• Journal of agriculture & life science
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• v.45 no.1
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• pp.101-107
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• 2011

A Total of 48,101 performance records of sows for Yorkshire and Landrace breeds were collected from swine breeding farms in Korea from 2001 to 2008. A general ingredient analysis included the fixed effects of breed, parity, year, season, and farm. For the number of heads per 1st parity analysis by each growth traits, the data of 48,101 heads was used to analyze growth traits group. In the general ingredient analysis, the results showed high significance except for lean percentage by season (p<0.05). Average daily gain of Landrace breed ($640.48{\pm}0.749g$) was better than that of Yorkshire breed ($624.22{\pm}0.608g$), and the backfat thickness of Yorkshire breed ($13.44{\pm}0.030mm$) was thicker than that of Landrace breed ($12.50{\pm}0.037mm$). For the number of born alive and number of stillborn by growth traits for each breed, number of born decreased after test end day of 161 to 165 day, and average daily gain of 620 g to 640 g and the highest number of born appeared at the backfat thickness of 13 mm to 14 mm for yorkshire breed. In case of Landrace breed, number of born was the highest, and the number of stillborn increased together with average daily gain. The number of born was high when backfat thickness was less than 11 mm. The number of born trended to decrease when backfat thickness increased.

• Geophysics and Geophysical Exploration
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• v.1 no.2
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• pp.127-135
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• 1998

The Born approximation is widely used for solving the complex scattering problems in electromagnetics. Approximating total internal electric field by the background field is reasonable for small material contrasts as long as scatterer is not too large and the frequency is not too high. However in many geophysical applications, moderate and high conductivity contrasts cause both real and imaginary part of internal electric field to differ greatly from background. In the extended Born approximation, which can improve the accuracy of Born approximation dramatically, the total electric field in the integral over the scattering volume is approximated by the background electric field projected to a depolarization tensor. The finite difference and elements methods are usually used in EM scattering problems with a 2D model and a 3D source, due to their capability for simulating complex subsurface conductivity distributions. The price paid for a 3D source is that many wavenumber domain solutions and their inverse Fourier transform must be computed. In these differential equation methods, all the area including homogeneous region should be discretized, which increases the number of nodes and matrix size. Therefore, the differential equation methods need a lot of computing time and large memory. In this study, EM modeling program for a 2D model and a 3D source is developed, which is based on the extended Born approximation. The solution is very fast and stable. Using the program, crosshole EM responses with a vertical magnetic dipole source are obtained and the results are compared with those of 3D integral equation solutions. The agreement between the integral equation solution and extended Born approximation is remarkable within the entire frequency range, but degrades with the increase of conductivity contrast between anomalous body and background medium. The extended Born approximation is accurate in the case conductivity contrast is lower than 1:10. Therefore, the location and conductivity of the anomalous body can be estimated effectively by the extended Born approximation although the quantitative estimate of conductivity is difficult for the case conductivity contrast is too high.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.179-183
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• 2002

The fragment in intron I of FSH-${\beta}$ gene was amplified by PCR. According to the polymorphism, we analyzed the distribution of FSH-${\beta}$ retroposon in different pig breeds; its inheritance pattern in Large White${\times}$Meishan reference family; and the association of FSH-${\beta}$ retroposon with litter size, female reproductive organs measurement, ultrasonic backfat and other traits. The results showed that almost each Chinese indigenous pig had the retroposon, while foreign pig breeds rarely had; the frequencies of porcine FSH-${\beta}$ retroposon were strongly associated with breeds (p<0.01); the pattern of inheritance was consistent with Mendelian fashion; total number born (TNB) and number born alive (NBA) were increased per FSH-${\beta}$ retroposon (p<0.01) with additive effects of 1.2-1.8 and 1.4-1.8 pigs/litter, respectively; between the FSH-${\beta}$ retroposon carriers and non-carriers, there was an insignificant difference in the measurement of female reproductive organs, body weight at birth, backfat thickness, loin meat height, lean meat percentage, teat number, days to 100 kg, and average daily gain.

