K. Chitakasempornkul，M. B. Menegat，G. J. M. Rosa，F. B. Lopes，A. Jager，M. A. D. Gon?alves，S. S. Dritz，M. D. Tokach，R. D. Goodband，and N. M. Bello

翻译：刘素利 

养猪生产系统的有效管理需要了解复杂的生殖生理机制。本研究的目的是探讨高生产力后备母猪和母猪繁殖特性之间潜在的生物学因果关系。数据来源于一个商业养猪场的一项由200头母猪和440头后备母猪组成的营养实验，在妊娠后期按照猪只体重随机分配到各日粮处理组中。繁殖性能包括妊娠后期体增重、产仔数（TB）和产活仔数（BA）、平均活仔初生重（BABW）、断奶到发情间隔以及总产仔数。将结构方程模型与归纳因果方法相结合，同时采用分层贝叶斯框架，去搜索、评估和推断每一胎次猪只繁殖性能的因果联系。

结果表明，在后备母猪和母猪的繁殖性能之间存在着潜在的不同的脉络联系。母猪的繁殖特征之间的联系很稀疏，而后备母猪的脉络却是紧密相连的，这表明在年轻雌性机体上生理机制是紧密关联的，作为对早期实施有针对性的管理干预措施的回应，在整个生产周期中存在着潜在的连锁效应。交叉验证分析表明，无论是对于一般结构还是对于各自链接，都存在着实质的脉络稳定，尽管在本研究中关于这些联系的方向性问题的结果并不稳定，需要进一步研究。对后备母猪和母猪的相对统计能力评估表明，观察到的脉络差异可以在生物学基础得到部分解释。

综上所述，我们的研究结果表明，后备母猪和母猪的生殖生理机制存在明显的脉络联系，这与各组间母猪的生理差异相一致。这些发现对后备母猪和母猪的综合认识和差异管理具有潜在的实际意义，可以提高猪生产系统的效率。

Efficient management of swine production systems requires understanding of complex reproductive physiological mechanisms. Our objective in this study was to investigate potential causal biological relationships between reproductive performance traits in high-producing gilts and sows. Data originated from a nutrition experiment and consisted of 200 sows and 440 gilts arranged in body weight blocks and randomly assigned to dietary treatments during late gestation at a commercial swine farm. Reproductive performance traits consisted of weight gain during late gestation, total number born (TB) and number born alive (BA) in a litter, born alive average birth weight (BABW), wean-to-estrous interval, and total litter size born in the subsequent farrowing. Structural equation models combined with the inductive causation algorithm, both adapted to a hierarchical Bayesian framework, were employed to search for, estimate and infer upon causal links between the traits within each parity group. Results indicated potentially distinct reproductive networks for gilts and for sows. Sows showed sparse connectivity between reproductive traits whereas the network learned for gilts was densely interconnected, suggesting closely linked physiological mechanisms in younger females, with a potential for ripple effects throughout their productive lifecycle in response to early implementation of tailored managerial interventions. Crossvalidation analyses indicated substantial network stability both for the general structure and for individual links, though results about directionality of such links were unstable in this study and will need further investigation. An assessment of relative statistical power in sows and gilts indicated that the observed network discrepancies may be partially explained on a biological basis. In summary, our results suggest distinctly heterogeneous mechanistic networks of reproductive physiology for gilts and sows, consistent with physiological differences between the groups. These findings have potential practical implications for integrated understanding and differential management of gilts and sows to enhance efficiency of swine production systems.