywords: Age Factors; Animals; Female; Forelimb; Hindlimb; Horse Diseases/*epidemiology/etiology; Horses; Inflammation/epidemiology/etiology/*veterinary; Japan/epidemiology; Ligaments/injuries/*pathology; Male; Musculoskeletal Diseases/epidemiology/etiology/veterinary; *Physical Conditioning, Animal; Prevalence; Retrospective Studies; Risk Factors; Sex Factors; Sports; Tendinopathy/epidemiology/etiology/*veterinary; Tendon Injuries/epidemiology/etiology/*veterinary
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Pinchbeck, G. L., Clegg, P. D., Proudman, C. J., Morgan, K. L., & French, N. P. (2004). Case-control investigation of the factors affecting the risk of horses falling during steeplechase racing in the UK. Vet. Rec., 155(1), 11–15.
Abstract: A concurrent case-control study of 12 UK racecourses was made between March 1, 2000, and August 31, 2001, to identify and quantify the factors associated with the risk of horses falling in steeplechase races. Cases were defined as a jumping effort at a steeplechase fence that resulted in a fall and controls were defined as a successful jumping effort over any steeplechase fence at any of the 12 racecourses within 14 days before or after the case fall. Information on the horse, the jockey and the race were collected and all the fences on all the courses were surveyed. Conditional logistic regression was used to examine the relationships between the predictor variables and the risk of falling. There was one fall per 254 jumping efforts. The risk of a horse falling decreased the more times it had raced on a particular racecourse. The number of fences, the distance from the previous fence and the nature of the previous fence also affected the risk of falling. If the previous fence was a water jump the risk of falling increased; fences that were sited on flat or slight uphill gradients (up to approximately 1 in 25) were associated with a lower risk of horses falling than downhill fences, and higher takeoff boards were associated with a higher risk of falling.
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