• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.97-98
• /
• 2004

The observed means and standard divisions of the major laying traits per generation in korean native chickens were as follow. The age at first egg, the egg weight at the first egg, the weight at 270days and the egg production to 270days were 147.1$\pm$1.9 days. 32.3$\pm$0.9 g, 49.4$\pm$0.7 g and 76.2$\pm$1.7 eggs. The regression coefficients were -0.75$\pm$0.01 days, 0.33$\pm$0.08 g, 0.19$\pm$0.05 g and 0.47$\pm$0.3 eggs respectively.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.53-68
• /
• 2004

Eggshell quality is one of the most important factors that influence hatchability. The porosity and overall quality of eggshell have a very significant effect on exchange of vital gas (carbon dioxide and oxygen) between the developing embryo and the air during incubation. Thin-shelled eggs showed the greater weight loss than do thick-shelled eggs. causing the chick to have difficulty in hatching. Thin-shelled eggs also have a much greater chance of being cracked during handling. On the other hand. thick-shelled eggs showed the higher hatchability as a result of greater fertility and lower intermediate and late embryonic mortalities. Even a small percentage improvement in the eggshell quality could result in significant saving to the breeder industry in an increasingly competitive environment. Many factors including nutrition. management practices, environmental conditions and breeding are known to be related to eggshell quality. In this review brief accounts of each factor associated with eggshell quality and hatchability were provided. We conducted three experiments to investigate the effects of dietary Ca. vitamin D3 metabolite and some bioactive materials on eggshell quality and hatching egg production. The results of our studies showed that relatively high levels of dietary Ca in combination with 25-hydroxycholecalciferol had beneficial effects on improving eggshell quality and reproductive performances in aged egg-type breeder hens. It was also suggested that the proper use of some feed additives such as isoflavon and chitosan might provide means of improving eggshell quality and reproductive performances in aged egg-type breeder hens.

• Korean Journal of Poultry Science
• /
• v.24 no.1
• /
• pp.29-37
• /
• 1997

An experiment was conducted for 20 days( from July 21 to August 10, 1996) to investigate the differences in thickness of eggshell and eggshell membrane in Korean native chicken. All the eggs were purchased from a farm located in Chinju area. All eggs were categorized into Treatment I (34.89~51.39 g), H (53.32~60.70 g), and III (34.89~60.70 g) according to their weights. Eleven items were measured in all three treatments, i.e., egg weight, egg length, egg width, breaking strength, eggshell thickness of large end(STLE), eggshell membrane thickness of large end(SMTL), eggshell thickness of small end (STSE), eggshell membrane thickness of small end(SMTS), eggshell thickness of middle part(STMP), and eggshell membrane thickness of middle part(SMTM). Correlation coefficients between egg weight and eggshell weight, among eggshell thickness of large end, small end and middle end and eggshell weight were significant (P<0.01). Correlation coefficients between egg weight and large eggshell membrane were nega-tively significant(P<0.01). Breaking strengths were higher in Treatment I than in Treatment H. Correlation coefficients among thickness of eggshell and eggshell membrane at each point at 3 parts of large end, small end and middle end were not significant.

• Korean Journal of Poultry Science
• /
• v.21 no.3
• /
• pp.195-205
• /
• 1994

Effects of the addition of \beta-glucanase to barley-based layer diets were examined by feeding 200 Leghorn layers with corn-based (Control) and \beta-glucanase supplemented diets (Barley+ Enzyme). The results obtained are sumrrarized as follows. 1. There were no siginificant (P>0.05) differences in hen-day egg production(%) and average egg weight between two treatments, indicating that the \beta-glucanase supplemented barley could successfully replace the commonly used corn in the layer diets. 2. Although there was no statistical difference (P>0.05) between two treatments, the daily feed consumption was numerically high in layers fed the barly diet compared to the corn-based diet. 3. Availabilities of crude fat and crude fiber of the barley diet were significantly poor (P<0.05) as compared to corn diet. 4. The \beta-glucarase supplementation depressed the viscosity of barley diets and excreta from therm. 5. Both serum and egg yolk cholesterol were not significantly affected by the addition of \beta-glucarase in the barley based diet. Our data indicate that the barley grain supplemented with \beta-glucarase can be sucessfully used as an energy source of layer diet when there is a price advantage. Although some possibilities to produce low cholesterol egg were recognized in this study, further studies pertaining to long-term feeding experiment and elucidaton of the metabolic interrelationship between serum and yolk cholesterol, are required to confirm the result.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2003.11a
• /
• pp.115-116
• /
• 2003

The significant strain effects were investigated In all the major economic traits in Korean native chicken. The highest Least Square(LS) means of the body weights at 150 and 270days of age were observed in Black strain as 1, 594.38 and 1, 911.57 g. The earliest LS mean of the ages at first egg was 146.88 days in White strain. The heaviest LS means of egg weights at the first egg and 270 days of age were observed in Red brown strain as 33.20 and 50.74 9. The LS mean of the largest number of egg production was 79.50 eggs in Yellow strain.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2003.11a
• /
• pp.127-128
• /
• 2003

