Reproductive performance, offspring characteristics, and injury scores according to the housing system of gestating gilts

The time of mixing is a key factor that influences the success of group housing system for gestating swine females. This study compared the effects of three gestation housing systems for gilts on body injuries, locomotion problems, farrowing rate and litter characteristics. The gilts were randomly assigned to 1 of the 3 treatments: STALL = gilts housed in individual stalls throughout gestation; PEN7 = gilts group-housed in pens at 7 d after breeding, and PEN30 = gilts group-housed in pens at 30 d after breeding. Farrowing rate was different (P = 0.04) between STALL and PEN7 (89.7% and 83.2%, respectively) whereas an intermediate farrowing rate was observed in PEN30 (84.9%). Treatment did not affect pregnancy maintenance from 28 d to 55 d after AI or from 28 d till farrowing and, as well, the parameters such as the total number of piglets born, born alive, birth weight, the coefficient of variation of birth weight within the litter, and the proportion of piglets weighing less than 1000 g also remained unchanged. The gilts in the STALL group had greater weight and gained more weight up to 107 d of gestation compared to those in PEN7 and PEN30 groups (P < 0.001). A greater chance of increased injury score for skin and claws was observed at 3, 12, and 23 d after housing in PEN7 and PEN30 than in STALL. At 107 d of gestation, PEN7 and PEN30 groups had greater odds for skin injuries, claw lesions, and lameness compared to STALL (P < 0.001). There was no increase in the chance of lameness in STALL but PEN7 and PEN30 groups had greater odds (122.2 and 76.4, respectively) of lameness (P < 0.001) at the end (4.9%, 39.2%, and 26.7%) than at the onset of gestation (3.1%, 0.5%, and 0.5% for STALL, PEN7, and PEN30, respectively). The culling rate as manifested by locomotor problems was found to be greater in PEN7 group than in PEN30 and STALL groups (P < 0.001). In conclusion, mixing gestating gilts at 7 d after breeding compromised farrowing rate; however, mixing gilts on day 30 post-breeding did not impair reproductive performance or litter characteristics. Regardless of the mixing time (7 or 30 d after breeding), more sow injuries (skin lesions and lameness) were observed in the ESF system compared to the individual housing in stalls.