Respiratory system of the horse

The respiratory system of the horse is the biological system by which a horse circulates air for the purpose of gaseous exchange. Horses, like all animals, need oxygen to produce energy and remove carbon dioxide from their bodies. This system includes the horse's nostrils, trachea, bronchi, and lungs, all working together to bring in fresh air and expel waste gases.

Understanding a horse's respiratory system helps animal care experts keep these animals healthy. It explains how horses breathe during rest and intense activity, such as racing. This knowledge is important for veterinarians and horse owners to ensure proper care and prevent respiratory problems.

Horses have unique adaptations in their respiratory system that help them thrive. For example, their large lungs and efficient airflow allow them to take in more oxygen quickly when needed. This ability is especially important for horses that run long distances or perform high-intensity work.

Anatomy

The respiratory system of a horse starts with the nostrils, or nares. These nostrils can open wide when the horse is running or working hard. They have a flexible ring to keep them open when the horse breathes in, or inhalation. Inside the nostrils, tiny hairs help catch dust and other particles.

Air then moves through the nasal passages. These passages have special structures called conchae that give more space for air. The passages lead to the larynx, which helps the horse make sounds and stops food from going into the airway. After that, air goes down the trachea and into the lungs, where oxygen enters the blood. The diaphragm, a strong muscle, helps the lungs grow bigger to take in air.

Respiration rate of the horse

An adult horse usually takes 12 to 24 breaths per minute when resting. Young foals breathe faster, with about 36 to 40 breaths per minute. When it’s hot, humid, or the horse is excited, its breathing can speed up. This change in breathing can help people understand if a horse is healthy.

When a horse gallops, it breathes in a special way. With each stride, the horse inhales as its body moves. This helps the horse get the oxygen it needs while running.

Ability to smell

Horses have a very good sense of smell. They have many special cells in the upper part of their nose that help them detect different smells better than humans can.

Horses also have a special organ called the vomeronasal organ, or Jacobson's Organ, located in the roof of their mouth. This organ helps them sense certain scents, especially when they show a behavior called the flehmen response. During this response, air passes through special slits in the nose directly into the vomeronasal organ. Unlike some other animals, a horse's Jacobson's Organ does not connect to the mouth.

Main article: vomeronasal organ

Main articles: Jacobson's Organ, flehmen response

Respiratory diseases

Horses can get sick in ways that make it hard for them to breathe. Some common problems include Influenza, a virus that gives them fever and a cough. Another condition is Left Recurrent Laryngeal Hemiplegia, also called "Roaring," which makes it difficult for a horse to breathe when running or playing hard.

Other illnesses such as Recurrent airway obstruction ("Heaves") and Strangles can also affect a horse’s breathing. There are issues like Exercise induced pulmonary hemorrhage, where bleeding can happen in the lungs during hard exercise, and nasal problems such as Equine nasal cysts, Ethmoid hematoma, and Nasal polyps. Bacterial infections like sinusitis and pleuropneumonia can also make breathing harder for horses.