• Korean Journal of Veterinary Research
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• v.59 no.3
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• pp.141-149
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• 2019

From 1996 to 2014, 14 foals from nine farms in Jeju were diagnosed with a Rhodococcus equi infection. Clinically, most foals showed characteristic respiratory signs, including hyperthermia and dyspnea. The seasonal occurrence of R. equi infection in foals was higher in summer, such as June (eight foals; 57.1%) and July (four foals; 28.6%), than in the other seasons. The major cases of R. equi infections were observed among two-month-old (eight foals; 57.1%) and three-month-old (three foals; 21.4%) foals. Histopathologically, bronchopneumonia, abscess, and granulomatous pneumonia were the most prevalent lesions in the lungs of foals. Colonic ulcers and submucosal abscesses were found in a foal. Some foals showed granulomatous lymphadenitis and abscesses in the mesenteric and other lymph nodes. According to the polymerase chain reaction using 10 tissue samples of foals and nine R. equi isolates, the vapA gene was detected in 11/11 (100%) foals. Immunohistochemical staining using the anti-VapA monoclonal antibody was applied to detect the R. equi VapA antigen in the organs of foals. R. equi VapA antigens were demonstrated in most lungs and some mesenteric and hilar lymph nodes of 13 foals. Isolated virulent R. equi VapA bacteria showed high sensitivity to gentamicin, quinolones, rifampin, and vancomycin.

• Animal cells and systems
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• v.7 no.2
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• pp.119-122
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• 2003

In order to determine whether foals of move dominant mothers were harassed less by mares than those of lower-ranked mothers, harassment of foals was studied in a herd of Jeju ponies (Equus caballus) consisting of 73 mares, their 53 foals, and one stallion. Mares Harassed the foals on 71 occasions between March to September,1998. The frequency of harassment tended to decrease as foals aged, but the relationship was not significant (P = 0.079). Foals were harassed when sleeping (n = 14), grazing (n = 19), moving (n = 8), approaching a mare in the vicinity (n = 13), or play-fighting with the foal of the harassing mare (n = 17). Mares harassed foals of younger, more subordinate mares than those of older, more dominant mares (P < 0.001). We conclude that early social experience of foals is associated with the dominance rank of its mother.

• Korean Journal of Veterinary Research
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• v.42 no.1
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• pp.115-121
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• 2002

The present study was conducted to investigate the pattern of fracture of 50 Thoroughbred foals in Jeju from January 1997 to August 2001. A total 50 Thoroughbred foals were investigated to figure out the relationship between breeding condition and fracture. The fracture was diagnosed by physical and radiological examinations after lameness test. Most sites of fracture were limb, skull and vertebrae. Age analyzed that the most popular is the 1-year-old foals. Most places of the occurrence of the fracture were pasture, paddock, track and stable. Main cause of the fracture were play, training and foal's dam. These results suggest that there were the 1-year-old foals have a lot of fracture during play at pasture in winter.

• Journal of Veterinary Clinics
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• v.40 no.5
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• pp.323-329
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• 2023

Peripheral blood-derived mesenchymal stem cells (PB-MSCs) have shown promise in cell-based therapy, as they can be harvested with ease through minimally invasive procedures. This study aimed to isolate PB-MSCs from foals and mares and to compare the proliferation and cellular characteristics of the PB-MSCs between the two groups. Six pairs of mares and their foals were used in this study. MSCs were isolated from PB by direct plating in a tissue culture medium, and cell proliferation (population doubling time [PDT], and colony-forming unit-fibroblast assay [CFU-F]), and characterization (morphology, plastic adhesiveness, colony formation, trilineage differentiation) were examined. There was no significant difference in the PB-MSC yield, CFU-F, and PDT between the mares and foals. PB-MSCs from both mares and foals showed typical MSC characteristics in terms of spindle-shaped morphology, plastic adhesive properties, formation of colonies, trilineage differentiation. These results suggest that PB-MSCs isolated from horses, both adult horses, and foals, can be used for equine cell-based therapy.

• Journal of Microbiology
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• v.40 no.3
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• pp.183-192
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• 2002

Cells infected With equine herpesvirus type-1 (EHV-1) Produced both infectious and non-infectious Virus-related particles. Compared to the whole virion, non-infectious particles termed L-particles were deter-mined to lack 150 kDa protein, commonly known as nucleocapsid protein. The potential of L-particles to induce immune responses was studied in mice and foals. Intranasal immunization with L-particles or whole virions induced poor IgG antibody responses in mice. Interestingly, despite the poor antibody response, the conferred immunity protected the host from challenge infections. This was indicated by a significant reduction in virus titers in line with recovery towards normal body weight. Subsequently, the test on the usefulness of L-particles as immunizing agents was extended to foals. Immunization of specific-pathogen-free (SPF) foals resulted in similar results. As determined by a complement-fixing-antibody test (CFT), foals seroconverted when they were immunized either with inactivated L-particles or whole virions via intramuscular (i.m.) injections. The presence of the antibody correlated with the degree of protection. Beyond day 1 post challenge infection (p.i.), there was no virus shedding in the nasal mucus of foals immunized with whole EHV-1 virions. Virus shedding was observed in foals Immunized with L-particles but limited to days 6 to 8 p.i. only. In contrast, extended vim shedding was observed in non-immunized foals and it was well beyond day 14 p.i. Viremia was not detected for more than four days except in non-immunized foals. Immunization in mice via intranasal (i.n.) conferred good protection. However, compared to the i.n. route, a greater degree of protection was obtained in foals following immunization via i.m. route. Despite variation in the degree of protection due to different routes of immunization in the two animal species, our results have established significant evidence that immunization with L-particles confers protection in the natural host. It is suggested that non-infectious L-particles should be used as immunizing agents for vaccination of horses against EHV-1 infection.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.255-260
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• 2005

