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Abstract：
Environmental conditions profoundly impact the health, welfare, and productivity of laying hens in commercial poultry farming. We investigated the association between microclimate variations, production indices, and histopathological responses to accidental Newcastle disease virus (NDV) infection within a controlled closed-house system. The study was conducted over seven months in a laying hen facility in Cairo, Egypt. Microclimate measurements included temperature, relative humidity (RH%), air velocity (AV), and the temperature humidity index (THI) that were obtained from specific locations on the front and back sides of the facility. Productivity indices, including the egg production percentage (EPP), egg weight (EW), average daily feed intake, and feed conversion ratio, were assessed monthly. During an NDV outbreak, humoral immune responses, gross pathology, and histopathological changes were evaluated. The results demonstrated significant (p < 0.05) variations in EPP and EW between the front and back sides except in April and May. AV had a significant (p = 0.006) positive effect (Beta = 0.346) on EW on the front side. On the back side, AV had a significant (p = 0.001) positive effect (Beta = 0.474) on EW, while it negatively influenced (p = 0.027) EPP (Beta = - 0.281). However, temperature, RH%, and THI had no impact and could not serve as predictors for EPP or EW on either farm side. The humoral immune response to NDV was consistent across microclimates, highlighting the resilience of hens. Histopathological examination revealed characteristic NDV-associated lesions, with no significant differences between the microclimates. This study underscores the significance of optimizing microclimate conditions to enhance laying performance by providing tailored environmental management strategies based on seasonal variations, ensuring consistent airflow, particularly near cooling pads and exhaust fans, and reinforcing the importance of biosecurity measures under field challenges with continuous monitoring and adjustment.
摘要：
环境条件对健康影响深远，福利,和产蛋鸡在商业家禽养殖中的生产力。我们调查了小气候变化之间的关联，生产指数，以及在受控的密闭系统中对意外新城疫病毒（NDV）感染的组织病理学反应。这项研究在开罗的一个蛋鸡设施中进行了七个月，埃及。微气候测量包括温度，相对湿度(RH%),空气速度(AV),以及从设施正面和背面的特定位置获得的温度湿度指数(THI)。生产力指数，包括产蛋率(EPP)，鸡蛋重量（EW），平均日采食量，和饲料转化率，每月评估一次。在NDV爆发期间，体液免疫反应，大体病理学，并对组织病理学改变进行了评价。结果表明，除4月和5月外，正面和背面之间的EPP和EW存在显着变化（p<0.05）。AV对正面的EW具有显著的(p=0.006)正效应(β=0.346)。在背面，AV对EW有显著(p=0.001)正效应(β=0.474),而对EPP(β=-0.281)有负面影响(p=0.027)。然而,温度,RH%,和THI没有影响，不能作为EPP或EW在任一农场方面的预测因子。对NDV的体液免疫反应在整个微气候中是一致的，突出母鸡的韧性。组织病理学检查显示特征性NDV相关病变，微气候之间没有显着差异。这项研究强调了优化小气候条件的重要性，通过提供基于季节变化的量身定制的环境管理策略来提高铺设性能，确保一致的气流，特别是靠近冷却垫和排气扇，并通过持续的监测和调整来加强在实地挑战下采取生物安全措施的重要性。
