• Korean Journal of Poultry Science
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• v.13 no.1
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• pp.1-14
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• 1986

The subject of this study was to obtain some genetic information for developing superior layer chickens. Heterosis and combining ability effects were estimated with 5,759 progenies of full diallel crosses of 6 strains in White Leghorn. Fertility, hatchability, brooder-house viability, rearing- house viability, laying-house viability, age at 1st egg laying, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion were investigated and analyzed into heterosis effect, general combining ability, specific combining ability and reciprocal effect by Grilling's model I. The results obtained were summarized as follows; 1. The general performance of each traits was 94.76% in fertility, 74.05% in hatchability, 97.47% in brooder-house viability, 99.72% in rearing-house viability, 93.81% in laying-house viability, 150 day in the age at 1st egg laying, 1,505g in the body weight at 1st egg laying, 60.08g in average egg weight, 77.11% in hen-day egg production, 269.8 eggs in hen-housed egg Production, and 2.44 in feed conversion. 2. The heterosis effects were estimated to -0.66%, 9.58%, 0.26%, 1.83%, -3.87%, 3.63%, 0.96%, 4.23%, 6.4%, and -0.8%, in fertility, hatchability, brooder-house viability, laying-house viability, the age at 1st egg laying, the body weight at 1st egg laying, average egg weight, hen-day egg Production, hen-housed egg production and feed conversion, respectively. 3. The results obtained from analysis of combining ability were as follows ; 1) Estimates of general combining ability, specific combining ability and reciprocal effects were not high in fertility. It was considered that fertility was mainly affected by environmental factors. In the hatchability, the general combining ability was more important than specific combining ability and reciprocal effects, and the superior strains were K and V which the additive genetic effects were very high. 2) In the brooder-house viability and laying-house viability, specific combining ability and reciprocal effects appeared to be important and the combinations of K${\times}$A and A${\times}$K were very superior. 3) In the feed conversion and average egg weight, general combining ability was more important compared with specific combining ability and reciprocal effects. On the basis of combining ability the superior strains were F, K and B in feed conversion, F and B in the average egg weight. 4) General combining ability, specific combining ability and reciprocal effects were important in the age at 1st egg laying and the combination of V ${\times}$F, F${\times}$K and B${\times}$F were very useful on the basis of these effects. In the body weight at 1st egg laying, general combining ability was more important than specific combining ability and reciprocal effects, relatively. The K, F and E strains were recommended to develop the light strain in the body weight at 1st egg laying. 5) General combining ability, specific combining ability and reciprocal effects were important in the hen-day egg production and hen-housed egg production. The combinations of F${\times}$K, A${\times}$K, and K${\times}$A were proper for developing these traits. 4. In general, high general combining ability effects were estimated for hatchability, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion and high specific combining ability effects for brooder-house viability, laying house viability, age at 1st egg laying, hen-day egg production and hen-housed egg production, and high reciprocal effects for the age at 1st egg laying.

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.225-230
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• 2003

This study was carried out to analyze the environmental variation of layer house at Iowa State in the USA. The analyzed seasons for this study were summer and winter. Analyzing factors are inside temperature and relative humidity, carbon dioxide concentration, ammonia concentration and emission. All factors were collected every 30 second from each house with portable monitoring units. In this study, two types of laying hen houses were monitored at the same season. One was a manure belt house, the other was a high-rise house. In order to estimate the ventilation rates of the laying hen houses, carbon dioxide concentration balance was used in this study. Ammonia concentrations and emission rates of the manure belt house are much lower than those of the high rise house. Daily mean ammonia concentrations in the manure belt house and high-rise house ranged from 3 to 7 ppm and 5 to 34 ppm, respectively. The daily ammonia emission rates averaged 0.68g/h$\cdot$500kg and 0.73g/h$\cdot$500kg for the manure belt house and 0.93g/h$\cdot$500kg and 2.89g/h$\cdot$500kg for the high-rise house in summertime and wintertime, respectively. Summertime is associated with much higher ammonia emission rates than wintertime because of much higher ventilation rates and ambient air temperature, even though the concentrations may be lower.

