INFLUENCE OF DIFFERENT THERMAL ENVIRONMENTS ON THE PERFORMANCE OF LAYING HENS DURING THE INITIAL STAGE OF REARING

ABSTRACT This study was conducted with the aim of assessing the effects of different ambient temperature values on the performance of laying birds from one to 42 days of age in order to obtain optimal comfort temperatures. A total of 864 laying hens were distributed in four climatic chambers with different temperature ranges. One of the chambers was maintained within the thermal range recommended by the literature and the others were maintained under temperatures that consisted of mild and moderate cold stress and moderate heat stress. The experiment was conducted according to a completely randomized design in a split-plot arrangement and six replications. The data were analyzed by means of the analysis of variance and regression. The final performance of birds with temperatures of 33, 28, 26, 23, 19, and 19 °C (for the first, second, third, fourth, fifth, and sixth week of age, respectively) presented better productive results, confirming the assertiveness regarding the best thermal comfort and welfare of laying birds during the rearing stage. The results showed that under conditions of cold thermal stress, birds presented a worse performance, thus affecting their development and productive efficiency.

摘要 本研究旨在评估不同环境温度对1至42日龄产蛋禽生产性能的影响，以确定其最优舒适温度。共计864羽产蛋母鸡被分配至4个具备不同温度区间的气候舱中。其中一个气候舱维持于文献推荐的热环境区间，其余三个则分别处于轻度、中度冷应激以及中度热应激环境下。本实验采用完全随机裂区设计，设置6次重复。数据通过方差分析与回归分析进行处理。针对1至6周龄分别设置33、28、26、23、19、19℃的温度条件时，产蛋禽的最终生产性能表现更佳，这证实了育雏阶段产蛋禽最佳热舒适与动物福利相关结论的准确性。研究结果同时显示，当产蛋禽处于冷应激环境时，其生产性能会出现下降，进而对生长发育与生产效率造成不利影响。