Department of Animal Sciences, University of Florida, Gainesville 32611.
Department of Animal Sciences, University of Florida, Gainesville 32611.
J Dairy Sci. 2022 Oct;105(10):8387-8400. doi: 10.3168/jds.2022-21921. Epub 2022 Aug 12.
Although social contact between dairy calves has broad effects on their behavioral development, influences of calf social housing on human-animal relationships are less well understood, despite implications for longer-term calf management and welfare. We characterized human-animal interactions in 3 distinct testing contexts to examine effects of social housing on development of human-directed behavior. At birth, Holstein heifer calves were randomly assigned to individual housing (n = 17 calves) or pair housing (n = 17 calves; 1 focal calf/pair). A human approach test was performed twice in the home pen (wk 3 and 5 of life), within an open testing arena (13 × 7 m; wk 4 of life), and within group-housing pens 6 d after all calves were weaned, mingled between treatments, and moved to groups (4 calves/pen; wk 8 of life). For these tests, a human approached, and then extended their hand, over a 2 min period for home and group pen tests and a 5 min period for the arena test, and behavior was recorded from video. During preweaning human approach tests in the home pen, individually housed calves had shorter latencies to contact the human (22.4 vs. 45.1 s; individual vs. pair housing) and spent more time in contact with the human [80.5 vs. 41.1 s; standard error (SE) = 9.9; individual vs. pair housing], with similar responses between repeated tests. In the arena approach test, individually housed calves spent more time oriented toward the human (134.6 vs. 81.3 s; SE = 16.5; individual vs. pair housing), whereas pair-housed calves were more likely to perform pen-directed non-nutritive oral behavior (60 vs. 40% of calves; pair vs. individual housing), suggesting differences in interest directed toward the human compared with the novel environment. We also found that total duration of human contact was correlated between the first home pen approach test and the novel arena test, but that specific response to human approach varied between testing contexts. Effects of treatment persisted during the postweaning group pen approach test, with previously individually housed calves tending to spend more time looking toward the human (53.0 vs. 30.0 s; SE = 9.4; individual vs. pair housing) and more likely to contact the human (47 vs. 12% of calves; individual vs. pair housing). Overall, these results show persistent effects of early life social housing on human-directed behavior which may have implications for longer-term management.
尽管奶牛犊牛之间的社会接触对其行为发育有广泛影响，但犊牛的社会饲养对人际关系的影响却知之甚少，尽管这对犊牛的长期管理和福利有影响。我们在 3 个不同的测试环境中描述了人类与动物的相互作用，以研究社会饲养对人类指向行为发展的影响。在出生时，荷斯坦小母牛犊牛被随机分配到单独饲养（n = 17 头犊牛）或成对饲养（n = 17 头犊牛；1 头焦点犊牛/对）。在生命的第 3 周和第 5 周，在家庭畜栏内进行了两次人类接近测试，在开放式测试场（13×7 m；生命第 4 周）和断奶后所有犊牛混合处理并移至群体畜栏后 6 天内进行了一次群体畜栏内的测试（4 头/栏；生命第 8 周）。对于这些测试，人类在 2 分钟内接近并伸出手，对家庭畜栏和群体畜栏进行测试，对竞技场测试进行 5 分钟测试，然后从视频中记录行为。在断奶前的家庭畜栏人类接近测试中，单独饲养的犊牛与人类接触的潜伏期更短（22.4 与 45.1 秒；个体与配对饲养），与人类接触的时间更长[80.5 与 41.1 秒；标准误差（SE）= 9.9；个体与配对饲养]，两次重复测试的反应相似。在竞技场接近测试中，单独饲养的犊牛更倾向于将注意力指向人类（134.6 与 81.3 秒；SE = 16.5；个体与配对饲养），而配对饲养的犊牛更倾向于进行指向畜栏的非营养性口腔行为（60 与 40%的犊牛；配对与个体饲养），这表明与新颖环境相比，犊牛对人类的兴趣不同。我们还发现，第一次家庭畜栏接近测试与新颖的竞技场测试之间的总人类接触时间呈正相关，但特定的人类接近反应在不同的测试环境中有所不同。在断奶后的群体畜栏接近测试中，治疗效果仍然存在，以前单独饲养的犊牛往往会花更多的时间看向人类（53.0 与 30.0 秒；SE = 9.4；个体与配对饲养），更有可能接触人类（47 与 12%的犊牛；个体与配对饲养）。总的来说，这些结果表明，早期社会饲养对人类指向行为的影响具有持久性，这可能对长期管理产生影响。
