Context Automated feeding units allow the recording of individual feeding behaviour of group-housed sheep and provide data for research into feed efficiency. Aim It was hypothesised that measures of feeding behaviour such as the number of non-feeding events, meal size, eating rate and meal duration would change under different levels of feeding. Method Maternal Composite ewes (n = 126, 18 per pen) were fed a hay-based pellet using automated feeding units (2 per pen) for four periods differing in total daily feed allowance (kg/day) and meal allowance (g/meal). Sheep were initially fed ad libitum (meal allowance ~1000 g) for 19 days during an adaptation period, before restricted feeding for 41 days at daily allowances of 40%, 60%, 80%, 100%, 140% and 180% of estimated maintenance requirements, with a meal allowance of ~100 g. These restricted daily allowances were the experimental treatments that were randomly applied to sheep and replicated three times per pen. The daily allowance was then adjusted to 1.4 kg/day (with a ~200 g meal allowance) for all sheep over 5 days, before ad libitum feeding of all sheep for a period of 16 days. All feeding and non-feeding events were recorded. Key results Under restricted feeding, sheep altered the timing of their meals to consume more meals during the early morning after daily allowances were reset at 0000 hours. This change was more pronounced for sheep fed a smaller proportion of maintenance. The number of non-feeding events (~8/day) was not affected by the level of restricted feeding, but meal size was smaller, meal duration was longer and eating rate was lower for sheep fed 40% of their maintenance requirement. Under ad libitum feeding, sheep reverted to a preferred meal size and number of meals, with fewer than two non-feeding events per day, but differences in eating rate remained. Conclusions Sheep feeding behaviours adapt and respond quickly to changes in daily allowance and offered meal size, but the similar number of non-feeding events at different proportions of maintenance feeding suggest that non-feeding events may not reflect levels of hunger. Implications Our observations suggest that sheep are capable of learning and adapting to different levels of feeding and that this may allow for automated feeding systems to supplementary feed larger numbers of sheep under extensive situations.

中文翻译：

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自动喂羊。1. 限制进食和随意进食时进食行为的变化

背景 自动化饲喂装置可以记录群养绵羊的个体饲喂行为，并为饲料效率研究提供数据。目的 假设喂食行为的测量值，如不喂食事件的次数、进餐量、进食率和进餐时间，在不同喂食水平下会发生变化。方法 母羊复合母羊（n = 126，每栏 18 头）使用自动饲喂装置（每栏 2 只）喂食干草颗粒饲料，持续四个时间段，每日总饲料量（公斤/天）和膳食量（克/餐）不同）。绵羊最初在适应期内随意饲喂 19 天（膳食津贴约 1000 克），然后限制喂养 41 天，每日津贴为估计的 40%、60%、80%、100%、140% 和 180%维持要求，膳食津贴约为 100 克。这些受限制的每日津贴是随机应用于绵羊并在每个围栏重复 3 次的实验处理。然后在 5 天内将所有绵羊的每日允许量调整为 1.4 公斤/天（约 200 克膳食允许量），然后在 16 天内随意喂养所有绵羊。记录所有进食和非进食事件。主要结果 在限制喂食的情况下，在每日零点重置后，羊改变了进餐时间，以便在清晨吃更多的饭。对于喂食较少维持量的绵羊，这种变化更为明显。不进食事件的数量（约 8 次/天）不受限制喂养水平的影响，但喂食维持需要量 40% 的绵羊的餐食量更小，进餐时间更长，进食率更低。在随意喂食的情况下，绵羊恢复到偏好的膳食大小和膳食数量，每天少于两次的非喂食事件，但进食率的差异仍然存在。结论 绵羊喂食行为对每日允许量和提供的膳食量的变化迅速做出适应和反应，但在不同比例的维持喂养下相似数量的不喂食事件表明不喂食事件可能无法反映饥饿程度。影响 我们的观察表明，绵羊能够学习和适应不同的饲养水平，这可能允许自动饲养系统在广泛的情况下补充喂养更多的绵羊。结论 绵羊喂食行为对每日允许量和提供的膳食量的变化迅速做出适应和反应，但在不同比例的维持喂养下相似数量的不喂食事件表明不喂食事件可能无法反映饥饿程度。影响 我们的观察表明，绵羊能够学习和适应不同的饲养水平，这可能允许自动饲养系统在广泛的情况下补充喂养更多的绵羊。结论 绵羊喂食行为对每日允许量和提供的膳食量的变化迅速做出适应和反应，但在不同比例的维持喂养下相似数量的不喂食事件表明不喂食事件可能无法反映饥饿程度。影响 我们的观察表明，绵羊能够学习和适应不同的饲养水平，这可能允许自动饲养系统在广泛的情况下补充喂养更多的绵羊。