Comparative Analysis of Ultradian and Circadian Behavioural Rhythms for Diagnosis of Biorhythmic State of Animals

Abstract

Abstract A chronobiological procedure has been developed for evaluation of living conditions, behaviour and internal state of free-ranging animals. It is based on continuous recordings of activity and feeding with subsequent comparison of levels, daily patterns as well as daily and ultradian rhythms. Telemetric observations were carried out on alpaca, sheep, Przewalski horse, roe deer, red deer and mouflon under various conditions. The time patterns of the different species were analysed macroscopically and by autocorrelation function and power spectral analysis. A stable ultradian structure of behaviour was obvious especially for ruminants. A more unstable, adaptive time pattern was found in Przewalski horses. Activity as a multi-purpose behaviour was generally more variable than feeding which in most cases was of clearly rhythmic and harmonic structure. Degrees of Functional Couplings (DFCs) were used for comparison of rhythmic structure. DFCs express the percentage of the circadian component and harmonic ultradian components in relation to all rhythmic components of a spectrum. They were found to be high in well adapted, healthy and undisturbed individuals but were lowered during periods of adaptation, sickness or social interactions.