Effects of different levels of feed intake during four short periods of gestation and housing systems on sows and litter performance

The current study investigated the effects of different levels of feed intake during 4 short periods of gestation and of housing systems on sow and litter performance. A total of 255 multiparous sows were allotted to 1–4 dietary treatments using a randomized complete block design blocking by initial body weight (BW), backfat (BF) and parity. Sows were housed either in individual stalls (n = 129) or group pens (n = 126) with 55 sows in each pen with electronic sow feeder during gestation. All sows were fed one common corn-soybean meal-based diet with the amount of 1.0 × maintenance energy level of feed intake (106 × BW^0.75) throughout gestation except 4 periods of 7 d when dietary treatments were imposed on day 27, 55, 83 and 97 of gestation. During the 4 periods, sows were fed 1 of 4 different levels of feed intake: 0.5, 1.0, 1.5 and 2.0 × maintenance energy level (0.5 M, 1.0 M, 1.5 M and 2.0 M, respectively). Results showed that both BW gain and BF change during gestation for sows on 1.5 M (49.7 kg and 3.1 mm, respectively) and 2.0 M (52.5 kg and 3.7 mm, respectively) levels of feed intake were significantly (P < 0.01) greater than sows on 0.5 M (26.1 kg and −0.1 mm, respectively) and 1.0 M (35.6 kg and 0.1, respectively) levels of feed intake. In contrast, lactation weight gain for sows on 1.5 M (3.3 kg) and 2.0 M (3.4 kg) levels of feed intake during 4 short periods of gestation were significantly (P < 0.01) less than sows on 0.5 M (18.4 kg) and 1.0 M (11.4 kg) levels of feed intake during 4 short periods of gestation, whereas BF loss during lactation for sows on 1.5 M (−3.6 mm) level of feed intake during 4 short periods of gestation were significantly (P = 0.03) higher than sows on 1.0 M (−2.1 mm) level of feed intake during 4 short periods of gestation. Additionally, average daily feed intake during lactation for sows on 0.5 M (6.6 kg/d) level of feed intake during gestation tended (P = 0.06) to be greater than sows on 2.0 M (5.9 kg/d) level of feed intake. There were no differences (P > 0.1) among 4 levels of feed intake in terms of numbers of total born and weaning piglets. However, both piglet weight at birth (1.46, 1.52, 1.53 and 1.51 kg for piglets from sows on 0.5 M, 1.0 M, 1.5 M and 2.0 M levels of feed intake during gestation, respectively) and at weaning (6.37, 6.55, 6.64 and 6.38 kg for piglets from sows on 0.5 M, 1.0 M, 1.5 M and 2.0 M levels of feed intake during gestation, respectively) were maximized at 1.5 M level of feed intake. Sows housed in group pens had greater (P < 0.01) net BW gain (24.7 vs. 19.2 kg) from day 27 of gestation to weaning compared with sows housed in individual stalls. However, there were no differences (P > 0.1) between the 2 housing systems in terms of litter size and piglet weight at birth and at weaning. In conclusion, increasing levels of feed intake during 4 short periods of gestation increased BW and BF gain during gestation and led to less BW gain and more BF loss during lactation. Piglet weight at birth and at weaning was maximized at 1.5 M level of feed intake. However, housing systems did not affect reproductive performance. Group pen housing system may be beneficial in terms of increased overall BW gain during gestation and lactation.