Animal Science Research Centre, Harper Adams University, Shropshire, TF10 8NB, United Kingdom.
J Dairy Sci. 2013 Jul;96(7):4387-96. doi: 10.3168/jds.2012-6421. Epub 2013 May 9.
Several factors influence whether dairy cattle prefer to be indoors or at pasture, including weather conditions and milk yield, but it is unclear how motivated cows are for access to pasture. One way to measure motivation is to require the animal to work (e.g., walk different distances) for access to a resource. This study investigated whether pasture access located 60, 140, or 260m from the indoor housing would affect the proportion of time dairy cows spent at pasture. Thirty-two Holstein-Friesian dairy cows were used during the study, which took place in the United Kingdom from May to July 2010. The experiment consisted of four 18-d experimental periods, with 8 cows in each period, which were further divided into 2 groups of 4 cows. Following a training period, the cows were randomly allocated to distances of 60, 140, or 260m to pasture over three 4-d measurement periods. A video camera was used to record time spent indoors and outdoors 24h/d, and manual behavior observations (0700 to 2200h) took place 6 times during each period to record how the cows spent their time in each location. The video data showed that cows spent, on average, 57.8% (±3.44) of their time outside (either at pasture or on the track). One-sample t-tests revealed that this value was different from 0% (t=16.80), 50% (t=2.26), and 100% (t=-12.28). Analysis of the percentage time spent outside revealed that distance did not influence nighttime pasture use (2100 to 0430h; F2,8=0.16; 81.0% vs. 81.0% vs. 76.7%, for 60m vs. 140m vs. 260m, respectively). In contrast, during the day (0700 to 2100h; from behavior observations), time spent at pasture declined as distance increased; that is, cows spent more time at pasture when they had to walk 60m (F2,80=10.09) than when they had to walk 140 or 260m (45.3% vs. 27.4% vs. 21.2%, respectively). Time spent at pasture decreased on rainy days (y=-1.0672x + 59.646, R(2)=0.09, n=48d), but the indoor temperature-humidity index (THI), the outdoor THI, and body condition score did not influence time spent outside. Under the climatic conditions of the current study in the United Kingdom, cows had a partial preference for pasture, which was influenced by distance to pasture during daytime but not at night. This shows that dairy cows were more motivated to access pasture at night compared with during the day.
一些因素会影响奶牛是喜欢待在室内还是在牧场上，包括天气条件和产奶量，但目前尚不清楚奶牛对牧场的需求有多大。一种衡量动机的方法是让动物为获得资源而工作（例如，走不同的距离）。本研究旨在调查距离室内牛舍 60、140 或 260 米的牧场是否会影响奶牛在牧场上的时间比例。在 2010 年 5 月至 7 月期间，在英国进行了这项研究，共有 32 头荷斯坦-弗里生奶牛参与了该研究。该实验包括四个 18 天的实验期，每个实验期有 8 头奶牛，进一步分为两组，每组 4 头。在训练期后，奶牛被随机分配到距离牧场 60、140 或 260 米的三个为期 4 天的测量期。摄像机 24 小时记录奶牛在室内和室外的时间，在每个实验期内进行 6 次手动行为观察（07:00 至 22:00），以记录奶牛在每个位置的时间分配。视频数据显示，奶牛平均有 57.8%（±3.44）的时间在室外（要么在牧场上，要么在轨道上）。单样本 t 检验显示，这一数值与 0%（t=16.80）、50%（t=2.26）和 100%（t=-12.28）不同。对室外时间的百分比分析表明，距离并没有影响夜间牧场的使用（21:00 至 04:30）；F2,8=0.16；60m 组（81.0%）与 140m 组（81.0%）和 260m 组（76.7%）相比差异不显著。相反，在白天（07:00 至 21:00），从行为观察来看，随着距离的增加，奶牛在牧场上的时间减少；也就是说，当奶牛需要走 60 米时，它们在牧场上的时间更多（F2,80=10.09），而当它们需要走 140 或 260 米时，它们在牧场上的时间更少（45.3%、27.4%和 21.2%）。雨天（y=-1.0672x + 59.646，R(2)=0.09，n=48d）时，奶牛在牧场上的时间减少，但室内温度-湿度指数（THI）、室外 THI 和身体状况评分都没有影响奶牛在室外的时间。在英国当前研究的气候条件下，奶牛对牧场有一定的偏好，这种偏好受到白天牧场距离的影响，但晚上不受影响。这表明与白天相比，奶牛在夜间更有动力进入牧场。
