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  • Author or Editor: René van Weeren x
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Objective—To determine whether differences in jumping technique among horses are consistent at various ages.

Animals—12 Dutch Warmblood horses.

Procedure—Kinematics were recorded during free jumps of horses when they were 6 months old (ie, no jumping experience) and 4 years old (ie, the horses had started their training period to become show jumpers). Mean ± SD height of the horses was 1.40 ± 0.04 m at 6 months of age and 1.70 ± 0.05 m at 4 years of age.

Results—Strong correlations were found between values from 6-month-old foals and 4-year-old horses for variables such as peak vertical acceleration generated by the hind limbs ( r, 0.91), peak rate of change of effective energy generated by the hind limbs ( r, 0.71), vertical velocity at takeoff ( r, 0.65), vertical displacement of the center of gravity during the airborne phase ( r, 0.81), and duration of the airborne phase ( r, 0.70).

Conclusions and Clinical Relevance—Although there are substantial anatomic and behavioral changes during the growing period, certain characteristics of jumping technique observed in naïve 4-year-olds are already detectable when those horses are foals. ( Am J Vet Res 2004;65:945–950)

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in American Journal of Veterinary Research


Objective—To determine the speed of sound (SOS) in equine articular cartilage and investigate the influence of age, site in the joint, and cartilage degeneration on the SOS.

Sample Population—Cartilage samples from 38 metacarpophalangeal joints of 38 horses (age range, 5 months to 22 years).

Procedure—Osteochondral plugs were collected from 2 articular sites of the proximal phalanx after the degenerative state was characterized by use of the cartilage degeneration index (CDI) technique. The SOS was calculated (ratio of needle-probe cartilage thickness to time of flight of the ultrasound pulse), and relationships between SOS value and age, site, and cartilage degeneration were evaluated. An analytical model of cartilage indentation was used to evaluate the effect of variation in true SOS on the determination of cartilage thickness and dynamic modulus with the ultrasound indentation technique.

Results—The mean SOS for all samples was 1,696 ± 126 m/s. Age, site, and cartilage degeneration had no significant influence on the SOS in cartilage. The analytical model revealed that use of the mean SOS of 1,696 m/s was associated with maximum errors of 17.5% on cartilage thickness and 7.0% on dynamic modulus in an SOS range that covered 95% of the individual measurements.

Conclusions and Clinical Relevance—In equine articular cartilage, use of mean SOS of 1,696 m/s in ultrasound indentation measurements introduces some inaccuracy on cartilage thickness determinations, but the dynamic modulus of cartilage can be estimated with acceptable accuracy in horses regardless of age, site in the joint, or stage of cartilage degeneration. (Am J Vet Res 2005;66:1175–1180)

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in American Journal of Veterinary Research