Kinematics of the equine transverse gallop

High-speed cinematography was used in documenting linear and temporal kinematic variables of the equine transverse gallop gait. The stride characteristics of four Quarter Horse fillies were used as a model. Horses were approximately thirty months of age and had been raised and trained similarly. Horses were filmed by two cameras simultaneously (243 frames/s) while galloping under the standardized conditions of a specially constructed 1.5 m wide track. The same saddle and bridle was used on all horses, and the horses were all ridden by the same person. Velocities averaged 13.1 m/s, stride lengths 5.06 m, and stride frequencies 2.60s⁻¹. Kinematic variables determined for 29 gallop strides (16 left lead, 13 right lead) included timings and locations for maximum and minimum vertical positions of body surface markers; timings and angular measurements for maximum and minimum absolute angles of body segments; timings, angular measurements and angular velocities for maximum and minimum relative angles between body segments. Of 211 separate kinematic variables measured and reported for the gallop stride, 131 differed significantly (p<0.05) between leading and trailing sides of the body. Stride variables determined in this study may serve as reference values for normal equine gallop motion patterns.     

The interrelationships of stride lengths and stride times to velocities of galloping horses

Side view slow motion movies of galloping horses were taken and analyzed to determine horse velocity, limb velocity, stride length, stride time, and the swing and support timesof the stride. Multivariate statistical methods were used to evaluate the interrelationships of theseparameters. A linear relationship between horse velocity and limb velocity was observed; however, two groups could be distinguished within the trials. In one group, in which the horses were galloping normally, a one-to-one relationship of limb velocity to horse velocity was noted. In the other group, in which the majority of the horses were either lame or restrained by the rider, limb velocities were higher than horse velocities.In general, as horse velocity increased, stride length increased and stride time decreased due to decreases in both the swing and support times of the stride. Increases in stride length contributed more to increases in horse velocity than changes in either swing or support times. Changes in stride length had the greatest effect upon the velocities of those horses that were either lame or restrained by the rider, while the effects of changes in swing and support times contributed relatively more to changes in velocities of the horses which were galloping normally.This study suggests that in lame horses, limb velocity is proportionally greater than horse velocity due to decreases in stride length and stride time.     

Relationships between stride length, stride frequency, velocity, and morphometrics of foals

Velocity-dependent changes in stride length and frequency were studied in 19 male foals, 6 to 8 months of age, and were related to body morphometrics. Eighteen distance and 8 angle measurements were digitized from 16-mm films of standing foals. The total mass and the percentage of total mass acting through the forelimbs were also recorded. Stride length and frequency data were extracted from 16-mm films of 239 strides of the walk, trot, and canter-gallop. Polynomial-regression analysis was used to determine the equation that best described the relationship between data of stride length or frequency vs velocity and stride length vs stride frequency for each foal, for the total population, and for the walk, trot, and canter-gallop data from the total population. Stepwise-regression analysis was done of stride length, or slope of the stride length-velocity line (frequency-1) vs distance, angle, and mass measurements. The stride length for each foal was calculated for a stride frequency of 2 strides/s. The maximum recorded velocity was 11.45 m/s. There was overlap in the velocity ranges at which gaits were used: the walk or trot were used at velocities between 1.7 to 2.0 m/s and a trot or canter were used over a wider velocity range of 3.2 to 5.8 m/s. Stride length did not exceed 4.72 m. The mean stride length at a frequency of 2 strides/s was 2.57 m and was significantly (P less than 0.05) correlated to total mass (r = 0.6335) and length of the metacarpus (r = -0.5115), but not to wither height.(ABSTRACT TRUNCATED AT 250 WORDS)     

辽宁省饲料工业步入发展快车道

<正>饲料工业是畜牧业发展的物质基础和有力保障,是推进农村经济结构战略性调整的重要组成部分。辽宁省作为畜牧业大省,饲料工业发展已经成为转化粮食,拉动畜牧经济发展的重要一环。     

Evaluation of the passive function of the biceps brachii muscle-tendon unit in limitation of shoulder and elbow joint ranges of motion in horses

OBJECTIVE: To quantify the passive contribution of the biceps brachii muscle-tendon unit to the limits of elbow joint extension during shoulder joint flexion in horses. SAMPLE POPULATION: Normal right forelimb specimens from 6 Thoroughbred cadavers. PROCEDURE: Specimens included the scapula, humerus, radius-ulna, biceps brachii muscle-tendon unit, and stabilizers of the shoulder and elbow joints. Specimens were mounted to a rigid board by transfixation pins through the humerus and instrumented for mechanical manipulation of the limb and joint angle and load measurements. Flexion and extension limits of shoulder and elbow joint ranges of motion were measured in each joint separately, while the other joint was fixed. Measurements were made before and after transection of the biceps brachii muscle-tendon unit. RESULTS: The biceps brachii muscle-tendon unit limited elbow joint extension when the shoulder joint was fixed in flexion, limited shoulder joint flexion when the elbow joint was fixed in extension, and inhibited shoulder joint extension to a lesser degree when the elbow joint was fixed at midrange angles of 75 degrees to 90 degrees. CONCLUSIONS AND CLINICAL RELEVANCE: Clinical manipulation of the elbow joint into hyperextension during shoulder joint flexion is indicative of biceps brachii injury.     