This study was conducted to obtain for genetic information with 11, 538 progenies of 5 strains in Korean native chicken. The heritability estimates of the body weights at 150 and 270days of age were 0.25~0.61 and 0.32~0.59 in 5 strains, the heritabilities of the body weight at 270 days were relatively higher than that of the body weight at 150 days. The medium or low heritability estimates were observed in the ages at first egg as 0.15 ~0.31, and heritability estimates of the egg weights at the first egg and 270 days of age were 0.06~0.09 and 0.24~0.41. Medium or low heritability estimates were observed for the number of egg production as 0.09 ~0.26, respectively.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2003.11a
• /
• pp.80-81
• /
• 2003

The aim of this study was the evaluation of the dietary effect of garlic powder(GP) and copper(Cu) on productivity, storage qualify of egg and egg yolk cholesterol in laying hens. 52-week-old layers were fed one of six diets containing 0 ％GP(Control), 1·3·5 ％ GP, 200 ppm Cu, 3 ％ GP-200 ppm Cu, respectively, for 5 wks. There were no differences in egg production performances and feed intake among treated groups. With the increase in dietary GP levels, the Haugh unit were higher linearly after 7-d and 14-d storage. The cholesterol contents of serum and egg Yolk in 3 ％ GP-200 ppm Cu groups were significantly lower than those of Control.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.11
• /
• pp.1638-1642
• /
• 2006

An experiment was conducted to elucidate the effect of graded levels of vitamin $D_3$ in White Leghorn (WL) layer breeders on egg production, shell quality, hatchability of eggs and juvenile performance of offspring during their late laying period (72-88 wk). White Leghorn breeder females were randomly divided into 5 groups of 50 each and were housed in individual California cages in an open-side housing system. Considering birds in five cages as a replicate, 10 such replicates were randomly allotted to each treatment. A basal diet was formulated containing all the nutrients as recommended for WL layers except vitamin $D_3$, which served as control. Another, four diets were formulated by supplementing graded levels of feed grade crystalline cholecalciferol to the basal diet that contained 300, 600, 1,200 and 2,400 ICU of vitamin $D_3$ per kg. Each diet was offered ad libitum to one of the above five treatment groups. The egg production, egg weight, daily feed consumption and the feed intake per dozen eggs or kg egg mass of the birds fed diet without any supplemental vitamin $D_3$ was comparable with those of supplemental groups. Similarly, the level of vitamin in the diet did not have any effect on any of the above parameters. However, the specific gravity of eggs laid by the birds fed the diet without supplemental vitamin $D_3$ was comparable with either 600 or 2,400 ICU supplemental groups but significantly higher when compared to the 300 and 1,200 ICU groups. The egg -shell breaking strength was significantly lowered in the 600 ICU supplemental groups as compared to the strength of other dietary groups. The Haugh unit, egg shell weight, shell thickness, tibia breaking strength, bone ash and calcium content were not influenced by vitamin $D_3$ concentration in the diet. Serum Ca concentration was influenced by vitamin $D_3$ level in the diet. The serum Ca concentration of birds fed either control or the vitamin supplemented diet up to 1200 ICU/kg diet was comparable. However, increasing the concentration of vitamin $D_3$ to 2,400 ICU/kg diet significantly enhanced the concentration of Ca in the serum, which was significantly higher compared to other dietary groups. The serum concentration of P and protein, however, was not influenced by level of vitamin $D_3$ in the diet. Neither fertility nor hatchability was influenced by vitamin $D_3$ concentration in the diet. Feeding a vitamin $D_3$ deficient diet or supplementation of vitamin to hens did not have any influence on their progeny chicks. It can be concluded that dietary supplementation of vitamin $D_3$ may not be essential for optimum production, shell quality, hatchability, and juvenile performance of WL breeders during 72 to 88 weeks of age.

• Korean Journal of Poultry Science
• /
• v.4 no.1
• /
• pp.41-49
• /
• 1977

최근 축산물의 소비가 증가함에 따라 쇠고기의 품질현상을 빚어 육류의 수입마저 허용케 되었으며 이로 인하여 양계산물의 소비도 늘어나게 되어 양계업도 근래보기 드물게 성업을 이루고 있다. (중략)

• Korean Journal of Poultry Science
• /
• v.24 no.3
• /
• pp.127-137
• /
• 1997

This study was conducted to estimate the laying performance and heterosis of Korean Native Chicken(KNC), Rhode Island Red(RIR), and KNC x RIR crossbreds A total of 1,274 female pullets were produced from KNC, RIR and RIR crossbreds in National Livestock Research Institute, Korea. The experiment was conducted for 2O~64 weeks from Jan 20. to Nov.25, 1996. The age at first egg of crossbreds were 144.1~148.7 days. The first egg weight of crossbreds was 39. 4~40.3 g, and body weights at first egg of KNC dark brown strain x RlR(DR), KNC light brown strain x RlR(LR) and KNC dark black strain x RlR(BR) were 1,943 g, 1,925 g and 2,044 g, respectively. During the laying period the average viability of crossbreds was 96.6~98.3%. The hen-day egg production of crossbreds were 111.1~113.O eggs at 40 weeks of age, and 223.5~227.5 eggs at 64 weeks of age, respectively. The hen-day egg production peaks were 78.2~80.1% in KNC, and 85.8~87.5% in crossbreds. The heterosis were estimated to be 3.61%, 9.21%, 4.78%, 2.97% and -1.63% for the first egg days, body weights at first egg, layer viability, hen-day egg production, and feed conversion ratio, respectively.