The Animal and Plant Quarantine Agency conducts a targeted sampling plan and analysis for veterinary drugs within the country every year. Target compounds included tetrachlorvinphos as an organophosphate, diminazene as an anti-infective medication, ketoprofen as a nonsteroidal anti-inflammatory drug, triclabendazole and clorsulon as flukicides in 2022. These compounds were not included in National Residues Program (NRP), despite their high sales ranking. A total of 94 bovine muscle samples and 20 equine muscle samples were collected from various locations across the country. The analysis of target compounds in muscle was performed using LC-MS/MS coupled with Food code 8.3.1 revised in 2022. A 2 g sample of muscle tissue was extracted using a water: acetonitrile (1:4, v/v) solution, then cleaned up with C18 and hexane saturated with acetonitrile. Compounds were separated with C18 column and mobile phases consisted of 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B). All analytes exhibited good linearity with correlation coefficients (R2) higher than 0.992. The limit of quantification (LOQ) of these compounds ranged from 0.21 to 2.79 μg/kg except for diminazene (3.85~6.86 μg/kg). The average recoveries of these analytes were 89.45~129.13% in muscle at spiked level of 10 or 20 μg/kg. Relative standard deviations (%) (intra-day and inter-day) were lower than 20% for all target compounds, except for diminazene and triclabendazole, whose intra-day RSD % was slightly higher than 20% in equine muscle. Testing confirmed that all 94 bovine and 20 equine muscle samples from 9 provinces were free from residues of veterinary drugs. Monitoring of compounds not included in the NRP should continue to ensure consumer health and food safety.

This study investigated changes in psychological stress levels of 60 firefighters after participation in an eight-week Equine-Assisted Learning (EAL) program consisting of 16 sessions. The Korean versions of the Posttraumatic Diagnosis Scale (PDS-K), the Center for Epidemiological Studies Depression Scale (K-CESD), and the Difficulties in Emotional Regulation Scale (K-DERS) were used for measurements. Participants were divided into two groups according to level of posttraumatic stress symptoms (PTSS): the PTSS risk group and the PTSS non-risk group. Results showed that PDS-K, K-CESD, and K-DERS scores were significantly reduced after the program in the PTSS risk group. Significant reduction was also found in all sub-scales of PDS-K: re-experiencing, avoidance/emotional numbing, and hyperarousal. Moreover, in the PTSS risk group, there were greater improvements with significant group x time interactions. These findings suggest that EAL is effective in relieving PTSD and PTSD-related symptoms of firefighters with subsyndromal or more severe levels of PTSD.

Mutations in the luteinizing hormone/chorionic gonadotropin receptors (LH/CGRs), representatives of the G protein-coupled receptor family, have been rapidly identified over the last 20 years. This review aims to compare and analyze the data reported the activating and inactivating mutations of the LH/CGRs between human, rat, equine and fish, specifically (Japanese eel Anguilla japonica). Insights obtained through detailed study of these naturally-occurring mutations provide a further update of structure-function relationship of these receptors. Specifically, we present a variety of data on eel LH/CGR. These results provide important information about LH/CGR function in fish and the regulation of mutations of the highly conserved amino acids in glycoprotein hormone receptors.

In this study, antibody responses after vaccination against equine influenza were investigated among 1,591 horses in the Republic of Korea using the hemagglutination inhibition (HI) test. Equine influenza has not occurred since 2011 and a commercial vaccine against H3N8 has been used. The equine influenza virus, A/equine/South Africa/4/03 (H3N8), was used as the antigen in the HI assay. The mean seropositive rate was 90.5% in 2019. Except for stallion whose seropositive rate was 78.5%, all seropositive rates of other horse types were over 90%. Regionally, except for Gangwon-do and Jeju-do whose seropositive rates were 89.0% and 87.1%, all seropositive rates in other provinces were over 90%. In the future, more through vaccination against equine influenza needs to be done based on this investigation result.

