• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.83-92
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• 2017

The purpose of this study was to estimate the inbreeding level and effective population size of Korean indigenous chickens. In the study, two variables were considered to evaluate the pedigree completeness: (1) the proportion (%) of animals with complete pedigree, and (2) the proportion of animals with inbreeding coefficients greater than zero. In the proportion of animals having complete pedigree, all strains reached almost 100% completeness in 1~2 years. In the proportion of animals with inbreeding coefficients greater than zero, all strains reached almost 100% completeness in 5~6 years. We considered that the pedigree recoding system is well managed and that the inbreeding coefficient is a reliable measure. Over the past 20 years, the increase of inbreeding coefficients in Korean indigenous chicken strains has been 7.6~10.9%. The S strain showed the most rapid increase of inbreeding coefficient of 8.2% in 10 years. The reason for this rapid increase is considered to be associated with the fact that the numbers of sires and dams involved in reproduction was 115 and 91, respectively, which are lower than those of the other strains. According to average rates of increase in inbreeding coefficients (${\Delta}F$), all strains have ${\Delta}F$ values of 0.39~0.85%, which is lower than 1%, and the effective population size is above 50. The results showed that inbreeding levels were within the acceptable range and that Korean indigenous chicken population scan be regarded as safe from the threat of extinction.

• Korean Journal of Agricultural Science
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• v.42 no.2
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• pp.141-149
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• 2015

The data of Duroc swine species that were born from 2000 to 2014 excluding missing ones collected by Korea National Institute of Animal Science were used in the present study. After removing missing data we used 9756 of productions data and 1728 of reproductive reference of breeding research to study the level of inbreeding and to investigate the impact on the reproductive traits, production traits. The correlation of reproductive traits and inbreeding coefficient are -0.07, -0.08 for total number pigs born, number of pigs born alive respectively and birth weight per litter is -0.10, number of pigs born alive per litter to 21days is -0.06 and body weight per litter to 21days is -0.09. The correlation coefficients of the inbreeding coefficients of reproductive traits are shown within 10% with negative correlation (P < 0.05). Days of 90kg and Backfat in the correlation coefficient and inbreeding coefficient production traits were not observed significant correlations, Average daily gain was investigated by the positive correlation of 0.05. According to the above results, the inbreeding level gave a negative effect on the improvement of the breed traits, investigating a relatively high compared to a negative effect on other traits. But overall correlation degree is less than 10% was observed. This inbreeding coefficient has not been clearly observed due to degeneration of the average inbreeding coefficients of these generations was maintained within 10% of the population. The scale of the experimental group was about 150 degree pig husbandry is very small compared to the advanced countries. However, the level of inbreeding in the population group with the appropriate mating combinations is maintained below 10% of population is thought to be small and can minimize the effects of inbreeding degeneration. further testing utilizing this selection is constantly considered to be necessary.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.297-302
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• 2011

This study was carried out to estimate average inbreeding coefficients, relatedness and effective population size of breeding bulls and to suggest optimal alternatives on problems of current Hanwoo improvement system. Data on proven and young bulls were obtained from 1,128 heads of Livestock Improvement Main Center from 1983 to 2008. Pedigree information on proven and young bulls was obtained from 3,760 heads of Korea Animal Improvement Association. Average inbreeding coefficients and average relatedness of proven and young bulls were estimated at the range of 0.04-0.07%, 0.10-6.82%, respectively. Effective population size was estimated for 220 heads from the average rate of inbreeding of last 26 years. Average inbreeding coefficient is rising rapidly for the last two years as well as average relatedness. Effective population size was estimated for 47 heads for the last five years. These results suggest that selection criteria of proven bulls should include not only genetic evaluation of carcass performance from progeny-test, but also inbreeding and relationship coefficients, in order to maintain genetic variability of Hanwoo. In addition, effective population size should be increased by increasing the number of proven bulls.

• 종축개량
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• v.12 no.9 s.79
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• pp.72-75
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• 2007

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.514-520
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• 2019

The reduction in performance due to inbreeding (i.e. inbreeding depression) has long been documented in plant and animal populations. The population of Korean native pigs are small and this breed is valuable in Korea.. This study was aimed to investigate effects of inbreeding depression on total number of piglets born (TNB) and number of piglets born alive (NBA) in Korean native pigs. We used 2,806 pedigree and 303 sows's data with 483 phenotypic records. After estimating genetic parameters for each traits, inbreeding depression was estimated using a mixed model in which the inbreeding coefficient was included as a covariate. Korean native pigs had high heritability for each traits. Inbreeding coefficient constantly increased from 1998 to 2017~2018 but there is no reduction for each traits in 2017~2018 in compared with those in 1998. Significant inbreeding depression was detected for TNB (p=0.03) but not for NBA (p=0.41). In addition there are significantly positive interactions between inbreeding coefficient and breeding value for both traits (p<0.05). These results suggest that Korean native pigs are still having genetic variation for TNB and NBA, which could overcome reproductive risks from inbreeding coefficient increase.

