Comparative Analysis Of Laying Performance Between Early Feathering And Late Feathering Strains In Qingyuan Patridge Chickens

Qingyuan Patridge Chickens is one of the Quality Chickens in Guangdong.However,there were few researches on egg laying performance of Qingyuan Patridge chickens,and there were no reports between the effects of different strains of early-feathering and late-feathering.In this paper,the egg production were analyzed between two strains,including the age at first egg,body weight of first egg,egg weight of first egg,the body weight,egg weight at the age of 40 weeks and egg-laying rate.The laying rate of two strains was fitted by using egg laying model,the phenotypic correlation were analyzed for the egg production traits.Moreover,L1 subgroup with endogenous virus 21 insertion(ev21~+)and L2 subgroup without ev21 insertion(ev21~-)were established in healthy late-feathering strains,depending on enzyme digestion results of ev21.Then,comparison of laying performances were analyzed.in two subgroup.All results were as follows:1.The age at first egg in late-feathering chicken was significantly later than that in the early-feathering chicken(P<0.01),while the body weight of first egg and egg weight of first egg in late-feathering chicken was significantly higher(P<0.01);2.The body weight of late-feathering chicken at 40 weeks was significantly lower than early-feathering chicken(P<0.01),and the egg weight of late-feathering at 40 weeks was significantly higher than early-feathering chicken(P<0.01);3.The laying rate of early-feathering chicken and late-feathering chicken were fitted by three egg production curves,and the best model was Yangning model,which fitting degree is 0.974 and 0.966;4.Body weight of first egg was highly significantly positive correlated with the age at first egg and egg weight of first egg(P<0.01);5.The differences of laying performance between L1 subgroup(n=193)and L2 subgroup(n=57)were not significantly(P>0.05).Results showed that in the Qingyuan Patridge Chickens,feathering speed had significant effects on egg laying performance.The laying performance of the late-feathering strains should be improved in the future,and nutrition management at egg-laying peak should be strengthen in these two strains.The establishment of a non ev21 resistant strains of late-feathering would be helpful for the further study on the mechanism of leukemia.