The Influence of Speed and Height at the Withers on the Kinematics of Sound Horses at the Hand-Led Trot

The influence of speed and height at the withers on some biokinematic stride parameters (linear, temporal and angular) was measured in 15 Spanish Thoroughbreds (Andalusian Purebred) trotted hand-led along a track; analysis was made of the correlation between speed and height at the withers and of some biokinematic parameters of equine locomotion. Both height at the withers and speed were positively and significantly correlated to the linear parameters examined. Temporal parameters did not reveal a significant correlation with the height at the withers. The correlations with the angular parameters were variable, often being significant for both height at withers and speed, although in most cases the coefficient was relatively low, probably owing to the narrow ranges of speed and height at the withers and their low variability. It was concluded that horses at the hand-led trot tend to have low variability in speed during successive trials, although the speed at which they move does have a significant influence on both linear and temporal stride parameters, and also on several angular parameters, while height at the withers has a major effect on linear parameters but less on angular parameters, and does not affect the temporal parameters.     

The effect of training on stride parameters in a cohort of National Hunt racing Thoroughbreds: A preliminary study

Reasons for performing study: The influence of training on stride parameters is controversial and to date there is no information on how training influences stride parameters during high‐speed locomotion in the field. Objective: To determine the influence of training on stride variables during high‐speed locomotion in Thoroughbred racehorses. Methods: Speed, stride frequency, stance and protraction times were quantified in 8 Thoroughbreds with foot mounted accelerometers and GPS sensors during their first week of canter after the summer break and 6 months into training. Results: At a speed of 11 m/s, stride frequency was (mean ± s.d.) 2.160 ± 0.120 strides/s pre‐ and 2.167 ± 0.083 strides/s post training; mean stance time was 125.3 ± 9 ms pre‐ and 125.9 ± 7 ms post training; protraction time was 340.7 ± 20.4 ms pre‐ and 337.2 ± 14.3 ms post training. The increase in stride frequency and the decrease in protraction time after training were significant. There was no statistically significant difference in the maximum speed reached by each horse pre‐ and post training. Conclusions: Stance time stayed constant throughout the training season in the tested horses. A significant decrease in protraction time and a corresponding significant increase in stride frequency were observed after training. Potential relevance: Training of racehorses could be adapted to maximise the effect on modifiable parameters and reduce the risk of training‐induced pathologies. Further research will be conducted to investigate the effect of different training protocols on a large number of horses.     

Kinetics and kinematics of the horse comparing left and right rising trot

Reasons for performing study: At rising trot the rider sits alternately down on one diagonal pair of limbs and rises up on the other. The possible effects on asymmetry of locomotion induced by rising trot have rarely been studied. Objectives: To demonstrate whether, and if so to what extent, rising trot causes asymmetrical loading in the vertical ground reaction force (VGRF) and/or asymmetrical effects on the locomotion pattern, comparing left and right side. Methods: Seven elite horses were ridden in left and right rising trot on a treadmill, while VGRF and kinematics were measured, with the horses' neck raised, the poll high and the bridge of the nose slightly in front of the vertical. Results: Force loading was generally increased in the limbs of the sitting diagonal. The lumbar back was lower between mid‐stances of the sitting and nonsitting stance, pelvic roll was limited and the tuber coxae heights were lower on the sitting side. Maximal hindlimb protraction was decreased. Forelimb retraction was increased and the T6 height decreased. Conclusion: The rider movement induces an uneven biphasic load that affects the back, pelvis and limb kinematics and VGRF. Potential relevance: The generally advocated technique of alternating limbs when riding in rising trot is supported. The VGRF changes between rising on the left or right diagonal were distinct, but minor in absolute terms and therefore unlikely to have direct impact on the occurrence of locomotor injuries. Knowledge of an increase of asymmetry in rising trot is potentially useful for riders/trainers.     

