Effects of heat stress on the accuracy of an ear-tag accelerometer for monitoring rumination and eating behavior in dairy-beef cross cattle using an automated gold standard

Authors: Weinert-Nelson, Jennifer; WERNER, JESSICA - University Of Hohenheim; JACOBS, ALAYNA - Orise Fellow; ANDERSON, LESLIE - University Of Kentucky; WILLIAMS, CAREY - Rutgers University; Davis, Brittany

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2024
Publication Date: 12/24/2024
Citation: Weinert-Nelson, J.R., Werner, J., Jacobs, A.A., Anderson, L.H., Williams, C.A., Davis, B.E. 2024. Effects of heat stress on the accuracy of an ear-tag accelerometer for monitoring rumination and eating behavior in dairy-beef cross cattle using an automated gold standard. Journal of Dairy Science. 108(1):735-749. https://doi.org/10.3168/jds.2024-24858.
DOI: https://doi.org/10.3168/jds.2024-24858

Interpretive Summary: Technologies that monitor feeding behavior can be useful for research and practical herd management. Little is known about effects of environmental conditions on sensor performance. Specifically, accelerometer technologies have not been tested under varying temperature and humidity. This study evaluated if an ear-tag accelerometer could accurately report the time cattle ruminated and ate during cool or hot conditions. In general, ear-tags were more successful for rumination than eating time. In general, accuracy declined during heat stress. This decline was most pronounced later in the day when cattle had been exposed to heat for multiple hours. Eating time accuracy did improve when evaluating only the time with the head down. This indicates errors in the system when cattle were chewing with the head up. Thus, potential for use in research may be limited. However, farmers may still gain insights from this system. Further research is needed to assess effects of heat stress on other accelerometer technologies.

Technical Abstract: Accelerometer-based technologies can be utilized for precision monitoring of feeding behaviors, but limited information is available regarding the impact of varying environmental conditions on sensor performance. The objective was to determine if a commercially available ear-tag sensor (CM; CowManager SensOor, Agis Automatisering BV) could accurately quantify eating and rumination time under heat stress conditions. Data obtained from CM sensors was compared with data collected using an automated gold standard (RW). Automated measurements were obtained from two experiments in which cattle were exposed to heat stress conditions. In the principal study (Experiment 1), 3428 h of data were collected from nine Holstein × Angus steers (470.9 ± 23.9 kg) subjected to thermoneutral (TN; 21.0 °C; 64.0% humidity; temperature-humidity index [THI] = 67; 12- and 12-h light and dark cycle; n = 1714 h), and heat stress conditions (HS; cyclical daily temperatures to mimic diurnal patterns; 0800 – 2000 h: 33.6 °C, 40.0% RH, THI: 83.5; 2000 – 0800 h: 23.2 °C, 70.0% RH; THI: 70.3; n = 1714 h). Data (n = 719 h) from six Holstein x Angus steers (487.9 ± 9.1 kg) were obtained from a subsequent experiment (Experiment 2) to confirm consistency of ear-tag accelerometer performance under elevated THI (HS conditions as described above). In Experiment 1, CM was capable of quantifying rumination time with high accuracy under TN conditions (CCC: 0.75 – 0.81). Overall, agreement between CM and the automated gold standard declined 6 – 7 % during HS, which was most apparent later in the day when cattle had been subjected to HS for multiple hours (moderate agreement; CCC: 0.68). Accuracy for rumination time was also only moderate for data collected during Experiment 2 (CCC: 0.55 – 0.61). In contrast, CM reported total eating (eating with the head down + head up while masticating) time with moderate accuracy for TN (CCC: 0.53 – 0.54), only achieved negligible to low accuracy during HS (CCC: 0.39 – 0.44 [Experiment 1] and 0.17 – 0.34 [Experiment 2]). Sensor performance did improve when CM eating time was compared specifically to the time spent with the head down reported by RW; HS still negatively influenced sensor performance, however, with high agreement during TN (CCC: 0.72 – 0.73) but low to moderate agreement during HS (CCC: 0.65 – 0.69 [Experiment 1] and 0.40 – 0.58 [Experiment 2]). Results of this study suggest accuracy of ear-tag accelerometers may be impaired when cattle are subjected to heat stress.