Roman L. Hruska U.S. Meat Animal Research Center, USDA, ARS, Clay Center, NE 68933, USA.
J Anim Sci. 2022 Apr 1;100(4). doi: 10.1093/jas/skac031.
Energy demands during lactation greatly influence sow body condition and piglet performance. We hypothesized that primiparous sows or sows with reduced body condition would produce piglets with reduced growth and delayed sexual maturation. Eight weekly farrowing seasons were used to evaluate sow body condition (post-farrowing, PF and weaning, WN) and piglet growth from 157 dams. 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 (PF or WN). Individual pig weights were recorded on approximately 1, 10, WN, 45, 100, and 145 d of age. At 100 and 145 d of age, 10th-rib backfat and loin eye area were measured on 567 pigs and first estrus was monitored in 176 gilts reserved for breeding selection beginning at approximately 170 d of age. Sows had similar (P > 0.10) PF last rib caliper measurements but at WN, first parity sows had the smallest caliper measurements compared to other parities (P < 0.05). Parities 1, 2, and 3 sows had similar (P > 0.10) loin eye area at PF; however, at WN first parity 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). At 1 d of age and WN, piglets from first parity sows weighed the least (P < 0.05) but were the heaviest (P < 0.05) at 100 and 145 d of age. Pigs from first parity litters had larger (P < 0.05) loin eye area at 100 and 145 d of age and greater backfat (P < 0.05) at 145 d of age. Fat sows at WN (last rib or hip) had the lightest (P < 0.05) piglets at 10 d of age and WN. However, at 45 d of age, piglets from fat sows (last rib or hip) were heavier (P < 0.05) than piglets from moderate and thin sows. Tenth rib backfat at 100 and 145 d of age tended (P < 0.10) to be less in pigs reared by thin sows (PF and WN hip). Tenth rib loin eye area was similar among pigs reared by fat, moderate, or thin sows. Gilts developed in litters from fourth parity sows had (P < 0.05) delayed age at puberty in contrast to gilts from first or third parity sows (200.9 ± 4.96 d vs. 189.0 ± 2.29 d and 187.5 ± 2.84 d, respectively). Although progeny body weights were typically less from first parity dams through 45 d of age, these progeny were similar or heavier at 100 and 145 d of age in contrast to progeny from other parities. Furthermore, gilt progeny from first parity dams did not have delayed pubertal attainment.
哺乳期的能量需求对母猪体况和仔猪性能有很大影响。我们假设初产母猪或体况较差的母猪所产仔猪生长和性成熟延迟。使用 8 个周分娩季节评估了 157 头母猪的母猪体况（分娩后、断奶时）和仔猪生长情况。使用母猪卡尺（最后一根肋骨和臀部）和第 10 根肋骨超声测量母猪体况（分娩后和断奶时）。通过卡尺（分娩后或断奶时）将母猪分为瘦、中等或胖。大约在 1、10、断奶时、45、100 和 145 日龄记录个体猪的体重。在 100 和 145 日龄时，在 567 头猪上测量第 10 根肋骨背部脂肪和腰眼面积，并在大约 170 日龄开始的后备母猪中监测首次发情。母猪的最后一根肋骨卡尺测量值相似（P > 0.10），但在断奶时，初产母猪的卡尺测量值最小，与其他胎次相比（P < 0.05）。胎次 1、2 和 3 的母猪在分娩时的腰眼面积相似（P > 0.10）；然而，在断奶时，初产母猪的腰眼面积最小（P < 0.05；38.2 ± 0.63 cm2）。初产母猪在哺乳期的背脂和腰眼面积减少最多（P < 0.05；分别减少 2.9 ± 0.31 mm 和 2.6 ± 0.49 cm2）。在 1 日龄和断奶时，初产母猪的仔猪体重最小（P < 0.05），但在 100 和 145 日龄时最重（P < 0.05）。初产仔猪的第 10 根肋骨腰眼面积在 100 和 145 日龄时较大（P < 0.05），145 日龄时背脂较大（P < 0.05）。断奶时肥胖的母猪（最后一根肋骨或臀部）所产仔猪在 10 日龄和断奶时体重最轻（P < 0.05）。然而，在 45 日龄时，肥胖母猪（最后一根肋骨或臀部）所产仔猪比中等和瘦弱母猪所产仔猪重（P < 0.05）。100 和 145 日龄时，第 10 根肋骨背脂在瘦母猪（分娩时和断奶时臀部）饲养的猪中趋于较低（P < 0.10）。在饲养的猪中，第 10 根肋骨腰眼面积在肥胖、中等和瘦弱母猪之间相似。第四胎母猪所产仔猪的初情期（P < 0.05）延迟，而第一胎或第三胎母猪所产仔猪的初情期分别为 200.9 ± 4.96 d、189.0 ± 2.29 d 和 187.5 ± 2.84 d。尽管初产母猪的仔猪体重通常在 45 日龄之前较小，但与其他胎次的仔猪相比，这些仔猪在 100 和 145 日龄时体重相似或更重。此外，初产母猪的后备母猪初情期没有延迟。
