• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.23-30
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• 2023

This study was conducted to analyze the correlation between egg breakage rate and cumulative external forces on eggs during the egg transfer system in 12 commercial layers farms. The commercially available electronic egg device was used to detect the external forces on eggs during egg collection systems. In addition, egg breakage rate per farm was collected. It was found that the external force on eggs were greater in the order of washer and dryer connection part, conveyor connection part, transfer, sorter, collecting elevator, packer, egg transfer connection part, and egg tray. A positive relationship between the external forces on eggs during egg transit system and the incidence of cracked eggs per farm was noted. The external forces on eggs varied from 5G to 38G depending on the location and the egg breakage rate ranged from 3.2 to 14.5% per farm. Although efforts to produce eggs with high eggshell quality are considered important, extra care should be made to lower the external forces on eggs during the egg transfer system from laying house to egg packing center.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1769-1774
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• 2005

This experiment was carried out to evaluate the effects of feeding green tea powder on laying performance and egg quality in hens. A total 180 'Tetran Brown' laying hens aged 40 weeks were assigned to 6 treatments in a completely randomized design. Each treatment consisted of five replicates accommodating six layers per replication. The experimental diets were a negative control containing no green tea, a positive control diet containing antibiotics (0.05% chlortetracycline) and diets containing 0.5%, 1.0%, 1.5% and 2.0% green tea powder. Egg production rate of layers fed the diets containing green tea powder did not differ significantly from that of the negative and positive controls (p>0.05). Egg weight was decreased significantly in the group fed the diet containing 0.5% green tea powder (p<0.05). Feed intake of layers was significantly higher for the diet containing 1.5% green tea powder compared to that of negative and positive control diets (p<0.05). The eggshell thickness reduced significantly in the layer group fed the diets containing green tea powder regardless of dietary levels (p<0.05). Green tea powder tended to reduce egg yolk cholesterol in this experiment. Particularly, dietary 2% level of green tea powder significantly suppressed the cholesterol contents of the egg yolk (p<0.05). Thiobarbituric acid value (TBA) of egg yolk was significantly reduced by green tea diets (p<0.05). The yellowness of egg yolk was increased in the layers fed the 2.0% green tea diet compared with that of control diet (p<0.005). The Linoleic and $\alpha$-linolenic acids tended to increase in the group fed diets containing 1.5% green tea powder even though there were no significant differences among treatments (p>0.05). The oleic and docosahexaenoic acid contents of the egg yolk were similar among treatments (p>0.05). Based on the results of the experiment, it is concluded that green tea powder inclusion in the diet for layers at 2.0% level can reduce the cholesterol content and TBA value of the egg yolk, implying its potential effect on egg quality parameters.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.193-200
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• 2018

The purpose of this study was to evaluate the influence and safety of spraying Farm Clean-S (FC-S) containing 70% Chamaecyparis obtusa essential oil on the elimination of red mite in laying hens. In total, 300 laying hens (ISA brown) aged 72 weeks and infected with red mite were assigned to individual cages for five treatments with five replicates for 18 days. Treatments consisted of distilled water (negative control; NC), commercial spray product (positive control; PC), FC-S 0 (original concentration), FC-S 50 (50 times diluted) and FC-S 100 (100 times diluted). The number of red mites, egg production and weight of each group were evaluated daily throughout the whole experimental period. Egg quality and blood biochemical parameters were measured at the end of the experiment. Safety tests were confirmed by feed intake, respiration, lethargy, diarrhea and mortality symptoms after the feeding trial. As the result, more than 80% of red mites were eliminated by the FC-S 0 spray treatment, and FC-S 50 also showed a higher elimination percentage than did PC (P<0.01). However, the elimination effect of the FC-S 100 spray was lower than that of the PC, but higher than that of the NC (P<0.01). These results confirmed that the optimum FC-S dilution rate ranged from 0~50 times with distilled water to eliminate the red mite effectively. The performance, egg quality, blood parameter and safety tests were not significantly different among treatments. Thus, FC-S 0 and FC-S 50 spray treatments can effectively and sustainably control red mite infestations without detrimental effects on the performance, egg quality and plasma biochemical properties of laying hens.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.675-684
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• 2020

