University of Veterinary Medicine Vienna Early Detection of Respiratory Diseases in Calves by Use of an Ear-Attached Accelerometer Accelerometers (ACL) can identify behavioral and activity changes in calves. In the present study, we examined the association between bovine respiratory disease (BRD) and behavioral changes detected by an ear-tag based ACL system in weaned dairy calves. Accelerometer data were analyzed from 7 d before to 1 d after clinical diagnosis of BRD. All calves in the study (n = 508) were checked daily by an adapted University of Wisconsin Calf Scoring System. Calves with a score ≥ 4 and fever for at least two consecutive days were categorized as diseased (DIS). The day of clinical diagnosis of BRD was defined as d 0. The data analysis showed a significant difference in high active times between DIS and healthy control calves (CON), with CON showing more high active times on every day, except d -3. Diseased calves showed significantly more inactive times on d -4, -2, and 0, as well as longer lying times on d -5, -2, and +1. These results indicate the potential of the ACL to detect BRD prior to a clinical diagnosis in group-housed calves. Furthermore, in this study, we described the 'normal' behavior in 428 clinically healthy weaned dairy calves obtained by the ACL system. en TEXT article Dairy Heifer Calves; Technical-Note Evaluation; Feeding-Behavior; Automated Detection; Early Indicators; Mortality; Cattle; Rumination; System; Health 2022 2022 Ramezani Gardaloud, Nasrin (University of Veterinary Medicine Vienna / Smartbow GmbH) Klein-Jöbstl, Daniela (University of Veterinary Medicine Vienna) Drillich, Marc (University of Veterinary Medicine Vienna) Iwersen, Michael (University of Veterinary Medicine Vienna) Auer, Wolfgang (Smartbow GmbH) Öhlschuster, Manfred (Smartbow GmbH) Kickinger, Florian (Smartbow GmbH) Steininger, Alexandra (Smartbow GmbH) Lidauer, Laura (Smartbow GmbH) Guse, Christian (University of Veterinary Medicine Vienna) MDPI