Fractured Ribs in Neonatal Foals
Livestock Update, May 1997
Larry A. Lawrence, Animal and Poultry Sciences, Virginia Tech
Fractured ribs should be considered a common clinical entity in neonatal foals. The problem may frequently be subclinical, but is potentially capable of causing peracute death due to secondary thoracic trauma. All foals should be considered as subject to fractured ribs although large birthweight foals and foals extracted from dystocias are at greatest risk.
The clinical signs may vary from subtle to obvious respiratory compromise associated with thoracic asymmetry. Some foals are assessed as lethargic and spend an inordinate amount of time laying down, usually in the sternal position. When they get up to nurse, they may "moan" and appear to walk as though "stiff." The physical examination requires palpation of the ribs and is best performed while the foal is standing. Both hands are gently and synchronously passed over the chest bilaterally to compare symmetry while feeling for crepitus. The costochondral junction should be palpated and followed forward enough to feel beneath the shoulder muscles and over the heart. Frequently, a series of ribs may be felt as indented on one side. Bilateral rib fractures are extremely rare when compared to the common unilateral incidence. Multiple and severe fractures may be obvious as "frail" chests, whereas thoracic motion is abnormal with inspiration causing a "caving-in" motion instead of expansion of the thorax.
The clinical consequences of fractured ribs include sudden death due to laceration or puncture of the heart and lacerations of the greater vessels causing acute and fatal hemorrhage. Pericardial and lung lacerations can also occur leading to hemopericardium, hemothorax, pulmonary tamponade, and pneumothorax. Fractures located more caudal within the chest cavity are capable of sawing through the diaphragm and can cause hemorrhage in both the thoracic and abdominal cavities as well as susceptibility to colic due to a subsequent diaphragmatic hernia.
The diagnosis of fractured ribs is usually made by physical examination, although ultrasound can be used for the detection of hemorrhage, pulmonary lesions, or the presence of herniated bowel, while thoracic radiographs are useful for the visual assessment of actual rib fractures.
The treatment of choice is early detection and stall rest. Hopefully, local hemorrhage and edema will eventually fibrose sufficiently to cushion and restrict the sharp edges of the fractures. In our practice, we commonly recommend not turning the foal out for two weeks. Treatments for more severe secondary damage may include thoracocentesis to remove hemothorax which has a volume sufficient to cause pulmonary compression while whole blood transfusion is performed to treat the hemorrhage shock. Foals which are recumbent with flail chest should be sedated, cushioned on a pad, and given intranasal oxygen. The recumbent position should be with the "bad-side-down" to keep the better-aerated lung from being compressed. Analgesics may be required to control pain, but once the foal becomes capable of ambulation, they are usually restricted to discourage excessive activity. Surgical stabilization of rib fractures has not been successfully documented, although a surgical protocol has been established within our practice by Dr. Bob Hunt to be used in severe cases.
The actual number or incidence of neonatal foals with rib fractures is not know. However, veterinarians and horse owners should recognize the problem as relatively frequent one and hopefully not one to be diagnosed postmortem in a foal found dead in the paddock.
Credit: T. D. Byars, DVM, American Association of Equine Practitioners Report, March 1997