Validation of a new textile sensor band for on-farm heart rate variability assessment in calves.

Heart rate variability (HRV) has been studied as an indicator of stress and welfare in various species, including dairy calves, where significant changes in HRV were linked to cow-calf separation, isolation and disbudding. Wearable bands with smart textiles biotechnology offer a promising, low-stress alternative due to their comfort and ease of use without shaving or taping. The aim of this study was to examine if smart textiles biotechnology could be compared to a Standard base-apex ECG for measuring HRV in dairy calves. Twenty healthy Italian Holstein calves aged (20-60 days old) were recruited. Standard base-apex ECG and Smartex ECG were simultaneously acquired for 16 min in the standing, unsedated, unclipped calves. After extracting HRV parameters, comparisons were made using time, frequency, and nonlinear analyses. Agreement between devices was assessed using the Bland-Altman test and Spearman's 𝜚 correlations. Sperman's 𝜚 showed a very strong correlation for Mean RR, SDNN and LF (p value < .001), and a strong correlation for RMSSD, LF/HF and SampEn, indicating the most stable relationship between the two systems. Smart textiles biotechnology can be used for HRV measurement in calves, offering a valuable tool for animal welfare assessment.