Mohr Elmar, Langbein Jan, Nürnberg Gerd
Agrar- und Umweltwissenschaftliche Fakultät, FB Agrarökologie, Universität Rostock, Justus-von Liebig-Weg 8, 18051 Rostock, Germany.
Physiol Behav. 2002;75(1-2):251-9. doi: 10.1016/s0031-9384(01)00651-5.
The aim of this study was to evaluate the usefulness of heart rate variability (HRV) and its specific parameters as a new approach to assess stress load in cattle. We recorded HRV in 52 calves in three groups and in 31 cows in two groups. In calves we divided Group 1 with no obvious stress load (n=18), Group 2 with external stress load (n=17), and Group 3 with internal stress load from sickness (n=17). In cattle we divided lactating cows (n=21) and nonlactating cows (n=10). HRV parameters were analyzed in the time domain and in the frequency domain. Moreover, we applied Recurrence Quantification Analysis (RQA) to quantify nonlinear components of HRV. In calves, linear HRV parameter decreased from Group 1 to Group 3 (P<.05). However, not a single parameter showed significant differences regarding all three groups. The value of all nonlinear measurements increased at the same time (P<.05). The only parameter that exhibited significant differences between all three groups was the longest diagonal line segment in the recurrence plot (L(MAX)) which is inversely related to the Lyapunov exponent. We did not find differences concerning the linear HRV parameters between the two groups in the cows. The nonlinear parameter Determinism showed significant higher values in lactating cows compared to nonlactating cows. The importance of particular HRV-parameters was tested by applying a discriminant analysis approach. In calves and cattle nonlinear parameters were most important to indicate the level of stress load on the animals. Based on the results we assume HRV to be a valuable physiological indicator for stress load in animals. Whereas linear parameters of HRV are supposed to be useful to separate qualitative different level of stress, nonlinear components of HRV distinguish quantitative different challenges for the animals.
本研究的目的是评估心率变异性（HRV）及其特定参数作为评估牛应激负荷新方法的有效性。我们记录了三组52头犊牛和两组31头母牛的HRV。在犊牛中，我们将第1组设为无明显应激负荷组（n = 18），第2组为有外部应激负荷组（n = 17），第3组为因病产生内部应激负荷组（n = 17）。在母牛中，我们区分了泌乳母牛（n = 21）和非泌乳母牛（n = 10）。对HRV参数进行了时域和频域分析。此外，我们应用递归定量分析（RQA）来量化HRV的非线性成分。在犊牛中，线性HRV参数从第1组到第3组下降（P <.05）。然而，没有一个参数在所有三组中显示出显著差异。所有非线性测量值同时增加（P <.05）。在所有三组之间表现出显著差异的唯一参数是递归图中的最长对角线线段（L(MAX)），它与李雅普诺夫指数呈负相关。我们没有发现母牛两组之间线性HRV参数的差异。与非泌乳母牛相比，泌乳母牛的非线性参数确定性显示出显著更高的值。通过应用判别分析方法测试了特定HRV参数的重要性。在犊牛和母牛中，非线性参数对于指示动物的应激负荷水平最为重要。基于这些结果，我们认为HRV是动物应激负荷的一个有价值的生理指标。HRV的线性参数应该有助于区分定性不同的应激水平，而HRV的非线性成分则能区分动物面临的定量不同的挑战。
