Conditioning Programs for Transabdominal Ultrasound Gestational Monitoring in an Eastern Black Rhinoceros (Diceros bicornis michaeli), African Elephant, (Loxodonta africana), African Lion (Panthera leo), and Bornean Orangutan (Pongo pygmaeus pygmaeus)
Wm. Kirk Suedmeyer, DVM, DACZM
Traditional handling methods for medical procedures in exotic animals required the use of chemical immobilization or manual restraint, many times in conjunction with ancillary restraint materials.
Recent advances in conditioning programs have changed our thinking on what can be accomplished with medical procedures as invasive as phlebotomy, intramuscular injections, transrectal ultrasound and general examinations.1,2,4-9
At the Kansas City Zoo, daily keeper routines incorporate conditioning programs to facilitate medical procedures and animal management. Specifically, methods for non-invasive monitoring of gestation with ultrasound in an Eastern black rhinoceros, African elephant, African lion, and Bornean orangutan have been developed and strengthened with subsequent pregnancies.
A 6-year-old female Eastern black rhinoceros (Diceros bicornis michaeli) was confirmed to be pregnant through observed matings, weekly serum hormonal progesterone levels, and transabdominal ultrasound. The rhinoceros had been conditioned for phlebotomy10 shortly after arrival with the use of fresh, hand-held browse as the primary positive reinforcer, and soft monotone vocalization and tactile stimulation as the secondary reinforcers. For transabdominal ultrasound, she was conditioned on a daily basis with small food rewards as the primary reinforcer, monotone vocalization, and tactile stimulation as secondary reinforcers to enter a stock restraint. Extraneous auditory stimulation was kept to a minimum. A cart, television, and cables were assembled to resemble the noise and appearance of the ultrasound unit. Once comfortable with the introduction of each new stimuli (as noted by resumption of eating, relaxed body pose, and focused attention,) conditioning sessions were increased in time. The animal was constantly talked to while feeding small amounts of favored food items (apple, carrot, banana) to focus on the keeper. We utilized a real-time B mode ultrasound system (Ausonics Impact VFI, Universal Medical Systems, Bedford Hills, NY, USA) with a variable 2.5 MHz sector probe. Warmed ultrasound gel was applied during several sessions without the use of the probe. Once comfortable with each session, more time was spent conditioning. Food rewards and lack of abrupt auditory stimulation were key to comforting the animal.7 Ultrasonic imaging of the calf was performed on a weekly basis. Most of the appendicular anatomy (ears, nares, feet, tail) and several reproductive structures (placenta, umbilical cord, uterine wall, amnion) were visualized and monitored throughout pregnancy. Viability of the calf was assessed with each session through a combination of ultrasound and tactile sensation of the abdomen. Records were maintained and will be used to compare to future pregnancies. This pregnancy resulted in the birth of a healthy female calf in August of 1999.
A female African elephant (Loxodonta africana) was conditioned to calmly remain in a standard elephant restraint device (ERD) while transabdominal ultrasound is performed. The elephant was conditioned to enter the restraint by combining desensitization with vocal commands. This allowed hydraulic flaps and doors to be positioned and strapping of the legs to prevent self-injury and aided in maintaining a stationary position.3 Additional desensitization was needed to allow the application of ultrasound gel and the positioning of the ultrasound probe. Small food rewards were consistently offered during the procedure. Positive reinforcement, in the form of returning to the herd and being allowed outdoors, aided future procedures in the restraint. Weekly transabdominal ultrasound imaging was performed via a small “window” defined by the caudal extent of the rib cage, ventral abdominal wall, and the cranial extent of the femoral muscles. Numerous images of the appendicular appendages, amnion, uterine wall, and placental membranes were documented. This allowed documentation of fetal viability until 1 week prior to delivery, which in hindsight probably documented the demise and subsequent retention of the calf.
Two 4-year-old female African lions (Panthera leo) were conditioned to enter and station in a standard restraint before being allowed outside in their daily exhibit. Each lion was confirmed as pregnant through visual observations of natural matings, weight gain, and transabdominal ultrasound. Small “windows” were clipped on the abdomen once the lion was desensitized to the noise. Slowed motions of all personnel facilitated the animal’s composure. Food was not an important tool with the lions, although food rewards were occasionally used as the primary enforcer. Transabdominal ultrasound was performed on both sides of the abdomen to confirm the number and viability of fetuses present. Biparietal measurements and biophysical fetal profiles were ascertained. The entire axial anatomy was visualized and documented on a regular basis. Echocardiography was occasionally performed. This information prepared the management staff for the exact number of viable cubs and estimated due dates. In two of three pregnancies, the exact number of fetuses was documented. In the last pregnancy four cubs were born instead of the three observed on ultrasound. The primary conditioning of the lions was desensitization to mechanical and auditory stimulation.
A 23-year-old female Bornean orangutan (Pongo pygmaeus pygmaeus) has been monitored with the use of transabdominal ultrasound through three pregnancies. Small food rewards are utilized as the primary reinforcer, with the animal’s inherent curiosity and desire for attention as secondary reinforcers. Behavioral positioning allows for weekly transabdominal ultrasounds. The use of a target pole, clicker, and food reward allows very specific positioning of the orangutan. Ultrasonic imaging has documented numerous aspects of the pregnancies, including appendicular growth, echocardiography, biophysical fetal measurements, amniotic development, internal organ development, and placental mineralization.9 Specific positioning has also allowed the use of ultrasonic imaging of the reproductive tract during non-pregnant periods.
The use of several positive conditioning techniques greatly improves the success of transabdominal imaging in a wide array of species. In each of these cases, a written program of conditioning, a dedicated and flexible staff, and a realization that many animals will allow minor invasive procedures can lead to successful procedures which contribute to our knowledge about the animals in our care.
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