Effect of sex and slaughter weight on carcass traits measured in vivo with ultrasound and post-mortem in the carcass in Iberian pigs

Carcass composition of Iberian pigs is very important because it influences the quality of their cured products. Therefore, the objective of this study was to determine the effects of sex and slaughter weight on carcass traits measured in vivo with ultrasound and subsequently in the carcass. One hundred and sixty five castrate males and females with a weight ranging from 130 to 175 kg were ultrasoundscanned before slaughter with a 12-cm long, 3,5 Mhz probe. Two images were collected across the Longissimus dorsi muscle, one between the 10th and 11th ribs and another after the last rib. After slaughtering, carcass, hams, shoulders and loins were weighted, and the same measurements performed for the ultrasound images were also done in the carcass as follows: loin area, and fat thickness (external, middle, internal, external + middle layers and total). Sex effects were significant for shoulder traits, for ultrasound fat thickness measurements taken between 10th and 11th ribs, and also for some other traits at the last rib level. Slaughtering pigs over 165 kg did not improve carcass or cut yields.