Hmmm, is this my answer? Short cool breaths are a sign that the
horse is cooling itself, not fatigued? And long, gulping breaths more of an
indication of fatigue?
Referring to Part 4 where we discussed
the dangers of Heat and Humidity and Tying-up, there is a third warning signal
of a fatigued horse, and that is inversion.
A horse uses respiration - breathing - for two things : to get oxygen into his body and to cool himself
down. When he's tired, he'll be taking long, gulping breaths with his neck
stretched out, trying to replenish the oxygen debt. His pulse will remain high
and his body temperature won't come down, often hovering above 40 deg C. His
respiration rate - number of breaths - will remain far below his pulse rate.
He'll look deflated and dull, indicating fatigue.
In contrast to the above, a
horse who pants but whose pulse has dropped as usual and his body temperature
remains below 40 deg C, is trying to cool himself down by taking short, cool
breaths. Hot blood is rushed over the lungs, cooled with the new air and the
old, hot air is expelled. The respiration is much higher than his pulse, often
as high as 100 breaths per minute. This is known as inversion.
Inversion is commonly seen in
high heat and humidity conditions, where the horse is using all available means
to cool himself down. Heavily muscled horses tend to pant more as well, as the
muscle mass inhibits heat dispersal through the skin - he now has to use his
respiratory equipment to help cool him down. It's estimated that respiration
contributes as much as 33% to cooling the horse down.
When out riding, pay attention to the quality of your horse's
breaths at different gaits. If he's exerting himself beyond his capability,
he'll be taking gulping breaths of air while trotting or cantering, he's in
oxygen trouble and you'd better slow down to help him recover - and don't push
so hard, your horse told you that he cannot handle that particular exertion
level yet. He'll be breathing easily and lightly if the particular exertion
level is within his capability and you can safely continue.
