Studies in beef production II. The estimation of live weight of beef steers from chest girth and other body measurements

Abstract

1. Records collected on the steers reared during the long-term experiment on beef production on the Cambridge University Farm from 1946 to 1955 have been analysed to examine the relation of live weight to various body measurements and the dependence of these relations on breed, treatment and age.2. Among the measurements considered singly, chest girth was most closely related to live weight.3. There were marked differences in the slopes of the regression lines relating log live weight to log chest girth during the two phases of the experiment—from birth to 8 months of age and from 8 months to slaughter.4. The regression coefficients in the first period were affected by the treatment on which the calves were being reared. Those in the second period were affected both by the level of feeding the steers were receiving during that period and by the manner in which they had been reared to 8 months.5. Height at shoulder was the measurement which, as a second variate in the regression equations, led to the greatest increases in the accuracy of prediction of live weight. However, the relation of this measurement to live weight was also affected by the treatment.6. It was considered that these measurements show little promise as estimators of live weight which could be generally applied, since their relations to live weight were affected by the treatment of the animal.