Evaluation of the effect of errors in the sorting of pigs for market on financial loss at a range of marketing ages

The BW growth curves for twenty-five 4,000-head finishing barns were simulated to evaluate the effect of 2 types of market pig sorting errors on the sort loss at different mean carcass weights (CW). Two types of errors were evaluated: BW estimation error (BWEE) and percentage of pigs not visually evaluated (PNVE). Four levels of BWEE with SD of 0, 4, 6, and 8% of BW and 4 levels of PNVE (0, 8, 16, and 24%) were simulated. Sort loss was calculated using a market value system for a United States pork processor. Pigs were initially marketed in 3 marketing cuts, 25% at 169, 25% at 179, and the remaining 50% at 193 d of age. Then the marketing ages for the pigs were shifted in weekly intervals with mean ages of 155.5 to 211.5 d. The number of pigs with sort loss and mean sort loss per pig were fitted to a model including the fixed effects of level of marketing age (AGE), BWEE, PNVE, and their interactions and random effect of replicate barn. The effects of AGE, BWEE, and PNVE, and AGE × PNVE, AGE × BWEE, and AGE × BWEE × PNVE interactions affected both variables (P < 0.001). Sort loss increased more rapidly with increased CW at higher levels of BWEE and PNVE (P < 0.001). The effect of sorting accuracy on financial loss is dependent on the CW. The effects of sorting accuracy and interactions with CW must be considered in the evaluation of alternative marketing strategies.