• Asian-Australasian Journal of Animal Sciences
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• v.33 no.10
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• pp.1544-1557
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• 2020

Objective: Genomic selection (GS) is becoming popular in animals' genetic development. We, therefore, investigated the single-step genomic best linear unbiased prediction (ssGBLUP) as tool for GS, and compared its efficacy with the traditional pedigree BLUP (pedBLUP) method. Methods: A total of 9,952 males born between 1997 and 2018 under Hanwoo proven-bull selection program was studied. We analyzed body weight at 12 months and carcass weight (kg), backfat thickness, eye muscle area, and marbling score traits. About 7,387 bulls were genotyped using Illumina 50K BeadChip Arrays. Multiple-trait animal model analyses were performed using BLUPF90 software programs. Breeding value accuracy was calculated using two methods: i) Pearson's correlation of genomic estimated breeding value (GEBV) with EBV of all animals (r_M1) and ii) correlation using inverse of coefficient matrix from the mixed-model equations (r_M2). Then, we compared these accuracies by overall population, info-type (PHEN, phenotyped-only; GEN, genotyped-only; and PH+GEN, phenotyped and genotyped), and bull-types (YBULL, young male calves; CBULL, young candidate bulls; and PBULL, proven bulls). Results: The r_M1 estimates in the study were between 0.90 and 0.96 among five traits. The r_M1 estimates varied slightly by population and info-type, but noticeably by bull-type for traits. Generally average r_M2 estimates were much smaller than r_M1 (pedBLUP, 0.40 to0.44; ssGBLUP, 0.41 to 0.45) at population level. However, r_M2 from both BLUP models varied noticeably across info-types and bull-types. The ssGBLUP estimates of r_M2 in PHEN, GEN, and PH+ GEN ranged between 0.51 and 0.63, 0.66 and 0.70, and 0.68 and 0.73, respectively. In YBULL, CBULL, and PBULL, the r_M2 estimates ranged between 0.54 and 0.57, 0.55 and 0.62, and 0.70 and 0.74, respectively. The pedBLUP based r_M2 estimates were also relatively lower than ssGBLUP estimates. At the population level, we found an increase in accuracy by 2.0% to 4.5% among traits. Traits in PHEN were least influenced by ssGBLUP (0% to 2.0%), whereas the highest positive changes were in GEN (8.1% to 10.7%). PH+GEN also showed 6.5% to 8.5% increase in accuracy by ssGBLUP. However, the highest improvements were found in bull-types (YBULL, 21% to 35.7%; CBULL, 3.3% to 9.3%; PBULL, 2.8% to 6.1%). Conclusion: A noticeable improvement by ssGBLUP was observed in this study. Findings of differential responses to ssGBLUP by various bulls could assist in better selection decision making as well. We, therefore, suggest that ssGBLUP could be used for GS in Hanwoo proven-bull evaluation program.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.7
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• pp.951-960
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• 2018

Hanwoo cattle are an important food source in Korea and their supply can have a major impact on meat availability for Korean consumers. The Hanwoo population was 1.8 million head in 2005 and gradually increased to 2.6 million in 2015. Per capita beef consumption has also increased, to 11.6 kg per year in 2015, and is expected to continue to increase. Because intramuscular fat percentage is a critical contributor to meat quality, Hanwoo cattle are fed a high-energy corn-based diet for long fattening periods. Long fed diet causes significant alterations in fat percentage in the loin muscle and other areas of the carcass. However, these long feeding periods increase feeding costs and beef prices. Recently, there has been increased Korean consumer demand for lean beef which has less fat, but is tender and priced more reasonably. These consumer demands on the Korean beef industry are driving differing beef production systems and also changes to the beef grading methodology. Korean government has made a significant investment to select bulls with favorable production traits using progeny testing. Progeny tested bull semen has been disseminated to all Hanwoo farmers. A beef traceability system has been employed for all cattle breeds in Korea since 2009. Hanwoo cattle are ear-marked with a 12-digit identification number from birth to slaughter. This number allows traceability of the management history of individual cattle, and also provides information to consumers. Traceability including management information such as herd, farm, year of birth, and carcass data can determine estimated breeding values of Hanwoo. For a sustainable Hanwoo industry, research scientists in Korea have attempted to develop feeds for efficient fattening periods and precision feeding systems based on genetic information for Hanwoo cattle. These initiatives aim to Korean consumer demands for beef and provide more precision management in beef production in Korea.

