In the dairy industry, young dairy calves are often housed individually in restrictive environments. There is limited understanding of how approaches to increase complexity of individual rearing, such as through dietary complexity and accommodating more varied feeding behavior, may affect cognitive development in young calves. The objective of this study was to evaluate effects of provision and presentation of hay on cognitive ability of pre-weaned dairy calves. Individually-housed Holstein heifer calves were assigned at birth to 1 of 3 treatments: pelleted starter only (n = 10), hay and starter provided in separate buckets (n = 12), or hay and starter offered as a mixture (n = 11). During week 5 of age, calves were tested daily in a procedural learning task consisting of a T-maze with a milk reward (0.2 L milk) placed in one arm. Calves were subjected to an initial learning and reversal learning stage, where the reward location was changed to the opposite arm of the maze. Calves received 5 sessions/d until they met learning criteria (moving directly to correct side in 3 consecutive sessions) for initial and reversal learning. Dietary treatment did not affect pass rate or the number of sessions required to pass the initial learning stage. During the reversal learning stage, calves provided only starter tended to require more sessions to meet the learning criteria. Provision of hay also affected behavior during the reversal learning stage of the cognitive task, where calves provided hay separately spent more time exploring the testing area. The results of this experiment provide the first evidence that dietary factors alone may affect cognitive performance in dairy calves.

See methods in associated publication

Data were collected from the University of Florida Dairy Research Unit on 33 calves in 2018. Variables are defined in the Excel file. The SAS code used to analyze the data is provided.