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

翻譯：劉素利 

養豬生產系統的有效管理需要了解復雜的生殖生理機制。本研究的目的是探討高生產力后備母豬和母豬繁殖特性之間潛在的生物學因果關系。數據來源于一個商業養豬場的一項由200頭母豬和440頭后備母豬組成的營養實驗，在妊娠后期按照豬只體重隨機分配到各日糧處理組中。繁殖性能包括妊娠后期體增重、產仔數（TB）和產活仔數（BA）、平均活仔初生重（BABW）、斷奶到發情間隔以及總產仔數。將結構方程模型與歸納因果方法相結合，同時采用分層貝葉斯框架，去搜索、評估和推斷每一胎次豬只繁殖性能的因果聯系。

結果表明，在后備母豬和母豬的繁殖性能之間存在著潛在的不同的脈絡聯系。母豬的繁殖特征之間的聯系很稀疏，而后備母豬的脈絡卻是緊密相連的，這表明在年輕雌性機體上生理機制是緊密關聯的，作為對早期實施有針對性的管理干預措施的回應，在整個生產周期中存在著潛在的連鎖效應。交叉驗證分析表明，無論是對于一般結構還是對于各自鏈接，都存在著實質的脈絡穩定，盡管在本研究中關于這些聯系的方向性問題的結果并不穩定，需要進一步研究。對后備母豬和母豬的相對統計能力評估表明，觀察到的脈絡差異可以在生物學基礎得到部分解釋。

綜上所述，我們的研究結果表明，后備母豬和母豬的生殖生理機制存在明顯的脈絡聯系，這與各組間母豬的生理差異相一致。這些發現對后備母豬和母豬的綜合認識和差異管理具有潛在的實際意義，可以提高豬生產系統的效率。

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.