• Journal of Embryo Transfer
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• v.12 no.1
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• pp.75-90
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• 1997

This study was carried out to establish the techniques for producing the calves of genetically superior Korean Native cattle by transfer of frozen-thawed embryos. The effects of some factors related to embryo recovery following superovulation and pregnancy rate following transfer of frozen-thawed embryos were evaluated. Also calving state was investigated. The results obtained were as follows ; The mean number of total and transferrable embryos recovered per superovulated cow was 8.72 and 4.90, respectively, from a total of 72 superovulations using 34 donor cows. There were no significant differences in the number of total or transferrable embryos recovered per superovulated cow between products of follicle stimulating hormone (FSH), years, seasons, and collection numbers. The pregnancy rate was found 44.44% following transfer of frozen-thawed embryos of Korean Native cattle to a total of 180 recipient cows including 82 Angus, 27 Charolais, 62 Hereford and 9 Korean Native cows. The pregnancy rate was significantly (P<0.05) higher in the transfer of excellent (42.99) and good embryos (40.17%), compared with fair (5.90%) grade embryos. And the pregnancy rate was significantly (P<0.05) higher in the transfer of embryos of morula stage (43.86%) than blastocyst stage (15.51%). But there were no significant differences in pregnancy rates between natural and induced estrus estrus asynchrony of 1 days, breeds, and parities of recipient cows. The normal calving rate of 80 pregnant cows following transfer of frozen4hawed em-bryos was 87.5% and the other 10 pregnant cows showed abortion during the period from pregnancy diagnosis at 50~60 days to calving. The average gestation length of normally delivered recipients was 288.50 days and the average birth weight of 70 calves born was 24.22 kg. The gestation length was significantly (P<0.05) shorter in the recipients delivering female calves (286.70 days) than males (289.39 days). But there were no significant differences in gestation tength and birth weight of calves born between the recipient breeds.

• Journal of Animal Science and Technology
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• v.60 no.5
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• pp.13.1-13.7
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• 2018

Background: The objective of this study was to underline that litter size as a key trait of sows needs new parameters to be evaluated and to target an individual optimum. Large individual variation in litter size affects both production and piglet's survival and health negatively. Therefore, two new traits were suggested and analyzed. Two data sets on 5509 purebred German Landrace sows and 3926 Large White and crossing sows including at least two parental generations and at least five parities were subjected to variance components analysis. Results: The new traits for evaluating litter size were derived from the individual numbers of total born piglets (TBP) per parity: In most cases, sows reach their maximum litter size in their fourth parity. Therefore, data from at least five parities were included. The first observable maximum and minimum of TBP, and the individual variation expressed by the range were targeted. Maximum of TBP being an observable trait in pig breeding and management yielded clearly higher heritability estimates ($h^2{\sim}0.3$) than those estimates predominantly reported so far. Maximum TBP gets closer to the genetic capacity for litter size than other litter traits. Minimum of TBP is positively correlated with the range of TBP ($r_p=0.48$, $r_g$ > 0.6). The correlation between maximum of TBP and its individually reached frequency was negative in both data sets ($r_p=-0.28$ and - 0.22, respectively). Estimated heritability coefficients for the range of TBP comprised a span of $h^2=0.06$ to 0.10. Conclusion: An optimum both for maximum and range of total born piglets in selecting sows is a way contributing to homogenous litters in order to improving the animal-related conditions both for piglets' welfare and economic management in pig.

• Korean Journal of Veterinary Research
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• v.30 no.3
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• pp.343-348
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• 1990

Total 51 calves born from both 28 seropositive and 23 seronegative dams were subjected to study both prenatal and postnatal infections of bovine leukemia virus (BLV), and the duration of passive colostral antibody by means of immunodiffusion (ID) test. All calves were tested for precolostral and postcolostral periods by 16 months of age. The results were as follows: 1. Of 28 precolostral sera of the calves born from infected dams, one appeared positive, indicating in utero BLV infection from the dam. 2. BLV-antibody test for the postcolostral sera of the calves born from seropositive or seronegative dams showed that the colostral antibody of the calves disappeared from 2 to 6 months of age, and the increase of the number of seropositive calves initiated from 3 to 4 months of age indicated postnatal infection.

• Journal of Family Relations
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• v.21 no.2
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• pp.129-147
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• 2016

Objective: This study examined the role of siblings with respect to living arrangements between married children and their parents. Previous studies have rarely considered the possibility that family context such as siblings may be associated with intergenerational residential proximity. Method: Using data from first wave of the Korean Longitudinal Study of Ageing (2006), I investigated if, among married children, their sibling characteristics may be associated with the probability of their coresiding with the parent(s), living nearby (within a 30-minute distance from parent(s) by public transportation), or living further away. Specifically, the total numbers of sisters and brothers, the numbers of siblings coresiding with the parent(s) and living nearby, their relative position in the sibling network (first-born son, later-born son, first-born daughter, later-born daughter), and sibship existence and gender configurations (only child, son with brother(s) only, son with sister(s) only, son with both brother(s) and sister(s), daughter with brother(s) only, daughter with sister(s) only, daughter with both brother(s) and sister(s)) were evaluated in the study. For data analysis, multinomial logit models with robust standard errors were estimated using the Stata mlogit procedure. Results: Results suggest that the probability of a married child living together with the parent(s), relative to living close by, was significantly higher the more sisters he or she has. Being a son, especially first-born son, was associated with a higher probability of intergenerational coresidence compared to near residence, respectively. Also, the numbers of siblings coresiding with the parent(s) and living in close proximity were linked to a higher risk of intergenerational coresidence and near residence. Supplementary analyses revealed that the last finding was held over and above the total number of siblings, their relative position in the sibling network, as well as sibling existence and gender configurations. Conclusion: Overall, the study findings indicate that sibling characteristics have significant impacts on intergenerational living arrangement. The influence of traditional patrilineal norm of intergenerational coresidence and a trend towards modified extended family have emerged when siblings characteristics are taken into consideration as determinants of intergenerational living arrangement.

• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.233-236
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• 2008

In recent years, Korea has experienced a steadily declining birth rate, which is a serious social problem in the country. Although living conditions have improved, the birth rates for low birth weight infants and preterm babies has increased because more and more women choose to give birth later in life and the social environment has changed. The rise in low birth weight infants may increase infant mortality rates and morbidity rates. However, the recent improvements in neonatal care has elevated the survival rate of low birth weight infants up to 90 percent and lowered the weight of the very low birth weight infants that can now be saved. In this study, we used dynamic population statistics from the Korea National Statistical Office, which represents the current trend of social stratification and the population of this period. We analyzed birth records for a seven-year period and studied the changes in the delivery rate of preterm and low birth weight infants and the problems related to those changes. The results show that the rate of low birth weight infants has increased from 3.79% to 4.35% for the past seven years. The rate of preterm babies rose from 3.79% to 4.89%. The number of babies born from mothers aged 35 or more went up from 6.69% to 11.83% of the total number of the babies born. As maternal age has risen, the risks of delivering a preterm or low birth weight infant have also increased.

• Korean Journal of Animal Reproduction
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• v.12 no.1
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• pp.15-19
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• 1988

This study was carried out to investigate the fertility and farrowing date in post-weaning sows using PG600 and inseminated with frozen semen. A total of 48 sows of Landrace, Large White and Duroc after 7-week lactation were used at the Chungnam Provincial Animal Breeding Station. The results obtained were summarized as follows: 1. Motility had no significant differences between the breeds, but NAR acrosome was highest in Landrace, followed by Duroc and Large White(p<.01). 2. Interval from weaning to estrus and length of estrus were, respectively, 3.7 days and 52.6hours of sows treated with PG600, and 6.5 days and 53.8 hours for control sows. The average interval from weaning to onset of estrus was significantly(p<.01) shorter by 2.8 days in PG600 treated sows compared to control sows. 3. In Landrace, Duroc and Large White, farrowing rate and number of pigs born alive per litter were 55.0%, 10.0; 43.8%, 8.1; and 16.7%, 3.5, respectively. Average pig weight at birth and survival rate at 56 days had no significant differences between the breeds. 4. Farrowing rate, number of pigs born alive per litter, average pig weight at birth and survival rate at 56 days were, respectivey, 45.8%, 101, 1.56kg and 94.5% for sows treated with PG600, and 37.5%, 7.0, 1.66kg and 93.8% for control sows. Sows treated with PG 600 had an average of 3.1 more pigs at farrowing compared to control sows.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.9
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• pp.1232-1236
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• 2002

Direct and service sire genetic parameters for total number of pigs born (TNB), number of pigs born alive (NBA), total pig weight at birth (TWB), and average pig birth weight (ABW) were estimated by DF-REML under a multiple trait animal model. Data on 3,078 litters of the Yorkshire from Jan, 1975 to Dec, 1998 at National Livestock Research Institute were obtained. The animal model included fixed contemporary group effects and random additive direct, service sire, and residual effects. Additive genetic relationships among animals were included. A separate relationship matrix for service sires and their sire was also included. Additive direct heritability estimates for TNB, NBA, TWB, and ABW were 0.19, 0.18, 0.25 and 0.39, respectively. Service sire heritability estimates for TNB, NBA, TWB, and ABW were 0.02, 0.01, 0.02 and 0.01, respectively. The genetic and phenotypic correlations of TNB with NBA estimated in this study were 0.81 and 0.81, respectively, and the genetic and phenotypic correlations of TNB with TWB estimated were 0.82 and 0.76, respectively. Results indicate that service sires account for 1 to 2% of the total variation for TNB, NBA, TWB, and ABW. Further investigation is needed to determine whether the service sire effect is primarily genetic or environmental.