A summary review of carcass cutability data comparing primal value of immunologically and physically castrated barrows.

The objectives were to 1) assess cutability, quality, and value of carcasses from immunologically castrated (IC) barrows compared with carcasses from physically castrated (PC) barrows and 2) evaluate the effect of hot carcass weight (HCW) on cutability and value of IC barrows summarizing U.S. data. Lean cutting yield (LCY) was defined as: LCY = [(whole ham + trimmed loin + Boston butt + picnic + spareribs)/chilled side wt] x 100. Carcass cutting yield (CCY) was determined using the following equation: CCY = [(lean cutting yield components + natural fall belly)/chilled side wt] x 100. To evaluate the effects of HCW of IC barrows on carcass cutting yields, IC barrows were grouped by HCW: light ( < 90.9 kg), average (90.9-97.7 kg), or heavy ( > 97.7 kg). Differences in the value of the carcass components for IC and PC barrow carcasses were calculated using a 5 yr average of meat prices from the USDA Agriculture Marketing Service and the carcass cutting yield estimates generated from this summary. Data were analyzed using the MIXED procedure of SAS with fixed effects of Improvest treatment or HCW group. Study was included as a random effect. This review allowed for a summarization of the treatment averages of 851 IC and PC barrow carcasses. Lean cutting yield of IC barrows was 1.41 units greater (P < 0.0001) than PC barrows (70.97 vs. 69.56%). Similarly, CCY of IC barrows was 1.29 units greater (P < 0.001) compared with PC barrows (87.27 vs. 85.98%). As HCW of IC barrows increased, both CCY and LCY declined (P < 0.01), with light IC barrow carcasses having a 1.43 unit advantage in CCY compared with heavy IC barrow carcasses (P < 0.01). Natural fall bellies of PC barrows comprised a greater (P < 0.05) percentage of side weight than those from IC barrows (15.81 vs. 15.50%). A reduction in belly primal value was confirmed by a 3.43 unit reduction in the commercial bacon slicing yields of IC barrows. However, belly yield and slicing yield differences were minimized when IC barrows were marketed at a heavier weight. Using carcass cutout estimates determined in the summary as the foundation for value calculations, lean cuts of IC barrow carcasses were worth $2.66 to $3.80 more than PC barrow carcasses. Therefore, after adjustment for the reduction in belly primal value, the primal value of an IC barrow carcass was $2.08 to $3.13 greater than a PC barrow carcass.