• Korean Journal of Agricultural Science
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• v.41 no.1
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• pp.41-46
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• 2014

The pedigree data of 86,639 heads from six major swine breeding farms were investigated to check levels of inbreeding and effective population size of breeding stocks. The average rate of inbreeding was 1.04%, 0.87%, 3.17%, 1.05%, 3.23% and 3.33% for farms A, B, C, D, E and F, respectively. The average inbreeding rate was highest for F farm and lowest for B farm. In farms D and E, there were quite large numbers of immigrant animals per generation compared to other farms. The effective population sizes calculated from the average rate of inbreeding were distributed between 83.0 and 814.8. Specific values were 282.3, 225.5, 83.0, 814.8, 302.9 and 175.7 for farms A, B, C, D, E and F, respectively. The results showed that there was no cause for concern over the current inbreeding level of major swine breeding farm populations and the inbreeding level was within an acceptable range. In addition, internal sharing rather than importing pig is necessary to strengthen seed sovereignty.

• The Korea Swine Journal
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• v.11 no.2 s.114
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• pp.133-135
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• 1989

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.367-371
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• 2013

This study was carried out to estimate the average inbreeding coefficients and effective population size (EPS) and to seek alternatives on the problems of Holstein cattle in Korea. The data used in this study was obtained from the Korean Animal Improvement Association (KAIA) and 635,268 heads of Holstein records out of 1,872,195 Holstein registration data were used for the analysis. The average inbreeding coefficients were estimated at a range of 0.11 to 1.07%. The average inbreeding coefficients at the $14^{th}$, $19^{th}$ and $22^{nd}$ generation were estimated at 0.43%, 0.92% and 1.07%, respectively. The estimated inbreeding coefficients within the range of 0%, 0 to 6.25%, 6.25 to 12.5%, 12.5 to 25%, and >25% were observed in 50.5%, 48.3%, 0.8%, 0.1%, and 0.3% of the animals, respectively. The estimated effective population size (EPS) was 619 heads from the $8^{th}$ to $22^{nd}$ generation, and 922 heads from the $19^{th}$ to $22^{nd}$ generation.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.507-518
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• 2002

A multiple-trait stochastic computer simulation model was constructed to predict the breeding schemes and selection methods on Hanwoo(Korean cattle). The model could be used four kinds of selection criteria (random, phenotype and true or estimated breeding values). At the test run in various population size for 20 years, all estimated parameters of the each simulated populations were resulted similar to input parameters. The deviations between input and output values of parameter in the large population were smaller than in the small population. The simulated results obtained from ten small populations consisted with one sire and ten dams in each population for 500 years were as follows; Inbreeding coefficients of population were similar to theoretical estimating function. Mean values of each traits selected were randomly drifted by generation, but they were converged into a value when inbreeding coefficients came close to one. Additive genetic variances within each population were reduced by generation, and they were converged into zero when inbreeding coefficients came close to one. These results indicated that the simulated populations hold to statistical properties of input parameters.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.107-116
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• 2016

The study was aimed to analyze pedigree structure and inbreeding coefficients for performance tested Holstein cows in Korea. A total of 400,029 Holstein cows data which born between 2002 and 2012 were obtained from Dairy Cattle Improvement Center of National Agricultural Cooperative Federation(NACF). Their related pedigrees, as obtained from Korean Animal Improvement Association(KAIA), consisted of 509,740 animals. Pedigree depth of the cows were traced back to 3 generations earlier. The percentage of cows with fully identified ancestors in various provinces of Korea were 55.18%(Gyeonggi-do), 23.49%(Gangwon-do), 47.83%(Chungcheongnam-do), 53.62%(Chungcheongbuk-do), 56.38%(Gyeongsangbuk-do), 51.35% (Gyeongsangnam-do), 26.58%(Jeollanam-do), 49.41%(Jeollabuk-do), and 56.90%(Jeju-do), whereas, it was about 63.20% as a whole in Korea. The average inbreeding coefficients showed increment across the consecutive years of birth such as, 0.43(2002), 0.44(2003), 0.58(2004), 0.64(2005), 0.78(2006), 0.93(2007), 1.08(2008), 1.23(2009), 1.46(2010), 1.77(2011), and 2.03 (2012). However, this coefficient was 0.93 in overall Korean population. An average generation interval for sire to daughter genetic path was 8.15 years; which was about 4.20 years considering dam to daughter genetic path. The estimated effective population sizes (Ne) were 56.5, 51.3, and 32.2 animals born in 2004, 2009, and 2012, respectively. These results indicated that an increased rate of inbreeding has led to a significant reduction in the Ne over the decade.