To prevent safety accidents caused by aging pipe infrastructure and to maintain water quality, construction projects for water and sewage pipes are actively conducted across Korea. This study analyzed the criteria situations, site survey details, and regulation revisions related to the calculation of construction cost standards for pipe laying and joining work. The analysis showed that the major causes for revision are the unclear construction scope, limitations in implementing some pipe materials due to installation facility types, workforce focused on ordinary labor, limitations of manual laying work, and the lack of tool hire cost and machine expense-calculation criteria. Field studies were conducted to categorize the pipes according to their features, in addition to identifying the use of lifting heavy equipment and light equipment. In addition, excavation and testing work conducted in connection to pipe laying, as well as the use of skilled labor, were investigated. The current study clarified the work scope through new common items, provides an organization based on the pipe material, adjusted the workforce ratio to focus more on skilled labor, and developed grounds for calculating machine expenses. These revisions were estimated to save approximately 1.28% of the construction costs in each project according to an analysis of the construction cost impact study. truction costs in each project, according to an analysis of construction cost impact study.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.1006-1013
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• 2015

Heat-stress remains a costly issue for animal production, especially for poultry as they lack sweat glands, and alleviating heat-stress is necessary for ensuring animal production in hot environment. A high ${\gamma}$-aminobutyric acid (GABA)-producer Lactobacillus strain was used to investigate the effect of dietary GABA-producer on laying performance and egg quality in heat-stressed Hy-line brown hens. Hy-Line brown hens (n = 1,164) at 280 days of age were randomly divided into 4 groups based on the amount of freeze-dried GABA-producer added to the basal diet as follows: i) 0 mg/kg, ii) 25 mg/kg, iii) 50 mg/kg, and iv) 100 mg/kg. All hens were subjected to heat-stress treatment through maintaining the temperature and the relative humidity at $28.83{\pm}3.85^{\circ}C$ and 37% to 53.9%, respectively. During the experiment, laying rate, egg weight and feed intake of hens were recorded daily. At the 30th and 60th day after the start of the experiment, biochemical parameters, enzyme activity and immune activity in serum were measured. Egg production, average egg weight, average daily feed intake, feed conversion ratio and percentage of speckled egg, soft shell egg and misshaped egg were significantly improved (p<0.05) by the increasing supplementation of the dietary GABA-producer. Shape index, eggshell thickness, strength and weight were increased linearly with increasing GABA-producer supplementation. The level of calcium, phosphorus, glucose, total protein and albumin in serum of the hens fed GABA-producing strain supplemented diet was significantly higher (p<0.05) than that of the hens fed the basal diet, whereas cholesterol level was decreased. Compared with the basal diet, GABA-producer strain supplementation increased serum level of glutathione peroxidase (p = 0.009) and superoxide dismutase. In conclusion, GABA-producer played an important role in alleviating heat-stress, the isolated GABA-producer strain might be a potential natural and safe probiotic to use to improve laying performance and egg quality in heat-stressed hens.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1318-1323
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• 2008

Corn distiller's dried grains with solubles (DDGS) is a completely new feed ingredient in the Korean feed market. There is an ever increasing need for the Korean feed industry to import and make the best of it as a high protein and high energy feed ingredient. A layer feeding trial was conducted for 10 weeks to investigate the effects of addition of light-colored DDGS to layer diets on laying performance, egg qualities and yolk fatty acid composition. Also, the economics of using DDGS in the Korean situation was analyzed. Nine hundred Hy-line Brown layers, 24 weeks of age, were employed in a feeding trial consisting of four dietary treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared as iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight and feed conversion ratio (p>0.05). The color and breaking strength of eggshell, as well as the albumin height and Haugh unit were not affected by the addition of DDGS up to 20% in the diet. The yolk color was significantly increased by DDGS supplementation (p<0.05). As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (p<0.05) in egg yolk. The degree of saturation of yolk fatty acids was not affected by DDGS supplementation. The inclusion of light-colored DDGS up to 20% in layer diets resulted in a decrease of feed cost per kg without any undesirable effect on laying performance. In conclusion, the light-colored DDGS (L* 56.65) could be used up to 20% in layer diets without any harmful effect on laying performance, and possibly provide economic benefits to the Korean poultry industry.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.697-702
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• 2005

