The effect of progeny numbers and pedigree depth on the accuracy of the EBV with the BLUP method

Abstract

This study was done to estimate the effect of progeny numbers and pedigree depth on the accuracy of the estimated breeding value (EBV) using best linear unbiased prediction (BLUP) method in Hanwoo. The experiment groups (sire = 100, 200, and 300; progeny = 4 and 8) were made by random sampling and by genetic evaluation of the following traits: Body weight (BW), carcass weight (CW), eye muscle area (EMA), back fat thickness (BFT) and marbling score (MS9). As a result of the genetic evaluation, the accuracy of the EBV was roughly 30 - 60% with 4 progenies, and the accuracy of the EBV increased by about 50 - 75% with 8 progenies. In the other words, when the number of progenies increased from 4 to 8, the accuracy of the EBV simultaneously increased by about 15 - 20%. Moreover, when the number of sires was higher, variations in the accuracy of the EBV within the groups for each trait decreased. Therefore, this result indicates that not only the number of progeny but also the number of sires can affect the accuracy of the EBV. Consequently, collecting information on the progeny and careful management of that information are very important things in the Hanwoo breeding system. Therefore, the EBV can show more precise results when conducting genetic evaluations.

Fig. 1. Diagram of study design (a) and random sampling (b) for sire families with progeny. KPN, Korean proven bulls; dam, female cattle; sire, Male cattle; BLUP, best linear unbiased prediction.

Fig. 2. Box plot to accuracy of estimated breeding value (EBV) for carcass traits by the number of sire and progeny.

Fig. 3. Variance of estimated breeding value (EBV) accuracy on increasing number of sire. BFT, back fat thickness; BW, body weight; CW, carcass weight; EMA, eye muscle area; MS, marbling score.

Table 1. Descriptive statistics of traits of 3789 sires.

Table 2. heritability of carcass traits for all groups.

Table 3. Accuracy of estimated breeding value (EBV) on their number of progeny.

Table 4. Results of t-test for fve traits by diferent number of progeny.

Table 5. Results of the estimated breeding value (EBV) and accuracy of EBV on diferent pedigree depth.