• 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 Preventive Medicine and Public Health
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• v.9 no.1
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• pp.153-158
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• 1976

It is clearly defined through a number of authoritative studies that the age of menarche influenced by the various combined factocs such as nutrition status, physical status, physical growth and development status, socio-economic status, locality, culture, education level, climate, race heredity etc. In order to obtain statistical data regarding the menarche of Korean school girls, anthers investigated on 4207 middle school girls and 703 woman college students in Seoul and Teagu during the period of September 10 to 30, 1973 and the result are summarized as followings; 1. The rates of menses experience by years were 18.2% in the age group of 12 years girls, 31.9% in 13 years, 64.6% in 14 years, 89.8% in 15 years, 98.1% in 16 years respectvely. 2. The average age of menarche for the 2504 school girls who were born during the yrar of 1957-1961 is 13.4 years with the rang of 9 years to 16 years. And the most frequent age of menarche is 13 years. 3. The average age of menarche for the 703 woman college students who were born during the year of 1950-1954 is 14.3 years with the rang of 9 years to 18 years. And the most frequent age if menarche is 13 years. 4. The appearence of menarche is most common in August (20.7%) for the group who were born during the year of 1957-1961 and most rear in November (4.2%). And it is also most common in August (19.9%) for the group who were born puring the year of 1950-1954 but most rear in June (3.4%).

• 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.

• Journal of agricultural medicine and community health
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• v.3 no.1
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• pp.10-17
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• 1978

There are numerous reports on menarche age in korea and other countries but only few reports are available on menopausal age. This is a result of surveys on 509 women for menarche and 341 women for manopause among the rural areas of Choongnam and Kyungbuk province. For those born between 1894 and 1929. aver age ageof menarche was 16.63 years. The earliest was 13 years and latest was 22 years old. Majority (78.8%) had their menarohe at the age of between 15 and 18. It was noted that there was gradual advancement of menarche age among those born in later years than earlier. More menarche started in the months of October and April and fewest was in the month of June. Spring was the time when the largest number of women had menarche and this was followed by Autumn. Winter, and Summer. The most common menstrual cycle was 39 days type which is followed by 28 days and 26 days. The average monpausal age among rural korean women was 46.97 years. The number of years between menarche and menopause appears to be dependent upon individual physical and mental condition. socioeconomical circumstances. and also hereditary as well as ethnic differences. 87.1 % of rural korean women had menstrual ages of between 20 to 35 years according to this statistics and the average was 29.67 years.

• 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.

• 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.

• Korean Journal of Child Studies
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• v.23 no.3
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• pp.139-148
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• 2002

This study examined differences in children's social competence by number, birth order, and sibling relation types. The subjects were 489 three- to five-year old boys and girls enrolled in 4 kindergartens in Seoul and Gyeonggi Province. Instruments were the California Preschool Social Competency Scale and a questionnaire for the home environmental variables. Data were analyzed by ANCOVA, Tukey test and Cronbach ${\alpha}$. The major findings were that siblings' social competence was higher than only children, first-born children's social competence was higher than the later born, and older brother's social competence was higher than younger brothers and sisters.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1358-1362
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• 2017

Objective: The objective of the present study was to compare growth performance of Berkshire purebred pigs (BB), Hereford (HB) and/or Tamworth (TB) sired Berkshire crossbred pigs reared in a hoop structure in two experiments. Methods: In the first experiment, BB was compared to TB while HB and TB were compared in the second. Body weights (BW) were recorded at 3 days of age and every 28 days from birth until 140 days of age. There was no significant difference between the BW of BB and TB, but HB was heavier than TB by 84 days of age. Least square means of average daily gain (ADG) were evaluated using one-way analysis of variance. Results: The mean parity (${\pm}$standard deviation) of the sows was $3.42{\pm}2.14$ and a total of 45 farrowing occurred from year 2012 to 2014. The mean number of total born, number born alive, number of mummies, and number weaned were $9.23{\pm}2.52$, $7.87{\pm}2.53$, $0.04{\pm}0.21$, and $5.94{\pm}2.74$, respectively. Parity did not have a significant effect on the growth performance of the pigs. For BB and TB, there was only one time frame in which there was a significant difference in the ADG: between 28 and 56 days of age. For HB and TB, the overall ADG of HB was significantly greater than the total ADG of TB. Conclusion: The breed of the sire did not affect the growth performance of the progeny between Berkshire purebreds and Tamworth${\times}$Berkshire crossbreds. The breed of the sire did have an effect between Hereford and Tamworth sired Berkshire crossbreds (p<0.05). The Hereford sired pigs were found to have increased growth performance compared to Tamworth sired.

