On Mythbuster Monday, we tackle a variety of equestrian myths to either bust or confirm. Today’s discussion: Can horses breathe through their mouths?
It’s Mythbuster Monday, where Horse Nation dives into different equestrian myths and provides research-based evidence to either bust or confirm those myths. Today’s topic: Can horses breathe through their mouths? Do different bits in a horse’s mouth hinder breathing? What happens if their nose is stuffed? Read further to find out!
Myth: Horses can’t breathe through their mouths
Myth or Fact: Fact
The upper respiratory tract begins at the horse’s nose and runs down the back of the throat to the trachea and then to the lungs. The soft palate separates the nasal cavities from the oral cavities. This makes horses obligate nasal breathers. The epiglottis sits on top of the soft palate and blocks air flow from the mouth to the trachea and lungs.
An article by Camille Saute of Equisense compares the soft palate of a human versus a horse. While a human’s soft palate ends as a drop, horses have a longer soft palate that closes the connection between the nose and digestive tract. Therefore, horses can only breathe out of their noses.
While this may seem like it would cause issues during activity, horses have different ways they obtain the amount of oxygen needed. One of the ways horses can capture oxygen is by contracting their spleens. When doing this, they release red blood cells into the bloodstream which allows the capture of more oxygen.
According to Grace Eire in her article, the upper respiratory tract only being connected to the nostrils aids in the prevention of inhaling and choking on food particles. However, it is a downfall when horses are in respiratory distress because they can not use their mouth to aid in breathing.
Dr. David Marlin, an exercise physiologist, states in his article that horses can only breathe from their noses. This is because the soft palate completely separates the mouth from the airway. When horses breathe while working, they breathe in time with their strides. A cantering horse takes one breath for every stride. The inability to use the mouth to breathe makes this important. If the horse can not get his breaths to match his strides he may become anxious or unsettled.
During exercise, when humans begin to get winded, they tend to start to breathe out of their mouths. Because horses can not do this, they adjust their breathing to their gait When going from a trot to canter to gallop, instead of breathing faster horses tend to breathe deeper. The longer the stride, the more time the horse has to fill his lungs.
David J. Mellor, PhD and professor of animal welfare science, states in an article by The Horse, that tack can affect a horse’s breathing and feelings of breathlessness. Horses are obligate nasal breathers but factors in the mouth can interfere with the breathing from the nose. Mouth-gaping due to bit pain puts the horse in positions that make it more difficult for him to breath from his nose.
A horse that gives to the bit or is bit-free can hold the soft palate down onto the tongue allowing optimal breathing from the nose. The slightest gape from fighting the bit can make it more difficult for a horse to breathe.
An equestrian who rides on a tight rein cramps a horse’s head and neck into a position that also decreases nasal breathing.
After diving into the research, it appears that horses can only breathe through their noses. Ill fitting bits can cause a horse to gape his mouth open, causing a decrease in air flow to the lungs. While exercising horses have some “tricks” they use to maintain optimal air flow through their nose. The sync their breathing to their strides and/or use spleen contractions to increase oxygenation.
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