Equine follicle stimulating hormone receptor (eFSHR) has a large extracellular domain and an intracellular domain containing approximately 10 phosphorylation sites within the G protein-coupled receptor. This study was conducted to analyze the function of phosphorylation sties at the eFSHR C-terminal region. We constructed a mutant of eFSHR, in which the C-terminal cytoplasmic tail was truncated at residue 641 (eFSHR-t641). This removed 10 potential phosphorylation sites from the C-terminal region of the intracellular loop. The eFSHR-wild type (eFSHR-wt) and eFSHR-t641 cDNAs were subcloned into the pCMV-ARMS1-PK2 expression vector. These plasmids were transfected into PathHunter CHO-K1 Parental cells expressing β-arrestin 2 enzyme acceptor fusion protein and analyzed for agonist-induced cAMP response. The cAMP response in cells expressing eFSHR-t641 was lower than the response in cells expressing eFSHR-wt. EC50 values of eFSHR-wt and eFSHR-t641 were 1079 ng/mL and 1834 ng/mL, respectively. eFSHR-t641 was approximately 0.58-fold compared with that of eFSHR-wt. The maximal response in eFSHR-wt and eFSHR-t641 was 24.7 nM and 16.7 nM, respectively. The Rmax value of phosphorylation sites in eFSHR-t641 was also decreased to approximately 68.4% of that in eFSHR-wt. The collective data implicate that the phosphorylation sites in the eFSHR C-terminal region have a pivotal role in signal transduction in PathHunter CHO-K1 cells, and indicate that β-arrestin is involved in coupling the activated receptors to the internalization system.

Electrical stimulation (ES) is known to guide the development and regeneration of many tissues. Use of low-frequency ES for therapeutic purposes has been increasing during the last decades. Mesenchymal stem cells (MSCs) represent an appealing alternative cell source for cartilage repair. There are studies that induce differentiation into cartilage cells by treating the growth factors in stem cells or altering the properties of stem cells by genetic modification. In this study, we exposed equine adipose tissue-derived MSCs (eAD-MSCs) to ES and assessed changes in the chondrogenic differentiation potential. The cells obtained from equine adipose tissue attached to culture plates and expanded in vitro. Flow cytometric analysis at third passage indicated that the cells were strongly positive for CD44, CD90, and CD105, but negative for CD13, CD34, and CD45. Next, ES was applied to eAD-MSCs cultured under condition of high-density micromass under ES of 10 V/cm, with duration of 10 ms and a frequency of 2.0 Hz for three days. Gene expression of chondrogenic markers such as collagen type II, Aggrecan, and Sox9 was analyzed at three days of ES. As a result, we observed the differentiation potential of eAD-MSCs into chondrocytes by specific ES in absence of exogenous growth factors. We also found that ES upregulated the expression of heat shock protein 70, which affects cartilage formation. This study may contribute to the differentiation of MSCs into chondrogenic lineage under specific ES condition.

Equine reproductive failures for many different reasons are the main contributors to economic losses in the horse industry. This paper describes major bacterial agents isolated from thoroughbred mares that had reproductive failures in the previous year as well as the antimicrobial susceptibility of these bacterial isolates. A total of 146 vaginal and uterine swab samples were submitted to Jeju Self-Governing Veterinary Research Institute by equine veterinarians from 2011 to 2015. Streptococcus equi subspecies zooepidemicus were the most frequently encountered bacteria in 29 samples (48.3%). Other identified species included 21 samples (35%) with Escherichia coli, six samples (10%) with Klebsiella pneumoniae, and four samples (6.7%) with Pseudomonas aeruginosa. All Streptococcus equi subsp. zooepidemicus isolates were sensitive to amoxicillin-clavulanic acid, cefazolin, cefuroxime, and florfenicol, while all were resistant to tetracycline and kanamycin. All E. coli were sensitive to enrofloxacin, ciprofloxacin, and sulfamethoxazole-trimethoprim, and most were susceptible to cefazolin, amoxicillin-clavulanic acid, cefuroxime, florfenicol, and gentamicin. All K. pneumoniae isolates were sensitive to amoxicillin-clavulanic acid, cefazolin, cefuroxime, florfenicol, and ciprofloxacin, while all were resistant to sulfamethoxazole-trimethoprim. P. aeruginosa exhibited sensitivity to quinolones and aminoglycosides, particularly gentamicin, while all were resistant to cefazolin and cefuroxime.

