• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1411-1416
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• 2014

Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR) assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP) gene and sex-determining region Y (SRY) were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99%) comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05). The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90%) as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

• Korea journal of population studies
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• v.17 no.2
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• pp.77-97
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• 1994

Despite the fact that the national family planning program in korea has accomplished its primary goals of fertility reduction and universal contraceptive use, the induced abortion is still high and there has been an increasing trend in the population sex ratio at birth. It seems that the changes in the imbalance of sex ratio have originated from traditonal boy preference. This indicates that much of the current family planning program can be overhauled, so that the program quality could be better controlled, by preventing the number of unwanted pregnancies and the imbalance of sex ratios. This paper aims, therefore, to examine the determinants of induced abortion through the investigation of pregnancy outcomes and their changes over time and to study the interaction between induced abortion, boy preference and the imbalance of sex ratio in Korea. The abortion rate had increased rapidly until the mid-1980s when there were about the same number of abortions as live births. Thereafter, the abortion rate has been maintained at this high level. By parity it shows a much higher abortion rate for a higher parity at all time. From the first parity, the sex composition of previous children stands out as the most important factor in deciding the pregnancy outcome at all time. The probability of a pregnancy ending in an abortion increases substantially when parents already had a son. The decline of the desired family size and the sustained strong son preference has made the sex of children a more important factor in the determination of the pregnancy outcome. Women's education has had consistently positive effects on the probability of a pregnancy ending in an abortion, but the effect shows a steady decline over time. The premarital pregnancy and urban residence also increase the abortion probability. This study suggests that the main concerns of the family planning program should be to strengthen the social support policies so as to weaken the son preference value leading to a balanced sex ratio and prevention of induced abortions.

• Journal of Embryo Transfer
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• v.33 no.3
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• pp.169-175
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• 2018

It has been claimed that artificial insemination (AI) of cows with frozen-thawed semen treated with commercially produced kits, Wholemom (in favour of female gender) increases the birth chance of calves with desired sex ratio by approximately 85% without decrease of pregnancy rates. Hence, this study was conducted to investigate the efficacy of wholemom kits as combined with frozen-thawed bovine semen during in vitro fertilization on the in vitro fertilization and developmental efficiency and sex ratios such as some reproductive parameters in bovine. For this, 1,737 oocytes were in vitro fertilized and developed. Agglutination effects on bovine after treatment of Wholemom kit were observed by time passage and dose respectively. To determine sex of embryos, Bovine embryo Y-specific gene primers(ConEY) and Bovine specific universal primer(ConBV) were used as multiple PCR method. Fertilization rate of wholemom-treated group was significantly lower than its of control group[66.9% (1,156/1,737) in Wholemom-treated group; 75.0% (610/813) in control group]. However, developmental rate after fertilization of both wholemom-treated and control groups were not significantly different [26.1% (404/1,156) in Wholemom-treated group; 27.4% (224/610) in control group]. Sex ratio of in vitro fertilized embryo with frozen-thawed semen treated with wholemom kit was determined by multi PCR. Female ratio in wholemom-treated group [85.4% (173/201)] was significantly higher than its of control group [47.2% (66/141)]. In conclusion, wholemom treatments of semen used in the in vitro fertilization and development of bovine oocytes provided increase in female ratio with decrease of fertilization rate.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.702-710
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• 2017

Recently, in many reptiles (14 genera of turtles in five families), common characteristics of incubation temperatures are known to determine the sexes of hatchlings in many species of turtles, including the map turtles, painted turtles and snapping turtles, emys turtle, etc. According to many researcher's reports, in general, incubation at $25^{\circ}C$ (cooler temperatures) produces all or mostly males, however, incubation at $31^{\circ}C$ (higher temperatures) or higher produces all or mostly females. Exceptionally, even cooler temperature ($20^{\circ}C$) produce females, they produced all or mostly females. Accordingly, it is well-known that incubation temperature is the sex determining agent in these turtles. However, this paper presents study of the sex ratio and nest ecology in natural spawning nest: Observations on hatching sex ratios of eggs collected from natural nests of T. sinensis are similar to a previous report of the same genus Trionyx in the soft-shelled turtles. However, this genus (or species) showed some different phenomena to other kinds of turtles such as various kinds turtles mentioned above. After collection of naturally spawned eggs (17 eggs of T. sisnensis) on the natural nests, a laboratory experiment by the constant incubation temperatures was conducted with natural fluctuating soil temperatures in the natural nest with the soft-shelled turtle, T. sinensis. And also laboratory experiments were conducted using constant incubation temperatures of $25^{\circ}C$ (cooler temp.) and $30^{\circ}C$ (higher temp.) with the turtle, T. sinensis. Exceptionally, it was confirmed that the first and second incubation temperatures can't control sex-determination in the freshwater soft-shelled turtle, T. sinensis. The sex ratio approximated 1:1 (${\chi}^2=0.06$, P>0.05 (the Ist experiment). And the sex ratio approximated 1:1 independently of incubation temperature (${\chi}^2=0.33$, P>0.05 (the 2nd experiment). Consequently, temperature has no effect on sex determination in the genus Trionyx in a soft-shelled turtle.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.43-49
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• 2010

