Genetic analysis of resilience indicators based on milk yield records in different lactations and at different lactation stages

Resilience is the ability of cows to cope with disturbances, such as pathogens or heat waves. To breed for improved resilience, it important know whether resilience genetically changes throughout life. Therefore, aim was perform a genetic analysis on 2 indicators based data from 3 periods first lactation (d 11–110, 111–210, and 211–340) full lactations, estimate correlations health traits. The were natural log-transformed variance (LnVar) lag-1 autocorrelation (rauto) daily deviations in milk yield an expected curve. Low LnVar rauto indicate low variability quick recovery, good resilience. Data 200,084 first, 155,784 second, 89,990 third lactations used. Heritabilities similar different (0.12–0.15 LnVar, 0.05–0.06 rauto). However, heritabilities higher than those (0.20 0.08 rauto), due lower residual variances. decreased 0.20 1 0.19 0.06 rauto. For well rauto, strongest correlation between period (0.97 0.96 rauto) weakest (0.81 0.65 Similarly, both traits (0.99 0.95 (0.91 0.71 resilience-related traits, udder health, ketosis, longevity, adjusted yield, almost always favorable (?0.59 0.02). In most cases these stronger periods. Genetic across but increased substantially ?0.31 ?0.51 3. not other weak (?0.27 0.15). indicator breeding, preferred over A multitrait index estimated breeding values 1, 2, recommended improve lifetime cow.