• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.341-347
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• 1999

Pregnant Yorkshire gilts were utilized to investigate the efficacy of exogenous administration of pST and/or insulin in enhancing prenatal piglet survival, uteroplacental and umbilical cord growth and development. Gilts were randomly assigned in a $2{\times}2$ factorial arrangement to four treatment combinations consisting of either daily i.m. injections of 5 mg pST (P, n=23); 0.50 IU/kg of insulin (I, n=23); combination of pST and insulin (P+I, n=23); or 1 ml of saline as control (C, n=23) from gestation Day 30 to 70. All gilts were sacrificed on gestation d 113 to evaluate piglet survival and uteroplacental or umbilical cord development Uteri were longer (346.3 vs 325.7 cm; p<0.05), and heavier (3122.8 vs 2940.7 g; p<0.05) in insulin treated gilts. Only placental macroscopic surface area was enhanced by maternal insulin injections (p<0.05) Incidence of umbilical cord abnormalities were low (14.3%), and they were independent of maternal treatment, occurring more in short cords than in long ones (21 vs 12%; p<0.05). A 6% increase in cord length (53.2 vs 48.6 cm; p=<0.05) was observed in piglets from treated gilts compared with controls. Significant sex differences (in favour of males) were observed in piglet weight, crown rump length and for most umbilical or placental parameters. Gilt weight gains from breeding to Day 113 of gestation were 10% and 15% greater in pST and insulin treated gilts compared with controls. These data indicate that prepartum injections of pST and/or insulin to gestating gilts seem to have a beneficial effect on uteroplacental or umbilical cord development and promote conditions conducive for perinatal piglet survival.

• Korean Journal of Poultry Science
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• v.20 no.1
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• pp.43-54
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• 1993

Egg production in Korea was 393 thousand M/T in 1990. More than 10 thousand M/T egg was imported and the amount imported has increased every year. Despite consumption tendency of increasing processed food, creation of additional demand is not likely because domestic egg consumption mainly depends upon table eggs. Processed eggs for marketing in Korea could be classified into two kinds. One is primary processed eggs including liquid eggs and egg powders. The other is secondary processed eggs which are further processed such as egg flake and egg curd. In addition to the above egg products, specific nutrient fortified eggs are produced through the modified feed formula and breeding techniques. The technologies developed so far including Korean patents are introduced. Convenient foods using egg and nutrient controlled eggs will be popular in the near future. For example, low cholesterol egg and polyunsaturated fatty acid fortified egg will be produced to meet the consumer demand. However, facing problems such as introducing egg quality grading systems and extending the short shelf-life of washed eggs should be solved as well.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.5
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• pp.625-629
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• 2013

The melanocortin 1 receptor (MC1R) gene is related to the plumage color variations in chicken. Initially, the MC1R gene from 30 individuals was sequenced and nine polymorphisms were obtained. Of these, three and six single nucleotide polymorphisms (SNPs) were confirmed as synonymous and nonsynonymous mutations, respectively. Among these, three selected SNPs were genotyped using the restriction fragment length polymorphism (RFLP) method in 150 individuals from five chicken breeds, which identified the plumage color responding alleles. The neighbor-joining phylogenetic tree using MC1R gene sequences indicated three well-differentiated different plumage pigmentations (eumelanin, pheomelanin and albino). Also, the genotype analyses indicated that the TT, AA and GG genotypes corresponded to the eumelanin, pheomelanin and albino plumage pigmentations at nucleotide positions 69, 376 and 427, respectively. In contrast, high allele frequencies with T, A and G alleles corresponded to black, red/yellow and white plumage color in 69, 376 and 427 nucleotide positions, respectively. Also, amino acids changes at position Asn23Asn, Val126Ile and Thr143Ala were observed in melanin synthesis with identified possible alleles, respectively. In addition, high haplotype frequencies in TGA, CGG and CAA haplotypes were well discriminated based on the plumage pigmentation in chicken breeds. The results obtained in this study can be used for designing proper breeding and conservation strategies for the Korean native chicken breeds, as well as for the developing breed identification markers in chicken.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.316-322
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• 2013

