• Journal of Embryo Transfer
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• v.28 no.2
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• pp.87-93
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• 2013

The efficiency of artificial insemination (AI) for horses remains unsatisfactory. It is mainly because each process of AI causes a detrimental effect on semen quality. To sustain quality of semen properly, several factors including libido of stallions and sperm damage during sperm processing and preservation should be considered. Stallions with decent libido produce a high ratio of sperm to seminal plasma in their ejaculates, which is the ideal semen composition for maintaining sperm quality. Thus, to maximize the fertility rate upon AI, stallions should be appropriately managed to enhance their libido. Seminal plasma should have a positive effect on horse fertility in the case of natural breeding, whereas the effects of seminal plasma on both sperm viability and quality in the context of AI remain controversial. Centrifugation of semen is performed during semen processing to remove seminal plasma and to isolate fine quality sperm from semen. However, the centrifugation process can also result in sperm loss and damage. To solve this problem, several different centrifugation techniques such as Cushion Fluid along with dual and single Androcoll-E$^{TM}$ were developed to minimize loss of sperm and to damage at the bottom of the pellet. Most recently, a new technique without centrifugation was developed with the purpose of separating sperm from semen. AI techniques have been advanced to deliver sperm to optimal region of female reproductive tract at perfect timing. Recombinant equine luteinizing hormone (reLH) and low dose insemination techniques have been developed to maximize both fertility rate and the efficiency of AI. Horse breeders should consider that the entire AI procedure should be optimized for each stallion due to variation in individual horses for a uniformed AI protocol.

• Journal of Sericultural and Entomological Science
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• v.44 no.1
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• pp.9-12
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• 2002

The agronomic characteristics and fertility of Morus tiliaefolia growing wild in Korean peninsula are as follows. The possibility of seed formation is 46∼80% and that of germination is 19∼28%. The height period of making flower is April 4-May 3, it means that is later than Morus bombycis, faster than Kaeryangppong. Green tip sprouting stage in spring is April 21∼24. This is later than Morus bombycis and faster than Kaeryangppong. The leaf has very big width and the ratio of leaf length to leaf width is 1.05. The thickness of leaf is thicker than Morous bombycis. There are a lot of matter of soluble nitrogen free, crude ash, and are little crude protein, crude fat and crude fiber in chemical contents of maturation leaf. The attitude of low cutting is spread out type and the branch is long type. The internord length is long. It is weak against cold and die-back.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.653-665
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• 2009

All the policies and plans need to be carried out at the proper times in order that they would work properly for what they are made for. It is will known that statistics are one of the most useful tools in deciding the proper times for the policies. In this paper we show how to use statistics in evaluating the policies already carried with respect to the time when they were executed in dealing with the population policy we had in 1983 when the total fertility rate hit the population replacement level 2.1. Two methods have been tried to show that the policy carried in 1983 missed the proper changing time. The one is to make forecasting only with the data possible before 1982 and show how close they can be to the real situation of today. The other is to show what would happen if the policies aiming to suppress population growth had been changed or abandoned. Both results from two methods give some quantified information about the population policy of 1983. Especially the prediction tells that we could have forecasted the problem of low fertility of this century in 1983.

• Korea journal of population studies
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• v.29 no.1
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• pp.241-268
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• 2006

This study aim to examine the optimum population in Korea, which has the lowest fertility rate in the world. This study has significance because this rapid decline in the fertility rate is expected to bring the decrease of the population and unbalance in the population composition in Korea. From the social welfare perspective, the optimum population is guided by maximization of the social welfare level per person or the social welfare level in a society. The optimum population can be defined as follows: The proportion of older adults 65 and over is 15-17%, the proportion of work force is 64-69%, the index of aging is 72-104. Within the current population and population composition, the optimum population is estimated as 4.85-4.95 million. These findings imply that we need to remove causes of low fertility rate and prepare for policies encouraging immigration of labor force from foreign countries. In addition, policies and programs where children can be grown up in good environments and women and older adults can participate in labor force should be established.

• Journal of Society of Preventive Korean Medicine
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• v.25 no.3
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• pp.117-124
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• 2021

Objectives : The purpose of this study is to analyze the factors affecting the enactment of local municipalities' ordinance for supporting Korean Medicine infertility treatment in the metropolitan area. Methods : For Seoul, Incheon, and Gyeonggi Province, data on the enactment of Korean Medicine infertility treatment and socio-demographic data of the local municipalities were collected through the Enhanced Local laws and regulations Information System and on-line statistical database. Logistic regression analysis was performed to analyze the factors affecting the enactment of the ordinance, The enactment of the ordinance was dependent variable, and the budgeting of local municipalities, the number of population, the number of births, the number of Korean Medicine doctors, and the total fertility rate were used as independent variables. Results : Up to 2000, the ordinances for supporting Korean Medicine infertility treatment were enacted in 16 local municipalities and the budget for that was supported by 18 local municipalities. Regarding the effect on the enactment of the ordinances, it was found that budgeting of Korean Medicine infertility treatment had a positive (+) effect, and the metropolitan government's budgeting and the total fertility rate had a negative (-) effect. Conclusions : This study suggests that the ordinance for Korean Medicine infertility treatment is a policy tool derived based on the problem of low fertility faced by each local municipality rather than the political influence of health provider's groups.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.605-611
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• 2015

