본 연구는 한우 개체식별 및 친자감별에 있어 기존의 di-nucleotide repeat microsatellite marker 사용 시 발생했던 stutter로 인한 대립유전자 판별 오류 등의 문제들을 극복하고, 분석결과의 신뢰도와 정확도를 높이기 위해 tri-, tetra-, penta-, hexa-nucleotide repeat microsatellite 좌위들로 이루어진 새로운 개체식별 마커 13 종(BTRC6_01, BTRC19_02, BTRC11_03, BTRC16_05, BTRC9_07, BPC19_08, BTEC17_09, BPC21_10, BTEC4_11, BPC7_12, BPC1_13, BHXC29_14, BPC1_15)을 개발하였다. 선발된 13개의 좌위를 가지고 소 1,530두에 microsatellite typing을 실시한 결과, 총 61개에 대립유전자가 발견되었으며, 좌위별로 평균 4.69개의 대립유전자를 가지는 것으로 확인되었다. 마커의 다형성과 정보력의 척도인 PIC (Polymorphism Information Contents)값은 0.25(BTRC9_07)~0.59(BTEC17_09)로 나타났으며 BHXC29_14, BPC1_13, BTEC17_09, BTRC16_05, BTRC19_02, BTRC6_01 좌위들은 PIC 0.5 이상 그리고 나머지 좌위들 모두 PIC 0.25 이상의 값을 가지는 것으로 확인되어 마커로서 다형성이 있음이 검증되었다. 개발한 마커를 활용하여 한우(영암, 장흥)와 유럽우 7종 (Brown Swiss, Limousin, Angus, Simmental, Hereford, Charolais, Holstein)의 유전적 특성을 분석하였으며, 총 9개 집단의 Heterozygosity와 FIS (inbreeding coefficient) 값을 측정하였다. 기대이형접합율은 0.451(BS)~0.605(AG) 범위 내로, 한우는 0.532(영암), 0.545(장흥)의 값을 가지는 것으로 나타났다. 한우(영암, 한우)와 7종의 유럽우들 간의 유연관계 분석은 특정 대립유전자 빈도를 근거로 한 유전적 거리의 추정으로 이루어졌다. 한우집단과 Simmental 간의 유전적 거리(0.1848)가 가장 가깝고 비교적으로 Brown Swiss와의 유전적 분포(0.3352)가 가장 먼 것으로 나타났으며, 계통발생학적으로 유전적 분화 양상을 확인함으로써 본 마커의 한우 유전적 다양성 및 유연관계 분석에 활용 가능성을 제시하였다.

This study was conducted to determine the effect of pentoxifylline levels on sperm motility, survival rate, sperm membrane integrity of frozen semen and fresh-extended equine semen in Jeju cross-bred horses. As a result of sperm characteristic comparison depending on pentoxifylline levles at 30 minutes post-thaw, the progressive motilities were 53.25±2.87 (4mM pentoxifylline) and 50.28±2.14 (8mM pentoxifylline) and significantly higher compared to the control group(40.09±5.15) and other treatment group (16mM pentoxifylline, 41.27± 2.82). The progressive fast motility were 22.44±1.62 (4mM pentoxifylline,) and 22.74±3.07 (8mM pentoxifylline) and significantly higher compared to the control group (13.47±1.48) and other treatment group (16mM pentoxifylline, 14.66±3.68) (p<0.05). As a result of sperm characteristic comparison depending on pentoxifylline levles at 30 minutes post-thaw were 68.96±1.64 (4mM pentoxifylline) and 67.90±6.72 (8mM pentoxifylline) and significantly higher compared to the control group (53.48±4.84) and other treatment group (16mM pentoxifylline, 58.14±2.65) (p<0.05). In conclusion, these results suggest that treatment groups with 4mM and 8mM pentoxifylline were higher compare to equine seperm mobility and the control group and treatment groups with more than 16mM pentoxifylline has a negative effect on sperm characteristics. After thawing, the total motility in post-thawed equine sperm has increased by 10 percent for 1 hour. these results suggest that pentoxifylline contributes to the improvement of the equine sperm motility and characteristics in post-thawed semen.

