The effect of extensive human presence at an early age on stress responses and reactivity of juvenile ostriches towards humans
Date
2018-07
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
The effect of extensive human presence and regular gentle handling performed at an early
age (0–3 months old) on stress responses and reactivity of juvenile ostriches towards humans was
investigated. A total of 416 ostrich chicks over two years were exposed to one of three treatments
for three months after hatching; namely, Human Presence 1 (HP1, N = 144): extensive/prolonged
human presence with physical contact (touch, stroking), gentle human voice, and visual stimuli;
Human Presence 2 (HP2, N = 136): extensive/prolonged human presence without physical contact,
but with gentle human voice and visual stimuli; and the Standard treatment (S, N = 136): human
presence limited to routine feed and water supply as a control. At 7.5 months of age, the plasma
heterophil/lymphocyte (H/L) ratio was measured before and 72 h after feather harvesting and feather
clipping to determine acute stress responses, while chronic stress was measured by quantification of
corticosterone (CORT) concentrations in the floss feathers of the birds. Birds’ behavioural response
towards a familiar or an unfamiliar handler was evaluated at 12 months using docility and fear tests,
and through behavioural observations conducted on random days between the ages of 8–13 months.
Willingness to approach, and to allow touch interactions, aggressiveness, and exhibition of sexual
display towards the handler, was recorded. No difference in the H/L ratios before and after feather harvesting and clipping was observed in HP1 birds, whereas H/L ratios showed a significant increase
72 h post feather harvesting and clipping in HP2 and S birds (p < 0.05). Birds from the S treatment
exhibited a significantly (p < 0.05) higher feather CORT concentration compared with HP1 birds,
while HP2 birds had intermediate responses. Birds’ reactivity towards humans and temperament
as evaluated using behavioural observations, docility, and fear tests was not affected by treatment
(p > 0.05). However, HP1 and HP2 birds were more inclined (p < 0.05) to approach a familiar rather
than an unfamiliar handler during the behavioural observations, indicating an ability to distinguish
between a familiar and an unfamiliar handler. Overall, the results indicate that early gentle human
interactions with ostrich chicks can be beneficial in reducing physiological stress sensitivity later in
life and facilitate the ability of ostriches to distinguish between familiar and unfamiliar handlers.
Description
CITATION: Muvhali, P. T., et al. 2018. The effect of extensive human presence at an early age on stress responses and reactivity of juvenile ostriches towards humans. Animals, 8(10):175, doi:10.3390/ani8100175.
The original publication is available at http://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at http://www.mdpi.com
Publication of this article was funded by the Stellenbosch University Open Access Fund.
Keywords
Ostriches, Ostriches -- Behavior
Citation
Muvhali, P. T., et al. 2018. The effect of extensive human presence at an early age on stress responses and reactivity of juvenile ostriches towards humans. Animals, 8(10):175, doi:10.3390/ani8100175