Musculoskeletal disorders including fracture, tendonitis, osteoarthritis, and laminitis are common diseases in racehorses that can cause large economic losses in the racehorse industry. Mesenchymal stem cells (MSCs) are being applied as new clinical tools for treatment of musculoskeletal disorders of racehorses. To investigate the immunomodulatory effects of stem cell therapy, we analyzed the anti- and pro-inflammatory factors in peripheral blood mononuclear cells of racehorses before and after stem cell application using quantitative real-time RT-PCR. The expression levels of pro-inflammatory factors (CCL5, IFN-γ, IL-2, and IL-18) were decreased while those of anti-inflammatory factors (TIMP-1, IL-10, TGF-β1, and VEGF) were increased significantly after application of equine adipose tissue-derived MSCs (eAD-MSCs) to racehorses with fracture. Moreover, the expression levels of pro-inflammatory factors (IL-2, IL-18, and TNF-α) were decreased while those of anti-inflammatory factors (TIMP-1, TIMP-2, IL-10, TGF-β1, and VEGF) increased significantly after stem cell application of eAD-MSCs in racehorses with tendonitis. After evaluating immunomodulatory effects of stem cell therapy on equine musculoskeletal disorders such as fracture and tendonitis, our results showed that expression levels of pro-inflammatory factors were decreased, while those of anti-inflammatory factors increased significantly after stem cell application of eAD-MSCs. These findings suggest that the healing effects of the stem cell therapy might be due to its modulation of inflammatory factors.

In this study, we analyzed signal transduction by equine follicle-stimulating hormone receptor (eFSHR) on stimulation with recombinant eelFSHβ/α (rec-eelFSHβ/α), natural porcine FSH (pFSH), and natural human FSH (hFSH). cAMP stimulation in CHO-K1 cells expressing eFSHR was determined upon exposure to different doses (0-1450 ng/mL) of these hormones. The EC50 value of rec-eelFSHβ/α was 53.35 ng/mL. The Rmax values of rec-eelFSHβ/α and pFSH were 28.12 and 2.88 ng/mL, respectively. The activity of rec-eelFSHβ/α was much higher than that of natural pFSH. However, signal transduction in CHO PathHunter Parental cells expressing eFSHR was not enhanced by stimulation with natural hFSH. Thus, rec-eelFSHβ/α was completely active in cells expressing eFSHR. However, natural hFSH did not invoke a signal response in cells expressing eFSHR. Particularly, natural pFSH was weakly active in the same cells. These results showed that eelFSHβ/α has potent activity in cells expressing eFSHR. Thus, rec-eelFSHβ/α may efficiently bind to eFSHR, where as natural hFSH does not bind to eFSHR.

Mesenchymal stem cells (MSCs), which are present in all tissues, can differentiate into cells with various specific functions. Recently, cell-based therapies using MSCs have been increasing in the veterinary research and related fields. In this study, we investigated the cellular morphology, proliferating capacities, expression of cell surface markers such as CD13, CD34, CD44, CD45, CD90, and CD105, mesodermal differentiation potentials, and expression of senescence-related markers of p53, p21, and telomerase reverse transcriptase in equine adipose tissue-derived MSCs (eAD-MSCs) after cryopreservation. The eAD-MSCs were analyzed immediately and after being frozen in liquid nitrogen for 1 year (< 1 year, G1) and more than 3 years (> 3 years, G2), respectively. After cryopreservation for 1 - 3 years, G2 eAD-MSCs showed similar cellular morphology, proliferating capacities, and expression of cell surface markers when compared with G1 eAD-MSCs. Moreover, cryopreservation did not affect the adipogenic, chondrogenic, or osteogenic differentiation potentials of G1 and G2 eAD-MSCs. Collectively, cryopreservation for (or over) 3 years maintained the stem cell phenotype and differentiation potentials of eAD-MSCs. These results will be an advantage that can be effectively used for future development of cell-based therapies.

