The ability of riders to judge the soundness of their horses has been called into question in a British study.
“It appears that both amateur and professional riders may be poor judges of the presence of lameness,” Dr Sue Dyson and Line Greve reported in study findings published online in the Journal of Equine Veterinary Science.
Their findings also highlighted the potential importance of including ridden exercise in pre-purchase examinations, with some horses in the study showing lameness only when ridden.
Dyson and Greve, both with the Centre for Equine Studies at the Animal Health Trust, conducted research involving 57 horses in regular work. All were considered by their riders, trainers and owners to be sound.
The soundness of each of the animals was assessed subjectively in hand, on the lunge and ridden. The assessments were carried out by Dyson, who is an experienced lameness clinician and head of clinical orthopaedics at the centre.
Twenty-seven of the horses showed lameness ridden, including 7 who showed lameness only under saddle.
Just 20 of the horses – 35 percent – were assessed as being free from lameness under all circumstances. However, when reassessed in the days following, a further 6 of these 20 were found to be lame, including another 2 under saddle.
The assessments of the horses involved not only visual observation of the movement of the horses on both soft and firm surfaces, but flexion tests of all four limbs, which were also carried out by Dyson.
Lameness was graded from 0-8 under each circumstance in which the horse was examined, and after each flexion test.
Dyson and Greve reported that 14 horses (24.6%) were sound under all circumstances. Six were sound in hand, on the lunge and ridden, but showed a grade 1 or 2 lameness after flexion of a single limb.
Sixteen horses (26.3%) were found to be lame in hand.
Twenty-four horses (42.1%) showed lameness on the lunge on a soft surface and 23 horses (40.4%) were lame on the lunge on a firm surface.
Twenty-seven horses (47.4%) showed lameness ridden; while 7 (12.3%) were lame only when ridden.
The researchers found no significant association between age or work discipline and lameness.
The pair noted that, traditionally, lameness has been evaluated in hand or in circles, but there was an increasing body of evidence that some lamenesses were only apparent when horses were ridden. Ridden exercise was not part of a pre-purchase examination in many countries in Europe and North America.
“Freedom from lameness in straight lines is not a reliable indicator of soundness,” the pair concluded. “Some lamenesses are only apparent ridden.”
The horses used in the study were based at four yards, three of which undertook dressage work and one was focused on showjumping.
An overall grading of sound was given if no lameness was detectable in hand, on the lunge or ridden and, lameness of not more than 1/8 was detected in a single limb after flexion tests.
“In accordance with our hypothesis, lameness may be apparent in ridden horses that was not detectable in hand or on the lunge,” the pair said, with 7 of the 57 horses showing lameness that was apparent only when being ridden.
“Furthermore, reassessment of the 20 horses considered sound in all circumstances revealed another two showing lameness when ridden.”
The pair said the results highlighted the potential importance of ridden exercise as part of both a pre-purchase examination and a lameness investigation.
“If a horse is not assessed ridden at a pre-purchase examination pre-existing lameness may be overlooked,” they said.
“During a lameness investigation a problem perceived by a rider during ridden exercise may not be accurately represented by examination in hand and on the lunge.”
It was a common clinical observation that horses with hindlimb lameness showed lameness only when ridden, or lameness is exacerbated ridden, especially when sitting on the diagonal of the lame limb, they noted.
“The results confirm previous observations that there is a disturbingly high proportion of lame horses which are in regular work and assumed to be sound.
“While these horses may be able to perform, it is likely that they would perform better if free from lameness.”
Dyson and Greve said the findings emphasised the importance of better education of riders and trainers to enable them to detect lameness.
They acknowledged some limitations in study, including that the gaits were assessed subjectively, not objectively.
“Nonetheless the proportion of lame horses was similar to a previous considerably larger study,” they wrote.
Greve is conducting doctoral research with the Animal Health Trust and the Royal Veterinary College.
Subjective gait assessment of 57 sports horses in normal work: a comparison of the response to flexion tests, movement in hand, on the lunge and ridden
Sue Dyson, Line Greve.
The abstract can be read here.