Clein D A, Lindner E E, Bonney-King J, Miller-Cushon E K
Department of Animal Sciences, University of Florida, Gainesville, FL 32611.
Department of Animal Sciences, University of Florida, Gainesville, FL 32611.
J Dairy Sci. 2024 Dec;107(12):11524-11535. doi: 10.3168/jds.2024-25179. Epub 2024 Sep 17.
Dairy cattle are routinely managed in social groups and subject to various management and social transitions, yet conventional approaches to rearing dairy calves limit social experience during early weeks of life. The objective of this study was to evaluate long-term effects of dairy calf social housing on behavioral responses observed in pregnant heifers following social regrouping and introduction to a novel housing environment. Holstein heifers were raised during the milk-feeding period (provided 8 L/d milk replacer) in either individual housing (IH; n = 20) or pair housing (PH; n = 20 pens; 1 focal heifer/pen) and subsequently identically managed in groups on pasture from 9 wk of age. At 30 d before expected calving, pregnant heifers were moved from pasture to a freestall barn, which represented introduction to a novel social group and an unfamiliar housing environment. Behavior was continuously recorded from video for 24 h, beginning at 0000 h on the day after introduction, to characterize feeding behavior, locomotor activity, and stall usage, as well as social proximity and competitive behavior surrounding the feed bunk and stall. Stocking density of the freestall barn fluctuated and was categorized as low (≤75%, 100 × animals in pen/available stalls), medium (>75%, 100%), or high (≥100%). Body weights obtained following calving indicated that previously PH heifers were heavier (632.3 vs. 593.4 kg; PH vs. IH), and BW was included as a covariate in analysis of feeding behavior. Upon introduction to the freestall pen, previously PH heifers spent more time walking (1.9 vs. 1.3 min/h) with no effect of calf social housing on duration of lying time. However, stall use was subject to an interaction between previous housing treatment and stocking density and differed overall between previous housing treatments; previously PH heifers spent less time in the stall, particularly at high stocking density (29.4 vs. 48 min/h), due to shorter (29.6 vs. 95.7 min/visit) but marginally more frequent stall visits. Previously PH heifers were also less likely to be displaced from a stall (44% vs. 85% of heifers replaced; PH vs. IH). Feeding behavior was similarly influenced by previous housing treatment, particularly at high stocking density, with previously PH heifers spending more time feeding (8.2 vs. 4.2 min/h) and visiting the feed bunk more frequently (1.5 vs. 0.8 visits/h). These results suggest that preweaning social housing had long-term effects on behavior and ability to adapt to a novel environment, which became most apparent under heightened competitive pressure.
奶牛通常以群居方式饲养，并经历各种管理和社交转变，但传统的奶牛犊饲养方法限制了其生命早期几周的社交体验。本研究的目的是评估奶牛犊群居饲养对怀孕小母牛在社交重新分组并引入新的饲养环境后所观察到的行为反应的长期影响。荷斯坦小母牛在喂奶期（每天提供8升代乳品）分别饲养在个体栏舍（IH；n = 20）或成对栏舍（PH；n = 20个栏位；每个栏位1头焦点小母牛）中，随后从9周龄开始在牧场上以群体方式进行相同管理。在预计产犊前30天，怀孕小母牛从牧场转移到自由栏舍，这代表着引入一个新的社会群体和一个不熟悉的饲养环境。从引入后的第二天00:00开始，通过视频连续记录行为24小时，以描述采食行为、运动活动、栏舍使用情况，以及围绕饲料槽和栏舍的社交距离和竞争行为。自由栏舍的饲养密度波动，分为低（≤75%，栏位中动物数量×100/可用栏位数）、中（>75%，100%）或高（≥100%）。产犊后测得的体重表明，之前成对饲养的小母牛更重（632.3对593.4千克；成对饲养对个体饲养），体重被纳入采食行为分析的协变量。引入自由栏位后，之前成对饲养的小母牛行走时间更长（1.9对1.3分钟/小时），犊牛的社交饲养方式对躺卧时间没有影响。然而，栏舍使用情况受到之前饲养处理和饲养密度之间的交互作用影响，并且在之前的饲养处理之间总体上有所不同；之前成对饲养的小母牛在栏舍中停留的时间较少，特别是在高饲养密度时（29.4对48分钟/小时），这是由于停留时间较短（29.6对95.7分钟/次）但访问栏舍的频率略高。之前成对饲养的小母牛也不太可能被赶出栏舍（被赶出的小母牛比例为44%对85%；成对饲养对个体饲养）。采食行为同样受到之前饲养处理的影响，特别是在高饲养密度时，之前成对饲养的小母牛采食时间更长（8.2对4.2分钟/小时），访问饲料槽的频率更高（1.5对0.8次/小时）。这些结果表明，断奶前的群居饲养对行为和适应新环境的能力有长期影响，在竞争压力增加的情况下这种影响最为明显。
