Effects of a preweaning socialization system on piglet livability, lifetime growth performance, and subsequent sow performance.

A total of 3,307 (PIC L 42) sows and 55,160 piglets were used to determine the effects of different farrowing systems on piglet livability and lifetime growth performance. Treatments were assigned to farrowing rooms and consisted of a conventional farrowing system (sows and piglets housed in individual farrowing stalls) or a preweaning socialization system (stall dividers removed between farrowing stalls and walkways within 6 to 24 h post-farrowing such that 12 to 32 litters of piglets were co-mingled). A total of 40 farrowing rooms with 80 stalls each were used with 20 rooms per treatment. Pigs were weaned at approximately 23 d of age. No differences were observed in lactation length, total born, born alive, stillborn, mummies, or number of pigs weaned. Pre-wean mortality was increased (P < 0.001) for pigs from the preweaning socialization system compared to the conventional farrowing system (14.7% vs. 12.6%, respectively). At weaning, a subset of offspring (4,313 pigs initially 5.4 ± 0.15 kg) were transported to a commercial research facility to evaluate lifetime performance. Weaning weights were heavier (P < 0.001) for pigs in the conventional farrowing system compared to the preweaning socialization system. Pigs were housed in pens according to sow treatment with 44 to 46 pigs per pen and 48 pens per treatment. During the nursery and finishing periods, pigs from the conventional farrowing system had increased (P < 0.001) body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI), but decreased gain-to-feed (G:F) compared to the preweaning socialization system. In the nursery phase, removals, mortality, and total removals and mortality were greater (P ≤ 0.059) for pigs raised in the preweaning socialization system than the conventional farrowing system, but no differences were observed in the finishing phase. Overall (days 23 to 183), pigs from the conventional farrowing system had increased (P ≤ 0.001) BW, ADG, and ADFI, but decreased (P = 0.010) G:F compared to the preweaning socialization system. No differences were observed for overall removals and mortality after weaning. Pigs from the conventional farrowing system had increased (P ≤ 0.094) live BW, hot carcass weight, carcass yield, loin depth, and percentage lean compared to the preweaning socialization system. No differences were observed in backfat. In summary, pigs raised in a conventional farrowing system had increased livability, lifetime growth performance, and improved carcass characteristics compared to the preweaning socialization system.