PSI-16 Sow parity structure and body condition measurements throughout lactation and relationship to piglet growth

Abstract Energy demands during lactation can greatly influence sow body condition and piglet performance. Therfore, it was hypothesized that primiparous sows would have reduced sow body condition measurements and piglet growth. Eight weekly farrowing seasons (N=157 dams) were used to evaluate sow body condition (Post Farrowing; PF to Weaning; WN) and piglet growth. Final number of white composite sows within parity were as follows: Parity 1(P1), 62; P2, 50; P3, 30; and P4, 15. Body condition was measured at PF and WN using sow calipers (last rib and hip) and 10th rib ultrasound. Sows were categorized as thin, moderate, or fat by caliper. Piglets were weighed at Day 0 PF (D0), D10, WN, and D45. All data were analyzed using mixed models and reported as LSM ± SE. Fat sows at WN (last rib or hip) had the lightest (P < 0.05; Table 1) piglets at D10 and WN. However at D45, piglets from fat sows were heavier than piglets from moderate and thin sows(P < 0.05; Table 1). At WN, piglets from P1 sows weighed the least (P < 0.05; Table 1). Parity 4 sows had greater hip caliper measurement compared to P1 sows(P < 0.05; 15.5 ± 0.389 vs 13.92 ± 0.215). Sows had similiar (P > 0.10) PF last rib caliper measurements but at WN, P1 sows had the smallest caliper measurements compared to other parities (P < 0.05). Paraties 1, 2, and 3 sows had similiar (P > 0.10) loin eye area at PF; however, at WN P1 sows had the smallest loin eye area (P < 0.05; 38.2 ± 0.63 cm2). Parity 1 sows had the greatest (P < 0.05) reduction of backfat and loin eye area over the lactation period (-2.9 ± 0.31 mm and -2.6 ± 0.49 cm2, respectively). In conclusion, fat sows, had similar or smaller piglets throughout lactation, but by D45 piglet weights surpassed moderate and thin caliper groups.