Data from: Response to novel feed in dairy calves is affected by prior hay provision and presentation method

Animals raised in environments that prevent natural foraging opportunities
may show difficulties adapting to novelty, such as feeding and management
changes. Our objective was to evaluate how early provision and
presentation of forage in dairy calves affected response to novel TMR
(total mixed ration; grain and alfalfa) at weaning. Holstein heifer calves
were housed individually on sand and fed a diet of starter grain and milk
replacer (5.7–8.4L/d step-up) via a bottle (Control, n=9) or given
additional access to mountaingrass hay presented either in a bucket
(Bucket, n=9) or PVC pipe feeder (Pipe, n=9). Treatments were applied from
birth through 50 d of age when step-down weaning began. All calves had 3
buckets and a pipe feeder in their pens. On d 50, each calf was briefly
blocked inside their hutch. TMR was put in the 3rd bucket that previously
contained hay (Bucket) or was empty (Control, Pipe). The calf was released
and video-recorded for 30 min. Neophobia towards TMR was affected by prior
experience with presentation: Bucket calves began eating TMR faster than
Pipe and Control (P=0.012) and showed the fewest number of startle
responses (P=0.004). Intake was similar across groups (P=0.978),
suggesting this apparent neophobia was transient, but Control calves took
longer to eat than Bucket (P<0.001) and Pipe (P=0.070) calves and
were less likely to give up on eating to lie down instead. These results
suggest that previous experience with hay improves processing ability when
presented with novel TMR. Overall, response to a novel feed is affected by
both early life experience, such as opportunities to process forage, and
the presentation of the feed itself. Calves also appear motivated to
access forage, evidenced by transient neophobia, high intake, and
persistence in feeding by naïve calves.

在无法进行自然觅食的环境中饲养的动物，可能难以适应新异刺激（如饲喂方式与管理措施的改变）。本研究旨在评估奶牛犊牛早期饲草的供给方式与呈现形式，对其断奶时应对新型全混合日粮（TMR；谷物与苜蓿混合）反应的影响。荷斯坦小母牛犊牛单栏饲养于沙地上，对照组（Control，n=9）通过奶瓶饲喂开食料与代乳粉（5.7–8.4升/天逐步增加）；试验组则额外提供山地草干草，分别通过桶式饲喂器（Bucket组，n=9）或PVC管道饲喂器（Pipe组，n=9）呈现。处理措施从犊牛出生持续至50日龄（逐步断奶开始时）。所有犊牛栏内均配备3个桶与1个管道饲喂器。50日龄时，将每头犊牛短暂限制于栏舍内，随后将TMR放入第三只桶中——该桶在Bucket组中原本装有干草，而在对照组与Pipe组中为空桶。释放犊牛后进行30分钟视频记录。结果显示，犊牛对TMR的新物恐惧症受前期饲喂形式的影响：Bucket组犊牛开始采食TMR的速度显著快于Pipe组与对照组（P=0.012），且惊跳反应次数最少（P=0.004）。各组采食量无显著差异（P=0.978），表明这种明显的新物恐惧症具有暂时性；但对照组犊牛的采食时长显著长于Bucket组（P<0.001）与Pipe组（P=0.070），且更倾向于坚持采食而非放弃躺卧。上述结果表明，前期接触干草的经历可提升犊牛对新型TMR的采食适应能力。综上，动物对新型饲料的反应受早期生活经历（如采食饲草的机会）与饲料呈现形式的双重影响。犊牛对饲草的获取具有内在动机，这一点可通过新接触犊牛表现出的暂时性新物恐惧、高采食量及持续采食行为得到印证。