• Korean Journal of Poultry Science
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• v.30 no.3
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• pp.145-150
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• 2003

A feeding trial was carried out to investigate the effect of dietary complex probiotics on performance. egg qualities and intestinal microflora in laying hens. Three hundred twenty ISA Brown laying hens, 34 weeks of age, were randomly allotted to four dietary treatments containing 0, 0.1, 0.2 and 0.4% complex probiotics for 12 weeks. There were four replicates per treament. Total egg production, soft and broken egg number tended to improve as dietary complex probiotics increased, but was not significantly different. Average egg weight was significantly higher in the 0.1% and 0.2% complex probiotics than the control(P<0.05). Daily egg mass also increased by adding complex probiotics compared to that of control, but was not statistically different. No significant difference was found in feed intake and feed conversion ratio. Eggshell breaking strength and thicknes were not significantly different, whereas yolk color was significantly lower in the supplemental 0.2% probiotics than the comtrol at 12 weeks of age(P<0.05). There was no significant difference in Haugh unit. Total number of cecum Lactobacillus and naerobes were significantly higher in the complex probiotics than control(p.0.05). However, the number of ileal Lactobacillus and naerobe were not significantly different. It was concluded that dietary complex probiotics could improve the egg weight and intestinal beneficial microbes.

• Korean Journal of Poultry Science
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• v.8 no.1
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• pp.37-45
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• 1981

급격히 증가하는 세계의 인구수는 가축의 사료자원을 질이 좋은 인간 식량으로 효율적으로 전환할 필요성을 절실케 하고 있다. 산란계는 유전적인 선택에 의해 최소량의 사료로써 높은 산란율을 유지할 수 있도록 개선되어 왔다. 배합사료의 생산에 사용될 수 있는 단미사료의 종류와 품질은 어느 특정한 영양소의 요구량에 의하여 좌우된다. 산란계의 영양요구량은 오랜동안 연구되어 왔으며, 미국의 국립연구위원회 (NRC)는 영양소 요구량을 정기적으로 검토, 요약하고 있다. 새로운 정보들은 출판되어 왔으며 본인은 여기서 제7차로 개정된 NRC 사양표준(1977)에 발표된 요구량에 관련해서 몇 가지 분야를 검토하고자 한다. (중략)

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.305-308
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• 2004

경계요소법을 이용한 음향홀로그래피 구현에 요구되는 많은 측정 노력을 줄이기 위하여 강체 산란체를 이용한 홀로그래피의 기본이론을 제시하였다. 강체산란체를 음장에 위치시켰을 때의 기본이론을 제시하고, 피스톤의 자유공간방사경우에 산란체의 거리의 변화에 따른 음향진동전달함수의 특이성 변화를 관찰하였다.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• Korean Journal of Poultry Science
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• v.9 no.1
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• pp.35-42
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• 1982

Data pertaining to the first generation of a Synthetic White Leghorn flock were used to estimate the heritabilities of and genetic correlation between partial egg production(egg number or percentage) or diversely segmented part records and other traits such as age at sexual maturity, residual and annual egg production, and to compare the expected genetic gain from selection on partial egg number or partial percent production with correlated response in other traits. The estimated heritabilites for six measures of egg Production were ranged from 29 to 35, while heritability for age at sexual maturity (SM) was intermediate (48). Genetic correlations between partial egg number (P) and annual egg number. (A), and partial percent production (P') and annual percent production (A') were 51 and 72, respectively. Genetic correlation between P and SM was estimated largely negative (-.64), while correlation bettween P' and SM was positively intermediate(34). In comparing direct response from selection on partial production (P or P') with another response in correlated trait, selection on P would be 25% more efficient than selection of P' for improving A, while selection of P' would be 94% more efficient than selection P for improving A' For shortening SM selection of P would be 98% more efficient than selection on P'.

• Korean Journal of Poultry Science
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• v.33 no.1
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• pp.41-47
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• 2006

A study was conducted to investigate the effect of supplementing earthworm meal(EWM) on the egg quality and performance of laying hens. A total of 360 laying hens at 55 weeks of age were fed the experimental diets containing 0(Control), 0.3 and 0.6% of EWM for 5 weeks. Eggs were collected and weighed in every day and egg production and feed conversion were weekly recorded. However egg quality were measured fer last week of experimental period. When fed both 0.3 and 0.6% of EWM, egg production and daily egg mass tended to increase but were not different between those treatments. Feed intake and feed conversion ratio of laying hens were not different among three groups. Egg shell thickness, breaking strength, color and egg yolk color were tend to improve in both 0.3 and 0.6% of EWM compared to those of control. The haugh units(HUs) showed no difference among each treatments at 14 after laying egg, but increased in EWM treatments compared to control for storage period. As, Cd, Cr, Hg and Pb detected 4.41, 1.23, 1.18, 0.00 and 3.39ppm in EWM, respectively, but which were not detected in control. It assumed that supplementing 0.3% of earthworm meal in the 55 weeks old laying hens diet, improved the laying performance and egg quality.

