Photoplethysmography for bovine heat detection: the preliminary results

Abstract

In this study, we applied photoplethysmography (PPG) as an alternative, convenient, and affordable method for bovine heat detection. Heat detection is an essential part of effective herd reproduction management. Currently, there are many different heat detection techniques, but they can be ineffective or impractical to use. Since heat affects local vulvar blood circulation (resulting in swelling and erythema), photoplethysmography could represent an affordable alternative to detect this bovine phenomenon. In this study, we enrolled 20 animals in heat and other stages of the bovine reproduction cycle. We analyzed the PPG signal in terms of baseline (DC component), power, kurtosis, and erythema index. One vaginal measurement site, approximately 8 cm from the vulva, exhibited significant differences in mucous color (PPG green and red baseline, both erythema indices). What is more, cows in heat displayed higher PPG signal power and kurtosis, but differences were not significant. Photoplethysmography exhibited the potential to detect bovine heat.