Heart-rate (HR) of 30 Merino wethers was measured by radiotelemetry in two environments: standing alone in a handling race, but in sight of other sheep; and while moving within a group around yards. Subjects were selected three months previously on the basis of each animal's reaction to short-term social isolation. Ten responded physically by trying to escape from the yards or to rejoin the group in an adjacent wool-shed, 10 responded by vocalising, and 10 were unresponsive. No animals in the first group vocalised. Reliable individual differences in HR were observed in the two tests, and measures for both ranked agitated > vocal > unresponsive. However, HR for the two responsive groups was only significantly higher than the unresponsive group in the race, and there was no significant difference in HR between responsive sheep in either setting. The use of HR as an index of social stress and likely position preferences in forced movement orders in yards is discussed.
|Publication Title||Applied Animal Ethology|
|Author Address||CSIRO, Div. Land Resources Management, Wembley, Western Australia 6014.|
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