Study links higher milk intake to more play in dairy calves: full analysis

A new University of Bristol study is putting fresh data behind a familiar welfare question in dairy calf management: what does restricted milk feeding change beyond growth? Reporting in Scientific Reports on April 13, 2026, the researchers found that calves fed 12 liters of milk per day were more likely to prioritize play, while calves fed 6 liters per day were quicker and more motivated in a milk-reward task. The authors argue that the contrast points to hunger suppressing play and redirecting behavior toward feed seeking. (pubmed.ncbi.nlm.nih.gov)

The work builds on several years of Bristol-led research into how calves experience hunger and how feeding practices shape cognition and welfare. In a 2023 Bristol report on earlier work, researchers found that halving milk allowance from 12 liters to 6 liters impaired calves’ cognitive performance and suggested the animals likely experienced negative affect associated with hunger. That line of work fits with older dairy calf literature showing that restricted-fed calves make more unrewarded feeder visits, while higher milk allowances are associated with greater play behavior and improved performance. (bristol.ac.uk)

In the new study, Bristol investigators compared two groups of 10 calves over three weeks. One group received 12 liters of milk daily, and the other received 6 liters daily. The calves were then tested in a hole-board maze task involving milk rewards. According to the university’s release and the paper record, calves on the lower allowance completed tasks faster and remembered reward locations better, suggesting higher food motivation. Calves on the higher allowance were less engaged in the reward task and instead showed more play behavior. All calves had also gone 16 hours without food before testing, reflecting a twice-daily feeding schedule used in normal farm practice, making the persistence of play in the higher-fed group especially notable. (bristol.ac.uk)

Lead author Jillian Hendricks, a PhD student at Bristol Veterinary School, said the study is among the first to show that hungry animals trade off play to prioritize finding food. Co-author Dr. Ben Lecorps said the practical takeaway is that standard milk allowances may disrupt other important behaviors that signal calves are still hungry. While independent third-party reaction to this specific paper was limited in initial coverage, the study’s conclusions are broadly aligned with systematic reviews and prior experimental work indicating that milk feeding practices influence calf behavior, health, performance, and weaning outcomes. (bristol.ac.uk)

Why it matters: For veterinarians, this study contributes to a more behavior-based understanding of calf nutrition. Play is often treated as a positive welfare indicator, so a calf that forgoes play in favor of food-seeking may be signaling more than simple appetite. In practice, that could affect how veterinary teams advise producers on milk allowance, step-down weaning, feeding frequency, and the interpretation of behavior in preweaned calves. The findings also matter because restricted milk programs are still common, even though calves consume little solid feed early in life and may not be able to compensate nutritionally when milk is limited. (sciencedirect.com)

There’s also a communication angle for veterinarians working with producers and pet parents who care about farm animal welfare and food-system standards. Welfare discussions increasingly turn on whether animals can express species-typical or rewarding behaviors, not just whether they avoid overt disease. This study suggests that feeding level can shape whether calves have the capacity to engage in those behaviors, which may influence future herd-health recommendations, assurance standards, and research priorities around automated feeding and welfare monitoring. (arxiv.org)

What to watch: The next step will be whether these findings translate into changes in on-farm feeding recommendations, especially around milk volume, feeding frequency, and gradual weaning protocols, and whether follow-up studies tie play-based measures more directly to health, growth, and long-term productivity. (bristol.ac.uk)