伊犁马1000m速步训练赛各阶段静脉血中血气指标变化研究

利用i-STAT血气分析仪检测12匹伊犁马1000 m速步训练赛静息、热身后及赛后即刻、15 min、30 min、60 min时静脉血中的血气指标,并对各血气指标的差异性和相关性进行统计分析。结果表明,运动前后静脉血中PvCO₂、PvO₂、HCO₃、TCO₂、SvO₂和Glu变化差异不显著(P>0.05)。血液pH、BE和Ca²⁺在赛后即刻均明显降低,但经15 min休息后都基本回升到静息水平;K⁺、Hct和Hb在赛后即刻均显著增加(P<0.05),但经15 min休息后都基本回降到静息水平。血液pH与BE、HCO₃呈极显著正相关(P<0.01),与TCO₂浓度呈显著正相关(P<0.05),Hct、Hb与pH和HCO₃呈极显著负相关(P<0.01),与K⁺呈极显著正相关(P<0.01)。因此,BE、HCO₃、TCO₂、Hct和Hb对酸碱平衡均有一定的调节作用;Na⁺、K⁺和Ca²⁺对机体运动具有一定的调节作用。     

Analysis of Speed Characteristics on 1000 m Trot Training Race in Yili Horse

In order to provide some reference on scientific training and determination of horse trot training race, experiment was conducted on analysis of speed characteristic of Yili horse trot training race. The grade of 7 Yili horses 1000 m trot training race and the speed per 50 m were measured, which was used as a research object and sample, by statistical analysis, correlation analysis, the difference of the linear regression method for quantitative analysis. It was resulted that between subsection speed (2 to 18) and average speed were significantly or extremely significantly correlated (P<0.05;P<0.01), the 9^th subsection speed had the highest relevancy; 6 high correlation subsection speeds were choosed for regression analysis, equation:Y=4.039X₉+2.256X₈－2.653X₁₆－1.361X₅－3.739X₁₃+2.529X₁₉－0.728. The experiment preliminary proved the difference among every subsection speed of 1000 m speed training race and the correlation between subsection speed and average speed, establishing a regression equation of subsection speed and average speed.     

Influence of Fluid Therapy on Gentamicin Pharmacokinetics in Colic Horses

The aminoglycoside antibiotic gentamicin is commonly used in equine medicine for the prevention and treatment of Gram-negative and staphylococcal bacteria in surgically treated colic patients. The pharmacokinetics of gentamicin in these patients might be altered by the disease status, and/or under the influence of fluid therapy. The purpose of this study was to investigate the effect of intravenous fluid treatment on gentamicin kinetics in colic patients. Colic patients subjected to laparotomy were given fluid infusions according to clinical status. Following gentamicin administration, blood samples were taken for gentamicin analysis at different time points, and the main pharmacokinetic parameters including Vc, Vss, t(1/2) and MRT were calculated. Horses undergoing fluid therapy showed a significantly different t(1/2), clearance and MRT as compared to non-infused patients. However, taking into account the clinical status of the patients receiving fluid support, the data suggest that endotoxaemia, rather than fluid therapy, influence gentamicin pharmacokinetics following laparotomy.     

Effects of a synthetic all‐weather waxed track versus a crushed sand track on 3D acceleration of the front hoof in three horses trotting at high speed

Reasons for performing study: Inadequate track surfaces are believed to be a risk factor in the occurrence of musculoskeletal injuries, but quantification of the shocks and vibrations provoked by hoof impact on different ground surfaces (including new synthetic tracks) has been insufficiently documented in trotters under high‐speed training conditions. Objectives: To test the reliability and sensitivity of an accelerometric device to discriminate between the biomechanical effects of 2 different tracks at high speed. Methods: Three French Trotters were used and their right front hooves were equipped with one triaxial accelerometer. Two different track surfaces (crushed sand track: S and all‐weather waxed track: W) were tested when horses were trotting in a straight line. For each session of measurements, trials were repeated 3 times in a Latin square design. The speed of the runs was set at 10 m/s, controlled by the driver and recorded synchronously. Sample rate was set at 6 kHz. Acceleration of the hoof (resultant vector and 3D components), power spectral density at impact and variability (between strides, trials, sessions and horses) were analysed. Statistical differences were tested using a GLM procedure (SAS). Least square mean differences were used for comparisons between tracks (P<0.05). Results: Results showed that the deceleration of the hoof (magnitude of the resultant vector) was statistically different between the 2 tracks with an attenuation of the shock of about 50% on the all‐weather waxed track. Magnitude of the power spectral density was reduced at higher frequencies on W. Conclusions and clinical relevance: These preliminary results demonstrate the sensitivity of the tool to discriminate between the different behaviours of the hoof on the different track surfaces at high speed. Deceleration and vibration of the hoof at impact were reduced on W compared to S, suggesting a better shock‐absorbing quality of this track.     

