Relationship between backfat thickness of sows at d 109 of gestation and performance of sows and suckling pigs

Abstract Text: The present study investigated retrospectively the impact of sow backfat (BF) thickness at d 109 of gestation in different parities on reproductive performance of sows and performance of suckling piglets. A total of 11,536 sows were divided into ten groups on the basis of BF thickness (≤ 10, 11 to 12, 13 to 14, 15 to 16, 17 to 18, 19 to 20, 21 to 22, 23 to 24, 25 to 26, and ≥27mm) at 109 d of gestation for each parity (parity 1, 2, 3, 4, 5, 6, 7, and ≥ 8). The data were collected between 2000 and 2012. All the sows were fed as per NRC (1998) requirement for gestation and lactation. BF thickness was measured on both sides at about 5 cm from the midline at the last rib using a type A ultrasound probe and averaged. Our results showed that, for each parity, sow BW at d 109 of gestation, farrowing and weaning, or sows BF thickness at weaning were linearly and positively (P< 0.01) associated with BF thickness of sows at d 109 of gestation. However, increase in BF thickness of sows at d 109 of gestation led to a linear decrease (P< 0.01) in sow daily feed intake and a linear increase (P< 0.01) in maternal BF thickness loss and  BW loss during the lactation period for each parity. The litter size showed a quadratic (P< 0.01) pattern, increasing gradually and then reducing as d 109 gestation BF increases, for all parity at weaning and parity 4, 5, and ≥ 8 at birth. Similarly, for all parity, the litter weight at birth (except for parity 2 and 7) and at weaning, and litter gain during lactation changed quadratically (P<0.05) with increase of d 109 gestation back fat. Nevertheless, individual piglet weight at birth and weaning and daily gain were generally not significantly (P>0.05) associated with BF at d 109  of gestation except that piglet bodyweight at birth in parity 5 and at weaning in parity 3, 4, and 6 demonstrated a quadratic pattern (P<0.05) similar to the change of litter size. It seemed that best litter performance was obtained in sows having 19 to 22 mm BF thickness at 109 d of gestation. In conclusion, nutritional management of sows to maintain BF thickness during gestation would be beneficial in performance of sows and suckling piglets.

Keywords: Backfat thickness, reproductive performance, sow, suckling piglets.