Laboratory of Histology and Animal Disease Diagnosis, Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, 50200 Chiang Mai, Thailand; Department of Animal Science, National Chung Hsing University, 40227 Taichung, Taiwan.
Laboratory of Histology and Animal Disease Diagnosis, Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, 50200 Chiang Mai, Thailand; Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, 50200 Chiang Mai, Thailand.
Anim Reprod Sci. 2020 Feb;213:106281. doi: 10.1016/j.anireprosci.2020.106281. Epub 2020 Jan 10.
The objectives were to evaluate effects of tropical seasons on thermal biology, preovulatory follicle (POF) diameter, POF and luteal vascularities, and estradiol (E2) and progesterone (P4) concentrations; and to determine the associations among the values for these variables during preovulatory and postovulatory periods in Thai native cows in tropical climates: cold, hot, and rainy seasons. Development and vascularity of the POF and corpora lutea (CL) were evaluated using color Doppler ultrasonography. The temperature-humidity index (THI) was greater when the preovulatory period occurred during the rainy season when compared with the occurrence during the hot and cold seasons of the year. Furthermore, POF diameter was less when the THI was greater. The THI was greater when the postovulatory period occurred during the rainy season when compared to the occurrence of the postovulatory period during the hot and cold seasons of the year. Furthermore, the CL vascularity and P4 concentration were less when the THI was greater. The THI was inversely correlated with CL vascularity and P4 concentrations. When the THI was greatest during the hot and rainy seasons of the year, there were the greatest negative effects on POF size, POF and CL blood flow, and concentrations of E2 and P4 during the preovulatory and postovulatory periods. While native Bos indicus are capable of adapting to tropical conditions, there are still negative effects, such as impaired POF and CL functions, when the THI induces heat stress.
目的在于评估热带季节对热生物学、排卵前卵泡（POF）直径、POF 和黄体脉管系统以及雌二醇（E2）和孕酮（P4）浓度的影响；并确定在泰国本土牛的排卵前和排卵后期间这些变量的值之间的关联：在热带气候下的冷、热和雨季。使用彩色多普勒超声评估 POF 和黄体（CL）的发育和脉管系统。与热季和冷季相比，雨季排卵前期的温度湿度指数（THI）更高。此外，THI 越高，POF 直径越小。与热季和冷季相比，雨季排卵后期的 THI 更高。此外，THI 越高，CL 血管密度和 P4 浓度越低。THI 与 CL 血管密度和 P4 浓度呈负相关。当 THI 在一年中的热季和雨季最高时，对 POF 大小、POF 和 CL 血流以及排卵前和排卵后期间 E2 和 P4 的浓度产生最大的负面影响。虽然本土的 Bos indicus 能够适应热带条件，但当 THI 引起热应激时，仍然存在负面影响，例如 POF 和 CL 功能受损。
