Described herein is a method for identifying a farm animal having an impairment of regulative capacity in response to metabolic stress, the method including: a) assessing the value of the nonlinear domain heart rate variability component LMAX of a farm animal based on a heart beat interval data set obtained for the farm animal； and b) comparing the value of LMAX assessed according to (a) with a species specific threshold of LMAX, whereby a farm animal having an impairment of regulative capacity will be identified.
