| Summary: | 碩士 === 國立中興大學 === 動物科學系所 === 98 === The purposes of this study were to estimate the genetic parameters of egg quality traits and to investigate whether some physical characteristics measured by Quasi-Static compression method using Instron test machine are able to reveal eggshell quality of Taiwan Country chicken. There were 506 and 260 hens for L2 and D strains respectively, long term selected by the National Chung-Hsing University and totally 2606 eggs were used. The estimation of the genetic parameters for egg quality traits and compared the correlation between stress-strain curve parameter and eggshell quality at 38 and 50 weeks of age in Taiwan Country chicken. The age of first egg（AFE） was shorter in D strain than L2 strain（149 days vs.152 days）, but the egg production L2 were significantly higher than D. The genetic parameters of the AFE were not different between L2 and D（0.26 vs. 0.25）. Egg weight and yolk weight were not different between L2 and D (45.03g, 13.82g vs. 44.91g, 13.80g). For eggshell thickness and eggshell strength, L2 were higher than D at 38 and 50 weeks of age. L2 have rounded egg shape than D. D was light than the L2 of eggshell color. The estimated heritability of egg weight, egg index, yolk weight and eggshell color were ranged high to moderate of L2 and D (0.37, 0.29, 0.52, 0.45 vs. 0.34, 0.28, 0.37, 0.37). There was negative genetic correlation between egg weight and egg shape index. The results show the value of e2 was high than e1 by stress-strain curve for both L2 and D (16.15, 10.25 vs. 13.91, 10.14). The phenotypic correlation between eggshell and e2 was high than e1（0.48 vs. 0.35）. The results suggested that the e1 representative of the palisade layer stiffness and e2 representative of the mammilliary knob layer stiffness.
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