Feeding programs for immunocastrated male and female Duroc hybrid pigs in growing and finishing phases

The study aimed to evaluate the effects of different feeding programs (FP) on the performance, carcass yield, and meat quality of hybrid Duroc pigs during the growing and finishing phases. We used immunocastrated males (IC) and females crossbred from hybrid sows (Landrace × Large White) with Duroc terminal boars. The animals were distributed into two sex groups and three feeding programs: ad libitum feeding (AL), feeding program 1 (FP1): −15 % compared to AL, and feeding program 2 (FP2): −25 % compared to AL. The feed conversion ratio (FCR) decreased as the feed restriction increased, and it was better in IC males than females. Feed restriction reduced daily weight gain (DWG), leading to increased slaughter age and days in the finishing phase. The feeding programs did not influence hot carcass weight (HCW) or cold carcass weight (CCW). However, an interaction between feeding program and sex group was observed for carcass yield (CY), with no effect in females, but lower CY in FP2 males compared to AL males. However, loin weight and yield were affected by feed restriction, which was higher (P < 0.05) in FP1. The sex group significantly influenced (P < 0.05) carcass yield, with females showing higher yield and heavier cuts, such as leg, belly, rack, and jowl (P < 0.05). Feeding management did not affect meat quality, although females exhibited higher marbling (P < 0.05). We concluded that the feed restrictions imposed by the FP improved FCR in IC males but reduced DWG. Additionally, females showed higher yields, heavier cuts, and greater marbling than males.