Longevity and reproductive performance are economically important traits in the swine industry that are largely influenced by nutrition and other environmental factors. Reproductive performance and longevity through 4 parities was assessed in gilts of 2 genetic lines developed on ad libitum access to feed or restricted to 75% of ad libitum intake. A total of 661 gilts were used in a 2 × 2 factorial with half of the gilts allocated to an ad libitum diet (AL; n = 330), while the other half were energy restricted by 25% (R; n = 331) from 123 to 235 d of age. All gilts were sired by an industry maternal line. Dams of the gilts were from either a Large White (W) by Landrace (L) industry maternal line or Nebraska Selection Line 45X, producing gilts designated as W × L (n = 355) and L45X (n = 306), respectively. Daily estrus detection began at 140 d of age to obtain age at puberty (AP). Gilts (n = 510) were mated on their second or later estrus, beginning at 240 d of age. Sow weight and backfat were recorded at 110 d of gestation and weaning of each parity. Number of live-born, stillborn, and mummified pigs per litter and piglet birth and weaning weights were recorded through 4 parities. More L45X than W × L and more AL than R gilts reached puberty by 230 d of age (P < 0.01). Dietary treatment did not affect probability to produce parities 1 to 4 or any litter trait analyzed. The L45X females tended to be more likely to produce parities 1 (P < 0.08) and 3 (P < 0.06), while W × L had heavier litters at birth (P < 0.01) and weaning (P = 0.01). Treatment by parity interactions (P < 0.01) existed for weight and backfat prior to farrowing and backfat at weaning, and weight at weaning exhibited a line by treatment by parity interaction (P = 0.04) as R sows had lower weights and backfats in earlier parities, but caught up to AL sows in later parities. A treatment by parity interaction (P < 0.01) was also present for backfat loss from farrowing to weaning as R gilts lost less backfat than AL in parities 1 and 2, but more in parities 3 and 4. No significant differences were detected between lines or treatments for lifetime production traits. The populations of pigs and data presented here provide a framework for a diverse array of further studies. Alternative approaches to restrict energy have been assessed in addition to methods of marker-assisted and genomic selection for improvement of litter size and sow longevity.

中文翻译：

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后备母猪发育期间限制能量对瘦肉率不同的品系生长和繁殖的影响：繁殖性能和寿命的反应

寿命和繁殖性能是养猪业的重要经济性状，在很大程度上受营养和其他环境因素的影响。通过 4 胎次的繁殖性能和寿命在 2 个遗传品系的后备母猪中进行评估，这些后备母猪是在随意获取饲料或限制在 75% 的随意采食量的情况下开发的。在 2 × 2 阶乘中使用了总共​​ 661 头后备母猪，其中一半分配给随意饮食（AL；n = 330），而另一半的能量限制为 25%（R；n = 331）来自123 至 235 日龄。所有后备母猪均由行业母系繁殖。后备母猪来自 Large White (W) by Landrace (L) 工业母系或 Nebraska Selection Line 45X，生产的后备母猪分别指定为 W × L (n = 355) 和 L45X (n = 306)。每日发情检测从 140 日龄开始，以获得青春期年龄 (AP)。后备母猪 (n = 510) 在 240 日龄开始的第二次或更晚的发情期交配。在妊娠 110 天和每胎断奶时记录母猪体重和背膘。通过 4 胎次记录每窝活产、死产和木乃伊猪的数量以及仔猪出生和断奶体重。到 230 日龄达到青春期的后备母猪 L45X 多于 W × L 且 AL 多于 R（P < 0.01）。日粮处理不影响产生胎次 1 到 4 的概率或分析的任何窝性状。L45X 雌性往往更有可能生产第 1 胎 (P < 0.08) 和第 3 胎 (P < 0.06)，而 W × L 在出生时 (P < 0.01) 和断奶 (P = 0.01) 的产仔数较多。通过胎次相互作用进行治疗 (P < 0. 01) 分娩前的体重和背膘以及断奶时的背膘存在，并且断奶时的体重通过胎次相互作用显示出一条线 (P = 0.04)，因为 R 母猪在较早的胎次中体重和背膘较低，但赶上了 AL 母猪在后来的平价中。对于从分娩到断奶的背膘减少，胎次交互作用 (P < 0.01) 也存在，因为 R 后备母猪在第 1 胎和第 2 胎中比 AL 减少的背膘少，但在第 3 胎和第 4 胎中更多。未检测到品系之间的显着差异或针对终生生产性状的治疗。此处提供的猪群和数据为各种进一步研究提供了框架。除了用于提高窝产仔数和母猪寿命的标记辅助和基因组选择方法之外，还评估了限制能量的替代方法。