Use of carcass weight for predicting empty body weight in hair sheep in different physiological states

The objective of this study was to develop equations to predict empty body weight (EBW) by using fasting body weight (FBW) and hot carcass weight (HCW) for hair sheep in different physiological states. To generate the prediction models, a data set was composed of individual measurements from 278 sheep encompassing suckling males (21 Pelibuey and 15 Katahdin) and females (8 Pelibuey and 12 Katahdin) and growing males (55 Black Belly and 43 Katahdin) and females (56 Black Belly, 13 Dorper, 24 Katahdin, and 21 crossbreed Katahdin × Pelibuey). The coefficients obtained from the linear regression of EBW against FBW and EBW against HCW did not differ between sexes and among breeds (P > 0.05). However, they were influenced by physiological stage (P < 0.001). Four equations were generated for suckling and growing stages: EBW_suckling = -0.15_{(± 0.04)} + 0.91_{(± 0.02)} × FBW (root mean square error (RMSE) = 0.96, R² = 0.99); EBW_growing = -1.50_{(± 0.44)} + 0.91_{(± 0.02)} × FBW (RMSE = 0.96, R² = 0.99); EBW_suckling = 1.84_{(± 0.69)} + 1.46_{(± 0.06)} × HCW (RMSE = 1.94, R² = 0.96); EBW_growing = 5.93_{(± 0.72)} + 1.46_{(± 0.06)} × HCW (RMSE = 1.94, R² = 0.96). The results showed that sex and breed did not influence the linear regression of EBW as a function of FBW and HCW. However, the present study showed that models predicting EBW from FBW and HCW depended on physiological state.