• 한국가금학회지
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• 제10권2호
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• pp.113-121
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• 1983

국내에서 발생하고 있는 ILT의 역학적인 사항을 파악하기 위하여 1982년 6월부터 1983년 8월까지 ILT가 발생된 5개 종계농장과 1개 산란계농장의 총56개 계군을 대상으로 계군간 및 계군내 전파속도와 전파수단, 품종, 나이, 사양형태에 따른 감수성의 차이, 발병 전후의 백신접종이 피해를 줄이는데 미치는 영향 등을 조사하였다. 6개 대상농장 중 5개 농장에서는 ILT발생 직전 또는 직후 백신접종을 실시하였으며 겨울철에 발생한 2개 농장에서는 발생직후 철저한 전파수단의 차단에 의해서 농장별로 1-2계군의 발생에 그치고 나머지 5-7계군은 발생이 없었다. 계군간의 전파속도는 평사계군이 평균 6일로서 케이지계군(11.5일)보다 빨랐으나 유의적인 차이는 인정할 수 없었다. 한편 케이지계군 중 산란을 하지 않는 미성숙계군간의 전파기간이 17일인데 반하여 산란중인 계군에서는 8일로서 유의적인 차이가 인정되어 난좌나 집란과정에 의한 전파촉진 가능성을 엿볼 수 있었다. 발병계군 내에서의 폐사기간은 평균 18일로서 사육형태. 품종 및 나이에 따른 차이를 인정할 수 없었다. 또한 폐사율은 평균 6.5%로서 미성숙육계종계군(2.9%)이 미성숙산란계군(11.8%)이나 산란중인 육계종계군(6.9%)에 비하여 월등히 낮았을 뿐 다른 어떤 기준에서도 궤사율의 차이를 인정할 수 없었다. 조사대상 농장 중 여름철에 발생한 한 육계종계 농장에서는 계군의 나이에 따라 37주령 이상된 7개 계군에서는 모두 수탉이 암탉에 비하여 두배 이상의 높은 폐사율을 보여 주었다.

• The Korean Journal of Ecology
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• 제22권2호
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• pp.65-68
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• 1999

In December-January of 1996-1997 and 1997-1998, information was gathered about vertical distribution of foraging sites of tits in 34 flocks in coniferous and deciduous forests. There was a significant effect of forest type on the distribution of foraging sites of each species. Habitat was classified into 5 height layers vertically: ground, bushes (usually＜1.5 m, up to 3 m), tree layer 1 (up to 1/3 of tree height), tree layer 2 (1/3-2/3 tree height). and tree layer 3 (＞2/3 tree height). There were differences among species: great tit (Parus major) foraged mostly on the ground, coal tit (P. ater) and long-tailed tit (Acrocephalus caudatus) - on the highest tree layer, marsh tit (P. palustris) was often seen on bushes, and varied tit (P. varius) - in tree layer 2. Smaller species used upper and outer parts of trees. suggesting that, like in most other similar studies. larger dominant species prevented smaller species from using inner parts of trees.

• 대한수의학회지
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• 제45권3호
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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.

• 한국동물위생학회지
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• 제43권3호
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• pp.197-200
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• 2020

This study was performed to determine the seroprevalence of reticuloendotheliosis virus (REV) infection in layer chickens in Gyeonggi province, South Korea. Serum samples were collected from 820 layer chickens on 56 flocks in Gyeonggi province. The samples were tested for specific antibodies against REV using commercial enzyme-linked immunosorbent assay (ELISA). The seroprevalence of REV antibodies in the flocks was 62.50% (95% Confidence interval (CI) 49.33~74.40) and the overall seroprevalence in individual chickens was 39.27% (95% CI 35.97~42.65). The results of the present survey indicate that REV infection is prevalent in layer chickens in Gyeonggi province, South Korea. Therefore, effective measures should be taken to prevent and control REV of layer chickens in this province.

• 한국동물위생학회지
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• 제43권4호
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• pp.257-259
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• 2020

Ornithobacterium rhinotracheale (ORT) causes pneumonia, airsacculitis, and pleuritis in chickens and other avian species. Little is known about the seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea. The purpose of this study was to determine the seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea from May to September 2019. A total of 460 chickens in 28 flocks were tested for antibodies to ORT by using commercial enzyme-linked immunosorbent assay (ELISA) kit. The seroprevalence of ORT antibodies in the flocks was 100% (28/28) and the overall seroprevalence in individual chickens was 98.91% (455/460). This survey indicated the high seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea. Therefore, measures should be executed to control ORT in layer chickens in this province.

• 대한수의학회지
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• 제33권2호
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• pp.227-234
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• 1993

A serological survey for antibody to chicken anemia agent(CAA) was carried out by virus neutralization test. Antibody to CAA was detected in broilers and layers at different age groups. The results obtained were summarized as follows ; 1. Of a total of 1,035 chicken sera from 1.16 flocks 617 samples of sera were detected as positive(59.6%) and 95 flocks of a total flocks as positive(81.9%). 2. Proportion of positive sera by age were 92.3 %(88.9~100%) at 1 to 2 weeks of age, 56.4%(16.7~77.8%) at 3 to 9 weeks of age, 85.0%(50.0~100%) at 10 to 14 weeks of age and all tested sera were positive at over the 15 weeks age. 3. In each broiler and layer chicken 63.6% and 68.4% chicks possessed positive sera respectively. 4. Neutralizing antibody titer in age group was various from 1:10 to 1:6,400 and mean titer was 1:400 to 1:800.

