Genetic Analysis On Production Performance Among Pedigrees In Large White Pig

In this study,genetic analysis was carried out on 1289 sow's data of 10 families of a Large White pig farm from 2013 to 2017 in Anhui Province.The measured traits include sire index(SI),dam index(DI),age at 100 kg body weight(AD100),backfat thickness corrected for100 kg body weight(BF100),estimated breeding value of litter size(LSEBV)and generation interval(G).All the measurements are carried out in accordance with the genetic evaluation method of national core breeding farms.It is hoped that the analysis on the breeding progress in large-scale pig farms will be helpful to guide the general practical breeding systems in small and medium-sized pig farms,improve the production performance,and meet the needs of own pig farms,which is of great significance.The results showed that:1.According to SI and DI,10 families can be divided into three performance grades,A,B and C,and the differences among the grades reached significant level(P < 0.01).SI of Grade C and B increased with the generations(P < 0.05),while SI of Grade A did not change significantly(P > 0.05).There is no significant correlation between SI and DI in the 3rd and4 th generation.2.Based on the LSEBV,10 families can be divided into A,B,C and D performance grades,and the differences among the grades were significant(P < 0.01).The litter size of Y15 and Y16 families increased significantly with higher DI and SI in the second and third generations.3.The AD100 s of all families can be divided into three grades: A,B and C.The AD100 s of three grades were 156.54,161.16,and 168.54 days,respectively(P < 0.05).The higher SI,the less AD100 and the faster growth rate.4.The BF100 s of all families can be divided into three grades: A,B and C.BF100 s of three grades were 13.00,11.38,and 9.92 mm,respectively.There is no significant difference within the grades(P > 0.05),and the difference between the grades is significant(P < 0.05).The correlation between AD100 and BF100 was not significant,and the backfat thickness of family was not stable among generations.5.The complex correlation index of SI and DI to LSEBV,AD100 or BF100 was 0.8981,0.9928 and 0.9928 respectively(P < 0.01),and the partial regression coefficient was also significant(P < 0.01).6.Analyzing the selection progress of LSEBV,AD100 or BF100,The LSEBVs in Y5,Y4 and Y17 families increased with the generations,while the litter size of other families decreased.BF100 increased fat thickness in Y4 and Y21 families,and decreased fat thicknessin other families.The genetic progress of each generation averaged about 1 mm.The growth rate of AD100 decreased in Y15,Y20 and Y17 families,and increased by about 3 days for AD100 of each generation,while that of other families increased,among which,Y1,Y5 and Y21 families decreased by 3-6 days for AD100 of each generation.7.The results showed that SI and DI are helpful to the family selection.However,in the actual production process,due to the lack of unified measurement,insufficient data,and low data accuracy,it also affected the genetic progress in family selection.