We investigated interventions by mother Jeju ponies on Jeju Island, Korea, to determine whether mothers assisted their offspring to attain higher status within the dominance hierarchy. Because dominance rank is important within each gender, we predicted that mothers would be more likely to intervene when their foals were play-fighting with foals of the same gender. A total of 173 play-fighting events were recorded from March to October 1998 and from April to October 1999. Of these, foals were more likely to play-fight with a foal of the same gender as with a foal of the opposite gender (120 versus 53 occurrences, respectively). A mother of one of the foals that were play-fighting intervened in 17 of these interactions. Contrary to the prediction, a mare was more likely to intervene when opposite genders interacted than when the same gender interacted. Analyzing interactions between the opposite genders further, mothers were equally likely to intervene when a daughter was play-fighting with a male foal as when a son was play-fighting with a female foal. Hence, mothers were not more protective of daughters than sons. Mothers that were in the younger age class ($2\sim11$ years old) were as likely to intervene as those in the elder age class ($17\sim25$ years old). However, all foals that were harassed were offspring of mothers in the younger, more subordinate age class. intervention directly maintains the dominance rank of the intervening mother, and may indirectly assist the intervening mother's foal to achieve a higher dominance rank. By discouraging their foals from play-fighting with the opposite genders, dominant mothers may be encouraging their foals to play-fight with the same gender and participate in establishing its own dominance rank.

• Korean Journal of Veterinary Research
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• v.51 no.1
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• pp.55-58
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• 2011

Two 4-day-old Thoroughbred foals with acute clinical signs of depression, elevated pulse and respiratory rates, anemia, and jaundice were referred to the equine hospital of Korea Racing Authority. The foals were seemingly normal at birth, but showed clinical signs such as abnormal behavior, jaundice and anemia suddenly after ingestion of the mare's colostrum, followed by death at 4 days after birth. According to the results of the hematology, serum chemistry analysis, jaundice foal agglutination test, and blood groups test, the foals were diagnosed as neonatal isoerythrolysis (NI) caused by the mare's antibodies. These results suggested that the pregnant mares have a potential for NI.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.169-174
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• 2006

This work described 3 infection cases caused by Rhodococcus equi in foals between 3 and 5 months of age. The disease histories were not fully taken from local veterinarians. At least 1 sick foal has been treated with cephalothins followed by penicillins during approximately 1 week, but died without effectiveness and other foals rearing with the animal have been suffering from severe pneumonia which show high fever, laboring respiration, cough and/or nasal discharge. There were many abscessations into lungs of 2 foals in postmortem examination and another 1 sample was pus collected from abscess around the shoulder, indicating the osteomyelitis. Those bacteria were grampositive coryneform and were identified as a R. equi by a polymerase chain reaction (PCR) using primers for R. equi-specific vapA gene. The pathogens were usually resistant to penicillin, ampicillin, amoxycillin/clavulanic acid, cefazolin, clindamycin, sulfamethoxazol/trimethoprim, kanamycin, and tetracycline, while were sensitive to ciprofloxacin, norfloxacin, orfloxacin, gentamicin, erythromycin, neomycin, and vancomycin. Some more foals with respiratory symptoms in 1 horse farm were treated by orally administration with erythromycin during 2 weeks. Because the combination of erythromycin and rifampin has recommended as the treatment for R. equi infections in foals, the local equine veterinarian can choose those antibiotics for the treatment of this disease in future. However, another antimicrobial agent may be necessary if R. equi resistant to both agents is isolated.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.12
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• pp.1775-1779
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• 2012

The aim of the present work was to investigate how colour changes of foal meat can vary after thawing out in relation to the slaughtering age of the horses and to the post-thawing time. Eighteen Italian Heavy Draught Horse (IHDH) foals were used for the trial. They were subdivided in three groups according to their slaughtering age (6, 11 and 18 months). Two different surfaces were investigated for each sample: a fresh cut surface (daily renewed cutting surface: DRCS), and not-renewed cutting surface (NRCS). The redness of both investigated surfaces increased with slaughtering age (p<0.01). Moreover, this parameter decreased during post-thawing time (p<0.01) only on the NRCS, probably due to the myoglobin oxidation processes. Colour is an important visual cue denoting perceived quality by consumers. So, by a chromatic perspective the thawed meat of IHDH foals slaughtered at 6 and 11 months proved to be that which best meets the market requirements.

• Korean Journal of Veterinary Research
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• v.48 no.2
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• pp.139-143
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• 2008

We report here two cases of Rhodococcus (R.) equi-causing pneumonia of Throughbred foals in Gyeonggi-do in 2006. R. equi was isolated from the lung lesions of the dead foals, and from the feces and soils on the farms where the clinical cases of R. equi infection occurred. The isolates were characterized by biochemical properties, polymerase chain reaction for vapA gene and antimicrobial susceptibility. In drug susceptibility test, erythromycin, gentamycin, vancomycin, and rifampin were found to be the most susceptible for all isolates. These results suggest that R. equi pneumonia may be endemic in the horse-breeding farms in inland Korea and the farm environment may be widely contaminated with virulent R. equi.