Is Continuous Heart Rate Monitoring of Livestock a Dream or Is It Realistic? A Review

Abstract

For all homoeothermic living organisms, heart rate (HR) is a core variable to control the metabolic energy production in the body, which is crucial to realize essential bodily functions. Consequently, HR monitoring is becoming increasingly important in research of farm animals, not only for production efficiency, but also for animal welfare. Real-time HR monitoring for humans has become feasible though there are still shortcomings for continuously accurate measuring. This paper is an effort to estimate whether it is realistic to get a continuous HR sensor for livestock that can be used for long term monitoring. The review provides the reported techniques to monitor HR of living organisms by emphasizing their principles, advantages, and drawbacks. Various properties and capabilities of these techniques are compared to check the potential to transfer the mostly adequate sensor technology of humans to livestock in term of application. Based upon this review, we conclude that the photoplethysmographic (PPG) technique seems feasible for implementation in livestock. Therefore, we present the contributions to overcome challenges to evolve to better solutions. Our study indicates that it is realistic today to develop a PPG sensor able to be integrated into an ear tag for mid-sized and larger farm animals for continuously and accurately monitoring their HRs.

An Approach towards Motion-Tolerant PPG-Based Algorithm for Real-Time Heart Rate Monitoring of Moving Pigs

“…In the current work, we can conclude that the PPG theory is applicable to heart rate assessment for pigs. This can be attributed to the several documented [7] anatomical and physiological similarities between pig skin and human skin. However, it should be stated here that some technical and practical factors are to be considered, such as the contact pressure between the sensor and the animal skin, power consumption, weight/size, and last but not least, the cost.…”

“…Therefore, the transfer of PPG-based techniques to livestock applications is promising. Nie et al [7] pointed out one important consideration concerning whether the PPG theory based on skin blood perfusion is applicable for animals, which is an issue related to the similarities in skin characteristics between humans and animals. In the current work, we can conclude that the PPG theory is applicable to heart rate assessment for pigs.…”

An Approach Towards Motion-Tolerant PPG-Based Algorithm for Real-Time Heart Rate Monitoring of Moving Pigs

“…Additionally, for homoeothermic living organisms in general, the heart rate (HR) is a crucial variable (actuator) to control the metabolic energy production in the body. This includes the basal metabolism, the thermal component to control internal body temperature against external perturbations (thermoregulation) [4]- [6], the physical or mechanical component, as well as the mental component, which is a key component in transferring feed energy efficiently into production and to prevent depression of the immune system due to stress [7]. The less efficiently the metabolic energy is used in the body, the more feed energy will be wasted in manure, emissions, stress systems, etc.…”

“…The less efficiently the metabolic energy is used in the body, the more feed energy will be wasted in manure, emissions, stress systems, etc. Hence, animal HR is considered an important variable for health and welfare studies on farm animals [7]. However, it remains a challenge to monitor HR accurately and continuously by a reliable, affordable sensor on the animal or with a remote sensing technique.…”

“…The use of PPG-based technique in animal applications is so far limited except for some experimental studies (e.g., [10]). In a recent review study [7], Nie et al, showed the potential of transferring the PPG-based technique, which is successfully applied in human beings, to livestock. One important consideration pointed out, by Nie et al [7], is whether the PPG theory based on skin blood perfusion is applicable for animals, which is depending mainly on the the similarities of skin between humans and animals.…”