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The accuracy of the methods used to measure horses and ponies has been put in the spotlight by British researchers.
For ponies hovering around the 148cm mark, the results of official measuring can mean the difference between a career in the pony ring or life as a "too-small" hack. Few undersized horses do "make it" in open competition - take the eventing dynamo Theodore O'Connor for example. At 14.1¾hh - well under the pony height limit - he not only completed the four-star Kentucky three-day event earlier this year, but finished third, and has also topped USEA Horse of the Year Leaderboard for the season.
But how accurate are the methods we use to measure the height of a horse? And what factors affect the accuracy?
Researchers at the Queens Veterinary School Hospital, University of Cambridge, have been looking at different methods of measuring horse height, and assessing the effect of various factors on the resulting measurement. The study has been led by Dr Luis Lamas.
The traditional measuring stick has a scale on the vertical portion and a horizontal arm, which is placed onto the highest point of the horse's withers. A single spirit level helps to position the stick perpendicular to the ground.
The researchers compared the accuracy of three measuring sticks. The most accurate (or least variable) results were obtained by using a measuring stick with two spirit levels at right angles to each other on the horizontal bar. This stick gave a 57% improvement in accuracy compared with the traditional stick with only one spirit level. There was no further significant improvement in accuracy when a laser measuring device was fitted to the horizontal arm.
So for the second part of the study, which looked at the effect of various factors on the accuracy of the measurement, they used the modified measuring stick with the two extra spirit levels.
They found that there was often a slight variation in height when an individual horse was measured several times. This was the case even if the conditions were the same and the same examiner carried out the measurement. Three consecutive measurements carried out by one person on the same horse gave a range of measurements of ±1.06cm.
There was more variation (±1.89cm) when three different people performed the measurements. This is likely to be due to differences in the examiner's choice of the highest point of the withers and how hard they pressed the measuring arm down onto the withers.
Relaxation was an important factor in getting consistent readings. Unlike the hind limbs, which are attached firmly to the spine through the sacro-iliac joint, the forelimbs are attached only by muscle. The horse's trunk is suspended in a cradle of muscles that extends from one shoulder blade to the other. Contraction and relaxation of these muscles allows the chest (and hence the withers) to move up and down. Allowing the horses to adapt to their surroundings led to a reduction in height (0.84cm). Low doses of tranquillisers had a similar but less marked effect.
Head position had an effect on the measurements - especially if it was raised as high as possible or lowered to the ground. Raising the head resulted in a small increase in height. Lowering the head slightly produced a small reduction in height, but lowering the head to a grazing position resulted in a significant reduction.
In this study, neither transportation nor lunging had a significant effect on height.
For ponies hovering around the 148cm mark, the results of official measuring can mean the difference between a career in the pony ring or life as a "too-small" hack. Few undersized horses do "make it" in open competition - take the eventing dynamo Theodore O'Connor for example. At 14.1¾hh - well under the pony height limit - he not only completed the four-star Kentucky three-day event earlier this year, but finished third, and has also topped USEA Horse of the Year Leaderboard for the season.
But how accurate are the methods we use to measure the height of a horse? And what factors affect the accuracy?
Researchers at the Queens Veterinary School Hospital, University of Cambridge, have been looking at different methods of measuring horse height, and assessing the effect of various factors on the resulting measurement. The study has been led by Dr Luis Lamas.
The traditional measuring stick has a scale on the vertical portion and a horizontal arm, which is placed onto the highest point of the horse's withers. A single spirit level helps to position the stick perpendicular to the ground.
The researchers compared the accuracy of three measuring sticks. The most accurate (or least variable) results were obtained by using a measuring stick with two spirit levels at right angles to each other on the horizontal bar. This stick gave a 57% improvement in accuracy compared with the traditional stick with only one spirit level. There was no further significant improvement in accuracy when a laser measuring device was fitted to the horizontal arm.
So for the second part of the study, which looked at the effect of various factors on the accuracy of the measurement, they used the modified measuring stick with the two extra spirit levels.
They found that there was often a slight variation in height when an individual horse was measured several times. This was the case even if the conditions were the same and the same examiner carried out the measurement. Three consecutive measurements carried out by one person on the same horse gave a range of measurements of ±1.06cm.
There was more variation (±1.89cm) when three different people performed the measurements. This is likely to be due to differences in the examiner's choice of the highest point of the withers and how hard they pressed the measuring arm down onto the withers.
Relaxation was an important factor in getting consistent readings. Unlike the hind limbs, which are attached firmly to the spine through the sacro-iliac joint, the forelimbs are attached only by muscle. The horse's trunk is suspended in a cradle of muscles that extends from one shoulder blade to the other. Contraction and relaxation of these muscles allows the chest (and hence the withers) to move up and down. Allowing the horses to adapt to their surroundings led to a reduction in height (0.84cm). Low doses of tranquillisers had a similar but less marked effect.
Head position had an effect on the measurements - especially if it was raised as high as possible or lowered to the ground. Raising the head resulted in a small increase in height. Lowering the head slightly produced a small reduction in height, but lowering the head to a grazing position resulted in a significant reduction.
In this study, neither transportation nor lunging had a significant effect on height.