Exploring the Effects of Slaughter Weight Class on Belly Quality Attributes of Gilts and Barrows

This study examined the impact of slaughter weight class (SWC) on a comprehensive set of pork belly quality attributes for 2110 pigs (1055 barrows and 1055 gilts). Pigs were assigned to 2 live weight classes (weight 1: 114.7 kg; weight 2: 128.1 kg), and key carcass and belly traits were assessed. Weight 2 barrows had the greatest (P < .05) carcass fat percentage (34.2%) and intramuscular fat content (4.1%), while weight 1 gilts had the lowest (29.6% and 3.55%, respectively). The predicted lean meat yield was greater (P < .01) in weight 1 pigs (59.7%) and gilts (60.0%) compared with their counterparts. Belly weight was slightly but significantly higher (P < .05) in weight 2 pigs (18.8 kg) and in barrows (18.7 kg) than in weight 1 pigs (18.5 kg) and gilts (18.6 kg). Bellies from barrows showed higher fat percentage than those from gilts (P < .01). Belly length and width were greater (P < .05) in both weight 2 pigs and gilts. Fat-related components (total fat and side: fat, thickness, seam, subcutaneous) were all greater (P < .01) in weight 2 pigs and barrows. Iodine values were greater (P < .01) in weight 1 pigs and gilts, indicating softer fat. Belly bend angle, a firmness indicator, was greater (P < .01) in weight 2 pigs and barrows. These findings highlight the significant influence of SWC and sex on belly composition and firmness, warranting attention as market weights increase, particularly given the trade-offs between firmness and excessive fat deposition for premium belly markets.