The Effect of Tungsten Road Nails on Upper Body Movement Asymmetry in Horses Trotting on Tarmac

Tungsten road nails are commonly used by farriers to increase grip between the hoof and the ground surface. There is limited evidence relating the use of road nails to the fundamental mechanics of movement. Grip is important for efficient deceleration on landing and subsequent propulsion, but this must be balanced against an amount of slip to divide the landing force into horizontal as well as vertical subcomponents. Here, we conducted an intervention study to quantify the effect of lateral heel road nail placement on weight bearing and propulsion in 10 horses trotting on tarmac. Wireless inertial measurement units measured vertical movement asymmetry. Differences in head and pelvic movement asymmetry before/after subsequent application of laterally placed road nails to forelimb and hindlimb hooves in a randomized order were compared to zero value (no change) with a one-sample t-test, P < .05. Left-to-right tuber coxae movement amplitude difference was significantly more negative (−3.25 mm, P = .03), suggesting more right than left tuber coxae movement amplitude, after application of a road nail to the left hindlimb. No movement asymmetries at the poll, withers, or sacrum were detected after nail placement (all P > .055). Pelvic movement indicates a very small increase in weight bearing and propulsion provided by the hindlimb with a laterally placed road nail compared to the contralateral hindlimb. Further work is needed to investigate slip- and grip-related parameters at the level of the hoof and to investigate the long-term consequences of very small changes in movement asymmetry.     

Effects of Bedding Material on the Lying Behavior in Stabled Horses

The objective of this study was to investigate the effect of straw, sawdust, coconut husk (husk), and coconut fiber (fiber) on the welfare of stable horses by observing their resting behavior. Twenty horses with ages ranging from 3 to 21 years were used at the Equine Research Institute of the Japan Racing Association, Utsunomiya, Japan. Five horses were allocated to each bedding condition. The behavior of each horse was recorded by video camera for 3 days and was continuously sampled from 17:00 to 05:00. The total duration, the number of bouts, and the mean and the maximum duration of bouts in standing rest, sternal lying, and lateral lying were calculated and analysed by the Kruskal-Wallis test and post hoc Steel-Dwass test. There was no difference in the standing rest and the sternal lying among beddings. Significant differences were observed in these values in the lateral lying among the different beddings (P<0.05). The values of the means of the total duration, the number of bouts, and the mean and the maximum duration of bout in the lateral lying were greater when husk was used as the bedding material than when sawdust were used (P<0.05). The results of the observations show that the new bedding materials would be as usable as straw. However, lateral lying was observed less frequently when sawdust were used as bedding; this indicates that use of sawdust as bedding material will decrease the welfare of stabled horses.     

中国矮马运铁蛋白遗传多态性的初步研究

采用聚丙烯酰胺凝胶电泳对中国矮马运铁蛋白多态性进行了测定。在运铁蛋白位点共发现5种表型，即F2F2，DF2，F2H2，F2O和F2R，由Tf^D,Tf^F2,Tf^F2,Tf^H2,Tf^O和Tf^R等5个等位基因控制，其基因频率分别为0.0312,0.7188,0.0625,0.0312和0.1563；基因的杂合度（H），个体鉴别概率（Dp)和亲仔关系排除概率（PE）分别为0.4530,0.6875和0.2586。