Welfare implication of measuring heart rate and heart rate variability in dairy cattle: literature review and conclusions for future research

Abstract

Heart rate (HR) measurements have been used to determine stress in livestock species since the beginning of the 1970s. However, according to the latest studies in veterinary and behaviour-physiological sciences, heart rate variability (HRV) proved to be more precise for studying the activity of the autonomic nervous system. In dairy cattle, HR and HRV indices have been used to detect stress caused by routine management practices, pain or milking. This review provides the significance of HR and HRV measurements in dairy cattle by summarising current knowledge and research results in this area. First, the biological background and the interrelation of the autonomic regulation of cardiovascular function, stress, HR and HRV are discussed. Equipment and methodological approaches developed to measure interbeat intervals and estimate HRV in dairy cattle are described. The methods of HRV analysis in time, frequency and non-linear domains are also explained in detail emphasising their physiological background. Finally, the most important scientific results and potential possibilities for future research are presented.Keywords: heart rate, heart rate variability, stress, welfare, dairy cattle ImplicationsHousing and milking technology, health status and way of handling of animals influence the well-being of animals in intensive dairy farming. Non-invasive methods of assessing stress include heart rate and heart rate variability measurements that involve the monitoring of the autonomic nervous function by digital, high frequency, 24 h multi-channel electrocardiographic recorders. As high-producing cattle breeds are very sensitive to environmental factors, monitoring and decreasing stress is of major importance in terms of both animal welfare and production. IntroductionIn intensive dairy farming, housing and milking systems are main factors in determining the welfare of animals, as adaptation to environmental changes can be challenging for high-producing breeds.Important aspects in the improvement of dairy cattle management systems in respect of animal welfare are the recognition and evaluation of stress. The stressfulness of the technological environment has been examined in many different contexts. Certain welfare studies proved that for intensively farmed cattle, the milking technology (Rushen et al., 2001;Wenzel et al., 2003), fear from given routine treatments (Holst, 1998) and pain (Broom, 1991;Mellor et al., 2000) mean such load that may cause stress (Dantzer and Mormède, 1983;von Borell, 2001) having a negative impact also on milk production (Rushen et al., 2001). Effects of technology and of social interactions can be described not only by classical descriptive behavioural observations (e.g. Milmann, 2013;Theurer et al., 2013), but with physiological measures as well (Hopster and Blokhuis, 1994;Rietmann et al., 2004). Most dairy cattle studies have focused on the stress reactions of animals expressed in neuroendocrine changes that are considered to be reliable indicators of stress and pain in livestock species (...

Behaviour, heart rate, and heart rate variability in pigs exposed to novelty

“…However, since gilts had a significantly higher LF/HF ratio than the barrows, it is possible to argue that the mechanism was regulated on a different level. The fact that we found no changes in RMSSD and HF, in parameters that were previously used as indicators of vagal activity in cattle (Després et al, 2002;Kovács et al, 2014) and pigs (Zebunke et al, 2011), leads us to assume that our results point to a general increase in sympathetic activation. The increased LF/HF ratio by variations in sympathetic input was interpreted earlier in relation to a stressful context in sheep (Coulon et al, 2011).…”

Step behaviour and autonomic nervous system activity in multiparous dairy cows during milking in a herringbone milking system

“…HRV is referred to as the variability in the time interval between consecutive heartbeats (interbeat interval, IBI). For a recent review of HRV for stress assessment in dairy cattle, see Kovács et al (2014).…”

“…We investigated step behaviour, HR, parasympathetic tone index (high frequency component, HF) of HRV and sympathovagal index LF/HF ratio (the ratio between low frequency (LF) component and HF) for stress assessment in dairy cows milked in a conventional herringbone milking system. Each parameter has been studied extensively in dairy cattle welfare research (Kovács et al, 2014). To our knowledge, no reports are available on cardiac activity and behaviour after milking when animals are waiting in the milking stall for being released.…”

Research Tools for the Measurement of Pain and Nociception

“…A variety of methodologies work in this way including heart rate and measures of heart rate variability such as RR interval analysis [14], blood pressure [15], pupillary dilation [16] and probably infra-red thermography [17]. In general, they are easy to use and generate objective data that can be recorded over the short, medium and long terms.…”