• Asian-Australasian Journal of Animal Sciences
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• 제15권1호
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• pp.1-6
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• 2002

Eggs obtained from 46 and 42 weeks old meat (Hybro) and layer (Leghorn) breeders flocks, respectively were used to examine the effects of genetic type of birds and egg size (small, medium and large) on variables of eggshell characteristics and hatchability traits. The variables measured were egg weight (EW), egg surface area (ESA) and eggshell characteristics (shell conductance (EC), per cent shell (PS), shell thickness (ST), shell volume (SV), shell density (SD) and hatchability traits (per cent hatchability (HP), early dead embryos (ED), late dead embryos (LD), pips with live embryos (PL) and pips with dead embryos (PD)). Genetic type of bird influenced all egg characteristics and HP of eggs. Eggs produced by the small Leghorn bird had lower EW, ESA, EC, ST, SV and HP than those produced by the heavy Hybro bird. The reduction of HP was associated with an increase in the percentage of ED and PL. Egg size influenced all variables measured except ST. Small size eggs had lower EW, ESA and EC and higher PS and SD than those of large eggs. Medium size eggs produced a higher HP when compared with that of large size eggs. The reduction of HP in large eggs was associated with higher percentage of ED, LD and PL. There were significant interactions between the genetic group of birds and egg size on LD and HP. Large egg size of Hybro birds had higher LD and lower HP than those of small size eggs produced by the same flock. However, There was no difference in HP and LD among the different egg sizes produced by Leghorn birds. It was concluded that genetic make up of birds and egg size influence eggshell characteristics and HP. The type of bird (heavy or small) influences the optimum egg size for successful hatching. Attention should be given to the size and eggshell characteristics of eggs of breeders' flocks for achieving maximum HP.

• 대한수의학회지
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• 제40권3호
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• pp.563-573
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• 2000

Periodic outbreaks of Newcastle disease (ND) caused by velogenic viscerotropic ND virus (vvNDV) has become a major concern in Korea nowadays. Throughout last epidemic, the winter season in 2000, most chicken flocks infected early, under 2-4 weeks of age, showed high mortality up to 50-100%. Serum samples collected from 201 breeder, 284 layer and 112 broiler chicken flocks were examined to evaluate the efficacy of various vaccination methods and programs routinely used for mass vaccination in the field poultry farms. Despite repeated live vaccination, most poultry flocks vaccinated by drinking water route using nipple water supply system failed to produce solid active immune response to NDV during the growing time. In the present study, we applied the spray vaccination technique using Ulvavac or Desvac sprayer to the experimental poultry flocks and examined the efficacy of live vaccination effects induced by it under field condition. Measurable antibody to NDV as well as early protection against vvNDV challenge were found in poultry flocks vaccinated by spray route. Further, we did not found significant post vaccination reactions caused by spray vaccination if properly administered. These data indicate that the spray vaccination will be safe and reliable mass vaccination method for the prevention of ND.

• 한국가금학회지
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• 제40권4호
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• pp.379-388
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• 2013

Avian paramyxovirus (APMV) type 4 and 6 were isolated during an avian influenza (AI) surveillance program of wild birds. This study also conducted experimental infection of wild-bird-origin APMV type 4 and 6 in specific pathogen free (SPF) chickens to study pathogenicity and transmission within domestic flocks. In addition, serological prevalence data of APMV type 4 and 6 in domestic fowls was conducted with chicken sera collected from 2007 to 2009 in order to understand infection status. The results of the animal experiment showed that APMV type 4 and 6 had the ability to infect chickens with sero-conversion and to transmit the virus from infected birds to contacted birds, but showed low pathogenicity. Serological tests revealed that APMV type 4 was widespread in the poultry industry, especially in layer flocks, but the positive rate for APMV type 6 was very low. This study concluded that wild bird-origin APMV type 4 and 6 could infect the chickens by inter-species transmission and the seroprevalence of APMV type 4 was quite high in Korean poultry. However, since almost all the chicken flocks had a high level of antibody titer against APMV type 1, there was possibility of cross reaction between APMV type 1 and 4, which made the interpretations more complicated. In order to understand infection status in the natural environment, additional study is necessary regarding the seroprevalence of APMV type 4 and 6 in the wild bird population.

• 한국임상수의학회지
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• 제38권1호
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• pp.1-6
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• 2021

Avian haemosporidia, including malarial parasites, are geologically and biologically widespread. The protozoal pathogen has been a subject of intensive research in the past, which has resulted in major medical progress. Haemosporidia infection in avian species in South Korea has been studied in wild birds and layer flocks, but not in pet birds. At the Veterinary Teaching Hospital of Chungbuk National University, 75 birds that presented for health check-up were tested to evaluate the infection rate of Haemoproteus, Plasmodium and Leucocytozoon in birds without clinical symptoms. Haemoproteus spp. and Leucocytozoon spp. were simultaneously detected in a Major Mitchell's cockatoo (Lophochroa leadbeateri) by polymerase chain reaction, representing 1.33% of the tested birds. Phylogenetic analysis suggested that the infective Haemoproteus and Leucocytozoon strains were similar to those detected in foreign countries rather than those detected in the wild birds of Korea. Although the infection rate may not be indicative of a substantial infection in healthy pet parrots, the import of infected birds can pose a threat by allowing foreign pathogens to infect the local wild flocks or livestock. This is the first surveillance study of avian haemosporidia in pet parrots in South Korea.