Taking a breather! Tidbits on equine respiration

Last Wednesday afternoon I started to get a "funny feeling" in my lungs at work--raw and wheezy. By the next morning I was sure I had succumbed to the plague. Well, as my physician later explained to me, it was something less dire: bronchitis. I'm all better now, but in recognizion of this experience I thought I'd compile some info on equine respiration...

Facts about horses and breathing...

• Horses cannot breath through their mouth. All air intake is through their nostrils.
• A foal only a few months old has all the lung tissue it is ever going to have.
• The horse's long nasal cavity serves to take the chill off the air. Air entering a horses nostrils will warm by about 45 degrees F in 1/100th of a second.
• Horses hold their breath over jumps and do not breathe again until they land. When they land, they start breathing out.
• At canter and gallop normal horses take one breath perfectly in time with one stride.
• Tightening a horse's girth too much will affect the horse's performance--not because of constricting the chest and preventing the lungs from expanding, but because it decreases the effectiveness of the muscles around the front of the chest and shoulder that move the forelegs (from The Horse magazine).
• Training and excercise put pressure on the horse's nasal passages which can irritate the spiral, spongy bones in the nostril. This can result in bleeding and making the horse vulnerable to infection.
• If all the horse's airways in the lung were opened out and laid flat on the ground, they would occupy a total area equivalent to 10 tennis courts. The large lung surface assists in heat dissipation during and after exercise. Up to 20% of the muscle heat generated during exercise being exchanged across the lung surface
• The upper respiratory system has been implicated in 47-49% of cases affecting poor performance in racehorses, followed by the cardiac system in 22.3% of cases; and the musculoskeletal system in 15-20% of cases.
• About 25% of all equine veterinary calls are due to a respiratory problem.
• With regard to respiratory infections (and probably any infection): For every degree of fever, a horse should be rested for 7 days.

Normal horse respiration

A horse's inhalations should take about the same amount of time as its exhalations, and a normal horse takes 8-15 breaths per minute. You can count inhalation/exhalation cycles in three ways:

• watch the horse's nostrils move as it breathes
• watch the horse's body (belly rises and falls)
• listen at its trachea or windpipe.

A high respiratory rate can pain, excitement, stress, fever, or infection. Other vital signs will help narrow down the cause of respiration problems.


RESOURCES

Examination of the Upper Equine Respiratory Tract from Upenn.edu

When a Sneeze Is More than a Sneeze: Equine Upper Respiratory Viruses
L.E. Johnson In: NAVC Proceedings 2007, North American Veterinary Conference (Eds). Publisher: NAVC (www.tnavc.org). Internet Publisher: International Veterinary Information Service, Ithaca NY

Facts about Equine Respiratory Disease

from Pfizer

The airway and lungs from The Horse Magazine