Spermatozoa viability can be assessed by microscopy, flow cytometry, and other methods using fluorescent stain. Flow cytometry can be used to examine the morphological and functional characteristics of spermatozoa in a short time. The purpose of this study was to compare the viability of cryopreserved spermatozoa in Jeju black cattle by two dual fluorescent stain methods. Semen of Jeju black cattle raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA were collected with artificial vaginal technique. Sperm was diluted with Triladyl®-egg yolk diluent and then was performed cryopreservation.There was no significant difference in viability of spermatozoa according to the two dual fluorescent stain methods. However, when the distribution of spermatozoa according to the staining method was compared, the spermatozoa group stained with 6-CFDA/PI was more clearly distinguished than the spermatozoa group stained with calcein AM/PI.

This study was conducted to investigate the ovarian cycle changes of the mare according to the season. Twenty four Jeju crossbred horses(Thoroughbred x 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.

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 × 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 ± 24.5㎏ and the height was 124.5 ± 4.0㎝. 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.

Viral respiratory infections are common in horses, notably equine herpesvirus infection and equine influenza, which primarily initiate secondary bacterial respiratory infections such as strangles caused by Streptococcus equi equi. A decline in the production of stallions has been associated with these respiratory diseases leading to adverse financial implications. This study investigated the antibody responses against respiratory diseases in horses from Jeju Island a year after vaccination. A low level of equine herpesvirus type 1 (EHV-1) (11.36%) antibodies was detected from stallions, however a high level of EHV-4 (95.84%) antibodies was detected from horses without vaccination against this infection suggesting that EHV-4 is ubiquitous in this horse population. In case of equine influenza, ranch stallions showed low positive rate (12.06%) whereas stallions from Subtropical Livestock Research Institute displayed higher positive rate (81.32%). Antibody responses against equine influenza and strangles revealed positive rates of 26.32% and 55.12%, respectively. These findings may draw attention towards the importance of developing an improved disease prevention and/or immunization program that will effectively control respiratory diseases in horses.

Respiratory diseases among horses cause economic losses in foals and productivity decreases in horses being raised and in adult horses. In South Korea, fundamental studies of horses’ respiratory diseases and those related to disease occurrence are insufficient. Therefore, the aim if the current study was to use diverse hematological indicators, obtained through hematological tests and measurment of blood antibody level in horses suffering form respiratory diseases, to monitor disease occurrence and prognosis evaluation. Investigations of infection states by horses’ bacterial respiratory diseases, susceptible drugs, and resisted drugs according to pathogens showed differences between farms. Among the β-lactam-based antibiotics, cephalosporin-based antibiotics showed some efficacy against Streptococcus spp. To review age-based changes in erythrocytometer hemograms in hematological tests of riding horses, red blood cell (RBC) tended to gradually decrease with increasing age this tendency was statistically significant. In addition, leukocytometer hemograms analyzed by age showed that total white blood cell counts tended to decrease with increasing age. These results of drug susceptibility tests and hematological tests, which have not been presented thus far, will be useful as standardized data in future breeding management and disease tests of Jeju riding horses.

vThis study analyzed the coat color-related genes of MC1R, ASIP, ECA3-inversion, and STX17 of 1,462 Jeju horses administered by the Jeju Special Self-Governing Province. This was done to investigate the distributional characteristics of coat color-related genes in the Jeju horse group and the changes of its coat color-related genes by generation. The genotype frequency of the MC1R gene of E+/E+ and E+/Ee related to black coat color was 0.122 and 0.447, respectively, while Ee/Ee of the chestnut genotype was 0.429. The genotype frequency of the ASIP gene of AA/AA, AA/Aa, and Aa/Aa was 0.46, 0.448, and 0.091, respectively, where the genotype frequency of Aa/Aa turned out to be relatively low. The To/To and +/To genotype that manifests the Tobiano shape was 0.001 and 0.119, respectively, with the share of Tobiano shape around 12%. The genotype frequency of G/G and G/g of STX17 related to grey coat color was 0.002 and 0.680, respectively, with the share of grey horses among the Jeju horse group at 68.2%. As for the change of coat color genes by generation, no large changes were observed in the MC1R and ASIP genes. In ECA3-inversion, the To allele that manifests Tobiano significantly decreased following the generational change (p<0.05), while the STX17 G allele related to grey coat color significantly increased following the generational change (p<0.05). It will be necessary to examine the coat color genes when selecting breeding horses so that the diversity of coat colors among the Jeju horse group can be maintained.