Location: Livestock Behavior Research
Project Number: 3602-32000-009-09
Start Date: Aug 28, 2009
End Date: Aug 14, 2010
Heart rate variability is determined by the animal’s inter-beat interval. Inter-beat interval data will be extracted from electrocardiogram signals, re-sampled, and divided into data sets of 512 beats, then screened for the presence of any ectopic or anomalous beats and evaluated for stationarity necessary for subsequent Fourier analysis. Any spurious beats will be assigned to an error category and corrected according to previously published protocols for addressing the presence of artifacts in inter-beat interval series data. Blood pressure and respiratory data will be handled similarly. Individual epochs of data containing the 512 continuous inter-beat intervals will undergo frequency domain analysis. In doing so the fast Fourier transform will be determined with the sampling interval prefixed at 1 so that resultant frequency data is expressed in cycles per beat, rather than hertz. Power will be established using a Hanning window and the location of individual frequency bands will be confirmed by evaluating shifts in the distribution of spectral power in cardiac, blood pressure, and respiratory spectrums. These frequency ranges will then be applied to evaluate the effects of particular stressors on autonomic regulation of heart rate variability.