There is increasing interest from cattle lot-feeders in the use of shade to mitigate the effects of a potential heat-stress event, though it is unclear whether the reported benefits of shade in previous studies conducted in more high-risk heat-stress zones are pertinent in cooler temperate zones. The objectives of this study were to measure the welfare and performance benefits of shade provision for lot-fed cattle at a commercial feedlot located in a mild heat-stress risk zone in Western Australia. Six blocks of black Angus (Bos taurus) steers were inducted into the feedlot over 6 time windows across a southern hemisphere summer, with 80 cattle per block housed in a partially shaded pen (providing 3.125 m2 of shade per animal) and 80 in an unshaded pen. Parameters assessed in 960 cattle over the first 70 d in the feedlot included weight gain, feed intake, and physiological and behavioral indices of overall health and welfare. Over the months of October to May in which the experiment was conducted, shaded cattle demonstrated a modest 0.13 kg overall increase in average daily gain across the 70-d feedlot period (P = 0.13). There was no difference in dry matter intake between any block or treatment. The physiological and behavioral markers of health and welfare revealed that, even during to the hottest times of the experiment, the cattle were quite able to thermoregulate, via increased panting and seeking shade (if available), to maintain physiological homeostasis. In addition, we measured the effect of heat stress and shade provision on the affective state of the cattle. Qualitative behavioral assessment was used to indicate that the cattle in the “no stress” temperature humidity index (THI) category and the shaded cattle in the “moderate stress” THI category displayed the most positive demeanor (P < 0.05), being described as more “settled and sociable”, while the unshaded cattle in the “moderate stress” THI category and all cattle in the “severe stress” THI category were described as more “agitated/anxious” (P < 0.05). Overall, the findings from the present study suggest that there are definite welfare and modest performance benefits associated with providing cattle with shade in summer in a feedlot situated in a temperate climatic zone.

中文翻译：

---

温带气候区饲养场牛夏季遮荫的福利和性能优势


牛群饲养者对使用阴凉处来减轻潜在热应激事件的影响越来越感兴趣，尽管目前尚不清楚之前在高风险热应激区进行的研究中报告的阴凉处的好处是否与较冷的温带地区相关。本研究的目的是衡量位于西澳大利亚轻度热应激风险区的商业饲养场为裸料饲养牛提供遮荫的福利和性能效益。在南半球的夏季，在 6 个时间窗口内将 6 块黑色安格斯 （Bos taurus） 公牛引入饲养场，每块 80 头牛被饲养在部分遮荫的围栏中（每只动物提供 3.125 m2 的阴凉处），80 头牛被饲养在无遮荫的围栏中。在饲养场的前 70 天，对 960 头牛评估的参数包括体重增加、采食量以及整体健康和福利的生理和行为指标。在进行实验的 10 月至 5 月期间，遮阴牛在 70 天饲养场期间的平均日增重总体上适度增加 0.13 公斤 （P = 0.13）。任何块或处理之间的干物质摄入量均无差异。健康和福利的生理和行为标志物表明，即使在实验最热的时候，牛也非常能够通过增加喘气和寻找阴凉处（如果有）来调节体温，以维持生理稳态。此外，我们还测量了热应激和遮荫对牛情感状态的影响。 采用定性行为评估表明，“无应激”温度湿度指数 （THI） 类别的牛和“中度应激”THI 类别中的阴影牛表现出最积极的态度 （P < 0.05），被描述为更“稳定和善于交际”，而“中度应激”THI 类别中的无阴影牛和“严重应激”THI 类别中的所有牛被描述为更“激动/焦虑”（P < 0.05）。总体而言，本研究的结果表明，在位于温带气候带的饲养场中，在夏季为牛提供阴凉处具有明确的福利和适度的性能优势。