Basal and stress response cortisol levels and stress avoidance learning in sheep (Ovis ovis)

Authors: Cook CJ
Publication: New Zealand Veterinary Journal, Volume 44, Issue 4, pp 162-163, Aug 1996
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Animal welfare, Behaviour, Endocrine/autocrine/paracrine, Stress
Article class: Correspondence

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Abstract: Basal and stress related corticosteroid levels show complex patterns of relationship to age, social status and aggressive behaviour. I have investigated basal and stress related cortisol levels in sheep subjected to a model of learned stress avoidance, the results of which suggest that factors of stress avoidance learning ability and experience also contribute to cortisol levels. Sheep, Ovis ovis, (ewes only, bodyweights 35-55 kg) grazed in two flocks of twelve, were restrained for a period of 60 minutes within the laboratory, and subjected to a single forelimb electric shock (parameters: 50 mA, 50 V, 10 ms pulses for 1 second, bipolar delivery across shaved forelimb via two concentric saline moistened electrodes). Blood samples were obtained by jugular vein cannulation at 0800 hours while the animals were penned with minimal restraint, after they were penned overnight…

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