Equine metacarpophalangeal joint surface contact changes during walk, trot and gallop

Changes in the staining pattern for the metacarpophalangealjoint in the walking, trotting and galloping positions were studied. For this purpose, horse limbs from the third metacarpal bone distally were harvested and placed in the mid-stance position on a hydraulic press that applied the load required to obtain the palmar fetlock angles corresponding to the walking (218 degrees), trotting (226 degrees) and galloping positions (240 degrees), and a 1:1000 diluted aqueous dilution of methylene blue was injected into the fetlock joint.Based on the results, increasing the palmar fetlockangle in the anatomical specimen caused the contact zones of the proximal phalanx and the proximal sesamoidean bones with the third metacarpal bone joint surface to shift dorsally, thereby increasing the contact surface area between the involved bones.In the galloping position, the proximal phalanx wasfound to extend beyond the dorsal boundary of the third metacarpal bone joint surface and its basal portion to depart from the metacarpus in such a way that the distal sesamoidean ligaments forced the basilar zone of the proximal sesamoidean bones to separate.These phenomena may obviously assist in explaining the intricate biomechanics of the joint as well as its associated pathologies.     

The gait of pacers. 1: kinematics of the racing stride

Standardbred pacers have been studied under race conditions to describe the gait of the pacer, and to determine relationships between stage of the race, finish order and selected gait kinematics. Overlap increased with the stage of the race while pacing speed decreased marginally for low order pacers and increased for high order finishers. High order finishing pacers appear to have greater stance and stride lengths than do low order finishers. Pacers could be separated into low order and high order groups on the basis of their movement patterns. High order pacers exhibited greater ranges of limb motion than did low order finishers.     

The influence of lameness on equine stride length consistency

The aim of this study was to assess the influence of orthopaedic pain on the variation of stride length as a kinematic system-parameter in 21 horses with forelimb lameness. Data were collected while the horses were trotting on a treadmill during a minimum of 12 motion cycles, both before and after intra-articular or perineural anaesthesia. Stride length was assessed for each motion cycle, and the mean and standard deviation were calculated for each condition. Forelimb lameness was documented as percentage of asymmetry of vertical head movement. With significant decrease of forelimb lameness after regional anaesthesia, the SD of stride length increased significantly (+0.35%, P< 0.05). Our results show that in the presence of orthopaedic pain horses keep stride variability low, possibly because the lame horse employs an optimum compensatory mechanism to reduce the pain in the affected limb, and every deviation from this pattern increases pain.     

Technique for continuous stride analysis of horses exercising on a treadmill

A technique for continuous computerised recording and analysis of the stride of horses on a treadmill is described. Advantages of the system are low cost, the use of normal shoes and the calculation of stride parameters in real time.     

Arthrography of the equine shoulder joint

Techniques and normal radiographic anatomy for positive and double contrast shoulder arthrography in horses were evaluated. General anaesthesia was used for most radiographic projections of the shoulder. The mediolateral projection provided the most information during arthrography, although the supinated mediolateral view occasionally allowed better definition of the cartilage surfaces on the medial aspects of the humeral head. The craniocaudal mediolateral oblique and caudocranial projections provided limited additional information. Water soluble non-ionic contrast agents, such as metrizamide and iohexol, were suitable for shoulder arthrography; iohexol resulted in less synovitis and lameness. Arthrography in cases of osteochondrosis and osteochondritis dissecans allowed better evaluation of cartilage attachment to subchondral bone, better evaluation of the length and depth of cartilage lesions and more accurately defined the site and shape of osteocartilaginous free bodies. Cartilage thickening without detachment from the subchondral bone could only be determined by arthrography. Although these thick cartilage regions may later dissect from the subchondral bone, most cases where the cartilage was firmly adherent were not candidates for surgical debridement and carried a favourable prognosis. The determination of a free flap by arthrography indicated the need for surgery. Extensive humeral and glenoid cavity lesions were better defined by arthrography, allowing a rational decision between surgical debridement or euthanasia. Using arthrography, evaluation of the size and patency of the communicating canal to a subchondral cystic defect better separated cases with long, narrow and poorly patent canals for conservative rather than surgical therapy.     

为实现向饲料生产强国的跨越而努力

前不久召开的中央经济工作会议提出:"大力发展畜牧水产业".畜牧业和饲料工业有了新的发展契机.中国是一个畜牧业大国,也是畜产品消费大国,饲料工业大有可为.我们要用办工业的思路来管理饲料工业,继续实施"大原料、大安全、大企业、大市场"战略,为从饲料生产大国向饲料生产强国跨越而努力.     

Osteochondrosis of the shoulder and elbow joints in dogs

Osteochondrosis, a failure of normal endochondral ossification, represents a significant cause of forelimb lameness in medium to large dogs. This paper describes a series of 58 cases of osteochondrosis of the shoulder and elbow diagnosed at a referral centre over a 30-month period. Affected joints which were persistently painful were treated surgically while the non-painful joints were treated conservatively. Details of the radiographic findings are recorded and a grading system is described to enable comparison between the surgically and conservatively treated joints. The progress of the cases was followed over a minimum period of 6 months and the majority of the dogs were re-examined clinically and radiographically.     

Arthrodesis of the shoulder for synovial osteochondromatosis

A case of synovial osteochondromatosis (SOC) in a young deerhound's shoulder is reviewed. The age of onset and initially unaffected articular surfaces suggested primary SOC. Histological criteria for primary versus secondary osteochondromatosis are contradictory and unclear. Initial loose body removal and partial synovectomy resulted in several months of Improvement but loose bodies returned. Severe degenerative changes were found one year after the initial exploratory surgery. Arthrodesis resulted in a functional, non-painful joint.