The aim of this study was to divide vocalizations of laying hens (Hy-Line Brown) into general vocalizations (GVs), heat stress-related vocalization (HSV), and cold stress-related vocalizations (CSVs) and to determine if they are classified by the discriminant function analysis method. Thirty laying hens, 65-wk-old, were recorded using digital video recorders 2 times from 10:00 to 14:00 h in each thermal environment (thermoneutral: $22.0{\pm}1.8^{\circ}C$, too hot: $32.0{\pm}2.0^{\circ}C$, too cold: $8.0{\pm}1.9^{\circ}C)$ after a 7 day acclimation period. When the laying hens were not recorded, they were kept in thermoneutral conditions. The GVs, HSV, and CSVs were divided based on the shapes of spectrums and spectrograms. The GVs, HSV, and CSVs were identified as 5, 1, and 3 types, respectively. Pitch, intensity, duration, formant 1, formant 2, formant 3, and formant 4 among the thermal environment-related vocalizations were significantly different (P<0.001). The discrimination rate determined by discriminant function analysis was 86.2%. These results suggest that HSV and CSVs are present and may be used as an indicator of the thermal environment.

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.137-145
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• 2008

A layer feeding trial was conducted to investigate the effects of high quality corn distiller's dried grains with solubles(DDGS) on laying performance and nutrient metabolizabilities. A total of 216 Hy-line Brown layers, 23-wk of age, were employed in a 10-wk feeding trial consisting of three dietary treatments(0%, 10%, and 20% DDGS), and six replicates per treatment. All experimental diets were prepared as iso-protein(17%) and iso-calorie(2,780 kcal/kg). At the end of the trial, the effect of DDGS on fecal ammonia emission was also estimated. The use of DDGS up to 20% in layer diets did not affect the feed intake, laying rate, egg weight, and feed conversion ratio(P>0.05). The DM metabolizability decreased significantly(P<0.05) by the DDGS supplementation(P<0.05). The NFE metabolizability decreased gradually as the level of DDGS increased(P<0.05). The fecal ammonia emission from DDGS-fed birds tended to decrease as the storage days extended. In conclusion, albeit DDGS has some unfavorable effects on DM and NFE metabolizabilities, it could be included in layer diets up to 20% level without any harmful effects on laying performance.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.87-94
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• 2019

Huge amount of persimmon peels, which are byproducts usually arising after making dried persimmons from fresh persimmons, are generated in fall, every year. As the dry matter of persimmon peel contains carbohydrates over 80%, it could be a good candidate for feed. In this study, we evaluated the persimmon peel as a feed resource for a hen laying eggs. Persimmon peel has lower ratio of crude protein and fat composition while higher ratio of crude fiber composition compared to a basal laying hen feed. Feeding the persimmon peel by adding to the feed at the level of 2% or 5% did not affect the egg-laying rate from beginning to the peak of laying. In addition, feeding the persimmon peel did not affect the egg quality either, as the pH, Haugh unit, yolk color and shell thickness of the egg were not different from each other. The composition of amino acids and fatty acids were also almost same for each other, except for the linolenic acid which was slightly higher in the persimmon peel feeding groups. In conclusion, addition of persimmon peel to the feed up to 5% might be helpful to increase the income and reduce the waste produced from the agricultural byproduct.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.267-272
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• 2023

This study was conducted to investigate the effect of integrated pest management (IPM) with 3point 5score microscopic monitoring method for laying farms infected with poultry red mites. A total of 8 laying farms infected with poultry red mites were divided into two treatments: 1) integrated pest management with 3point 5score microscopic monitoring method and 2) normal pest management with 3point 5score microscopic monitoring method. The results revealed that there is no significant difference between the groups with respect to the score of poultry red mites not only regardless of disinfection for the laying farms but also from week 4 to week 20 (P>0.05). However, the farm with IPM had a lower (P<0.05) score than those with the normal pest management method on week 24. Based on the result of the present study, controlling the presence of poultry red mites using IPM, along with consistent monitoring and supplementation using the 3point 5score microscopic monitoring method, is deemed effective in reducing the ultimately targeted infection rate of poultry red mites.