RESUMO
Considerable research has been conducted on the effects of inter-institutional transfers, but far less consideration has been given to intra-institutional transfers and extended housing in off-habitat holding. On 15 May 2018, The Oregon Zoo's orangutans (n = 3) were moved from the Red Ape Reserve (RAR) to the Veterinary Medical Center (VMC) indoor holding areas and remained there until 22 December 2020, resulting in over two years of housing in a facility not specifically designed for orangutans. This study aimed to quantify potential changes in fecal glucocorticoid metabolites (fGM) typically associated with increased adrenal activity as a result of transfers, as well as potential differences in fGM concentrations associated with housing in the two different types of locations. We collected fecal samples from all orangutans during three time periods: the initial housing at RAR (RAR1), the time spent at VMC holding (VMC), and the return to RAR (RAR2). Samples were analyzed using enzyme-immunoassay (EIA) analyses and compared using two-way ANOVA tests with Games-Howell post-hoc evaluations. The results of our analyses showed the following: (1) significant differences in fGM concentrations based on location in two orangutans, with the highest fGM concentration occurring in fecal samples collected at the VMC; and (2) a lack of significant fGM peaks following multiple intra-institutional transfers for all three orangutans. Though requiring further corroboration through future studies, we speculated that pre-transfer behavior training and intensive, continued care by familiar animal care staff may have helped to mitigate the stress responses commonly associated with transfers and major changes in housing. Furthermore, this study highlights the individualistic nature of the stress response, as illustrated by the substantial variation in fGM concentrations across different housing regimens in the three orangutans.
RESUMO
The effect of visitor presence on zoo animals has been explored in numerous studies over the past two decades. However, the opportunities for observations without visitors have been very limited at most institutions. In 2020, the Oregon Zoo was closed, in response to the global SARS-CoV-2 (COVID-19) pandemic, from 15 March 2020 to 12 July 2020, resulting in approximately four consecutive months without visitor presence. This study aimed to quantify potential behavioral and hormonal changes expressed during two transition periods in zoo visitor attendance: the initial time period before and after closure in March 2020 and time before and after reopening in July 2020. Fecal glucocorticoid metabolite (fGM) concentrations of resident giraffes (n = 2) and cheetahs (n = 2) were tracked using enzyme immunoassay (EIA) analyses. Average fGM concentrations during the two transition periods were compared using a two-way mixed ANOVA. Additionally, twice-weekly scan sampling was used to quantify behavioral observations across the transitions, which were analyzed as individual behavior proportions. Individual behavior proportions were compared across the Zoo's opening status and time of day using Kruskal-Wallis (H) tests. The results of our analyses showed the following outcomes: (1) significant increases in fGM concentrations for cheetahs and giraffes between the transition periods but not within them; (2) a significant increase in time spent 'not visible' in the cheetahs in the second transition period; and (3) increased vigilance behaviors in the giraffes immediately after the Zoo's closure. However, the changes observed in fGM concentrations may be more strongly correlated with concomitant social changes (giraffes) and some medical events (cheetahs) rather than with the Zoo's opening status. Nevertheless, this study was able to quantify differences in behavioral frequencies and fGM concentration in cheetahs and giraffes at the Oregon Zoo during the times of transition between visitor's presence and absence. The results indicate that, while there was a possible, but relatively minor impact of the presence and absence of visitors on some behaviors, the differences observed in fGM concentration may have been more affected by some of the concomitant social changes and medical events that happened during the same period than by the presence or absence of visitors.
RESUMO
In 2001, the sudden collapse of the Columbia Basin population of pygmy rabbits prompted the initiation of a captive breeding program to facilitate reintroduction, but reproductive success in captivity has not met expectations. Therefore, the objective of this study was to characterize the reproductive and adrenal endocrinology of this endangered rabbit species so that appropriate management strategies could be developed to monitor animal welfare and increase reproduction. Fecal samples were collected from 27 female pygmy rabbits over three breeding and non-breeding seasons. HPLC analyses verified the presence of progesterone in the excreta of pygmy rabbits, but the majority of progestagen metabolites were unidentified polar compounds. By contrast, >70% of glucocorticoid immunoactivity was associated with cortisol. Longitudinal fecal hormone profiles during pregnancy were characterized by a large spike in progestagens shortly after mating, a gradual increase in progestagen and glucocorticoid concentrations throughout gestation and a return of hormones to baseline soon after birth (Day 24). The spike in progestagens 1 day after mating was a significant discovery for this species and appears to provide a reliable means of determining if a successful mating has occurred. Seasonal analyses of hormone excretion found that progestagen baselines did not vary between the breeding and non-breeding seasons, but, as expected, were highest during the breeding season in association with pregnancy. Across seasons, the lowest concentrations of glucocorticoids were associated with the highest rates of offspring production and survival, suggesting a possible link between heightened adrenal activity and lowered reproductive fitness in pygmy rabbits.