• Journal of Animal Environmental Science
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• v.7 no.1
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• pp.39-44
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• 2001

This research was carried out to determine the quantity and characteristics of layer excreta produced in different age and different types of layer house. Daily feed intakes in the growing stage were 60.8 and 92.9g/d the 6th and 12th week of age, respectively. Daily feed intakes in the early laying stage (19th wk of age) and the ending period of laying(55th wk of age) were 105.1 and 122.0 g/d, respectively. A laying hen consumed 193.1~222.5$m\ell$ of water per day. The amount of excreta produced by laying hen were 143.3~144.8g per day. The moisture contents of excreta produced by laying hen ranged over 74.7~80.5% in laying period. The average contents of N, $P_2O_5$ and $K_2O$ in layer excreta were 4.88, 1.92 and 1.71% in DM basis, respectively. In the laying period, CaO contents of excreta were 7.42~9.02%. The moisture contents of excreta produced by windowless poultry house, open-sided poultry house applied mechanical ventilation and open-sided poultry house applied natural ventilation were 65.4, 75.7 and 81.3% in summer, respectively.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.405-410
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• 2005

To analyze and identify selected risk factors for infectious bronchitis virus (IBV) infection in the growing and laying period of laying-hen flocks, a longitudinal field study was conducted with 27 commercial flocks reared in three provinces of Korea during the period from May 2003 to April 2004. Using monitored data for IBV infection status among study flocks we computed the multivariate odds ratios (ORs) and their corresponding confidence intervals (CIs), and population attributable risks (PARs). Multivariate logistic regression showed significant risk increments for: continuous entry of chick (OR=1.9, 95% CI, 0.7-69.1) and operation years of the layer house greater than or equal to 5 years (OR=3.2, 95%CI, 1.6-389.9). No significant interaction was found between variables. The PAR suggested that continuous entry of chick (PAR=32%) and ${\geq}5years$ of house operation (PAR=84%) had the highest impacts on IB presence in laying-hen flocks under study. Of the two significant factors, however, operation year of the layer house lacks an easy applicability in preventing IB control strategies, and the possibility of confounder cannot be ruled out.

• Journal of Animal Environmental Science
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• v.14 no.1
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• pp.47-52
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• 2008

Broken eggs not only cause the economic loss in the egg producing industry, but also may not be good for the consumer's health. In order to identify the causes of eggshell breakage in laying hen houses, analyses on the status of eggshell breakage in the step of egg conveyer system of the laying hen house were conducted. The survey of eggshell breakage rate was implemented by four different stages egg conveying system. In the results, the breakage rate showed 4.7% in the egg collection belt, 2.5% in the egg elevator, 1.7% in the egg grading system and 0.9% in the egg conveyor belt. In particular, to Hy-line Brown variety, as the hens' raising week old increased, the breakage rate of eggshell increased while the strength of eggshell decreased. In the regression analysis between the breakage rate of eggshell and the strength of eggshell, the coefficient of determination ($R^2$) by the test of significance was computed as 0.7, therefore the changes of the strength of eggshell affects the breakage rate of eggshell. However, between the strength of eggshell and thickness of egg shell, and between the strength of eggshell and strain of eggshell, there was no significant difference detected in the regression analysis.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.441-446
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• 2008

This study was conducted to determine the effect of heat stress on laying hen performance during summer. A total of 180 Hyline-brown layers, 98 days of age, were housed in a enclosed house. The daily maximum temperature in the house was ranged $26{\sim}36^{\circ}C$. The egg production was markedly fallen than other days when daily maximum temperature in the layer house became more than $33^{\circ}C$. As water intake and feed intake increased to $490\;mL\;bird^{-1}\;day^{-1}$ and $240\;g\;bird^{-1}\;day^{-1}$, the egg production soared. But it was hardly increased more than them. Based on these results, layer house roof should be amply insulated to improve the egg production of layers. If not insulated, the shade curtain should be installed above roof and cool water sprayed before and after 2 p.m. And layers should be provided cool drinking water of about $15^{\circ}C$ in the day time.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.23-30
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• 2021

In this study, we measured the concentration of particulate matter (PM) and ammonia (NH3) emission in the winters according to the breeding type of laying hen houses. Measurements were performed thrice in Barn, Aviary, and Cage houses every 2 weeks from December to January. The changes in the PM10 and PM2.5 concentrations were similar in all three breeding types. The PM10 and PM2.5 concentrations, measured three times, were the highest in the Aviary house. In the results measured by time, the PM10 and PM2.5 concentrations were the lowest during the dark period (22:00 to 4:00) of the day. The NH3 concentration was the highest in the Cage house and the lowest in the Barn house. Regarding emissions over time, the results of the three measurements showed different patterns and differed from those of the PM. In addition, with passage of time from the 1st (december) to 3rd (january), the NH3 concentration gradually increased. The daily PM10 and PM2.5 concentrations in the Aviary house, which were higher than those of the other houses, were 4,787 ㎍/㎥ and 388.6 ㎍/㎥, respectively, while, the PM10 and PM2.5 concentrations outside the poultry houses were 226.0 ㎍/㎥ and 39.3 ㎍/㎥, respectively. The daily NH3 concentration was 7.70 ppm and 9.20 ppm at the center and end of the Cage house, respectively. This was higher than that in the other houses. In conclusion, the concentrations of PM (PM10, PM2.5) and NH3 were the highest in the Aviary and Cage laying hen houses, respectively.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.303-311
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• 2008

