Thermography provides you with a non-invasive, objective reading of the circulatory and inflammatory status of your horse by measuring heat. In conjunction with EasyCare, I am using thermographic techniques to investigate any differences in the heat distribution through the hoof and lower limb of horses using different hoof protection protocols (barefoot, booted and shod). As it will be a while before we finish collecting and collating that data, I thought you might be interested in viewing a few images in the interim.
Dorsal view of a near fore hoof belonging to a well performed barefoot endurance horse. The middle image is a thermograph of the hoof prior to a half hour of barefoot (unbooted), low-intensity exercise on a sand surface. The third image is a themograph of the same hoof immediately on cessation of exercise.
These images reflect what we generally find with all well-trimmed barefoot horses. If you examine the pre-exercise image in the middle, notice:
- The band of heat (red and yellow) at the coronary band is thin and does not extend down the hoof;
- There is a thin cold band (navy) at the bottom edge of the hoof where the wall contacts the ground; and
- The majority of the hoof capsule is of moderate temperature (green and light blue).
Looking at the third, post-exercise image, we notice the entire hoof capsule has increased temperature. As the temperature scale for the two images is the same (16-31degrees C), the colours in the post-exercise hoof look ‘hotter’ but the heat pattern - thin band of heat at coronary band, thin band of cold near ground, majority of the hoof capsule warm – remains the same.
The same two thermographic images as above but with the temperature scale adjusted upward in the second, post-exercise thermograph, to compensate for the increase in temperature to due work. It is apparent just how similar the pre and post-exercise heat patterns are in a well trimmed barefoot horse.
It is probably becoming obvious to you that although it is very difficult to directly compare the feet of different horses, doing different things, in different locations on different days, it is possible to determine statistical trends in both
- changes in actual temperature; and
- changes in temperature patterns (or not) across the hoof.
Solar view of the same hoof with pre and post-exercise thermographs. Just for your interest, note that the collateral sulci by the frog (white and red), along with the coronary bands, and the skin around the eyes, nose and anus are always the hottest areas detected: this is not inflammation at the sulci and does not indicated impacted bars or other such nonsense.
Dorsal view of a near fore hoof belonging to a shod western pleasure show horse. The middle image is a thermograph of the hoof prior to an half hour of low-intensity exercise on a sand surface. The third image is a themograph of the same hoof immediately on cessation of exercise.
As noted, it is not possible to directly compare the thermographs of different horses in differerent location on different days. For example, the temperature scale here (25-35degrees C) is different to the barefoot horse at top (16-31degrees C). However, it is possible to compare patterns of heat across the hoof and changes to those heat patterns with work.
This shod hoof shows an extended hoof capsule, at least by barefoot standards and by the standards of shod horses competing in more athletic events (3-day eventing, endurance riding, etc), though not by show horse standards. Both the farrier and the trainer of this horse considered this a well-shod hoof. Looking at the middle, pre-exercise thermograph, notice:
- The band of heat (pink and red) at the coronary band extends down to encompass well over half the hoof capsule;
- There is a thick cold band (blue) from the bottom edge of the hoof, extending up and over the level of the nail clenches;
- The band of warm hoof (yellow and green) is very thin, merely a transition zone between the hot hoof above and the cold hoof below; and
- The nails are conducting heat. Where the nail clenches are in the cold (blue) portion of the foot they are warmer (green dots), where they are in the warm (green) portion of the foot they are colder (blue).
Although you may consider this a more extreme example, this is the heat pattern we observe in the majority of shod horses.
Looking at the third, post-exercise image, we notice the entire hoof capsule has not only increased temperature but the heat pattern has also changed radically: the entire hoof has become as hot as the coronary band (usually the coronary band is one of the hottest areas detected by thermography and much warmer than other hoof components). As you can see, no amount of image manipulation or temperature scale adjustment will produce a post-exercise image similar to the pre-exercise one.
Later in the year I look forward to sharing with you the results concerning the effects of different hoof protection protocols during more strenuous exercise, in the form of 50 mile rides. Stay tuned.
