Respiratory Diseases:

Who needs to breathe anyway?

Horses are susceptible to a wide variety of respiratory tract problems. These can be broken into two categories: upper respiratory tract (from the nose to the trachea) and, lower respiratory tract (trachea to the lungs) problems. They can also be divided by causes: viral, bacterial, and noninfectious (allergic). Prevention includes proper immunization against respiratory viruses, adequate nutrition, well-ventilated shelter, and checking newborn foals for adequate colostral intake. Also minimizing dust, allergens, and stressors such as long trailer rides can help decrease respiratory problems from occurring in your horse.

Viral respiratory diseases are common in horses, and are easily passed from horse to horse. The most common viruses are Equine Herpes Virus type 4 (rhinopneumonitis) and equine influenza, both of which are included in routine vaccination protocols. Viral respiratory infections usually cause high fevers, clear runny nasal discharge, a cough, swollen lymph nodes and loss of appetite. Treatment involves prolonged stall rest, anti-inflammatory drugs and fever reducers. Antibiotics are sometimes necessary to combat secondary bacterial infections.

Bacterial pneumonia is the number one cause of death in foals, 1-6 months of age. Bacterial infections can be secondary to viral infections, trailer rides, athletic events, parasitic migration through the lungs, upper airway dysfunction (resulting in aspiration of bacteria from the mouth and throat) and, anesthesia. Symptoms include depression, fever, and lack of appetite. Horses may also have abnormal sounds in the trachea such as rattling. As the pneumonia progresses, horses may have increased respiratory rate, respiratory distress, coughing, nasal discharge, decreased appetite, exercise intolerance and weight loss. Foals may show similar symptoms such as: diarrhea, arthritis, umbilical infections, and peritonitis.

The patient history and thorough physical examination findings are key factors in diagnosing bacterial pneumonia. Crackles and wheezes can typically be heard over the lower lung fields. Putting slight pressure on the throat can often induce a cough. Additional diagnostic tests can include bloodwork, ultrasound examination of the lungs, use of an endoscope to assess the upper and/or lower respiratory tract, and laboratory tests performed on samples of fluid taken from the trachea or lungs. Aggressive treatment involves antibiotics as well as supportive care such as: pain relievers and fever reducers, bronchodilators, expectorants, IV fluid therapy, and stall-rest.

Heaves, or COPD (Chronic Obstructive Pulmonary Disease) is a chronic, noninfectious respiratory disease, whose cause is under some debate. Heaves are thought to be a hypersensitive reaction to dust and mold in the air, most commonly occurring in older horses (> 6 yrs) during the winter when they are more likely to be stabled. Many horses are only mildly or seasonally affected by heaves. However, they can have a sudden "asthma" attack. Symptoms include: trouble exhaling, flared nostrils, a runny nose, exercise intolerance, and/or a cough. With time, horses may develop a "heave line", due to overdevelopment of the abdominal muscles used to exhale. Treatment and management of COPD includes minimizing dust in the environment, good ventilation in stabled conditions, steroids, and bronchodilators (to help open up the lower airways in the lungs). A sudden "asthma" attack usually requires emergency medical attention.

If you are concerned that your horse may be developing a respiratory problem or have any questions regarding your horse’s preventative health care, please feel free to call our office.