Design of a wearable textile piece for remote heart rate variability monitoring in dairy cows under grazing conditions

In veterinary medicine, heart rate variability (HRV) has emerged as a tool for assessing welfare, comfort, stress responses, and physiological status. This study aimed to design and validate a vest-type wearable textile piece for remote HRV measurement and monitoring in dairy cows under rotational grazing conditions in high tropics. The vest-type textile piece was developed to protect and stabilize the Holter-type measurement devices in field conditions while ensuring it did not affect the animals' comfort and allowed for proper HRV measurements. For the HRV measurement, a Polar H10® Heart Rate Sensor and a Polar Unite® watch were used respectively. To evaluate the practical application of the vests and animal comfort, lactating Holstein healthy dairy cows (n = 74) were used. An ethogram was conducted to ensure the vest did not affect cow comfort. Behavioral and physiological responses showed the behaviors and social interaction patterns of the cows wearing the vest were similar to those of animals without the vest. Holter-type devices can be integrated into tools such as the vest-type textile piece designed in the present study and constitute an innovative and effective tool for continuous and non-invasive HRV monitoring in cows grazing in the high tropics preserving comfort and welfare.