Influence of sickness condition on diurnal rhythms of heart rate and heart rate variability in cows

Parameters of heart rate variability would explain changes in heart rate during thedisease status in cows and to evaluate whether such changes might provide a more sensitiveand quantitative indicator of these conditions than crude indices. For this purpose, werecorded electrocardiograms for 24 hr using a Holter-type electrocardiograph and appliedpower spectral analysis of heart rate variability in both five clinically healthy and fourhospitalized cows. The significant findings of the current investigation were that thediurnal variations of autonomic nervous function are abolished in cows that are sick. Thisabnormal rhythm was induced by predominant parasympathetic inhibition in these cows.Therefore, the heart rate variability may be a useful indicator of sickness condition incows.