• Journal of Embryo Transfer
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• v.31 no.2
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• pp.109-116
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• 2016

The recovery of epididymal sperm in animals is considered as one of the important tools to preserve high value or endangered species. However, there are no appropriate castrating indicators such as months of age in bull, sperm morphology, and motility, particularly in young Korean native bull (Hanwoo). Therefore, this study aimed to investigate sperm number, morphology, and motility of sperm in the epididymis tail of young Hanwoo bulls at 8 and 15 months of age. After castration, epididymal tails were collected and minced with blades to recover sperm. In experiments 1 and 2, sperm number, morphology, and motility were examined. Total number of sperm and percentage of normal sperm from bulls at 8 months of age was lower than that of bulls at 15 months of age after collection (P<0.05). Percentage of abnormal head, tail, proximal cytoplasmic droplet, dead and damaged acrosome of sperm from bulls at 8 months of age were higher than those of bulls at 15 months of age (P<0.05). In experiment 3, sperm motility from bulls at 8 and 15 months of age were examined before freezing and after thawing. Frozen-thawed sperm at 8 months of age showed low total motility and motile sperm with ${\geq}25{\mu}m/sec$ compared to those at 15 months of age and commercially-used sperm (P<0.05). In conclusion, sperm derived from the epididymal tail of bulls at 8 months of age showed high abnormal morphology and poor motility, which are not adequate for AI and IVF. On the other hand, sperm derived from the epididymal tail of bulls at 15 months of age showed high normal morphology and motility.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1483-1503
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• 2011

To advance the effectiveness of the current Hanwoo improvement system, we developed a general simulation that compared a series of breeding schemes under realistic user circumstances. We call this system the Integrated General Model (IGM) and it allows users to control the breeding schemes and selection methods by manipulating the input parameters. The Current Hanwoo Performance and Progeny Test (CHPPT) scheme was simulated with a Modified Hanwoo Performance and Progeny Test (MHPPT) scheme using a Hanwoo Breeding Farm cow population of the Livestock Improvement Main Center (LOMC) of the National Agricultural Cooperatives Federation (NACF). To compare the two schemes, a new method, the Simple Hanwoo Performance Test (SHPT), which uses ultrasound technology for measuring the carcass traits of live animals, was developed. These three models, including the CHPPT, incorporated three types of selection criteria: phenotype (PH), true breeding value (TBV), and estimated breeding value (EBV). The simulation was scheduled to mimic an actual Hanwoo breeding program; thus, the simulation was run to include the years 1983-2020 for each breeding method and was replicated 10 times. The parameters for simulation were derived from the literature. Approximately 642,000 animals were simulated per replication for the CHPPT scheme; 129,000 animals were simulated for the MHPPT scheme and 112,000 animals for the SHPT scheme. Throughout the 38-year simulation, all estimated parameters of each simulated population, regardless of population size, showed results similar to the input parameters. The deviations between input and output values for the parameters in the large populations were statistically acceptable. In this study, we integrated three simulated models, including the CHPPT, in an attempt to achieve the greatest genetic gains within major economic traits including body weight at 12 months of age (BW12), body weight at 24 months of age (BW24), average daily gain from 6 to 12 months (ADG), carcass weight (CWT), carcass longissimus muscle area (CLMA), carcass marbling score (CMS), ultrasound scanned longissimus muscle area (ULMA), and ultrasound scanned marbling score (UMS).

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.741-747
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• 2016

The aim of study was to estimate genetic parameter of carcass traits in commercial Hanwoo steer using national animal model for selection of superior bull. Analyzed data (n=5,843) on carcass traits was collected from 107,020 Hanwoo steer. The animal model was used to estimate heritability and genetic correlations. The estimated heritability of carcass traits were 0.19, 0.17, 0.20 and 0.23 for carcass weight, eye muscle area, backfat thickness and marbling score, respectively. The estimated heritability for carcass traits in commercial Hanwoo are low than estimated heritability of national progeny test population for selection of superior bull because breeding environment, genetic performance of cow and feeding day was different. Therefore, we suggests that animal model can include practical genetic variable based on national animal model to improve genetic performance in commercial Hanwoo.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1205-1215
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• 2012

This study was conducted to establish genetic criteria for phenotypic characteristics of Hanwoo cattle based on allele frequencies and genetic variance analysis using microsatellite markers. Analysis of the genetic diversity among 399 Hanwoo cattle classified according to nose pigmentation and coat color was carried out using 22 microsatellite markers. The results revealed that the INRA035 locus was associated with the highest $F_{is}$ (0.536). Given that the $F_{is}$ value for the Hanwoo INRA035 population ranged from 0.533 (white) to 1.000 (white spotted), this finding was consistent with the loci being fixed in Hanwoo cattle. Expected heterozygosities of the Hanwoo groups classified by coat colors and degree of nose pigmentation ranged from $0.689{\pm}0.023$ (Holstein) to $0.743{\pm}0.021$ (nose pigmentation level of d). Normal Hanwoo and animals with a mixed white coat showed the closest relationship because the lowest $D_A$ value was observed between these groups. However, a pair-wise differentiation test of $F_{st}$ showed no significant difference among the Hanwoo groups classified by coat color and degree of nose pigmentation (p<0.01). Moreover, results of the neighbor-joining tree based on a $D_A$ genetic distance matrix within 399 Hanwoo individuals and principal component analyses confirmed that different groups of cattle with mixed coat color and nose pigmentation formed other specific groups representing Hanwoo genetic and phenotypic characteristics. The results of this study support a relaxation of policies regulating bull selection or animal registration in an effort to minimize financial loss, and could provide basic information that can be used for establishing criteria to classify Hanwoo phenotypes.

