Large Animal Surgery
Core concepts
Large animal surgery emphasizes the horse and food-animal patient: colic, gastrointestinal disorders, lameness, wound management, and reproductive surgery. Understand the equine abdominal examination, the decision for medical versus surgical colic, and the anatomy of the equine GI tract relevant to displacement, volvulus, and entrapment. Know common procedures such as celiotomy, enterotomy, resection-anastomosis, and the principles of aseptic technique in the field.
Traps to expect
Questions frequently test when NOT to operate: a horse with severe cardiovascular compromise, endotoxemia, or a poor surgical prognosis. Distinguish small intestinal from large intestinal colic based on reflux, rectal findings, and pain character. Lameness questions may test the flexion test interpretation or the value of diagnostic analgesia. Bovine questions often focus on cesarean section indications, displaced abomasum, and field anesthesia constraints. Watch for distractors that ignore the economics and welfare context of food-animal surgery.
Worked example
A horse with nasogastric reflux >4 L, moderate pain, and a distended small intestine on rectal exam. The trap is 'continue medical management.' The correct reasoning: significant reflux plus small intestinal distension suggests small intestinal obstruction requiring surgical exploration. Rule of thumb: reflux volume and pain that escalates despite analgesia point toward surgery.
Exam strategy
Prioritize patient stability and prognosis. Recognize that large animal decisions integrate anatomy, physiology, and practical constraints.