GROWTH RELATIONSHIPS FROM BIRTH TO 240 DAYS OF AGE AND THEIR ASSOCIATIONS WITH FEED EFFICIENCYIN DAIRY CALVES

Abstract

Weights at birth, 180 days, and 240 days of age as well as the gains and live weights from birth to 180 days and from 180 to 240 days on Jersey, Ayrshire and Holstein heifer calves were utilized in an attempt to predict pounds of TDN required per pound of gain during the interval 180 to 240 days. The variable most highly associated with feed efficiency was the gain from 180 to 240 days, and the simple regression indicated that 60 to 75 per cent of the variation in feed efficiency could thus be accounted for. The regression coefficient was of the order of −0.05 for the Jersey and the Holstein, and −0.06 for the Ayrshire. The other variables considered did not increase the accuracy of the simple regression equation in the prediction of feed efficiency.