• Korean Journal of Animal Reproduction
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• v.11 no.3
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• pp.223-229
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• 1987

This study was carried out to investigate effects of superovulation and time of embryo recovery on ovarian response, recovery rate and developmental stage of embryo in donor and effects of methods of synchronization, number of corpus luteum (CL), stage of embryo and time of embryo transfer on ovarian response, conception rate and number of newborn in recipients which were transferred on 2.5, 3.5 and 4.5 days after synchronization. The results obtained are as follows; 1. The ovulation point of superovulated donor on 2.5, 3.5 and 4.5 days after copulation was 23.3, 35.3 and 23.3, respectively. The number of embryos recovered from the donors on 2.5, 3.5 and 4.5 days after copulation was 23.3, 25.8 and 19.8, respectively. The ovulation point and number of embryos recovered on 3.5 days were greater than those of 2.5 and 4.5 days. Among 232 embryos recovered on 3.5 days after copulation, 84 were blastocyst and 62 were hatching blastocyst. 2. The number of CL in recipients on 2.5, 3.5 and 4.5 days after synchronization was 3.2, 2.9 and 3.8 and showed no difference among the days. 3. When the number of CL was 0, 2-3, 4-6 and more than 7 the pregnancy raet of recipients was 0, 37.5, 66.7 and 75%, respectively. The pregnancy rate of recipients increased as the number of CL increased. 4. The pregnancy rate of transferred morula, blastocyst and hatching blastocyst was 32.0, 37.2 and 24.7%, respectively. The blastocyst nhowed highest pregnancy rate. 5. When the recipients were synchronized by HCG, the number of CL, unruptured follicle, hemorrhage, pregnancy rate and number of young were 5.5, 6.4, 3.3, 72.7% and 3.3, whereas that of GnRH were 2.3, 4.4, 2.8, 25.0% and 1.2, respectively. Recipients synchronized by HCG showed better results than GnRH. 6. When the embryos were collected on 2.5 days after copulation and transferred to the synchromized recipients, the pregnancy rate and the number of young born was 62.58% and 3.1, respectively. Those of 3.5 and 4.5 days after copulation was 57.1% and 1.3, and 37.5% and 1.6. The 2.5 days showed higher pregnancy rate and number of young born than 3.5 and 4.5 days.

• Animal Bioscience
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• v.37 no.2
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• pp.184-192
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• 2024

Objective: This study aims to investigate the genetic structure and characteristics of the Angus cattle population in Hungary. The survey was performed with the assistance of the Hungarian Hereford, Angus, Galloway Association (HHAGA). Methods: Genetic parameters of 1,369 animals from 16 Angus herds were analyzed using the genotyping results of 12 microsatellite markers with the aid of PowerMarker, Genalex, GDA-NT2021, and STRUCTURE software. Genotyping of DNA was performed using an automated genetic analyzer. Based on pairwise identity by state values of animals, the Python networkx 2.3 library was used for network analysis of the breed and to identify the central animals. Results: The observed numbers of alleles on the 12 loci under investigation ranged from 11 to 18. The average effective number of alleles was 3.201. The overall expected heterozygosity was 0.659 and the observed heterozygosity was 0.710. Four groups were detected among the 16 Angus herds. The breeders' information validated the grouping results and facilitated the comparison of birth weight, age at first calving, number of calves born and productive lifespan data between the four groups, revealing significant differences. We identified the central animals/herd of the Angus population in Hungary. The match of our group descriptions with the phenotypic data provided by the breeders further underscores the value of cooperation between breeders and researchers. Conclusion: The observation that significant differences in the measured traits occurred among the identified groups paves the way to further enhancement of breeding efficiency. Our findings have the potential to aid the development of new breeding strategies and help breeders keep the Angus populations in Hungary under genetic supervision. Based on our results the efficient use of an upcoming genomic selection can, in some cases, significantly improve birth weight, age at first calving, number of calves born and the productive lifespan of animals.