Estimation of genetic parameters of major growth traits and existing problems in breeding of Large White pigs

Objective To estimate genetic parameters of growth traits of Large White pigs in Wens Group, and study the effects of change in method for measuring backfat (A to B ultrasonic) and variation in final body mass (age at 100 kg to age at 115 kg body mass) on pig breeding.

Method Single/multi-trait animal model and DMU software were used to estimate genetic variance and variance of common litter effects for age at 100 kg body mass (AGE) and backfat thickness at 100 kg body mass (BF). We evaluated the pearson and spearman correlations between estimated breeding value (EBV) from newly measured individuals in 2016 and EBV from normal genetic evaluation under the condition of 100 kg final body mass (AGE-100) or B ultrasonic (BF-B).

Result The estimates of heritabilities were 0.21 and 0.41, the common litter effects were 0.27 and 0.15 for AGE and BF respectively, and the single-model and multi-model were generally consistent. Under the condition of AGE-100 or BF-B, the pearson correlations were 0.96 and 0.94, the spearman correlations were 0.96 and 0.92 for EBV from newly measured individuals and EBV from normal genetic evaluation respectively, and the single-model and multi-model were generally consistent.

Conclusion Change in method for measuring backfat has a smaller effect on breeding than compared change in final body mass. The correction formula should be re-selected.