The methodology defines four indicators of general resistance to environmental perturbations based on variations in daily milk yield. The first indicator is based on the variance of milk yield in the first 100-150 days of lactation. The other three are based on deviations of actual yield from expected yield. The variance of the deviations characterises the extent of the impact of perturbations, the autocorrelation the speed of recovery and the skewness expresses the direction of the response. All parameters were affected by farm, year and season of calving, parity, breed and performance level within breed. All these effects will be taken into account when estimating breeding values for general resilience.