• Genes and Genomics
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• v.40 no.11
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• pp.1249-1258
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• 2018

The Jeju horse is an indigenous Korean horse breed that is currently registered with the Food and Agriculture Organization of the United Nations. However, there is severe lack of genomic studies on Jeju horse. This study was conducted to investigate genetic characteristics of horses including Jeju horse, Thoroughbred and Jeju crossbred (Jeju${\times}$Thoroughbred) populations. We compared the genomes of three horse populations using the Equine SNP70 Beadchip array. Short-range Linkage disequilibrium was the highest in Thoroughbred, whereas $r^2$ values were lowest in Jeju horse. Expected heterozygosity was the highest in Jeju crossbred (0.351), followed by the Thoroughbred (0.337) and Jeju horse (0.311). The level of inbreeding was slightly higher in Thoroughbred (-0.009) than in Jeju crossbred (-0.035) and Jeju horse (-0.038). $F_{ST}$ value was the highest between Jeju horse and Thoroughbred (0.113), whereas Jeju crossbred and Thoroughbred showed the lowest value (0.031). The genetic relationship was further assessed by principal component analysis, suggesting that Jeju crossbred is more genetically similar to Thoroughbred than Jeju horse population. Additionally, we detected potential selection signatures, for example, in loci located on LCORL/NCAPG and PROP1 genes that are known to influence body. Genome-wide analyses of the three horse populations showed that all the breeds had somewhat a low level of inbreeding within each population. In the population structure analysis, we found that Jeju crossbred was genetically closer to Thoroughbred than Jeju horse. Furthermore, we identified several signatures of selection which might be associated with traits of interest. To our current knowledge, this study is the first genomic research, analyzing genetic relationships of Jeju horse, Thoroughbred and Jeju crossbred.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.227-233
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• 2016

This study was conducted to analyze the effect of single nucleotide polymorphisms (SNPs) on the equine chromosomes (ECA) 3 for the body conformations of 12 month of age in Jeju crossbred (Jeju horses ${\times}$ Thoroughbred). A total of 199 Jeju crossbred horse samples were obtained from the National Institute of Subtropical Livestock Research Institute for this study. To correctly estimate the body conformations, we measured thirteen elements relevant to the body conformation such as body weight, wither height, body length for all the 199 horses at 12 month of age. Furthermore, all the horses were genotyped using four SNPs including the BIEC2-808466, BIEC2-808543, BIEC2-808967, BIEC2-809370, of which genomic coordinates range approximately from 105.1Mbp to 110 Mbp in the ECA3. For the phenotypic data sets, the average body weight was $193.7{\pm}24.5kg$ and the height was $124.5{\pm}4.0cm$. As for the genotypic data, the miner allele frequencies of the SNPs were shown to be varied from 0.01 to 0.291. Using the phenotypic and genotypic data sets, analysis of covariance was performed to find any association between those SNP genotypes and body conformations, using year of birth, month of birth, sex, and parity as the covariance components. The result showed that alternative genotypes in the BIEC2-808967 and BIEC2-809370 SNPs were significantly associated with the body length (P<0.05) and the wither height (P<0.05) respectively in the Jeju crossbred horses. Therefore, it is estimated that there are significant associations in the body conformation of 12 month of age of Jeju crossbred for those two SNPs used in this study.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1098-1102
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• 2018

Objective: Temperament can be defined as a type of behavioral tendency that appears in a relatively stable manner in responses to various external stimuli over time. The aim of this study was to estimate genetic parameters for the records of temperament testing that are used to improve the temperament of Jeju crossbred (Jeju${\times}$Thoroughbred) horses. Methods: This study was conducted using 205 horses (101 females and 104 males) produced between 2010 and 2015. The experimental animals were imprinted and tamed according to the Manual for Horse Taming and Evaluation for Therapeutic Riding Horses and evaluated according to the categories for temperament testing (gentleness, patience, aggressiveness, sensitivity, and friendliness) between 15 months and 18 months of age. Each category was scored on a five-point linear scale. Genetic parameters for the test categories were analyzed using a multi-trait mixed model with repeated records. The ASReml program was used to analyze the data. Results: The heritability of gentleness, patience, aggressiveness, sensitivity and friendliness ranged from 0.08 to 0.53. The standard errors of estimated heritability ranged from 0.13 to 0.17. The test categories showed high genetic correlations with each other, ranging from 0.96 to 0.99 and high repeatability, ranging from 0.70 to 0.73. Conclusion: The results of this study showed that the test categories had moderate heritability and high genetic correlations, but additional studies may be necessary to use the results for the improvement programs of the temperament of Jeju crossbred horses.

