Crossbred pigs (n = 240) from Pietrain x Large White sires mated to Landrace x Large White dams, with an average age of 100 d (60.5 +/- 2.3 kg of BW), were used to investigate the effects of sex and slaughter weight (SW) on growth performance and on carcass and meat quality characteristics. There were 6 treatments arranged factorially, with 3 classes (intact females, IF; castrated females, CF; and castrated males, CM) and 2 slaughter weights (114 and 122 kg of BW). Each of the 6 combinations of treatments was replicated 4 times, and the experimental unit was a pen with 10 pigs. Castrated males and CF ate more feed, grew faster, and had more carcass backfat depth and fat thickness at the gluteus medius muscle but lower loin yield than IF (P < 0.05). In addition, CF and CM had more intramuscular fat (P < 0.05) and less linoleic acid content in the subcutaneous fat (P < 0.01) than IF. Pigs slaughtered at 122 kg of BW had lower ADG (P < 0.05), decreased G:F (P < 0.05), and more gluteus medius fat than pigs slaughtered at 114 kg of BW (P < 0.05). It was concluded that CF and CM had similar productive performance and meat quality characteristics when slaughtered at the same age, and that castration of females improved ADG and increased weight and fat content of primal cuts with respect to IF. Therefore, castration of females is recommended in pigs destined for the dry-cured industry because of the beneficial effects on quality of the primal cuts.

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Two hundred and forty pigs of 56 ± 3 days of age were used to investigate the effects of sex (barrows; gilts), boar sire (DD, Danish Duroc; ND ✕ LW, Dutch Duroc ✕ Large White ; P ✕ LW, Pietrain ✕ Large White) and slaughter age (160; 175 days) on performance and carcass and meat quality. Treatments were arranged factorially (2 ✕ 3 ✕ 2) and there were four replicates (five pigs per replicate) per treatment. The female line was Landrace ✕ Large White in all cases. Barrows had greater daily food intake ( P < 0·001) and average daily gain ( P < 0·01) and had poorer food conversion ratio ( P < 0·001) than gilts. Carcasses from castrates were fatter and had a lower yield of trimmed lean cuts than carcasses from females ( P < 0·001). Longissimus muscle from barrows had more intramuscular fat and higher a* value than muscle from gilts ( P < 0·05). Pigs from DD sire line grew faster ( P < 0·05) and had a better food conversion ratio ( P < 0·001) than pigs from the other two lines. Dressing proportion and backfat thickness were greatest for P ✕ LW sired pigs ( P < 0·01) and proportion of trimmed lean cuts was greater for DD and P ✕ LW than for ND ✕ LW sired pigs ( P < 0·01). Longissimus muscle from DD sired pigs had less protein ( P < 0·01) and more intramuscular fat ( P < 0·001) than muscle from the remaining lines. Longissimus muscle from P ✕ LW line had more intense colour than muscle from DD and ND ✕ LW lines ( P < 0·01). Pigs slaughtered at 175 days had poorer food conversion ratio ( P < 0·01) and less trimmed primal cut proportion ( P < 0·001) than pigs slaughtered at 160 days. Also, increasing the age at slaughter increased intramuscular fat content ( P < 0·01), a* value ( P < 0·001) and colour intensity of the muscle ( P < 0·01). Danish Duroc boars are a good alternative to ND ✕ LW or P ✕ LW boars for production of heavy pigs whether the crossbreds are sacrificed at 160 or 175 days. Also, an increase in age at slaughter impairs growth efficiency and yield of lean cuts but improves some aspects of meat quality, which might be of interest in the production of heavy pigs destined for the dry-cured product industry.

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.

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