Prediction the Carcass Traits of Lambs Finish in Feedlot Using Zootechnical Indexes

The aim of this study was to develop equations for predicting empty body weight and economically important carcass characteristics using production indices for sheep finished in confinement. A total of 258 Dorper x Santa Inês lambs subjected to productive behavior during an experimental period of 32 days before slaughter were used. Initial and final weight (IBW, FBW), daily weight gain (DWG) and total weight gain (TGW), dry matter intake (DMI), feed efficiency (FE), empty body weight (EBW), hot and cold carcass weights (HCW, CCW) and Longissimus dorsi muscle area (REA) were analyzed. Descriptive statistical analyses and Pearson's correlations were carried out for all the variables, while equations were developed using multiple linear regression. With the exception of FE, all the variables correlated positively (p<0.01; 0.45≤r≤0.92) with EBW, HCW and CCW. REA correlated (p<0.01; 0.34≤r≤0.37) only with IBW and FBW. The equations selected for EBW, HCW and CCW included only FBW as a prediction variable (R2≥0.91). The predicted values coincided between 90 and 98% across the models, while the residuals were distributed around 0, confirming the regression assumptions and demonstrating high prediction precision and accuracy. The REA equation included FBW and DMI as predictor variables, but had low variability and moderate precision, resulting in a model with low prediction accuracy (R2=<0.5). It can be concluded that EBW, HCW and CCW can be predicted using equations developed according to zootechnical indices, particularly using FBW as the prediction parameter.