Thesis (M.Sc.)-Cairo University, 2024.

Bibliography: pages 85-92.

Climate change poses considerable challenges to poultry farming, as it affects the microclimate and air quality in poultry houses. This study investigated the influence of seasonal climate variations on the indoor microclimate of a commercial laying hen house in Egypt and investigated the interplay between microclimate variations, production indices, and histopathological responses to accidental Newcastle disease virus (NDV) infection. Over three seasons (autumn, winter & spring), outdoor and indoor temperatures (Ta.C), relative humidity (RH %), air velocity (AV), and temperature/humidity index (THI) were systemically measured. Productivity indices, including the egg production percentage (EPP), egg weight (EW), average daily feed intake (ADFI), and feed conversion ratio (FCR), were assessed monthly. During an accidental NDV outbreak, humoral immune response (HIR), gross pathology, and histopathological lesions were evaluated. Results revealed that, the indoor temperatures closely mirrored the outdoor trends and significantly differed from the outdoor temperatures, except for April and May. A Positive correlations were observed between the outdoor and indoor front and back temperatures. The indoor RH% was notably affected by the outdoor RH%, especially in warm season. Indoor AV consistently lagged outdoor values. The outdoor THI significantly influenced the indoor front and back THI. The indoor microbiological analysis revealed significant differences in the total colony count and the back side total fungal count... The significant variations in EPP and EW between the front and back sides were with microclimate factors influencing these variations, except in April and May. Notably, AV had a significant positive effect on EW in the front (p = 0.006) and back sides (p = 0.001), while it negatively influenced (p = 0.027) EPP in back side .However, temperature, RH%, and THI could not serve as predictors for EPP or EW on either farm side. Importantly, the humoral immune response to NDV was consistent across microclimates. Histopathological examination revealed characteristic NDV-associated lesions, with no significant differences between front and back sides. These findings underscore the challenges posed by microclimate elements fluctuations, highlighting the need for optimizing indoor conditions to enhance laying performance by providing tailored environmental management strategies, particularly near cooling pads and exhaust fans, and reinforcing the importance of biosecurity measures under field challenges with continuous monitoring and adjustment.

الرصد الموسمي لجودة الهواء الداخلي والدرجة الصحية لمسكن الدجاج البياض وتاثيره على إنتاج البيض
لتغييرالمناح دورا هاما في إنتاج دجاج البيض .لهذا أقيم العمل الحالي لاستيضاح تأثير تغيير المناخ في مصر (بفصول الخريف والشتاء والربيع) على جودة الهواء الداخلي (عناصر المناخ الدقيق ,تركيزغازالنشادر, الحمل الميكروبي بالهواء الداخلي للمسكن) في مناطق مختلفة داخل عنبر مزرعة الدجاج البياض المغلقة. كذلك تأثير الأختلاف في المناخ الدقيق بالمناطق المختلفة داخل مسكن البياض على مؤشرات الإنتاج ( نسبة أنتاج البيض , وزن البيضة بالجرام لكل دجاحة بياضة). بالإضافة لتاثيرهذة الأختلافات في المناخ الدقيق الداخلي بالمواقع المختلفة بالمسكن المغلق على رد الفعل المناعي(الإستجابة الخلطية) والتغيرات النسجية المرضية المرافقة للأصابة العارضة بعدوي فيروس النيوكاسل .

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Text in English and abstract in Arabic & English.