The aim of this study was to evaluate the impact of increased shadow supply in integrated crop-livestock-forest systems on in vitro embryonic development and physiological parameters related to stress response in Nellore heifers (Bos indicus). For the study, animals (n = 16) were randomly divided into two groups and kept in areas with different afforestation systems, the integrated crop-livestock-forest (ICLF) and the integrated crop-livestock (ICL) system. The microclimate of the ICLF system provided better comfort conditions than ICL. No differences of respiratory rate, rectal temperature, cortisol, T3, T4, oocyte quality, and cleavage rate between the systems were verified. A higher blastocyst rate was observed in the ICLF (p < 0.05). The results demonstrate that Nellore heifers managed in ICLF during summer in Midwest of Brazil showed higher production of in vitro embryos, without typical changes in its physiological parameters. The results observed in the present study indicate that zebu females are able to respond satisfactorily to the intense heat conditions; however, we believe that the long period to which these animals are exposed to these conditions interferes in the oocyte competence and embryo development.

中文翻译：

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在热带作物-畜牧-森林系统中，遮荫对热带适应的Nellore小母牛的生理参数和体外胚胎产生的影响。

这项研究的目的是评估农作物-牲畜-森林综合系统中影子供应量的增加对内罗氏小母牛（Bos indicus）的体外胚胎发育和与胁迫响应相关的生理参数的影响。为了进行研究，将动物（n = 16）随机分为两组，并饲养在具有不同造林系统，农作物—牲畜综合森林（ICLF）和农作物—牲畜综合（ICL）系统的区域。ICLF系统的微气候提供了比ICL更好的舒适条件。没有验证系统之间的呼吸频率，直肠温度，皮质醇，T3，T4，卵母细胞质量和卵裂率的差异。在ICLF中观察到较高的胚泡发生率（p <0.05）。结果表明，巴西中西部夏季在ICLF处理的Nellore小母牛显示出更高的体外胚胎产量，而其生理参数没有典型变化。在本研究中观察到的结果表明，牛雌性能够对强烈的高温条件做出令人满意的反应。但是，我们认为这些动物长期处于这些条件下会干扰卵母细胞的能力和胚胎发育。