• Journal of Life Science
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• v.33 no.12
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• pp.995-1001
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• 2023

This study investigated the effects of three music genres (classical, new age, and rock) on the stress levels of six Jeju crossbred horses (Jeju horse × Thoroughbred) in a horse stable. The horses were exposed to the three genres for seven days, and their stress levels were measured by analyzing physiological markers, including neurotransmitter (cortisol, β-endorphin, dopamine, serotonin, and oxytocin) plasma levels and creatine phosphokinase (CPK) and aldolase serum levels. The neurotransmitter analysis showed significant differences in cortisol levels between classical and new age music exposure. Dopamine levels decreased significantly only with new age exposure. Although there were no significant differences in β-endorphin levels between the three genres, β-endorphin levels decreased with increasing classical and new age music playback times and increased with increasing rock music playback times. There were no significant differences in serotonin levels between the three genres. Oxytocin levels decreased significantly with exposure to classical and rock music. The CPK and aldolase analyses showed that CPK levels decreased significantly only with exposure to new age music and increased after playback ended, while aldolase levels decreased significantly with classical and new age music exposure and increased after playback ended. These findings suggest that classical music and new age are the optimal music genres for the psychological stability of Jeju crossbred horses. Playing back an appropriate music genre could be used to improve breeding and promote the welfare of Jeju crossbred horses.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.177-182
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• 2017

This study was conducted to investigate the ovarian cycle changes of the mare according to the season. Twenty four Jeju crossbred horses(Thoroughbred ${\times}$ Jeju horse) raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA were used to identify follicles and corpus luteum with ultrasonography once a week(May 2016~June 2017). Blood samples of experimental horses were collected twice a week for analysis of P4 hormone levels. The mares were considered to have resumed ovarian cyclicity on the day of ovulation if they followed by regular ovarian cycles. Only 13 cases(61.9%) of the total 21cases showed normal ovarian cycle, and 8 cases (38.1%) showed delayed ovarian cycle. Three cases(16.7%) in October, 5 cases(27.8%) in November and 5 cases(27.8%) in December(27.8%) ceased the heat and the remaining 5 cases(27.8%) showed that the estrus was maintained in winter. Horses that stopped estrus ceased the heat until March of next year, and 27.8% were continued the heat during non-breeding season. Eleven cases(61.1%) of 18 cases in April and 2 cases(11.1%) of 18 cases in May returned the estrus.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.2
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• pp.186-191
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• 2006

The purpose of this research was to study the chemical compositions of pork for crossbred pig (female, 198 days old $102{\sim}118kg$) that were fed with tangerine byproduct from pregnancy through the whole rearing period. The samples for this study consisted of the pork from give the number of control pigs not fed with tangerine byproduct($T_0$), and the pork from give the number of study pigs fed with 8% tangerine byproduct during the whole breeding period, from the early pregnancy through the young, growing and finishing periods ($T_1$). Backfat thickness of the crossbred pigs was significantly decreased by feeding tangerine byproduct (p<0.05). The proximate composition, minerals, total amino acid, saturated fatty acid vs. unsaturated fatty acid and vitamin $B_2$ contents of loins were not significantly different among $T_0\;and\;T_1$, (p>0.05). Although those differences were not significant statistically, the tangerine byproduct tended to increase the amount of vitamin $B_1$, and decrease the crude fat and cholesterol contents.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.200-206
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• 2012