In order to evaluate the genetic diversity and discrimination among five Korean native chicken lines, a total of 86 individuals were genotyped using 150 microsatellite (MS) markers, and 15 highly polymorphic MS markers were selected. Based on the highest value of the number of alleles, the expected heterozygosity (He) and polymorphic information content (PIC) for the selected markers ranged from 6 to 12, 0.466 to 0.852, 0.709 to 0.882 and 0.648 to 0.865, respectively. Using these markers, the calculated genetic distance (Fst), the heterozygote deficit among chicken lines (Fit) and the heterozygote deficit within chicken line (Fis) values ranged from 0.0309 to 0.2473, 0.0013 to 0.4513 and -0.1002 to 0.271, respectively. The expected probability of identity values in random individuals (PI), random half-sib ($PI_{half-sibs}$) and random sibs ($PI_{sibs}$) were estimated at $7.98{\times}10^{-29}$, $2.88{\times}10^{-20}$ and $1.25{\times}10^{-08}$, respectively, indicating that these markers can be used for traceability systems in Korean native chickens. The unrooted phylogenetic neighbor-joining (NJ) tree was constructed using 15 MS markers that clearly differentiated among the five native chicken lines. Also, the structure was estimated by the individual clustering with the K value of 5. The selected 15 MS markers were found to be useful for the conservation, breeding plan, and traceability system in Korean native chickens.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.759-765
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• 2021

Recently, summer temperatures have frequently been abnormal in Korea owing to global warming. In summer, a decrease in feed intake rate and biological activity were observed in Hanwoo (Korean Native Cattle), leading to lower production rates in the industry. However, the precise scale of damage was not reported as with other animals of economic value. This study was conducted to investigate the effects of birth season on birth weight in Hanwoo. Data were collected from 100 local breeding farms from 2016 to 2019. A total of 41,081 Hanwoo calves were classified and analyzed by sex, year, month, and season (March-May, spring; June-August, summer; September-November, fall; and December-February, winter) of birth. The birth weight of Hanwoo calves differed according to birth month. The average birth weight of male calves was 30.47 kg and that of female calves was 28.16 kg. Hanwoo birth weight was the highest in March-born calves and the lowest in July-born calves. The birth weights of calves born in February, March, April, November, and December were significantly larger than those of calves born in July. In addition, the birth weight of Hanwoo calves from the summer was significantly lower than that of calves born in other seasons. Furthermore, Hanwoo steer slaughter age showed a negative correlation, whereas carcass weight had a positive correlation with birth weight. In the beef cattle industry, birth weight is a very important economic characteristic that is related to growth rate. These data will contribute toward planning the reproduction of Hanwoo and analysis of changes in characteristics of economic value owing to high temperatures.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.51-58
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• 2021

Fatty acid composition is an important economic trait that affects meat flavor. Several genes that influence fatty acid composition in meat have been investigated. In a previous study, we identified 51 significant SNP × SNP interactions (P≤0.05) between nine SNPs of six candidate genes (DEGS1, ELOVL6, FABP3, FABP4, FASN, and SCD) on meat fatty acid composition in Korean native chicken. This study further investigated the patterns of the SNP × SNP interactions to understand how they affect the fatty acid content in thigh and breast meat of Korean native chicken. The significant epistatic effects of SNP combinations showed various patterns for each fatty acid trait. The results of this study suggest that the respective additive effects of each SNP on polygenic traits, such as fatty acid composition, should be considered in combination with the epistatic effect of SNP combinations in animal breeding programs. The findings of this study have provided new genetic information for improving meat quality, especially the fatty acid composition, of Korean native chicken.

