In addition to warning clients of the complications associated with prosthetic laryngoplasty, it may be prudent to provide a guarded prognosis for full restoration of racing performance in older horses, unless they are especially talented and are free of other racing-related problems.

Bilateral dynamic laryngeal collapse associated with poll flexion is a serious performance-limiting upper respiratory tract disorder that is overrepresented in NCT racehorses. Our results suggest that VFC is not the initiating event in this complex obstructive airway disorder for which there is currently no consistently effective treatment.

Further anatomic or physiological studies comparing these breeds could potentially provide insight into the pathogenesis of certain URT obstructive disorders. Induced poll flexion should be included in routine HSTV examinations of all harness racehorses.

Induced poll flexion significantly affected peak inspiratory pressure (PIP) in all horses; however, PIPs were significantly more negative in those affected with DLC. Based upon the tracheal pressure measurements recorded in this study, DLC in NCTs is a severe obstructive upper respiratory tract disorder that is induced by poll flexion.

No abstract

The associations between certain dynamic diagnoses identified in this study seems best explained as due to local anatomic and functional weaknesses that influence other structures through the Bernouilli principle, rather than being due to a generalised neurological disorder.

The objective of this study was to determine if intraarticular pressure, elastance of the soft tissue forming the dorsal pouch, and range of motion in flexion measurements are significantly different in Thoroughbred metacarpophalangeal joints with clinical evidence of idiopathic synovitis, primary synovitis, synovitis/ capsulitis, or osteoarthritis relative to clinically normal joints. Forty-two metacarpophalangeal joints, in 25 active or retired Thoroughbred racehorses, were categorised by palpation and visual inspection of the palmar pouch into one of 4 increasing grades of distention. Intra-articular pressures were then measured using 2 pressure transducers attached to 22-gauge needles from both the dorsal and palmar pouches simultaneously while the horses stood squarely under mild sedation. After obtaining baseline pressure measurements, a third needle was inserted into the dorsal pouch, and 0.5 ml increments of saline solution were added every 10 s to perform a pressure/volume (elastance) study of the dorsal pouch. The elastance study for each joint ended when leakage into the palmar pouch was detected by the pressure transducer placed in that region. A lateral radiographic view was taken of each metacarpophalangeal joint in maximal flexion. The maximum angle of flexion was measured from the radiograph, and this angle was subtracted from 180" to acquire the range of motion in flexion.In this study, all Thoroughbreds with clinical evidence of lameness and/or sensitivity to flexion, referable to the metacarpophalangeal joint region, had fluid distention of the palmar pouch (grade 2 or 3 distention). The 16 metacarpophalangeal joints with no clinical abnormalities had a mean palmar pouch pressure of -1.25 mmHg. Joints afflicted with synovitislcapsulitis had the highest intraarticular pressures (mean +51.00 mmHg); however, joints with idiopathic synovitis (mean +15.71 mmHg), primary synovitis (mean +28.33 mmHg) and osteoarthritis (mean +26.20 mmHg) also had significantly elevated intraarticular pressures relative to the clinically normal group. Thoroughbred metacarpophalangeal joints diagnosed with *Present address: Department of Large Animal Surgery, Norwegian Veterinary College, Postbox 8146 Dep. 0033 Oslo, Norway. synovitis/capsulitis, or osteoarthritis, had significantly increased elastance (stiffness) of the soft tissue forming the dorsal pouch relative to the normal group and, probably, as a result significantly decreased range of motion in flexion. The presence of primary synovitis alone did not have a significant immediate effect on elastance of the dorsal pouch and range of motion in flexion. The 16 Thoroughbred metacarpophalangeal joints assessed as having no clinical abnormalities had a mean range of motion in flexion of 60.81". The mean range of motion in flexion of Thoroughbred metacarpophalangeal joints with a clinical diagnosis of primary synovitis was 53.67"; idiopathic synovitis 52.14'; synovitislcapsulitis 44.20'; and those with radiographic evidence of moderate to marked osteoarthritis 30.80'....

Background: The Icelandic horse is a pristine breed of horse which has a pure gene pool established more than a thousand years ago, and is approximately the same size as living and extinct wild breeds of horses. This study was performed to compare the length of the skeletal growth period of the "primitive" Icelandic horse relative to that reported for large horse breeds developed over the recent centuries. This information would provide practical guidance to owners and veterinarians as to when the skeleton is mature enough to commence training, and would be potentially interesting to those scientists investigating the pathogenesis of osteochondrosis. Interestingly, osteochondrosis has not been documented in the Icelandic horse.