Plasma and salivary cortisol levels were measured in stereotypic (n=46) and normal horses (n=46). No significant differences were found between the 2 groups of horses. The correlation between plasma and salivary cortisol concentrations of individual horses (n=66) was also examined. A significant correlation between plasma and salivary cortisol levels was found only in horses with an oral stereotypy (crib biting or wind sucking). Plasma beta-endorphin (BE) levels were compared between horses with an oral stereotypy (n=17) and normal horses (n=17). Mean plasma BE levels did not differ significantly between the 2 groups. Endogenous opioids are thought to facilitate stereotypic behaviour, and a hereditary component to stereotypic behaviour has been previously observed, suggesting that stereotypic horses have inherited opioid receptors with a greater sensitivity than those of normal horses.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Department of Animal Science, University of Sydney, Sydney, NSW, 2006, Australia.|
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