Genetic parameters for stayability of Holsteins in US organic herds

The objectives of this study were to estimate genetic parameters for stayability in US organic Holstein dairy cows and correlations with nationally evaluated traits interest. Stayability is the binary trait success or failure remain herd until a given time point. We used birth, calving, cull dates from 16 USDA certified farms recommended by industry personnel as herds maintaining individual cow records using artificial insemination. at 5 points was assigned based on presence calving date each parity up (STAY1 STAY5). also considered livebirth (vs. stillbirth), successful first second (STAY12), third (STAY23), repeated measure encompassing STAY1 STAY5. In total, 44,995 females study. Ninety-six percent born alive these, 64% reached parity. Animals sires no other identified breed 3 generations maternal side included. Heritabilities underlying scale estimated threshold model fixed effect random effects animal herd-year-season birth. Genetic among livebirth, STAY1, STAY12, STAY23 4-trait linear birth animal, dam calf (livebirth), (STAY12 STAY23). ranged 0.07 0.15 0.08 direct 0.06 livebirth. repeatability 0.60. 0.11 between 0.83 STAY12 STAY23. Excluding all significantly correlated productive life livability. general, positively associated milk yield negatively fat stillbirth. conclusion, heritable longevity suggesting that improvement can be achieved current national evaluations longevity.