The thesis examined whether, when applied to behavioural sequences, fractal measures could have diagnostic value in assessments of stress in farm animals. The fractal analysis methodology of Detrended Fluctuation Analysis (DFA) was applied to continuous focal observations of hens and instantaneous scan-sample observations of growing pigs. In experiment one, the complexity of vigilance behaviour increased in young hens; both during the acute stress of open field exposure or following a five-minute period of restraint. The total duration of vigilance was increased in the open field but not following restraint. The DFA measures therefore revealed an alteration in behavioural organisation under stress not identified during standard analysis. In experiment two, a chronic intermittent stressor regime was applied to adult hens. This stressor regime caused alterations in food intake, body weight and egg production, which suggested the birds were transiently stressed. However, the behaviour of the treatment group did not differ from controls at any time point, either when using a standard analysis or a DFA. In the third experiment, a stressor regime involving repeated social defeats and additional mild stressors was applied to growing pigs. Following this regime the treatment group had higher levels of average 24hr cortisol than controls. The DFA did identify behavioural differnces between treatment and controls groups; however, it is unclear if these were directly related to the stressor treatment. The data sets generated in the experiments were used to further investigate the DFA method. Analyses showed that alterations in the duration of observation and the frequency of behavioural sampling can affect the end result. Although the analysis has some limitations it allowed novel dimensions of behavioural organization - not identified during standard analysis - to be measured. These dimensions were independent of total durations of behaviour and they were sensitive to stressful stimuli in some circumstances. In conclusion, fractal analysis of behaviour shows promise as a tool for measuring stress but further validation is required.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661490 |
| Date | January 2003 |
| Creators | Rutherford, Kenneth Malcolm Desmond |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11346 |
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