The changes in physiologic parameters by swim exercise duration were examined in five female well-trained Jeju crossbred riding horses that had riding experience of more than three years without swim training experience. The horses were performed with swim exercise for 10 min (60.0 m/min) once a day for 14 days. Physiologic characteristics and haematic parameters were measured before swimming, immediately after swimming, and after a 10 min rest at first day ($D_0$), 7 days ($D_7$), and 14 days ($D_{14}$) of training. After 14 days of swim training, heart rate (p<0.05), blood glucose (p<0.05), lactate concentration (p<0.001), packed cell volume (p<0.01), and hemoglobin (p<0.01) measured immediately after swim and after 10 min rest showed significant lower values than those of $D_0$. The results illustrate the benefits of swim training for riding horses and the need for the establishment of swimming routines of appropriate duration and intensity to maximize the advantages of swim training.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.846-852
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• 2007

The objective of this study was to compare the physical and sensory characteristics of pork from Korean native black pigs ($78{\pm}7kg$, female) to the pork of crossbred black pigs ($115{\pm}5kg$, female), both of which were reared for the same period on Jeju Island. The Korean native black pig showed a lower $L^*$ value (lightness) and higher $a^*$-(redness) and $b^*$-values (yellowness) than the crossbred black pig. There were no statistically meaningful differences between the two pigs' loins, hams and bellies of the two breeds of pig in terms of water holding capacity, thawing loss, cooking loss, myofibrillar protein extract, and fragmentation index. The crossbred black pigs showed greater significant differences among the physical characteristics of each part, as compared to the Korean native black pigs. The cooked meat of the Korean native black pig had superior hardness to that of the crossbred black pig, whereas the raw meat had a lower hardness, chewiness, and shear force value. Finally, there was no significant difference between the two pigs in terms of palatability.

• Journal of Veterinary Clinics
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• v.30 no.6
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• pp.449-452
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• 2013

The present study was conducted to measure the cardiorespiratory endurance of Jeju crossbred horses according to hill tests and exercise intensity, thereby providing foundational data for evaluation of running capability of horses. The nine Jeju crossbred horses were subjected to the hill test with an inclination of around $30^{\circ}$ and six out of nine horses were used to measure the cardiorespiratory endurance according to three different exercise intensities (moderate, heavy, and very heavy). The running time for the hill test was 205 sec on average, while high deviation was observed between horses from 167 to 258 sec. In addition, the running time for the hill test was highly correlated with moderate exercise. While no significant difference in average heart rate was found between exercise intensities, a trend of large variation was found in the average heart rate between horses. The heart rate recovery was highly correlated with heavy exercise and very heavy exercise. The results showed that no significant difference in average heart rate was found among three exercise intensities, but there are large individual variations among horses.

• Korean Journal of Veterinary Research
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• v.49 no.4
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• pp.351-354
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• 2009

Diaphragmatic hernias, whether congenital or acquired (traumatic), are rarely observed in the horse. Acquired diaphragmatic hernias typically occur secondary to trauma or an increase in intraabdominal pressure due to falling, heavy exercise, or parturition. Diaphragmatic herniorrhaphy is difficult to perform in adult horses and the horses with symptomatic diaphragmatic hernias usually die. A 10- year old, 340 kg, Jeju horse (crossbred) broodmare with sudden onset of gait disorder and a moderate emaciation was examined. Findings on physical examination included conjunctivitis, dehydration, shallow breathing, dyspnea, weaken heart beat, lack of auscultatable sounds from the gastrointestinal tract, and anorexia. Rectal temperature was $38.4^{\circ}C$ and respiratory rates were moderately increased. There were slight signs of acute colic. The broodmare died one day after non-specific treatment of fluids, nutriment, antibiotics and non-steroidal anti-inflammatory drug. The cause of death was strangulation of the small intestine through a diaphragmatic hernia. The rent was about 2 cm in diameter and located in the central right part of diaphragm. Around 60 cm of small intestine was protruded into thoracic cavity through the rent. The cause of the hernia could not be ascertained. The broodmare had been pastured with many other horses, and the groom had not noticed any aggressive behavior among them. It was, however, speculated that trauma by stallion's attack may have been the cause of the diaphragmatic hernia, because the new horse may be the object of behaviors ranging from mild threats to seriously aggressive kicking, squealing, rearing, and biting.