The purpose of this study was to investigate the effects of the concentration of seminal plasma in aerobic and anaerobic conditions on the total motility(TM) and the progressive motility(PM) of spermatozoa in long term preservation of cooled equine semen. We also examine the pregnancy rates after artificial insemination using fresh, cooled or frozen semen, and different durations of cooled-preserved equine semen. In the aerobic state of cooledpreserved semen, As the increase of preserved duration to 24h, 48h, 72h, and 96h, TM tended to decrease in each of different concentrations of formalin-containing experimental group, TM tended to decrease regardless of the concentrations of SP. In different concentrations of SP, TM of without seminal plasma(SP W/O) group tended to be higher than that of SP 20%, SP 33% and SP 50%, especially TM of SP W/O group was significantly higher than other groups at 96 h (p<0.05). PM was higher in the groups of SP W/O and SP 20% than in the groups of SP 33% and SP 50% from 24 h to 72 h in cooled-preservation, especially PM of SP W/O group was significantly higher than other groups at 96 h (p<0.05). In the anaerobic condition of cooled-preserved semen, the results of TM and PM at different concentrations of SP were similar to the results in the aerobic condition although there was a difference in the ratio. The pregnancy rates of fresh-cooled, cooled-preserved and frozen semen were 66.3%, 60.7% and 34.5%, respectively, and the pregnancy rate of frozen semen was the lowest. We also found that it is possible to pregnancy after artificial insemination using 72 h cooled-preserved equine semen. There was similar of the pregnancy rates in the different month from April to August.

This study was conducted to evaluate the changes of pH, dry matter digestibility (DMD), NH3-N concentrate, gas production and volatile fatty acid (VFA) through in vitro fermentation by adding horse feces to various juice pomaces fermented with Bacillus, yeast and lactic acid bacteria. The pH range of fermented fluid with juice pomaces was 6.4-7.1, indicating that the digestion by microbial fermentation was normal. Juice pomaces adopted will be helpfully used to assist with digestion by microbes in intestines because approximately 109 CFU/㎖ microbes were grown after 48 hours in fermented fluid. DMD rate gradually increased from 12 hours. It was 39.19% in pomaces of apple, 38.22% in grape, 37.02% in carrot, 36.2% in citrus and 34.35% in mixture respectively after 48 hours. NH3-N concentrate was not changed significantly as it was maintained at 1.5 mg/100㎖ level in the entire treatment group from beginning of fermentation until 12 hours, but increased rapidly from 24 hours. Amount of gas produced was lowest in the mixture and increased rapidly after 12 hours. Total VFA increased from 24 hours and was highest at 48 hours. It was suggested that dry matter digestion was processed while fermented juice pomaces kept proper pH during in vitro digestion, and cellulose degrading microorganisms could act actively in the caecum and colon of horses.

Mesenchymal stem cells (MSCs) have restricted life spans in vitro and can therefore only be expanded for a limited number of cell divisions before entering a senescent state and unequivocally stopping proliferation. Several types of cell culture systems have been used for large-scale expansion of MSCs. A recent trend in cell culture has been the change from serum-use to serum-supplement media. This study was conducted to investigate the proliferative effects of vegetable resources (VR) on equine adipose tissue-derived mesenchymal stem cells (eAD-MSCs) in the absence of serum and their possible mechanisms of action. Regulation of cell cycling is a key process involved in the fate of stem cells, including renewal and differentiation. In this study, we observed that the viability of eAD-MSCs was increased significantly when treated with VR under serum-free conditions. We also observed that expression levels of cell cycling-related proteins such as p53 and p21 were decreased, and proliferating cell nuclear antigen increased significantly in response to treatment with VR in eAD-MSCs under serum-free conditions. Furthermore, expression levels of cell survival-related proteins were increased in response to treatment with VR in eAD-MSCs under serum-free conditions. Therefore, our results suggest that VR promotes proliferation of eAD-MSCs under serum-free conditions.

