Wool-biting behavior in housed sheep is a serious animal welfare problem and is difficult to control. Since we have found that sheep fed on rolled hay performed less post-feeding wool-biting than those fed on baled hay, here we mixed these two kinds of hay in four different proportions (0%, 33%, 67% and 100% of rolled hay) to test the effect of rolled hay on repressing wool-biting behavior. We also measured the pulling force needed to remove a piece of rolled hay, baled hay, wool and fresh grass. Wool-biting occurred most frequently in the treatment containing 0% rolled hay; however, there was no significant difference between the other three treatments. The pulling force needed to remove a piece of baled hay was significantly weaker than that for the other three objects; no other significant differences in pulling force were found. Our results suggest that the wool-biting behavior of sheep was due to feeding frustration, which arises when they lack the appropriate oral stimulation from performing their normal foraging movement; this then redirects to the wool on their pen-mates. Feeding sheep rolled hay, even in low quantities, can provide them with appropriate oral stimulation and was effective in repressing wool-biting behavior.

中文翻译：

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饲喂的粗饲料作为轧制和打包干草的比例对抑制圈养绵羊咬毛行为的影响。

圈养绵羊的咬羊毛行为是一个严重的动物福利问题，难以控制。由于我们发现以干草堆饲喂的绵羊的喂食后咬羊毛的情况要比以干草捆喂食的绵羊少，因此在此我们将这两种干草以四种不同的比例（0％，33％，67％和100％卷干草）以测试卷干草对抑制咬毛行为的影响。我们还测量了去除一块干草，打包干草，羊毛和鲜草所需的拉力。在含0％干草的处理中，最经常发生咬毛现象。但是，其他三种治疗之间没有显着差异。去除一条捆干草所需的拉力明显弱于其他三个物体。在拉力方面没有发现其他显着差异。我们的结果表明，绵羊咬羊的行为是由于进食受挫，这是由于绵羊在进行正常的觅食运动而缺乏适当的口腔刺激时出现的。然后重定向到笔友的羊毛。喂羊皮干草，即使数量很少，也可以为它们提供适当的口腔刺激，并有效抑制咬羊行为。