The Estimation of the Weight of Bulls from Heart Girth Measurements

Abstract

A study was made of the relationship between heart girth measurement and the body weight of 25 Holstein and 25 Guernsey bulls ranging in weight from 852 to 2351 pounds. The coefficients of correlation between heart girth measurement and body weight were 0.976 for all of the 50 bulls, 0.954 for the Holstein bulls, and 0.958 for the Guernsey bulls; all were highly significant statistically. A calculation of the regression of body weight on heart girth measurements indicated a straight line relationship. The error of estimate of body weight based on heart girth measurement was 83.8 pounds or 5.05 per cent. Estimates of the body weights of bulls were, therefore, very accurate. It was also of interest to note that the correlation coefficient between body weight and semen volume was 0.2079, which was not mathematically significant. © 1946, American Dairy Science Association. All rights reserved.