Mesenchymal stem cells (MSCs) are primary candidates for cell therapy and tissue engineering applications. A two-dimensional (2D) culture system is typically used for cell growth, but that method affects the characteristics of stem cells. The physiological cell environment connects cells not only to each other, but also to the extracellular matrix providing mechanical support, exposing the entire cell surface, and opening signaling pathways. The hanging drop method is the most widely used 3D culture method for spheroid formation. In this study, we investigated the relationship between spheroid size and changes in gene expression to determine the optimum spheroid size for use in tissue engineering. The expression levels of stemness factors such as NANOG, OCT4, and SOX2, angiogenic factors such as VEGF and IL-8, and osteogenic factors such as COX2 and TGF-β1 increased with spheroid size in the respective spheroid formation groups unlike the responses in their monolayer groups. Therefore, our results indicate that spheroid formation through the hanging drop method can increase the efficiency of MSCs-based tissue engineering over that obtained via traditional 2D cell culture systems.

Equine chorionic gonadotropin (eCG) is a member of the glycoprotein hormone. eCG, over 40%, is a heavily glycosylated glycoprotein than other glycoprotein hormones. eCG is composed of non-covalently linked α and β subunit. The α subunit is common to all glycoprotein hormones, whereas the β subunit was known distinct sequences and specific receptor binding. Unusually, eCG shows both FSH and LH activities in other species. eCG α subunit has two N-glycosylation sites (Asn56, Asn82) and β subunit has one N-glycosylation site (Asn13) and about 13 O-glycosylation sites in the C-terminal region. We constructed 3 type mutants (βα△56: α-subunit Asn56→ Gln56; β-Da: β-subunit C-terminal deletion; β-Dα△56: β C-terminal deletion & α Asn56→Gln56) in the tethered eCGβα (wild type) and all mutants included myc-tag between first and second amino acid of β subunit. The plasmid DNAs cloned into pcDNA3 mammalian expressing vector were transiently transfected into CHO-Suspension cells. We also constructed rat LH/CG receptor and rat FSH receptor into pcDNA3 expression vector. These receptors were transiently transfected into CHO-K1 cell. Each receptor cells were used for further assays at 3 days after transfection. cAMP and IP-one were evaluated by CISBIO cAMP HiRange and IP-one kits using the rec-eCGβα mutants. According to cAMP assay results, IC50 values of 4 type ligand treatment in the rat FSH receptor cells were: eCGβα: IC50_16.8841; eCGβα56: IC50_95.6099; eCGβ-Dα: IC50_395.0087; eCGβ-Dα56: IC50_1439.8702. In the rat LH/CG receptor cells of 4 types ligand treatments, cAMP results were: eCGβα: IC50_0.9760; eCGβα56: IC50_8.3884; eCGβ-Dα: IC50_9.2550; eCG β-Dα56: IC50_45.9439. As seen in these data, β C-terminal region and α Asn56 play an important role in rat FSHR and rat LH/CGR, respectively. And rat LHCG receptor cells was remarkably stronger than rat FSH receptor cells. According to IP-one assay, IC50 values in rat FSH receptor cells, the results were: eCGβα: IC50_561.4490; eCGβα56: IC50_361.3005; eCGβ-Dα: IC50_911.8577; eCGβ-Dα56: IC50_139.1193. And in rat LH/CG receptor cells, IP-one results were: eCGβα: IC50_422.7315; eCGβα56: IC50_406.4915; eCGβ-Dα: IC50_537.8300; eCGβ-Dα56: IC50_254.2004. As shown in these data, IP-one result was a little different to cAMP result. The β eCGβ-Dα56 of IC50 value was shown generally high signal. Now we are trying to analyse role of C-terminal region of eLH/CGR with cAMP, IP-one and ERK signal transduction assays.

