• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.1-11
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• 1996

This study was conducted to analyze the present status and the levels of mechanization and automation for raising, feeding, water supply, propagation, health management, ventilation and heat control, data analysis, and etc, and to establish the guide of the future study on development of the optimum production system models of swine facility from the results of this analysis. The scheme of the future study on the development of the optimum production system model of swine facility was established as follows : 1. A Korean and environmental control type slatted windowless swine housing model would be developed according to the following basis : \circled1 Boars, gilts and sows, delivery sows should be raised individually and piglets, growing pigs, and finishing pigs should be raised in group. \circled2 The arrangement of furrowing house were two rows of furrowing crates facing the center aisle. 2. The environmental control system and waste management system that are suitable to Korean and environmental control type slatted windowless swine housing model would be developed. 3. An electronic identification device would be developed. 4. The automatic individual wet feeding system by electronic identification device and computers would be developed. 5. The individual management system would be developed, which could manage individually the breeding pigs by the electronic identification device. 6. An expert system would be developed, which could manage the health and data base of pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1675-1683
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• 2005

In the process of crossbreeding, the linkage disequilibria between the quantitative trait loci (QTL) and their linked markers were reduced gradually with increasing generations. To study the potential of QTL mapping using the crossbred population, we presented a mixed effect model that treated the mean allelic value of the different founder populations as the fixed effect and the allelic deviation from the population mean as random effect. It was assumed that there were fifty QTLs having effect on the trait variation, the population mean and variance were divided to each QTL in founder generation in our model. Only the additive effect was considered in this model for simulation. Six schemes (S1-S6) of crossbreeding were studied. The selection index was used to evaluate the synthetic breeding value of two traits of the individual in the scheme of S2, S4 and S6, and the individuals with high selection index were chosen as the parents of the next generation. Random selection was used in the scheme of S1, S3 and S5. In this study, we premised a QTL explained 40% of the genetic variance was located in a region of 20 cM by the linkage analysis previously. The log likelihood ratio (log LR) was calculated to determine the presence of a QTL at the particular chromosomal position in each of the generations from the fourth to twentieth. The profiles of log LR and the number of the highest log LR located in the region of 5, 10 and 20 cM were compared between different generations and schemes. The profiles and the correct number reduced gradually with the generations increasing in the schemes of S2, S4 and S6, but both of them increased in the schemes of S1, S3 and S5. From the results, we concluded that the crossbreeding population undergoing random selection was suitable for improving the resolution of QTL mapping. Even experiencing index selection, there was still enough variation existing within the crossbred population before the fourteenth generation that could be used to refine the location of QTL in the chromosome region.

• Research in Plant Disease
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• v.8 no.3
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• pp.146-161
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• 2002

Incidence of soilborne diseases, as a major cause of failure of continuous monocropping becomes severe in recent years. For examples, recent epidemics of club root of chinese cabbage, white rot of garlic, bacterial wilt of potato, pepper phytophthora blight, tomato fusarium wilt and CGMMV of watermelon are the diseases that require urgent control measures. Reasons for the severe incidence of soilborne diseases are the simplified cropping system or continuous monocropping associated with allocation of major production areas of certain crop and year-round cultivation system that results in rapid degradation of soil environment. Neglect of breeding for disease resistance relative to giving much emphasis on high yield and good quality, and cultural methods putting first on the use of chemical fertilizers are thought to be the reason. Counter-measures against soilborne disease epidemics would become most effective when the remedies are seeded for individual causes. As long-term strategies, development of rational cropping system which fits local cropping and economic condition, development and supply of cultivars resistant to multiple diseases, and improvement of soil environment by soil conditioning are suggested. In short-term strategies, simple and economical soil-disinfestation technology, and quick and accurate forecasting methods for soilborne diseases are urgent matter far development. for these, extensive supports are required in governmental level for rearing soilborne disease specialists and activation of collaborating researches to solve encountering problems of soilborne diseases.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.125-132
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• 2010

Rice is the staple food of more than 50% of the worlds population. Cultivated rice has the AA genome (diploid, 2n=24) and small genome size of only 430 megabase (haploid genome). As the sequencing of rice genome was completed by the International Rice Genome Sequencing Project (IRGSP), many researchers in the world have been working to explore the gene function on rice genome. Insertional mutagenesis has been a powerful strategy for assessing gene function. In maize, well characterized transposable elements have traditionally been used to clone genes for which only phenotypic information is available. In rice endogenous mobile elements such as MITE and Tos (Hirochika. 1997) have been used to generate gene-tagged populations. To date T-DNA and maize transposable element systems has been utilized as main insertional mutagens in rice. A main drawback of a T-DNA scheme is that Agrobacteria-mediated transformation in rice requires extensive facilities, time, and labor. In contrast, the Ac/Ds system offers the advantage of generating new mutants by secondary transposition from a single tagged gene. Revertants can be utilized to correlate phenotype with genotype. To enhance the efficiency of gene detection, advanced gene-tagging systems (i.e. activation, gene or enhancer trap) have been employed for functional genomic studies in rice. Internationally, there have been many projects to develop large scales of insertionally mutagenized populations and databases of insertion sites has been established. Ultimate goals of these projects are to supply genetic materials and informations essential for functional analysis of rice genes and for breeding using agronomically important genes. In this report, we summarize the current status of Ac/Ds-mediated gene tagging systems that has been launched by collaborative works from 2001 in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.9
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• pp.1349-1354
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• 2019

