Abstract

A 2-wk-old female captive-bred 130 kg Asian elephant, born and housed at the Burnet Park Zoo in Syracuse, NY, was diagnosed with an umbilical hernia. The cord was sealed, but a 5 cm defect in the abdominal wall allowed tissues to protrude into the subcutaneous space. The length of the cone- shaped protruding tissues was about 5 cm. The hernia was located very caudally along the midline. Two weeks following the initial examination, characterization of the hernia was attempted with ultrasonography. Since no loops of bowel could be detected at this point, a conservative approach was elected. The animal was monitored for the following 3 wk. A small reduction in the diameter of the hernia was detected at 2 mo of age. At this time, the animal weighed 187 kg. Surgical correction was discussed with the zoo’s staff and elected because the defect had the potential to entrap a loop of bowel or interfere with reproductive potential in future years. An immediate surgical correction was elected to decrease the risks for anesthetic complications that would develop with increasing size. The trainers were able to achieve conditioning of the animals to reduce the stress of handling on the baby and facilitate its separation from the dam. It was elected to perform the surgery at the zoo utilizing a team from Cornell University.

The dam, weighing about 2,850 kg, received 230 mg (0.08 mg/kg) of xylazine hydrochloride i.m. (Miles, Inc., Agriculture Division, Animal Health Products, Shawnee Mission, Kansas USA). The animal became sedated within 10 min, and its calf was moved into an induction area in front of its stall in the elephant house. The calf received 20 mg of xylazine HCl (0.1 mg/kg) and 300 mg of ketamine hydrochloride (1.6 mg/kg) i.m. (Phoenix Pharmaceutical, Inc., St Joseph, Missouri USA). Within 20 min, the calf was ataxic and head pressing but did not become recumbent. An intravenous catheter was placed in an ear vein and an additional 25 mg of ketamine HCl (0.13 mg/kg) combined with 2.5 mg of diazepam (0.013 mg/kg) (Schein Pharmaceutical, Inc., Florham Park, New Jersey USA) were administered i.v. The animal then became recumbent and was transported to the operating room. Two supplemental doses of 25 mg ketamine HCl were given i.v.: one during the transfer to the operating room, and the second 3 min after intubation until the isoflurane took effect.

Intubation was accomplished with a cuffed 14 mm internal diameter, endotracheal tube. A semi- closed rebreathing system was connected to a large animal anesthesia machine. Ventilation was spontaneous and isoflurane (Abbott Laboratories, North Chicago, Illinois USA) was delivered in oxygen. Monitoring included heart rate, respiratory rate, electrocardiogram, direct arterial blood pressure (catheter in ear artery), temperature, arterial blood gases, and pulse oximetry. Hypotension was corrected by adding an intravenous infusion of dobutamine hydrochloride at a rate of 10 mg over 50 min (Ben Venue Laboratories, Inc. Bedford, Ohio USA).

The animal was placed in dorsal recumbency and the area prepped for surgery. A 12 cm fusiform incision was made around the umbilical hernia. Following sharp dissection the hernial ring was identified. The size of the hernial wall defect was 7 cm long; the depth of the hernial sac was 10 cm. Within the hernial sac a 3 cm fibrous mass and another softer structure could be palpated. It appeared that the intestine could be herniated and adhered to the sac; thus, it was decided to open the sac so that its content could be examined. Upon opening the sac, small intestine was present within the hernia. The palpably thick structure was identified as firm fibrous connective tissue, and the palpably softer structure was fat and small intestine. These were fully reducible due to lack of adhesions. The hernial sac was resected, and at that time some small intestine was seen prolapsing through the body wall defect. This defect was reapposed using #3 Vicryl® (Ethicon, Inc., Sommerville, New Jersey USA) in a simple interrupted pattern, which required 10–12 sutures. The loose fascial tissue immediately adjacent to the body wall was reapposed with 0 Maxon® (Davis & Geck Monofil, Inc., Manati, PR) in a simple continuous pattern. The subcutaneous tissue was also reapposed using the same suture material and pattern. A subcuticular suture was placed using 0 Monocryl® (Ethicon, Inc., Sommerville, New Jersey USA). Tissue glue was applied to the skin. Ceftiofur (The Upjohn Co., Animal Health Division, Kalamazoo, Michigan USA) was administered at 430 mg i.m. (2.3 mg/kg). The entire procedure from the sterile preparation to the end of the surgery lasted 1 hr. Within a few minutes after terminating the isoflurane, the calf began to move its legs and was transported back to the induction area in the elephant house. The animal was extubated 10 min after the isoflurane was discontinued. Supplemental oxygen was administered via a nasal tube inserted in the trunk, alternating nostrils every 5–7 min. Fifteen minutes later, 2.5 mg of yohimbine HCl (Lloyd Laboratories, Shenandoah, Iowa USA) was given i.v. and 2.5 mg was given i.m. Five minutes and 15 min later, two additional doses of 2.5 mg of yohimbine HCl were administered i.v. The total yohimbine HCl dose was 0.05 mg/kg. Increased muscle tone and activity were then noted. Forty-five minutes after extubation the animal picked its head up for the first time and 1.5 hr after extubation it became sternal and stood up. The animal was physically supported for 15 min until strong enough to ambulate without falling. The cow received 100 mg of yohimbine HCl i.m. (0.035 mg/kg) while the calf was being reintroduced.

Post-operative care was greatly facilitated by the previous training of the elephants. It included: (1) a 5-day 24-hr watch of the baby and its mother by the trainers; (2) prevention of self-induced or mother-induced trauma to the surgical site; (3) taking daily rectal temperature (calf); (4) assessment of the wound; (5) antibiotics (Ceftiofur 1.1 mg/kg i.m. for five doses); (6) butorphanol tartrate (Fort Dodge Laboratories, Inc., Fort Dodge, Iowa USA) 5 mg i.m. (0.027 mg/kg) every 6 hr for 48 hr post-surgery. Exercise was restricted to the stall for 14 days. Short daily outdoor sessions were then authorized under supervision. The calf had a tendency to roll and drag herself in the sand. The wound appeared to be healing well for 3 wk. A delay in healing was then noted and further examination revealed a purulent exudate around the scabs. A swab was submitted for aerobic bacterial culture and sensitivity. The wound was subsequently cleaned daily with a diluted Nolvasan® solution (chlorhexidine diacetate, Fort Dodge Laboratories, Inc., Fort Dodge, Iowa USA). Thirty days post operatively, a strand of exposed sutures was removed from the subcuticular layer. This was thought to be at the source of the tissue reaction. The wound closed and healed without further complication. Thirty-three days post operatively the calf and the dam were allowed to go outside on exhibit with the other elephants. Daily trainer checks and biweekly assessments by staff veterinarians continued to confirm the resolution of the inflammatory process and the final stages of healing.