• Journal of Animal Science and Technology
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• v.52 no.2
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• pp.83-90
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• 2010

Hanwoo proven bulls have been selected since 1987 and consequently contributed to farmers for the improvement of beef cattle in Korea. The demand for the quality beef production as well as higher production efficiency was erupted after early 2000 as relatively cheap imported beef released. Therefore the pressure on the reformation of selection index for Hanwoo proven bulls have been piled up to furnish with Hanwoo's competitive. A total of 734 progeny test data were analyzed to select traits and their weights in the selection index to meet the beef market requirement. Regression analysis with stepwise selection method was used to select proper trait and its weight for selection index. A series of computer simulation was carried out to compare the currently using selection index with the alternate two selection indices proposed in this study. New selection index using standardized breeding values of Loin eye Muscle Area (LMA), Backfat Thickness (BFT) and Marbling Score (MS) with weight ratio 1:-1:6 was proposed. Results showed higher performance in improving MS and BFT gain by 22% and 31% still holding 86%~89% of genetic gain achieved by current index in Carcass Weight (CW) and LMA when new selection index was fitted. Because, new index has little consideration for production cost, further research should be performed to build selection index including cost and income simultaneously.

• 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.

• Journal of Animal Science and Technology
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• v.45 no.4
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• pp.517-522
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• 2003

Scrotal measurements and semen production records of 19,742 during 7 years from 63 Hanwoo breeding bulls(6${\sim}$7 years of age) were used to determined the relationship between scrotal circumference(SC) and semen production including concentration and total number of sperm. The average of SC is 41.2$\pm$4.54cm; extreme ranges between a low of 34cm to a high of 48cm. Quantity of semen, concentration and total number of sperm are 5.47$\pm$0.89ml/ejaculation, 16.16${\pm}2.78{\times}10^8$/ml and 88.47${\pm}15.24{\times}10^8$/ejaculation, respectively. SC is positively correlated with semen production(0.14 with quantity of semen and 0.15 with total number of sperm). Reproduction data from 16 breeding bulls produced 1,289 offspring from spring 1993 to spring 2000 to examined relationship between SC and reproduction. Rate of fertility and delivery are 0.80$\pm$0.13 and 0.78$\pm$0.15, respectively. Also, SC is positively correlated with delivery rate(r=0.26) and favorably related to fertility rate(r=0.39). These results, that is, - SC correlates positively with semen production and with reproduction -, suggested that SC should be considered when selecting breeding bull.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.623-633
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• 2016

A total of 6,973 steer growth records of Hanwoo breeding bull's progeny test data collected from 1989 to 2015 were analyzed to identify the most appropriate growth curve among three growth curve models (Gompertz, Logistic and von Bertalanffy). The Gompertz growth curve model equation was $W_t=990.5e^{{-2.7479e}^{-0.00241t}}$, the Logistic growth curve model equation was $W_t=772(1+8.3314e^{-0.00475t})^{-1}$, and the von Bertalanffy growth curve model equation was $W_t=1,196.4(1-0.646e^{-0.00162t})^3$. The Gompertz model parameters A, b, and k were estimated to be $990.5{\pm}10.27$, $2.7479{\pm}0.0068$, and $0.00241{\pm}0.000028$, respectively. The inflection point age was estimated to be 421 days and the weight of inflection point was 365.3 kg. The Logistic model parameters A, b, and k were estimated to be $772.0{\pm}4.12$, $8.3314{\pm}0.0453$, and $0.00475{\pm}0.000033$, respectively. The inflection point age was estimated to be 445 days and the weight of inflection point was 385.0 kg. The von Bertalanffy model parameters A, b, and k were estimated to be $1196.4{\pm}18.39$, $0.646{\pm}0.0010$, and $0.00162{\pm}0.000027$, respectively. The inflection point age was estimated to be 405 days and the weight of inflection point was 352.0 kg. Mature body weight of the von Bertalanffy model was 1196.4 kg, the Gompertz model was 990.5 kg, and the Logistic model was 772.0 kg. The difference between actual and estimated weights was similar in the Logistic model and the von Bertalanffy model. The difference between market weight and estimated market weight was the lowest in the Gompertz model. The growth curve using the von Bertalanffy model showed the lowest mean square error.