Embryo transfer (ET) has been applied to many species, which also useful tools for genetic improvement in horses. ET enables to produce a multiple foals from one donor mare in the same breeding season. However, there have been no reports describing equine embryo transfer performed in Korea. In the present study, we performed an equine embryo collection and transfer procedure for the first time. We examined the embryo collection and pregnancy, size of embryo during the incubation period after collection, and progesterone (P4) and estradiol-17ß (E2) concentrations in mare’s serum at embryo collection and transfer. A total of 16 donors responded to estrus synchronization; estrus was induced in 12 donors and 4 recipients, and artificial insemination was successful in 10 donors and six blastocysts were collected from donors. Of these blastocysts, we monitored the size of blastocysts for 3 day during incubation and transferred 2 blastocysts to a recipient, with 1 successful pregnancy and foal achieved. The dimensions of equine embryo at day 7 to day 9 were 409 μm, 814 μm and 1,200 μm. The serum P4 and E2 concentrations were 7.91±0.37 ng/μL and 45.45±12.65 ng/μL in the donor mare, and 16.06±3.27 ng/μL and 49.13±10.09 ng/μL in the recipient mare.

TPR(체온, 심박수, 호흡수) 및 혈액 검사는 인간뿐만 아니라 동물의 건강상태와 질병 진단에 폭넓게 이용되고 있고, 말에서는 건강상태와 운동능력의 평가에 중요한 분야이다. 국내에 가장 많은 사육두수를 점유하고 있는 한라마(제주산마)에 대한 운동저항성에 대한 조사보고가 없었 다. 본 연구에서는 한라마의 운동 시간에 따른 TPR과 혈액검사를 통하여 운동저항성을 평가하 고자 실시하였다. 시험축은 한라대학교(제주)에서 관리 중인 한라마 5두를 이용하였으며, 각각 운동방법(평보, 속보)와 시간(5분, 10분, 20분)에 따른 TPR과 혈액화학치를 분석하였다. 혈액화 학치는 근육 운동과 관련성이 높은 Creatine kinase(CK), Ca ionaized, Calcium, Phosphorus, Sodium, Potassium, Lactic acid, Cortisol 및 Aldosterone을 분석하였다. 각각 결과는 mean±SD 로 나타냈으며, 통계처리는 t-test를 이용하였고 p<0.05 수준에서 유의성 검정을 하였다. 평보 지속시간(5분, 10분, 20분)에 따른 체온과 심박수는 각각 37.2 – 37.8℃ 및 45.3 – 52.0회/분 로 차이가 없었다. 하지만 호흡수는 운동전이 평균 28.8회/분에서 운동시작 후 33.8회/분 로 유의하 게 증가하였으나(p<0.05), 운동시간 경과에 따른 차이는 없었다(평균 32.5 – 33.8회/분). 속보 운 동시 체온은 운동전이 37.6℃으나 운동시작 후 평균 38.1℃이상, 심박수도 운동전 44.5회/분에서 10분 운동 후 49.3회/분, 호흡수도 운동전 31.0회/분에서 10분 운동 후 38.3회/분으로 유의하게 상승하였다(p<0.05). 한편 혈액화학치는 운동 강도와 지속시간에 따라 으로 CK 302.25 – 372.50, Ca ionaized 1.37 – 1.46, Calcium 12.05 – 12.22, Phosphorus 2.30-2.48, Sodium 100.84 – 137.25, Potassium 3.58 – 4.55, Lactic acid 0.70 – 1.06, Cortisol 6.67 – 7.88 및 Aldosterone 0.68 – 2.05 수준으로 차이가 없었다. 향후 다양한 운동강도에 따른 추가 연구가 필요할 것으로 생각된다.