The effect of sex ratio on behavior and welfare indexes in broiler chickens was investigated. Five variants of the sex ratio (male to female), namely, 100:0 (T1), 75:25 (T2), 50:50 (T3), 25:75 (T4) and 0:100 (T5) were tested in broilers between the ages of 7 to 35 days. It was found that the most common behavior in all sex ratios was resting behavior, ranging over 74.4 % of total behavioral frequency. The ranges of other behavior traits of total behavior traits were as follows: pecking, 5.4 to 23.1 %; standing, 1.8 to 24.8 %, and moving, 0.6 to 11.5 %. The behavioral frequency of resting, pecking, standing and moving were not affected by the sex ratio and between male and female. But the percentage of pecking, resting and moving behavioral frequency was significantly different by the age of birds (P<0.05). Age of birds had no effect on standing behavioral frequency. It seems that gait, food pad and hock burn score were no affect by sex ratio but tend to decreased in female than male. Claw length of 21 and 35 days was not affected by sex ratio and between male and female. The duration of tonic immobility (TI- reaction) was tend to decreased age of 21 than 35 days, and female than male. Both male and female of the study, hock burn score, claw length and TI-reaction were tend to lower in T4 than other treatments. The results suggest that, when male and female broilers are reared together, sex ratio can influence broiler welfare indexes in this study.

• Journal of Service Research and Studies
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• v.4 no.1
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• pp.71-81
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• 2014

It is important for regional comparative analysis about economically active population ratio by sex and total economically active population ratio to a policy data of central and local government. Through the result of comparative analysis, Central and local government can use policies distinctively according to the region and keep the efficiency of detail policy application. This paper shows regional comparative analysis about economically active population ratio by sex for the Seoul metropolitan region, Gangwon region, Chungcheong region, Youngnam region, Honam region using the economically active population survey data in 16 cities and provinces. We used the survey of economically active population for 13 years from 2000 to 2012, we calculated total economically active population ratio and economically active population ratio by sex about the 5 regions. And we analyzed the relative ratio between economically active population ratio of male and female by each region, we also analyzed the results of regional comparative analysis by sex.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.375-376
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• 2000

Sex ratio of a population is a key factor to determine reproductive rate of the population. If the population has skewed sex ratio to the male, the population size may decline gradually at an area which it inhabits, and, furthermore, if a species plays an ecologically important role in its community (e.g., a keystone species in Paine, 1966), its potential reproductive rate will be to form a characterized community because community structure is strongly influenced by the abundance of the ecologically important species (Hughes, 1986). A number of workers (e.g., Bryan et al., 1986 in Nucella lapillus; Spence et al., 1990 in Thais haemastoma) suggested that high frequency and/or late stage of imposex might affect the female mortality and normal reproduction adversely. Consequently, the imposex could affect sex ratio of natural population of some neogastropod including thaisid species. (omitted)

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.182-184
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• 2005

We examined the sex ratio, and insemination rate of Parapenaeus fissuroides and Parapenaeus lanceolatus using samples collected near Cheju Island, Korea, in January 2005. Females were more numerous than males in both species, and based on the gonad color pattern, sex ratio, and insemination rate, the spawning period of these shrimps was determined to be during winter.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.111-122
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• 2012

The sex ratio and spatial structure of different sexes are major components that affect the reproductive success and population persistence of dioecious plants. The differential reproductive costs between male and female plants are often believed to cause a biased sex ratio and spatial segregation of the sexes through slower growth and/or lower female survivorship. In this study, we examined the sex ratio and spatial structure of one population of $Torreya$ $nucifera$ trees in Jeju Island, Korea. We also tested the effects of the current tending actions in relation to tree vitality. At the population level, the sex ratio of the 2,861 trees was significantly biased toward males; however, it also showed considerable variation among different diameter at breast height classes and across habitats according to terrain level (from upper to lower). In 1999, before tree management (tending) began, among the ecological traits examined, only climber coverage correlated with tree vitality. Intensive tending such as climber removal since 1999 clearly enhanced the vitality of the majority of trees, but its effects were more conspicuous in medium-sized trees than in small ones, in upper terrain trees than those in other terrains, and in females than in males. Both male tree domination in small and large trees and tending effects on females are likely to reflect the effects of female reproductive costs regarding growth and/or survivorship. Spatial segregation between males and females was not observed in $T.$ $nucifera$. Habitat heterogeneity created by the forest's rocky ground and its implications regarding sex ratios and spatial structure require further studies.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.363-370
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• 2015

Olive flounder, Paralichthys olivaceus is one of the most target fish for aquaculture and national stock enhancement program in Korea. In order to find more information about hatchery fish stocking for stock enhancement we investigated the sex ratio of wild-caught fish populations which were artificially released into wild seas. The recapture rate was 9.0% to 94.5% in studied areas. The proportion of sex ratio ranged from 7.8% to 64.6% in female and from 34.4% to 92.1% in male respectively. This result suggests that the sex ratio of wild populations might be effected by the released fish. So we need more careful stocking program of the fish to preserve the balance of the sex ratio in the wild population.