Evaluation of the effect of the magnitude of errors in the sorting of pigs for market on the optimal market weight

Abstract

The objective was to estimate the effect that sorting accuracy at marketing has on the optimal market carcass weight (CW) and economic returns. 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. Initially, pigs were marketed in 3 marketing cuts: 25% at 169, 25% at 179, and the remaining 50% at 193 d of age. The timing of marketing was shifted in 7-d intervals. Sort loss was calculated using a market system for a United States pork processor. Sort loss ($/pig) values were fitted to a polynomial function of mean CW for each combination of BWEE and PNVE. The increase in mean sort loss for each unit increase in CW above 93 kg increased as BWEE and PNVE increased (P < 0.001). With accurate sorting (BWEE = 0%, PNVE = 0%), the optimal mean age for the 3-marketing-cut strategy was 190.5 d at a mean CW of 97.0 kg and profit of $3.35/pig. With less accurate sorting (BWEE = 8%, PNVE = 24%), the mean age decreased to 184.5 d with mean CW of 93.4 kg and profit of $2.00/pig. The optimal market ages and CW decreased as BWEE and PNVE increased (P < 0.001). Current marketing systems direct pork producers with less accurate sorting of pigs to market their pigs at lighter CW.