PHYSIOLOGICAL BASAL PARAMETERS OF FREE-RANGING OPOSSUMS ( DIDELPHIS VIRGINIANA) IN THE YUCATAN PENINSULA, MEXICO.

The aim of the present study is to determine the basal parameters in opossums ( Didelphis virginiana) during physical examination in Yucatan, Mexico. Sixty-six opossums were captured and manually handled for physical examinations. Sex, age, cardiac and respiratory rate, body temperature, pulse, mucous membranes, capillary refill time, hydration, size of superficial lymph nodes, mental status, and body condition were evaluated. Also, comparisons between rectal and auricular temperatures were performed. The means of physiological parameters obtained were: cardiac frequency 146 beats per minute (95% confidence interval [CI]: 138.91-155.24), respiratory frequency 27.33 breaths per minute (95% CI: 25.15-29.64), and body temperature 34.01°C (95% CI: 33.71-34.31). In 54% of animals, a sinus arrhythmia was present. A significant difference was found between rectal and auricular temperature measurements. A variation of -1.64 to 1.14°C was obtained via the auricular thermometer compared with the rectal device.

Intraocular pressure in captive black-footed penguins (Spheniscus demevsus) measured by rebound tonometry.

Intraocular pressure (IOP) measurement is a common procedure during eye examinations in birds. Differences in the IOP between avian species have been reported, which suggests the need to establish species-specific reference ranges. To determine IOP values of captive black-footed penguins (Spheniscus demersus), we obtained IOP readings with the use of a rebound tonometer by using two established calibration settings (dog and horse). No difference was seen in the IOP between the left and right eye when the horse setting was used; however, a difference was present when using the dog setting. No significant difference between the IOP of male and female penguins was seen in both eyes when the dog or horse setting was used. Rebound tonometry appears to be a safe and repeatable method to obtain IOP values in black-footed penguins.

Minimum anesthetic concentration of isoflurane in captive thick-billed parrots (Rhynchopsitta pachyrhyncha).

OBJECTIVE: To determine the minimum anesthetic concentration (MAC) of isoflurane in thick-billed parrots (Rhynchopsitta pachyrhyncha). ANIMALS: 15 healthy thick-billed parrots. PROCEDURES: Anesthesia was induced and maintained with isoflurane in oxygen. In the first bird that was anesthetized, end-tidal isoflurane concentration was maintained at 1.0% for 15 minutes. After this period of anesthetic equilibration, an end-tidal gas sample was obtained for verification of isoflurane concentration. A toe was pinched to determine the bird's response to pain, and the bird was then allowed to recover from aesthesia. To determine MAC, a so-called up-and-down approach was subsequently used in all 15 birds. Compared with the isoflurane concentration used for MAC determination in the first bird, maintenance isoflurane concentration for the second bird was increased by approximately 10% if the first bird reacted and decreased by approximately 10% if the first bird did not react to a toe pinch. These steps were then followed until all 15 birds had been anesthetized. Crossover events occurred when birds in sequence had discordant results (ie, 1 reactor and 1 nonreactor). The MAC was defined as the mean of the isoflurane concentrations measured during these crossover events. RESULTS: Mean MAC of isoflurane in thick-billed parrots was estimated to be 1.07% (95% confidence interval, 0.97% to 1.16%). CONCLUSIONS AND CLINICAL RELEVANCE: Isoflurane MAC appears to be lower in thick-billed parrots than the MAC determined for other bird species. Determination of the species-specific requirements of thick-billed parrots should allow isoflurane anesthesia to be performed more safely in this endangered species.