국내 경주마의 승용마로 전환에 있어서 가장 큰 문제 중 하나인 침착하고 온순한 성격의 말 을 조기에 판정이 필요하고, 특히 crib biting같은 행동을 보이는 사나운 성격의 말을 조기에 제 거하는 선발 기술이 필요하다. 본 연구에서는 성격적으로 민감하고 난폭한 그룹과 온순한 성격 의 말을 구분 지을 수 있는 유전적 특성을 파악하고자 연구를 수행하였다. 말의 성격적 특성을 구분 지을 수 있는 유전적 변이를 찾기 위해서 기존에 포유동물의 성격적 특징과 관련이 있는 것으로 알려진 유전자 후보군 71개를 선발하였다. 71개 유전자 중, 말 참조 유전체에 이미 존재 하는 16개 유전자와 인간 참조 유전체를 기반으로 말에서 찾은 orthologous gene 17개를 합하여 총 33개 성격관련 유전자를 선정하였다. 선정된 33개 유전자의 exon 부분에 probe를 제작하여 목표로 하는 유전자만 추출한 후 Illumina Hiseq2500을 이용하여 whole exome sequencing을 진 행하였다. Whole exome sequencing 결과로 얻어진 데이터를 이용하여 sanger validation기법을 통해 SNPs분석을 실시하였다. 그 결과 33개의 유전자 중 androgen recptor gene (AR)과 dopamine receptor D4 gene (DRD4)유전자에서 유전적으로 성격에 차이가 크게 나타난 결과를 확인할 수 있었다. 이러한 유 전자를 활용한다면 말 사육 농가의 조기 말 성격 검사를 통하여 사육 방향을 선택할 수 있는 경 제적 이득을 취할 수 있을 것으로 예측되며, 향후 추가적인 유전자 분석이 완료 된다면 현장에서 신속하게 사용할 수 있는 키트 개발등이 가능할 것으로 기대된다.

승용말 주요 생산 국가와 협회에서 약 90% 정도가 인공수정으로 망아지를 생산하고 있고, 인공수정에 이용되는 정액은 냉장정액이 90%, 동결정액은 10% 정도 활용되고 있다. 본 연구에 서는 국내 승용말 인공수정 저변 확대에 필요한 씨수말 냉장 정액의 장기보존성 향상을 위하여 냉장 보존용 희석제와 희석 후 보관 형태가 정자의 생존성 및 운동성에 미치는 효과에 대하여 조사하였다. 한국마사회 장수목장에서 관리 중인 씨수말 2두를 이용하였으며, 정액의 희석에는 INRA-96(IMV, France) 및 EZ-mixin(ARS, USA) 희석제를 각각 이용하였고, 냉장(4℃) 상태에 서 96시간까지 보관하면서 정자의 생존율과 운동성을 분석하였다. 보관 형태는 aerobic 및 anaerobic 상태로 하였다. 정자의 운동성은 CASA 시스템을 이용하여 분석하였다. 각각 결과는 mean±SD로 나타냈으며, 통계처리는 t-test를 이용하였고 p<0.05 수준에서 유의성 검정을 하였 다. 승용말 정액 채취 직후 생존율과 운동성은 각각 평균 65.5% - 73.8% 및 40.8% 및 47.8% 였 다. 실험 목적에 따라 INRA96 및 EX-mixin 그리고 aerobic 및 anaerobic 상태로 24, 48, 72 및 96시간 동안 보존 하였다. EZ-mixin 희석제의 aerobic 및 anerobic 상태에서 보존 시간 경과에 따라 생존율은 42.3% - 4.0%, 운동성은 50.4% - 16.0%로 낮아졌다. INRA96희석제에서 보존에 서 생존율은 aerobic 54,3% - 49.9% 및 anaerobic 58.7% - 47.5%로 낮아지는 경향이었으나 유의 차는 없었다(p<0.05). 한편 운동성은 aerobic 34.5% - 37.4% 및 anaerobic 36.6% - 31.9%로 차이 가 없었다. 따라서 각각 희석제에 따른 혐기 및 호기성 상태로의 보존은 생존율과 운동성에도 영향이 없었으나, 희석제의 조성에 따른 생존율과 운동성은 유의한 차이가 인정되었다.

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.