There were 310 observations used for the analysis of LPL, ofwhich 82were right censored.Management group and LPL had no significant association, but breed and age
at first calving were significantly associated with LPL (Table 7).Therewere no evident signs of violations against the proportional hazards assumption or the assumption of
independent censoring. The plots of deviance residuals showed that the fit of the model was adequate.