Selection Responses of Growth and Reproductive Traits in Duroc Pigs Based on Animal Model BLUP

PurposeTo investigate the effect of selection index based on animal model best linear unbiased prediction (AM-BLUP) for growth and reproductive traits in Duroc pigs.

MethodsFrom year 2013 to 2019, a closed herd of Duroc pigs had been selected continuously on an index of two main selected traits, age to 100 kg body weight (AGE, relative weight 0.7) and backfat thickness at 100 kg live weight (BF, relative weight 0.3), based on the estimated breeding value (EBV) by AM-BLUP. The dynamic changes of phenotypic values, EBV of six growth and reproductive traits, selection indexes and inbreeding coefficients of the herd during the breeding period were analyzed systematically.

ResultsCompared the year 2019 with 2013, the phenotypic values of AGE, BF and feed conversion rate during 30-100 kg (FCR) extremely significantly decreased 4.45 days, 0.52 mm and 0.05 (P<0.01), respectively; for the sows of first and latter parities, total number born increased 0.99 (P<0.05) and 1.02 (P>0.05), number born alive increased 0.72 and 0.49 (P>0.05), litter weight at 21 days decreased 0.39 kg and increased 6.20 kg (P>0.05), respectively; the EBVs of the two main selected traits, AGE and BF extremely significantly decreased 3.447 and 0.533 (P<0.01), and the selection index extremely significantly increased 23.62 (P<0.01); the EBVs of other secondary selection traits were all improved in varying degrees except FCR. At the end of selection, the average inbreeding coefficient of the herd was 3.1973%, with increment 0.4904% per year.

ConclusionThe index selection based on AM-BLUP can improve production traits for pigs, but the specific selection responses may be various for the traits with different genetic characteristics.