Indices of heart rate variability as potential early markers of metabolic stress and compromised regulatory capacity in dried-off high-yielding dairy cows

Abstract

High performing dairy cows experience distinct metabolic stress during periods of negative energy balance. Subclinical disorders of the cow's energy metabolism facilitate failure of adaptational responses resulting in health problems and reduced performance. The autonomic nervous system (ANS) with its sympathetic and parasympathetic branches plays a predominant role in adaption to inadequate energy and/or fuel availability and mediation of the stress response. Therefore, we hypothesize that indices of heart rate variability (HRV) that reflect ANS activity and sympatho-vagal balance could be early markers of metabolic stress, and possibly useful to predict cows with compromised regulatory capacity. In this study we analysed the autonomic regulation and stress level of 10 pregnant dried-off German Holstein cows before, during and after a 10-h fasting period by using a wide range of HRV parameters. In addition heat production (HP), energy balance, feed intake, rumen fermentative activity, physical activity, non-esterified fatty acids, β-hydroxybutyric acid, cortisol and total ghrelin plasma concentrations, and body temperature (BT) were measured. In all cows fasting induced immediate regulatory adjustments including increased lipolysis (84%) and total ghrelin levels (179%), reduction of HP (−16%), standing time (−38%) and heart rate (−15%). However, by analysing frequency domain parameters of HRV (high-frequency (HF) and low-frequency (LF) components, ratio LF/HF) cows could be retrospectively assigned to groups reacting to food removal with increased or decreased activity of the parasympathetic branch of the ANS. Regression analysis reveals that under control conditions (feeding ad libitum) group differences were best predicted by the nonlinear domain HRV component Maxline (L MAX , R 2 = 0.76, threshold; TS = 258). Compared with cows having L MAX values above TS (> L MAX : 348 ±17), those with L MAX values below TS (<L MAX : 109 ± 26) had higher basal blood cortisol levels, lower concentrations of insulin, and respond to fasting with a shift of their sympatho-vagal balance towards a much stronger dominance of the sympathetic branch of the ANS and development of stress-induced hyperthermia. The data indicate a higher stress level, reduced well-being and restricted regulatory capacity in < L MAX cows. This assumption is in accord with the lower dry matter intake and energy corrected milk yield (16.0 ± 0.7 and 42 ± 2 kg/day) in lactating < L MAX compared with > L MAX cows (18.5 ± 0.4 and 47.3 kg/day). From the present study, it seems conceivable that L MAX can be used as a predictive marker to discover alterations in central autonomic regulation that might precede metabolic disturbances.

Changes in biomarkers of nutrient metabolism, inflammation, and oxidative stress in dairy cows during the transition into the early dry period

“…For instance, overproduction of ketones such as BHB occurs during times of high circulating NEFA concentrations when there is not a sufficient amount of Kreb's cycle intermediates to appropriately oxidize the acetyl coenzyme A produced by NEFA (Kuhla et al, 2016;Han van der Kolk et al, 2017). Additionally, increased concentrations of certain biomarkers, such as NEFA and BHB, have been linked to early-lactation disease and altered immune competence (Erdmann et al, 2018). Furthermore, the presence of aberrant nutrient metabolism, chronic inflammation, or oxidative stress can intensify the other factors that can cause metabolic stress, causing further problems (Trevisi et al, 2012;Esposito et al, 2014;Sordillo and Mavangira, 2014).…”

A High Cattle-Grazing Density Alters Circadian Rhythmicity of Temperature, Heart Rate, and Activity as Measured by Implantable Bio-Loggers

“…Circadian variations in HR and arterial blood pressure in farm animal species is well known (Piccione et al, 2005), and HR has been used as a measure of autonomic regulation of cardiac activity in farm animals to assess stress and well-being under various housing and management conditions (von Borell et al, 2007). Furthermore, changes in HR are a possible early indicator of metabolic stress in cows (Erdmann et al, 2018). The circadian rhythm in activity is disrupted under chronic stress in animals and humans, and it can be less marked if the animal is diseased.…”

Evaluation of suitable temperature range for post‐harvest processing of mud crabs through cardiac performance

“…Meat flavours are related to changes in the metabolic rate and energy expenditure under stress (Castro et al, ; Cladis, Kleiner, Freiser, & Santerre, ; Hardy & Lee, ; Whiteley & Faulkner, ). A lower HRV represents a slower metabolic rate under stress in mammals (von Borell et al, ; Erdmann et al, ; Pohlin et al, ). The temperatures causing lower HRV were 10, 14, 18 and 22°C obtained from the experiment with ascending temperatures (Table ), and those were 2, 6, 10 and 14°C from the experiment with descending temperatures (Table ).…”