DOI: https://doi.org/10.5713/ajas.18.0733 [Accepted] Published online February 7, 2019.
Of a total of 2367 records used, 206 (8.7%) of open heifers were missing. Four penalty methods based on the number of inseminations were set as follows: C1 (FS average according to the number of inseminations), C2 (constant number of days; 359), C3 (maximum number of FS days to each insemination) and C4 (average of FS at the last insemination and FS of C2). C5 was generated by adding a constant number (21d) to the highest number of FS days in each contemporary group. The bootstrap method was used to compare among the 5 methods in terms of bias, mean squared error (MSE) and coefficient of correlation between estimated breeding value (EBV) of non-censored data and censored data. Three percentages (5%, 10% and 15%) were investigated using the random censoring scheme. The univariate animal model was used to conduct genetic analysis. Result: Heritability of FS in non-censored data was 0.012 ± 0.016. C1, C2 and C3 showed lower standard errors of estimated heritability but demonstrated inconsistent results for different percentages of missing records. C4 showed moderate standard errors but more stable ones for all percentages of the missing records, whereas C5 showed the highest standard errors compared with non-censored data. MSE in C4 heritability was 0.633 x 10-4, 0.879 x 10-4, 0.876 x 10-4 and 0.866 x 10-4 for 5, 8.7,10 and 15%, respectively, of the missing records. The coefficient of correlation for EBV was 0.88; 0.93 and 0.90 for heifer, sire and dam, respectively. We concluded that C4 was the best penalty method for missing records due to the stable value of estimated parameters and the highest coefficient of correlation.