This study was conducted to investigate the effect of dietary supplementation of Cu-methionine chelate(Cu-Met) and Cu-soy proteinate(Cu-SP) on the performance, small intestinal microflora and immune response in laying hens. A total of 960 Hy-line $Brown^{(R)}$ laying hens of 39 wks old were assigned to one of the following 6 dietary treatment: control(C), antibiotic(Avilamycine 6 ppm), Cu-Met 50 and Cu-Met 100(50 and 100 ppm Cu as Cu-methionine chelate), Cu-SP 50 and Cu-SP 100(50 and 100ppm Cu as Cu-soy proteinate). Each treatment was replicated 4 times with forty birds per replication, housed in 2 birds per cages. Forty birds units were arranged according to randomized block design. Feeding trial lasted 6 wks under 16 hours lighting regimen. Hen-day and hen-house egg production of groups treated with Antibiotic and Cu supplements tended to be higher than the control with significant difference (P<0.05) shown between Cu-Me 100 and control. Egg weight was significantly (P<0.05) heavier in antibiotic and Cu-SP treatments than Cu-Met treatments but they were not significantly different from the control. Eggshell strength, egg shell thickness, egg yolk color and Haugh unit were not significantly different among treatments. There were no significant differences in leukocytes and erythrocytes in the chicken blood. But mean corpuscular hemoglobin value(MCH) was significantly (P<0.05) higher in Cu-SP 100 than antibiotic treatment. The concentrations of serum IgG and IgA were not significantly different among treatments. Copper concentration in the liver tended to increase as the level of copper supplementation increased, that of Cu-SP 100 being significantly (P<0.05) higher than those of the control and antibiotic treatment. Concentrations of iron and zinc of the liver were not significantly influenced by treatments. Populations of Cl. perfringens and Lactobacilli in the small intestinal content were significantly (P<0.05) influenced by treatments. Population of Cl. perfringens decreased and that of Lactobacilli increased in the copper supplemented groups. The result of this experiment showed that Cu-Met and Cu-SP are comparable to antibiotic in improving egg production in laying hens. Birds fed diets supplemented with Cu-SP produced heavier eggs than those fed diets with Cu-Met. There were no significant differences in the performances between 50 ppm and 100 ppm copper supplementation as organic forms.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.55-63
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• 2019

This study was conducted to evaluate animal welfare approved farms in three housing systems (open, windowless, and free-range). The survey was conducted in 25 animal welfare approved farms, and 10 farms were surveyed for distribution status. The main breed in all animal welfare approved farms of laying hens was Hy-Line Brown variety. In the case of open house, laying hens were bred in traditional and panel houses simultaneously; however, the ratio of panel house was 58.3%, which was higher than that of the traditional house. All the windowless houses were made of panels and more than 15,000 laying hens were housed in a single windowless house. In the case of free-range house, it was maintained on a small scale of less than 12,000 birds. Fifty-six percent of the surveyed farms were breeding at $7{\sim}8birds/m^2$. In terms of male and female ratios, most farms maintained 1 male:15 females, but there was a farmhouse that switched 17 or 20 females to 1 male. The daily dietary allowance was 110~170 g, and 32% of the surveyed farms provided feed of more than 150 g/day, which showed that forage feed was important. The age of at the first egg was 123 days, 122 days, and 120 days, and the peak percent was 91.8%, 94.9%, and 86.5% in open, windowless and free-range houses, respectively. The average egg production rate was 74.0%, 84.6%, and 72.7% in open, windowless, and free-range houses respectively, thus, there was no correlation between feed intake and hen-housed eggs. Distribution of welfare certified eggs was mainly a direct deal with the consumer or through contract production. The ratio of direct transactions between large-scale marts and eco-friendly specialty stores of welfare approved eggs was higher than that of conventional eggs. The rate of contract sales of eggs in both the barn and free-range systems was high, and the percentage of courier sales farms was also high. Excluding courier services, price of eggs in the barn system rose to more than 30 won/egg in the second half of 2017 (after AI). Price of eggs in the free-range system rose to more than 50 won/egg in the second half of 2017 (after AI). In the case of courier sales, the same price of 500 won was maintained before and after AI. In conclusion, the results of this study can be used as basic data for improving the animal welfare certification system for laying hens in Korea.