• Korean Journal of Poultry Science
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• v.18 no.1
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• pp.9-31
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• 1991

The purpose of this study was to investigate the effects of dietary methionine and lysine levels on laying hen performance. The level of protein was fixed 15% during whole experiment period, but the levels of methionine and lysine were 0.30% and 0.58% (Low), 0.32% and 0.64% (Medium), 0.35% and 0 70% (High), respectively. Total 288 laying pullets of 22 weeks age were reared from January 28, 1989 to March 23, 1990 for 60weeks. The results obtained were summarized as follows : 1. The e99 Productions were highest in medium treatment in phase I (22~42weeks of age), phase II (42~62 weeks of age) and phase III (62~82weeks of age) and especially, there was significant difference among treatments during phase II (P＜0.05). 2. Egg weight was significantly increased as the levels of methionine and lysine were increased up to methionine and lysine were 0.32% and 0.64%, respectively(P＜0.01). 3. Daily egg mass was highest when the levels of methionine and lysine were 0.32% and 0.64%, respectively and there were significant differences among treatments during phase I and phase II (P＜0.01) 4. Daily feed intake was increased as the levels of methionine and lysine were increased, and there was significant difference among treatments during phase III (P＜0.05). 5. Feed efficiency was best in medium treatment in phase I and phase II (P＜0.01) 6, Viability was highest in medium treatment, but there was no significant difference among treatments. 7. Nutrient utilizability of experimental diets was not significantly different among treatments. 8. Eviscerated yield was highest and abdominal fat accumulation was lowest in medium treatment, but there was no significant difference among treatments. 9. Egg shell quality and chemical composition of egg content were not different among treatments. 10. The feed cost per kg egg mass was lowest in medium treatment and there were significant differences among treatments in phase I, phase II and whole egg laying period(P＜0.05)

• Proceedings of the Korea Society for Simulation Conference
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• 2003.06a
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• pp.15-18
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• 2003

Most numerical techniques such as FEM, BEM, and MOM are able to analize electromagnetic scattering problems from arbitrary shapes. Although these methods could be applied to compute electromagnetic scattering problems in frequency domain, it was limited for electrodynamic problem in time domain. In this paper, electromagnetic scattering problem from Fresnel zone plate lens are considered. Some numerical results computed by TLM are compared with Kirchhoff's approximation and PO method.

• Journal of agriculture & life science
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• v.53 no.2
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• pp.121-129
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• 2019

This study carried out to determine control factors for the improvement of productivity of laying hens suffering heat stress during hot weather. A total of 48,451 ISA Brown layers were housed in a farm located in Gyeongsangnam-do, Republic of Korea. Five thermo-hydrometer loggers were installed inside the house to collect data of dry-bulb temperature and relative humidity. The experiment continued for 81 days when the summer season begins from 19th June to 7th September, 2018. This study analyzed the correlations among layers' production index and daily average, highest, and lowest temperature; daily average, highest, and lowest relative humidity; and daily average, minimum, and maximum THI. The result indicated that feed consumption, hen-day egg production, egg weight, and FCR decreased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.01). On the other hand, water intake increased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.001). The relative humidity was not considered to have direct correlations to the layers' production index (p>0.05). However, it was noticeable that the mortality did not have significant relations with daily average and highest temperature; THI; or daily average, highest and lowest relative humidity while it was relevant to the daily lowest temperature and THI (p<0.05). In conclusion, to enhance the productivity of laying hens in a hot climate, it is recommended that daily average, highest, and lowest dry-bulb temperature and THI are maintained as low as possible. Especially, the daily lowest temperature is needed to lower to 20℃, which is the lowest critical temperature for layers.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.67-72
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• 2005

Forty-wk-old 480 ISA Brown layers were used in a 10-wk feeding trial to investigate the effects of additional various levels of limestone to a low calcium diet without any calcium additives on the performance of laying hens. There were significant differences in average egg weight (P<0.05) without any specific trend among treatments and hen-day egg production was not influenced by the dietary treatments. Daily intake and conversion per kg egg of feed excluded the calcium supplement were significantly reduced (p<0.05) as the level of additional calcium supplement increased in both types of layer diet, while those of feed included the calcium source were significantly increased (P<0.05) as the level of additional calcium supplement increased. Egg specific gravity, eggshell breaking strength and thickness were increased as the level of additional calcium supplement increased, however the significant differences were found only in egg specific gravity It would be possible to reduce the daily feed intake and feed conversion and to improve the eggshell quality by feed the low calcium diet devoid of calcium supplement from the conventional laying hen diet and by supply the additional calcium source at 3 to 4 p.m. instead of the continuous feeding of conventional high calcium diet.