A synthetic strain of ducks (Anas platyrhynchos) was developed by introducing genes for long duration of fertility to be used as mother of mule ducklings and a seven-generation selection experiment was conducted to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. Reciprocal crossbreeding between Brown Tsaiya LRI-2 (with long duration of fertility) and Pekin L-201 (with white plumage mule ducklings) ducks produced the G0. Then G1 were intercrossed to produce G2 and so on for the following generations. Each female duck was inseminated 3 times, at 26, 29, and 32 weeks of age. The eggs were collected for 14 days from day 2 after AI. Individual data regarding the number of incubated eggs (Ie), the number of fertile eggs at candling at day 7 of incubation (F), the total number of dead embryos (M), the maximum duration of fertility (Dm) and the number of hatched mule ducklings (H) with plumage colour were recorded. The selection criterion was the breeding values of the best linear unbiased prediction animal model for F. The results show high percentage of exhibited heterosis in G2 for traits to improve (19.1% for F and 12.9% for H); F with a value of 5.92 (vs 3.74 in the Pekin L-201) was improved in the G2. Heritabilities were found to be low for Ie ($h^2=0.07{\pm}0.03$) and M ($h^2=0.07{\pm}0.01$), moderately low for Dm ($h^2=0.13{\pm}0.02$), of medium values for H ($h^2=0.20{\pm}0.03$) and F ($h^2=0.23{\pm}0.03$). High and favourable genetic correlations existed between F and Dm ($r_g=0.93$), between F and H ($r_g=0.97$) and between Dm and H ($r_g=0.90$). The selection experiment showed a positive trend for phenotypic values of F (6.38 fertile eggs in G10 of synthetic strain vs 5.59 eggs in G4, and 3.74 eggs in Pekin L-201), with correlated response for increasing H (5.73 ducklings in G10 vs 4.86 in G4, and 3.09 ducklings in Pekin L-201) and maximum duration of the fertile period without increasing the embryo mortality rate. The average predicted genetic response for F was 40% of genetic standard deviation per generation of selection. The mule ducklings' feather colour also was improved. It was concluded that this study provided results for a better understanding of the genetics of the duration of fertility traits in the common female duck bred for mule and that the selection of a synthetic strain was effective method of improvement.

• Journal of the korean veterinary medical association
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• v.21 no.9
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• pp.533-540
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• 1985

Thirty-hundred and SIX gilts and sows that had culled at breeding period were obtained in 1982 and 1983 from Chonnam swine growers for a study of cause of low fertility in comparisons between gilt and sow. The total percentage of reproductive. failure was

• Journal of Family Resource Management and Policy Review
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• v.19 no.2
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• pp.27-49
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• 2015

The purpose of this study is to identify poorly understood factors related to the recent rapid decline in fertility in Korean society. Along with Becker's child demand theory, personal psychological traits, such as independence, nurturance, and affiliation, were given special attention in this study. We examine the processes of resource transfers between married women and their parents on childbearing intention in order to verify the effects of both factors. Five hundred and seventy-six women in their early stage of marriage from the 2009 wave of the National Survey of Marriage and Childbirth were analyzed. Main results of the study are as follows. First, Becker's child demand theory is not supported. Instead, the women who were not given economic support from their parents in getting a residence at the time of their wedding turned out to be more willing to have a child, potentially because they were more independent. Second, the women who provided caretaking and emotional support to their parents had higher childbearing intentions, potentially because they were more nurturing. In conclusion, these personal psychological variables are important in understanding the childbearing behavior of women. We suggest that the government should pay more attention to the micro-personal factors raised in this study when executing policies to reverse the current trend of low fertility.

• The Korean Journal of Community Living Science
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• v.17 no.1
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• pp.23-37
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• 2006

As the fertility rate of Korea has recently decreased to the lowest level in the world, the recognition of the needs for social support for the child-care has been increased. This resulted in the announcement of National Policy of Child-Rearing Support in 2004. This study attempted to propose the activation of the family child-care for the preparation of the introduction of the National Policy of Child-Rearing Support. Using literature review and interview, the following research questions were addressed. Firstly, the actual situation of the family child-care was compared with that of the other types of child-care. Secondly, the policies of child-rearing support and the family child-care systems in other countries such as United Kingdom, Sweden and Japan were introduced. Finally, activations of the family child-care were discussed in terms of the introduction of the National Policy of Child-Rearing Support. The results of this study implies that the family child-care in Korea is different from that of other countries as well as other types of child-care in Korea. Also, it suggests that key factors of the activation of the family child-care in Korea are to identify as the small, informal and family-like child-care, to differentiate as the infant-care and non-standard time child-care from other types of child-care, and to increase the level of professionalization. In conclusion, family child-care should become an alternative for the low fertility problem.

• Human Ecology Research
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• v.57 no.3
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• pp.353-367
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• 2019

This study investigates the influence of family-friendly workplace policies and organizational culture on the willingness of married female managers to have a child. The analysis includes 353 married female managers from the $6^{th}$ survey of the 2016 Korean Women Manager Panel. Factors that are found to influence the respondents include age, education, number of children, job position, promotional goals, accessibility to family leave, accessibility to shorter work hours during the child-rearing period, and organizational culture. Female managers who can easily use family leave or who have shorter work hours during the child-rearing period show a higher willingness to have a child. By contrast, those whose work places employ a fair and horizontal organizational culture are less willing to have a child. The introduction of family-friendly policies are not found to be statistically significant determinants of female managers' willingness to have a child. We find that influencing family-friendly policies between the first and second childbirth differ. The accessibility of family-friendly policies that affect the willingness of female managers to have a child when they have no child include parental leave, employer-supported childcare, and childcare subsidies. For improving their willingness to have a second child, accessibility to both family leave and shorter work hours during the child-rearing period are effective. In conclusion, the government should strongly consider micro-personal factors, such as family-friendly workplace practices and organizational culture, when executing policies to reverse the current trend of low fertility.