216 Is weaning body weight more important than early post-weaning feed intake? A meta-analysis exploring electronic feeding stations data

Abstract The present meta-analysis investigated the effects of initial voluntary post-weaning feed intake (FI) and weaning body weight (BW) on daily FI and body weight (BW) development in nursery pigs housed in electronic feeding stations (EFS). In total, 18 studies (2006-2017, Trouw Nutrition, The Netherland) were used containing 1,177 mixed-sex pigs weaned at ~25 d (7.3 ± 1.5 kg BW). Studies lasted for 14 d (3 studies;162 pigs), 21 d (3 studies; 154 pigs), 31 d (7 studies; 467 pigs), or up to 38 to 52 d (5 studies; 394 pigs) post-weaning. Pigs were housed in pens with single-space EFS with 10 to 12 pigs/pen. Daily individual FI and BW at different timepoints were determined. Across studies various dietary treatments were applied by EFS with a feed phase change on d 4-8 (13 studies) or d 14 (5 studies). Classes were created with pigs above or below their respective study median on a) cumulative FI over the initial 4 d post-weaning (Fid 0-3; Hfi and Lfi), and b) BW0 (Hbw and Lbw). Mixed models were used to analyze data including FId0-3 and BW0 classes, time post-weaning, and their interactions as fixed effects while study and pen were random effects and pig was repeated measure over time. In a separate model, the FI before and after change from phase 1 to phase 2 was studied in the 2 × 2 with the diet change day as covariate. Pigs with Hfi showed greater (P 0.05) daily FI until d 14 than their Lfi counterparts (Figure 1). Thereafter, LfiHbw pigs showed a greater FI to an intermediate level with HfiHbw being greatest and LfiLbw least (P 0.001). Between d 20-28, LfiLbw pigs had the least FI among groups (P 0.001). From d 28 onward, HfiHbw showed greater daily FI than the other groups (P 0.05) with LfiLbw often having the lowest FI (P 0.05) or similar to HfiLbw and LfiHbw (P 0.05). The BW0 was similar between FId0-3 classes (P 0.05), i.e., 8.26, 8.26, 6.85 and 6.77 kg BW for HfiHbw, LfiHbw, HfiLbw and LfiLbw, respectively whereas final BW were all different (i.e., 23.9, 21.8, 20.8 and 18.4 kg BW, respectively; P 0.001). In absolute figures, all groups had 10 g similar decrease of FI the day of feed phase change followed with 8 g increase the day after (P 0.05). Time spent eating per feeder visit, steadily increased from d0 (14 min) to d5 (170 min), being greater for Hfi than Lfi (P 0.05). From d 6 onward, it remained ~172 min/visit showing some tendencies (P 0.10) for HfiHbw spending less time. In conclusion, the present study pointed out the relevance of weaning BW and initial post-weaning FI as independent factors influencing both daily feed intake behavior and growth performance for the nursery phase.