• Journal of Embryo Transfer
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• v.29 no.3
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• pp.289-296
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• 2014

The pedigree information and race records of 1,000 m finishing time of Jeju race horses at KRA were used to study the effect of amount of pedigree information and parental misidentification on the estimates of genetic parameters. The modified data sets were made at the range of 2.5 to 25% parental misidentifications or loss of parental information of individuals with an increment of 2.5 percent. For each incremental level, 20 randomly replicated data sets were obtained and analyzed by single-trait analysis with a DF-REML(AI) algorithm. As the rate of misidentification increased or the amount of pedigree information decreased, the estimates of fraction of additive genetics variance component gradually decreased almost linearly (p<0.05), while the estimated fractions of error variance and permanent environmental variance components gradually increased for the finishing time. Regression coefficients of the percentage amount of both parents' information loss and incorrect pedigree information on additive genetic variances were -0.079 and -0.114, respectively (p<0.01). The estimate of heritability decreased by 0.92% for one percent loss of both parents' information and 1.39% for one percent increase of both parental misidentifications of progeny (p<0.01). For the consideration of probable incorrect and missing parent information of progeny in this early population of Jeju horses, the estimates of additive genetic parameters would be biased downward about ten percent. This results indicate that the amount of pedigree information loss and misidentification of progeny would severely affect estimates of genetic parameters and would reduce genetic gains for selection in Jeju horse population.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.309-314
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• 2008

The objective of this study was to estimate effects of the condition of racetrack on racing time in Thoroughbred racehorses, using 148,865 racing records for 8,189 heads that collected from KRA(Korea Racing Association). The results obtained were as follows. Based on moisture contents, the condition of racetrack was classified into Heavy, Good, Soft, Yielding and Sloppy. The condition of racetrack for last 12 years was 40.7%, 34.4%, 14.4%, 8.7% and 1.8% for Heavy, Good, Soft, Yielding and Sloppy, respectively. The frequency of heavy condition for racetrack was the highest and those of Yielding and Sloppy were relatively low. On the other hand, the frequency of heavy condition for racetrack was increased in spring and winter, whereas frequency of sloppy racetrack was increased in summer. The frequency of good condition was the highest in autumn. The regression coefficients of moisture contents in racetrack for racing time by racing distance ranged from －0.068~－0.162 seconds and the racing time was faster in sloppy condition than other track conditions. The time differences between Heavy and Sloppy ranged from －1.47~－3.41 seconds by distance.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.125-132
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• 2015

The report about equine anesthesias in Korea are very rare. This paper aimed at the mortality rate during anesthesia in Thoroughbred horses at Equine Hospital of Busan Race Park, KRA in South Korea from 2005 to 2010. Drugs used in anesthesia was IV injection of detomidine hydrochloride (0.01 mg/kg) or xylazine(0.5mg/kg) for sedation and premedication, Guaifenesin(50-100 mg/kg) for muscle relaxation, ketamine hydrochloride(2 mg/kg) for induction of anaesthesia and Inhalational isoflurane(1.3-1.5 %) to maintain anesthesia. Total number of anesthetic cases was 190, 150 of inhalational anesthesia and 40 of general anesthesia, repectively. The purpose of anesthesia was highest in the disorder of musculoskeletal system, followed by urogenital system and respiratory system Mortality case due to anesthesia was one during arthroscopic surgery for removal of osteochondral chip fragments. The time of anesthesia was 150 min, fatal sign was hypoxemia and the reason was improper machine operation of the anesthetist. In conclusion, the perianesthetic mortality rate during anesthesia in Thoroughbred horses at Busan Race Park was 0.52%(1 death per 190 anesthetics).

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.391-398
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• 2002

This study was conducted to determine the polymorphism of transferrin exons 13, 15 and 16 by Single-Strand Conformation Polymorphism(SSCP) analysis and to compare their genotypes of Cheju horse Group I (Cheju Institute), Cheju horse Group II (farms), and Thoroughbred (KRA). SSCP of transferrin exon 13, 15, and 16 showed two (A, B), three (A, B, C) and three (A, B, C) codominant alleles, respectively. The Group I and Thoroughbred showed the similar frequencies of allele A and B in transferrin exon 13, but only allele A was observed in Group Ⅱ. In transferrin exons 15 and 16, the frequencies of each allele were different in each Groups. The multiple allele frequencies in exons 15 and 16 suggested that the genotyping of this locus could be used to identify an individual and to test the parentage of offspring. The probability for parentage exclusion were 0.46 and 0.374 for exons 15 and 16 for Cheju horse Group I. Among the 13 combined genotypes of exons 13, 15 and 16, the genotype AA-AB-AB (0.372) is the most common in Cheju horse Group I, but genotype AA-AA-AA is common in the Cheju horse Group II (0.366) and Thoroughbred (0.767). The present study showed two new SNP, which was at the cDNA position 1626 (A/G) in B allele of the exon 13 and 2075 (C/T) in C allele of the exon 16 resulting in amino acid change (Threonine $\longrightarrow$ Methionine). Result showed that polymorphism of exons 13, 15 and 16 in Cheju horses was as high as in Thoroughbred and there was a differences of transferrin allele frequencies in Cheju horses.

• Journal of Life Science
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• v.31 no.9
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• pp.840-848
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• 2021

This study was conducted to estimate annual trends and the environmental effects in the racing records of Jeju horses. The Korean Racing Authority (KRA) collected 48,645 observations for 2,167 Jeju horses from 2002 to 2019. Racing records were preprocessed to eliminate errors that occur during the data collection. Racing times were adjusted for comparison between race distances. A stepwise Akaike information criterion (AIC) variable selection method was applied to select appropriate environment variables affecting racing records. The annual improvement of the race time was -0.242 seconds. The model with the lowest AIC value was established when variables were selected in the following order: year, budam classification, jockey ranking, trainer ranking, track condition, weather, age, and gender. The most suitable model was constructed when the jockey ranking and age variables were considered as random effects. Our findings have potential for application as basic data when building models for evaluating genetic abilities of Jeju horses.