The ability of ungulates to discriminate among vegetation patches depends largely on the senses of vision, olfaction, tactility, and gustation. However, little is known about how ungulates rely on the respective senses in response to varying distances to discrimination targets. This study aimed to assess how cattle discriminate between patches of green and dead forages by means of senses, with a particular attention to the role of vision in relation to the distance to the forages. Thirteen Japanese Black cows were allowed to choose between the two forages from a distance of about 1 m without (− BF) or with (+ BF) a blindfold. The green forage differed from the dead forage in color, texture, odor, quality, and animals’ preference. Cows located and ate the green forage as the first choice (Type 1), or as the second choice after touching (Type 2) or further biting (Type 3) the dead forage in error. Overall, the proportion of [Type 1]/[Types 1 + 2 + 3] was above the chance for both − BF and + BF with a decrease by blindfolding. The proportion of [Type 2]/[Types 2 + 3] was above the chance for both − BF and + BF with no effect of blindfolding. The results indicate that cattle discriminating green forage against dead forage rely greatly on vision and to a lesser degree on olfaction when away from the forages, but rely no longer on vision and at least on tactility on the muzzle or in the mouth when in contact with a wrong choice.

中文翻译：

---

牛如何通过感官通过头颈部运动来区分绿色草料和死草料：对视觉的依赖随与草料的距离而变化

有蹄类动物区分植被斑块的能力在很大程度上取决于视觉，嗅觉，触觉和味觉。然而，人们对有蹄类动物如何响应于与识别目标的距离变化的依赖于各自的感觉知之甚少。这项研究旨在评估牲畜如何通过感官来区分绿色草料和枯草料，并特别注意视觉与草料距离之间的关系。在不带（-BF）或带（+ BF）眼罩的情况下，允许约13 m的13头日本黑牛在两个饲草之间进行选择。绿色草料与死亡草料在颜色，质地，气味，质量和动物偏爱方面有所不同。奶牛是首选，吃绿色草料是第一选择（类型1），或触摸（类型2）或进一步咬咬（类型3）错误的死草后作为第二选择。总体而言，[类型1] / [类型1 + 2 + 3]的比例高于-BF和+ BF的机会，且蒙眼法降低。[类型2] / [类型2 + 3]的比例高于-BF和+ BF的机会，而没有蒙眼效果。结果表明，将绿色饲草与死饲草区分开的牛在很大程度上依赖于视力，而远离饲草则较少依赖嗅觉，但不再依赖视力，并且至少在与枪口或嘴接触时不依赖触觉。一个错误的选择。[类型2] / [类型2 + 3]的比例高于-BF和+ BF的机会，而没有蒙眼效果。结果表明，将绿色饲草与死饲草区分开的牛在很大程度上依赖于视力，而远离饲草则较少依赖嗅觉，但不再依赖视力，并且至少在与枪口或嘴接触时不依赖触觉。一个错误的选择。[类型2] / [类型2 + 3]的比例高于-BF和+ BF的机会，而没有蒙眼效果。结果表明，将绿色饲草与死饲草区分开的牛在很大程度上依赖于视力，而远离饲草则较少依赖嗅觉，但不再依赖视力，并且至少在与枪口或嘴接触时不依赖触觉。一个错误的选择。