Objective: The objective of this study was to determine the best approach for handling missing records of first to successful insemination (FS) in Japanese Black heifers. Methods: Of a total of 2,367 records of heifers born between 2003 and 2015 used, 206 (8.7%) of open heifers were missing. Four penalty methods based on the number of inseminations were set as follows: C1, FS average according to the number of inseminations; C2, constant number of days, 359; C3, maximum number of FS days to each insemination; and C4, average of FS at the last insemination and FS of C2. C5 was generated by adding a constant number (21 d) to the highest number of FS days in each contemporary group. The bootstrap method was used to compare among the 5 methods in terms of bias, mean squared error (MSE) and coefficient of correlation between estimated breeding value (EBV) of non-censored data and censored data. Three percentages (5%, 10%, and 15%) were investigated using the random censoring scheme. The univariate animal model was used to conduct genetic analysis. Results: Heritability of FS in non-censored data was $0.012{\pm}0.016$, slightly lower than the average estimate from the five penalty methods. C1, C2, and C3 showed lower standard errors of estimated heritability but demonstrated inconsistent results for different percentages of missing records. C4 showed moderate standard errors but more stable ones for all percentages of the missing records, whereas C5 showed the highest standard errors compared with noncensored data. The MSE in C4 heritability was $0.633{\times}10^{-4}$, $0.879{\times}10^{-4}$, $0.876{\times}10^{-4}$ and $0.866{\times}10^{-4}$ for 5%, 8.7%, 10%, and 15%, respectively, of the missing records. Thus, C4 showed the lowest and the most stable MSE of heritability; the coefficient of correlation for EBV was 0.88; 0.93 and 0.90 for heifer, sire and dam, respectively. Conclusion: C4 demonstrated the highest positive correlation with the non-censored data set and was consistent within different percentages of the missing records. We concluded that C4 was the best penalty method for missing records due to the stable value of estimated parameters and the highest coefficient of correlation.

• Journal of Life Science
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• v.20 no.6
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• pp.825-830
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• 2010

Two diallelic markers at candidate gene loci, the prolactin receptor 3 (PRLR3) gene and the retinol-binding protein 4 (RBP4) gene were evaluated for their association with growth and litter size traits in Berkshire. Genetic evaluation was conducted for 5,919 pigs with pedigree information, which included 3,480 growth performance records and 775 litter size records of 224 sows. From the same herd, genotyping was carried out on 144 and 156 animals for PRLR3 and RBP4, respectively. After assigning a genotype to subjects in which both parents had a homozygous genotype, numbers of genotyped animals increased to 474 and 338, for the PRLR3 gene and RBP4 gene, respectively. The genotype effects of two markers were estimated with breeding values of the genotyped animals. The additive effects of total number of piglets born and number of piglets born alive in the PRLR3 locus were -0.28 and -0.13, respectively. The dominance effect of the RBP4 locus on average daily gain was -10.58 g. However, the polymorphism of the RBP4 locus in total number of piglets born and number of piglets born alive has shown -0.34 and -0.33 of the additive genetic effects. In view of the results, MAS (marker-assisted selection) favoring B alleles of RBP4 and PRLR3 loci could potentially accelerate the rate of the genetic improvement in the litter size traits.

• Journal of agriculture & life science
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• v.51 no.2
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• pp.117-126
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• 2017

Hanwoo young bulls are selected based on performance test using the weight at 12 months and pedigree index comprising marbling score. Pedigree index was not based on the progeny tested data but the breeding value of the proven bulls; resulting a lower accuracy. The progeny testing of the young bulls was categorized into testing at farm and at the test station. The farm tested data was difficult to compare with those from test station data. Farm tested bulls had different slaughter ages than those for test station bulls. Therefore, this study had considered a different age at slaughter for respective records on ultrasound traits. Records on body weight at 12 months, ultrasound measures at 12 and 24 months(uIMF, uEMA, uBFT, and uRFT), and carcass traits(CWT, EMA, BFT, and MS) were collected from steers and bulls of Hanwoo national improvement scheme between 2008 and 2013. Fixed effects of batch, test date, test station, personnel for measurement, personnel for judging, and a linear covariate of weight at measurement were fitted in the animal models for ultrasound traits. The ranges of heritability estimates of the ultrasound traits at 12 and 24 months were 0.21-0.43 and 0.32-0.47, respectively. Ultrasound traits at 12 and 24 months between similar carcass traits was genetically correlated at 0.52-0.75 and 0.86-0.89, respectively.