Survival is the ability of cows to postpone untimely removing from the herd. Survival is an alternative trait expressing the rate of cows Chat reached given age border. In this study results of survival evaluation of more than 18000 dairy cows using random regression animal models are presented. Weighted analysis was made to handle the heterogeneous variability of culling during productive life of cows. Models involved fixed effect of HYS, fixed regression within groups of herd slze and average herd yield, random deviation of animal and permanent environment from the average curve, perhaps even an effect of mílk yield of cow.