Page 672 - The Veterinary Care of the Horse

Causes

• Viral infections can damage the respiratory epithelium and weaken the horse’s immune
VetBooks.ir • system allowing secondary bacterial infection. These bacteria are usually inhaled.

The bacteria most commonly involved are Streptococcus spp, Staphylococcus spp,
Klebsiella spp, Pasteurella spp, Actinobacillus spp, Mycoplasma spp, Rhodococcus equi,

E. coli and Pseudomonas spp.

• Inhalation of food or liquid, e.g. in any disease where the horse has difficulty
swallowing. It may follow a severe episode of choke.

• Stress can predispose to pneumonia, e.g. long journeys or strenuous exercise, before an
animal has fully recovered from an upper respiratory infection.

• Bacteria may enter the navel of a newborn foal, enter the bloodstream and reach the

lungs or the joints.

Clinical signs

These include:

• fever, 39–41 °C (103–106 °F)

• fast, shallow breathing

• coughing
• abnormal lung sounds

• lethargy and depression

• loss of appetite and condition

• chest pain
• abnormal posture with the elbows held away from the horse

• enlargement of the lymph nodes under the mandible

• in advanced cases, young animals may have flared nostrils and experience severe

respiratory distress.

When to call the vet

If you suspect your horse or foal has pneumonia, call the vet immediately.

Diagnosis

• The condition is diagnosed on: