Influence of feed restriction and sex on growth performance and carcass and meat quality of Iberian pigs reared indoors

Iberian x Duroc pigs (n = 168), with an average age of 152 d and 42 +/- 2 kg, were used to investigate the effect of feeding regimen [ad libitum access to feed (AL) vs. 82% of AL from 152 to 201 d of age and 72% from 202 to 263 d of age (FR)] and sex (intact females, castrated females, and castrated males) on growth performance and carcass and meat quality. For the last 54 d before slaughter at 317 d of age, all pigs had AL access to feed. Between 152 and 263 d of age, pigs consuming AL had greater (P < 0.001) ADFI and ADG than FR pigs; however, when all pigs received AL access to feed (264 to 317 d of age), ADFI (P < 0.05), ADG (P < 0.001), and G: F (P < 0.01) increased in FR pigs compared with AL pigs. During the entire feeding period (152 to 317 d of age), ADG in FR pigs was less (P < 0.01) than in AL pigs. Feed-restricted pigs tended to have greater (P < 0.10) yields of trimmed hams and shoulders and less carcass fat than AL pigs, but feeding regimens did not affect chemical composition and color of meat. Intact females tended (P < 0.10) to have greater G: F and produced carcasses with less (P < 0.05) fat, greater (P < 0.01) proportions of primal cuts, and greater (P < 0.05) CP in the LM than castrated females and castrated males. It was concluded from this experiment that feed restriction applied from 152 to 263 d of age improved primal cut yields without affecting G: F, pork quality, and cured ham production traits. Moreover, intact females were superior to their castrated counterparts (particularly castrated females) in growth performance and primal cut yields. Therefore, feed restriction in intact females can be recommended as an acceptable practice for the production of Iberian pigs under intensive conditions.