JB-Box®: A Web-Based Simulator for Young Cattle Fattening Performance14

The article describes the cooperative BEEFBOX project by ARVALIS, INRA and the Institut de l’Élevage to develop JB-Box®, a web-based simulator for young bull fattening. The core tool integrates a feed intake module, the mechanistic MECSIC growth model and a slaughter module to predict daily live weight, chemical composition and cold carcass weight from ration and animal group data. Validation for Charolais cattle (138 groups) showed a mean error of 3.2 kg for cold carcass weight and 12.6 kg for live weight at slaughter, with a finishing duration error of 4.9 days and feed intake error of 156 kg. The free online interface offers simple and intuitive access for farmers and advisors.