Calls for the term ‘lameness’ to be redefined
THE term “lameness” should be redefined to reflect new digital assessment techniques, according to a recent paper published in the Equine Veterinary Journal.
The traditional method for detecting lameness uses visual evaluation of the horse’s gait to identify the presence or absence and degree of asymmetries.
Professor René van Weeren, who wrote the paper with others, said those using this subjective method describe the lame horse as having a “disorder, defect or loss of function” and this clinical diagnosis has associated welfare implications if the horse concerned is still being asked to carry out his usual job.
But advanced computer technology is starting to change the process of determining lameness, using sensors on a horse’s body to record minuscule variations in movement, for example, to enable detailed study of gaits.
SUBTLE CHANGES
ALTHOUGH such methods can detect more subtle asymmetries than the human eye can, this does not necessarily mean a horse is lame in a traditional sense.
“While these digital systems can overcome the limitations of the human eye, they simply rely on one or a number of set gait parameters to decide about lameness and this can present obstacles,” said Professor van Weeren. “What about the effects of the environment or even the mental condition of the horse on these measured or clinically observed asymmetries and irregularities, which are too small to impede daily use of the horse and/or participation in competitions?”
The article, published in the autumn edition of the journal, concludes that on this basis, to use the term “lame” because a horse demonstrates a subtle gait alteration, could be inappropriate, particularly as it may not affect the horse’s welfare in any way.
“Using the term ‘lame’ for any horse not showing the ideal motion pattern when assessed clinically is inadvisable,” said Professor van Weeren. “We should reserve the use of that term for horses deemed unfit to compete based on a comprehensive assessment of the animal that includes, but does not rely entirely on, the appreciation of the degree of gait asymmetry.”
Dr Thilo Pfau of the Royal Veterinary College was one of those who worked with Professor van Weeren on the paper.
“I have spent over 10 years working in this area, trying to provide more and more evidence for what lameness is and I think there is a need to redefine this, because we can measure a small asymmetry but that does not always mean the horse is lame — that is an entirely different question,” he told H&H.
“We need to think about this and reconsider the consequences of making these measurements.”
‘A NASTY LABEL’
VET Karen Coumbe told H&H she is always cautious to use the term lameness, as it becomes a “nasty label”.
“I avoid the term soundness even more as it is even harder to define,” she said, adding that the rider’s ‘hopes’ for the horse should be considered in each case.
“Not only is there a huge variation with riders’ expectations of horses, but it is important to assess whether a horse is fit for purpose, especially if it moves in a particularly unusual way.
“Even more important is whether it is in pain or will come to harm by continuing to move the way it does.”
But Dr Sue Dyson, specialist in equine orthopaedics at the Animal Health Trust, said she does not agree the term “lameness” needs to be redefined.
“I witness daily the fact that people ignore signs of lameness until it deteriorates and it is then far more difficult to treat successfully,” she told H&H.
“I am therefore opposed to moving away from the term lameness — as I use it.”
Dr Dyson said she considers the definition of lameness to be a “pain-related gait abnormality”.
“It is clear there are some horses who have measurable asymmetries in gait that are not pain-induced,” she said.
“I think there are many aspects of lameness that cannot be measured, but which reflect the horse’s adaptation to pain, and cannot be measured in an easy way. These are often best appreciated in ridden horses.
“However for people making decisions based on objective analysis of gait, it is vital they realise that measurable asymmetry does not necessarily equate with a pain-related gait abnormality.
“Moreover, pain-related gait abnormalities can be present without measurable asymmetries.
“It is vital we continue to use our eyes to look at the horses in order to detect all the alterations in movement that can reflect underlying pain and lameness.”
‘It is vital that we continue to use our eyes to look at a horse’ DR SUE DYSON