• Korean Journal of Organic Agriculture
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• v.28 no.4
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• pp.643-658
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• 2020

Animal welfare has become a prominent concern around the world so that the laws and guidelines of animal welfare are being strengthened in many countries including the EU. In Korea, it is required to supplement animal welfare standards because social awareness of animal welfare has changed. This study was conducted to compare broiler welfare certification standards and improve the quality of practice. We found that broiler welfare certification standards differ among countries according to environmental and managemental differences. Standards for stocking density and perch which is considered more important for poultry welfare are similar, but there is a little difference in feed, water, litter and lighting. Therefore, we assumed that theses are able to revise standards taking into account the environment and suggested that the broiler welfare certification standard will serve as a more useful criterion if breeding conditions in Korea are considered.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.207-212
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• 2016

This work was carried out to investigate the ability of thirteen crossbreds for production of commercial chicken (CC) of Korean native chicken to be cut out for Korean circumstance. Total of one thousand three hundred of crossbreds were divided thirteen groups (100 birds/group) that were twelve groups (1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B) to crossbreed with two sires (A, B) and six dams (1, 2, 3, 4, 5, 6) of parent stock (PS) of Korean native chicken and one group (HH) as commercial Korean native chicken. Experimental diets were starter diet (0~7d; CP 22.0% ME 3,150 kcal/kg), early diet (8d~Wt 800 g; CP 19.0% ME 3,150 kcal/kg) and finished diet (Wt 800 g~12 wk; CP 18.0% ME 3,150 kcal/kg). Fertility of 1B group was higher than other groups. Hatchability per fertilization eggs and hatchability per setting eggs were 87.5~89% and 87.9~96.3%, respectively, and those of 4B and 6B groups were lower compared to other groups. Weekly body weight of HH group was lower than other groups. CV values of body weight of thirteen groups were showed over 12% as 12.5~18.2%, and especially, those of 2B, 3B, 5B, HH groups were lower compared to other groups. Weekly feed conversion ratios (FCRs) of 13 crossbreds were 1.7~2.3, 2.1~2.5, 2.4~2.7 and 2.7~3.2 at the age of 6, 8, 10 and 12 weeks, respectively. Weekly production indexes of 2A, 3A and HH groups were the lower than other groups and those of thirteen groups decreased following weeks. Feed costs per body weight gain (kg) were 1,069~1,255 won, 1,100~1,263 won, and 1.468~1,696 won at starter, earlier and finished period of broilers. These results leaded down to conclusion to be possible selection of new Korean native commercial chicken that have the excellent performance and economics.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.302-306
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• 2001

This study was carried out to construct mapping population and to evaluate the methods involved, including polymorphic DNA marker system and appropriate statistical analysis. As an initial step to establish chicken genome mapping project, White Leghorn (WL) and Korean Ogol chicken (KOC) were used for generating backcross population. From 8 initial parents, total 280 backcross progenies were obtained and 40 were used for genotyping and linkage analysis. For development of novel polymorphic markers for KOC, Random Amplified Polymorphic DNA (RAPD) markers specific for this chicken line were generated. Also included in this study were six microsatellite markers from East Lansing map as reference loci. For segregation analysis, 15 RAPD markers and 6 microsatellites were used to genotype the backcross population. Among the RAPD markers that we developed, 2 pairs of markers were identified to be linked and another 4 RAPD markers showed linkage with microsatellites of known map. In summary, this study showed that our backcross population generated from the mating of KOC to WL serves as a valuable genetic resource for genotyping. Furthermore, RAPD markers are proved to be valuable in linkage mapping analysis.

• Korean Journal of Veterinary Research
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• v.21 no.2
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• pp.93-97
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• 1981

It has long been believed for the presence of infectious coryza affecting serious economic loss in domestic poultry industry. However, the etiologic agent has not been isolated until quite recently. From 1979, several strains of Haemophilus-like organism were isolated from chickens with symptoms similar to infectious coryza, and their colonial morphology, growth requirement, biochemical properties and pathogenicity were assessed. In addition, serological properties of the isolates by cross hemagglutination inhibition test was also investigated. The results indicated that all the isolates were identified as Haemophilus gallinarum which had similar characteristics to the reference strains.