In vivo estimation of body composition in cattle with tritium and urea dilution. II. Accuracy of prediction equations of the che

Author: H.H. Meissner, J.H. van Staden and E. Pretorius
Year: 1980
Issue: 2
Volume: 10
Page: 175 - 181

Linear regression equations with tritium or urea space, live mass and carcass mass (where applicable) as independent variables, and the chemical components of the carcasses of bull were established. Similar equations were calculated for the chemical components of the non-carcass parts. The experimental procedure was described in the first paper of this series (Meissner et al., 1980a). By adding live mass and carcass mass to tritium or urea space as independent variables, the accuracy of prediction was improved, even to the extent of 60% in some cases. The most accurate prediction equations predicted water, protein and inorganic material in the carcass and non-carcass with a coefficient of variation of <10% at a live mass of 400 kg. In contrast, the error of prediction of the ether extract was considerably higher. The coefficient of variation at 400 kg live mass was 22 – 26%, which emphasizes that, as in the case of the whole body, quantification of compositional differences in the carcass and non-carcass would be possible only if a series of measurements on the same animal is made.

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