lining between the lungs and the chest wall.
• pneumonia— inflammation of the lungs, especially the tissues as contrasted to the air passages (bronchitis).
• recurrent airway obstruction (RAO, “heaves”)—respiratory disease, usually of mature horses, induced by exposure to dusts typically found in stables. The disease is recurrent, depending on environmental exposure.
• rhinopneumonitis— highly contagious disease caused by herpesviruses (EHV-1, EHV-4); characterized by fever, mild respiratory infection and, in mares, abortion. In rare cases, some strains of these herpesviruses also cause potentially fatal neurological complications.
• strangles (distemper)—highly contagious infection of the lymph nodes, usually of the head, caused by Streptococcus equi bacteria. The abscesses may become so large as to obstruct the airway (hence the term “strangles”) and may break internally, draining a thick, yellow pus through the nose, or externally, draining through a spontaneous or surgical opening in the skin.
COUGHS THAT OCCUR
A cough that develops a few hours after a horse has stepped off of a trailer is worth investigating promptly. One possibility, if the horse has been at a show or other event where he would have been exposed to others, is that he contracted a viral respiratory disease, such as equine influenza or rhinopneumonitis. “You often see multiple horses in a barn being affected, if it’s viral, or the horse has recently traveled and come home from somewhere, where he might have picked up a viral respiratory infection,” says Johnson.
Shipping fever, a serious and potentially deadly form of bacterial pneumonia, is another possibility. The risk for this infection rises if a horse spends hours riding in a trailer tied so
COUGHS ARISING FOR NO OBVIOUS REASON
When a horse starts to cough as he just stands around in a nondusty environment, you’ll want to investigate, especially if this new behavior appears suddenly. “If a horse in your herd has never coughed before and now has a cough, he should be examined by your veterinarian. There are some problems that might be unique to that one animal that could be causing the unexpected cough,” Buechner-Maxwell says. “Horses can develop things like guttural pouch mycosis, which would be a problem with just that horse, and that he cannot drop his head to clear his airways. “Shipping fever can be a combination of aspiration---breathing in particles of hay, for instance, while in a trailer---and not being able to get the head down to cough and clear out all of the foreign bodies and bacteria that have been inhaled, along with the stress of shipping,” says Johnson. “This can all contribute to shipping fever.”
Whatever the cause, you’ll want to call the veterinarian as soon as possible. If it’s a contagious disease, you will need to take measures quickly to prevent the disease from spreading throughout the herd, and if it’s shipping fever, your horse’s odds of survival are best if treatment is started within 48 hours. wouldn’t go through the herd.”
Other unusual issues that can cause coughing include tumors that press against the airways or injuries, such as from a kick to the ribs, that cause inflammation in the lung.
“If a horse has developed a high dry, infrequent cough, and this is the first time you’ve heard it, you might watch it closely for a day or two---and if it persists you need to have your vet come take a look. It may be a foreign body in the airway, such as a piece of hay or straw,” says Buechner-Maxwell.