Buranawit Krittaphak, Imboonta Nalinee, Tongsiri Siriporn, Masuda Yutaka, Phakdeedindan Praopilas
Department of Animal Husbandry, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.
Poultry Research and Development Center, Bureau of Animal Husbandry and Genetic Improvement, Department of Livestock Development, Prachin Buri 25110, Thailand.
Poult Sci. 2025 Apr 19;104(7):105196. doi: 10.1016/j.psj.2025.105196.
Heat stress is a considerable challenge for the poultry industry, impacting even native breeds well-known for their adaptability. This study aimed to examine the effect of heat stress, defined as a temperature-humidity index (THI), on egg production traits in Thai native chickens (Lueng Hang Kao Kabin breed, LHKK). The THI values were calculated using three different equations based on the weather data on the same day (day 0) as the observation and up to seven days (day -7) prior to the observation. The models were preliminarily tested to identify the significant effects on egg production traits based on adjusted R, residual error variance, and Akaike Information Criterion (AIC) values. The most impactful day of each THI was determined based on the absolute value of the greatest regression coefficient. These days were then analyzed to identify the THI breakpoint associated with a decline in egg production traits. Heat stress had a significantly negative effect on egg production traits in LHKK chickens. THI values effectively captured the impact of heat stress on these traits, with day -3 and day -1 prior egg laying exhibiting the strongest influence on egg weight at first egg and egg weight, respectively. The THI breakpoints for significant declines in egg weight at first egg were found to be higher than those for egg weight. The current findings suggest that heat stress should be considered as a significant variable in models of egg production traits in native chickens.
热应激对家禽业来说是一项重大挑战，即使是适应性强的本地品种也会受到影响。本研究旨在探讨以温湿度指数（THI）定义的热应激对泰国本地鸡（伦杭考卡宾品种，LHKK）产蛋性状的影响。THI值是根据与观察日（第0天）相同的当天以及观察前最多七天（第-7天）的天气数据，使用三种不同的公式计算得出的。基于调整后的R、残差误差方差和赤池信息准则（AIC）值，对模型进行初步测试，以确定对产蛋性状的显著影响。根据最大回归系数的绝对值确定每个THI影响最大的日期。然后对这些日期进行分析，以确定与产蛋性状下降相关的THI断点。热应激对LHKK鸡的产蛋性状有显著负面影响。THI值有效地反映了热应激对这些性状的影响，产蛋前第-3天和第-1天分别对初产蛋重和蛋重影响最大。初产蛋重显著下降的THI断点高于蛋重的THI断点。目前的研究结果表明，在本地鸡产蛋性状模型中，应将热应激视为一个重要变量。
