Relationship between Heart Rate and Heat Production of Goats and the Difference on Linear Regression Constants between Eating and Walking

Abstract

Heart rate (HR) and heat production (HP), and oxygen contents in arterial and venous blood were measured simultaneously before, during and after eating and walking with four or three native Japanese goats each. 1) A close relationship between HR and HP was obtained in all calibrations. The mean prediction errors (PE, Sy•x/y, %), for both eating and walking conditions, associated with the estimation of HP from HR were within the range of 4.7-8.9%. It is suggested that the HR measurements could offer a practical method for estimating HP of goats. 2) A distinct difference of regression coefficient was exhibited between eating and walking conditions. Considerable variations occured in changes in O2 content of arterial and venous blood, but the result suggested that the main reason for the difference of regression coefficient was an increased arteriovenous difference in O2 content with walking. 3) The relative HR (RHR) method could be applied for combining both eating and walking calibrations. RHR is a ratio of HR to basal HR, which is calculated by substituting the mean value of HP in all samples into the regression equations of each calibration, instead of resting HR before feeding. The suggested equation for the estimation of HP, using a mean grouped HR with a minimum of four goats, is shown in Table 1 and Fig. 2 [C]. The important experimental conditions are discussed in relation to the calibration.