• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.299-306
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• 2004

The objective of this study was to investigate the influence of egg storage, broiler breeder age, and the change of egg weight during incubation on growth rate of chicks and 43-day-old dressing percentage. The trials involved hatching eggs obtained from 27-wk-old hens and stored for 6 d for the Young-EXP group, from 28-wk-old hens and stored for 0 d for the Young-CON group, from 51-wk-old hens and stored for 6 d for the Old-EXP group, and from 52-wk-old hens and stored for 0 d for the Old-CON group, The hens were two commercial broiler breeder flocks of the same strain (Cobb) but of different egg producing stages(early and middle stages of egg production). The chicks were grown on floor pens for 6 wks, The differences of setting egg weights between Old-CON and Old-EXP groups were 1 g, but those between Young-CON and Young-EXP groups were 2.9 g(P<0,05). The loss of egg weight during 18 d incubation did not greatly differ among four groups, but the loss of egg weight during 21 d incubation was significantly (P<0.05) more in the middle stage of egg production groups than in the early stage of egg production groups. The mean birth weights of the middle stage of egg production groups were significantly(P<0,05) heavier by 8,7 g than those of the early stage of egg production groups; however, the differences of 6-wk-old body weight were not significant between egg producing stages. The differences of body weights in both egg producing stages were not significantly influenced by egg storage period in overall wks of ages. Egg storage and hen age did not greatly influence to the 43 d dressing percentages, either, The correlations of the setting egg weight with 18 d egg weight during incubation, growth rate of chicks, or 43 d dressing percentage were not significant.

• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.328-332
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• 1998

This study was carried out to investigate the occurrence and ecological characteristics of Ostrinia furnacalis(Guenee) in Yonchon, northern part of Kyonggi province, where it is main production region of adlay in Korea. The Asian corn borer in adlay field had three generations a year. The first stage of adult activity was greatest from middle May to late June, the second from late July to middle August and the third from late August to middle September. The egg period was $3{\sim}4$ days. The longevity of adult was $7{\sim}11$ days. The days of each development stage from egg to adult were $51{\sim}61$, $33{\sim}42$ and $29{\sim}37$ days in 1st, 2nd and 3rd generations, respectively. The overwintering stage of Asian corn borer was the last instar larvae and it overwintered in the adlay stubbles.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.29-34
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• 2003

It has been well documented that white egg layers are far more resistant to fowl typhoid than the brown egg layers. In Korea, however, most consumers prefer brown eggs to white ones. Therefore, a study was conducted to Produce fowl typhoid-resistant crossbred layers producing somewhat brown-colored eggs. Several crossbred strains were obtained from crossbreeding white egg lines (W) with brown egg lines (B). These crossbred layers (W${\times}$B) produced eggs with varying degrees of brown-colored shells between the white eggs obtained from W (White) and the brown eggs from B (Brown). Eggs from the peak stage of production were collected and their eggshell color values were measured. The mean eggshell color values of White and Brown were 81.9 and 36.4, respectively. Eggs from the crossbred lines (W${\times}$B) were collected, and their eggshell color values were measured to re-group these eggs according to their color. The mean eggshell color values of Trt-White, Middle, and Trt-Brown were 70, 60, and 50, respectively (Fig. 1). A total of 247 people living in Daejeon area, mainly housewives, took part in this survey. First, they were offered eggs with varying degrees of eggshell color in a paper egg-tray, together with a questionnaire. After they filled out the first questionnaire, they were instructed that the eggshell color has nothing to do with its nutritive value. In the second questionnaire, their preference on both eggshell color and price, i.e., purchasing will, were investigated. In the first questionnaire, the Brown (eggshell color lightness 36.4) were most preferred, and the Trt-white (eggshell color lightness 70) were least preferred. No statistical significance was detected between Brown and Trt-Brown, and White and Trt-White. In the second questionnaire, the trend was the same as in the first. Although no significant difference was found between Trt-Brown and Brown, however, the Trt-Brown were most preferred, surpassing the Brown. In conclusion, regardless of the nutritive values, the Korean consumers prefer brown eggs to white ones, and this trend could be changed gradually through consumer education.