• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1215-1221
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• 2002

Normal haematological and biochemical indices along with thyroid hormone status were studied in healthy Kathiawari horses of different age groups (yearling, young stock, adults and old stock) belonging to either sex. Effect of both age and sex was observed on thyroid hormone levels, haematological and biochemical indices. In females, hemoglobin levels was significantly lower in yearlings than adult animals while total leukocyte counts were higher in yearlings than equids of other age groups. Sex had effect only on total erythrocyte counts, mean corpuscular hemoglobin concentration and mean corpuscular hemoglobin in horses of 1-3 years age group (young stock) and on packed cell volume in adult female and male equids. Among biochemical indices, activities of enzymes were observed to be influenced both by age and sex. Creatine kinase, gamma glutamyl transferase, glutamate pyruvate transaminase, glutamic oxaloacetate transaminase and lactate dehydrogenase activities were significantly higher in young and adult equids than animals of other age groups in Kathiawari horses while activity of alkaline phosphatase was significantly higher in yearlings than equids belonging to other age groups in both male and females. However, activity of sorbitol dehydrogenase was unaltered due to both sex and age factor. Albumin, bilirubin direct, bilirubin total, cholesterol, creatinine, protein, triglyceride and uric acid were statistically different in various age and sex groups of horses. Calcium, magnesium and chloride contents were almost same in various age groups of male horses. Significantly higher levels of $T_3$ and $T_4$ were observed in both male and female yearlings as compared to equids of other age groups in both the sexes.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.792-799
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• 2022

Dopamine (DA) is known to be a key modulator of animal behaviors. Thus, the plasma concentration of DA might be used as a biomarker for the behavioral characteristics of horses. The behavioral characteristics of horses vary depending on the breed, age, and sex. Moreover, the DA receptor genotypes are also related to horse behaviors. Thus, the aim of this study was to investigate the DA concentration variations of horse plasma by breed, age, sex, or genotype of its receptor. The horses were divided by breed into Thoroughbred (n = 13), Pony (n = 9), Warmblood (n = 4), and Haflinger (n = 5). The age variable was divided into three different groups: post-pubertal (2-5 years, n = 6), adult (6-13 years, n = 19), and aged horses (15-24 years, n = 6). The sex variable was divided into geldings (n = 8) and mares (n = 23). Approximately 10 mL of blood was collected, and an ELISA kit was used to measure the plasma concentration of DA. Polymerase chain reaction analysis was performed to identify the genetic variation in the DA D4 receptor gene (DRD4). SPSS statistical software was used for statistical analysis. The DA concentrations in geldings were significantly lower than those in mares. There was no significant difference in DA concentrations among breed and age groups. Horses with the GG and GA genotypes had significantly higher plasma concentrations of DA compared to horses with the AA genotype for the G292A gene. Briefly, the plasma concentration of DA varied depending on the sex and genotype of G292A. These factors should be considered when the concentration of DA is used as a biomarker for the behavioral characteristics of horses. In conclusion, the DA concentration or DRD4 genotype of horse plasma has the potential to be used as a biomarker that can predict the behavioral characteristics of horses.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1632-1637
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• 2006

We studied the changes in biochemical markers of bone metabolism in growing Thoroughbred horses. Serum osteocalcin (OC), as a marker for bone formation, and carboxy-terminal propeptide of type-I collagen (PICP), as a marker for bone formation, carboxy-terminal telopeptide of type-I collagen (ICTP), as a marker for bone resorption, were determined in nine clinically healthy horses from 3 d to 17 mo of age. The BW and withers height (WH) increased during the study. On the other hand, a rapid reduction in body weight gain (BWG) was observed between 1 mo and 9 mo of age and a rapid reduction in withers height gain was observed between 1 mo and 5 mo of age. The serum markers decreased significantly with increasing age. In particular, dramatic changes in serum markers occurred between 3 d to 1 wk and 5 to 7 mo of age in these horses, which suggests that bone turnover rapidly decreased after birth. On the other hand, the ratio of PICP to ICTP decreased through the experiment. This result suggests that the reduction in bone formation exceeded that of bone resorption. There was a significant correlation between markers and growth parameters, except for the correlation between PICP and BWG on single linear regression analysis. Serum OC and ICTP were affected by the WH in multiple linear regression analysis. These results indicated that the age-related variation in serum biochemical markers of bone metabolism reflected bone growth, but neither BW nor BWG. Therefore, we consider that changes in bone modeling are the major factor affecting the levels of serum biochemical markers by 17 mo of age in horses.

• Journal of Animal Science and Technology
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• v.63 no.3
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• pp.651-661
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• 2021

This study aimed to investigate whether breed, sex, and age affected temperament differently (more or less neophobic) in mature horses during a novel object test. The study included Jeju crossbred (n = 12, age = 9.42 ± 4.57 y), Thoroughbred (n = 15, age = 10.73 ± 3.09 y), and Warmblood horses (n = 12, age = 13.08 ± 3.55 y) with the females (n = 22, age = 11.36 ± 4.24 y) and geldings (n = 17, age = 10.65 ± 3.66 y). Jeju crossbreds (Jeju horse × Thoroughbred) are valuable considering their popular usage in Korea, but limited studies have explored temperament of Jeju crossbred horses. A trained experimenter touched the left side of the neck with a white plastic bag (novel object). The test ended when the horse stopped escape response and heart rate (HR) dropped to baseline. Behavioral score and escape duration were measured as behavioral variables. Multiple variables related to HR and heart rate variability (HRV) were measured to reflect emotional state. These included basal HR (BHR), maximum HR (MHR), delay to reach maximum heart rate (Time to MHR), standard deviation of beat-to-beat intervals (SDNN), root mean square of successive differences (RMSSD), and ratio of low to high frequency components of a continuous series of heartbeats (LF/HF). Statistics revealed that Thoroughbreds had significantly higher behavioral scores, and lower RMSSD than Jeju crossbreds (p < 0.05), suggesting greater excitement and fear to the novel object in Thoroughbreds. None of the behavioral or cardiac parameters exhibited sex differences (p < 0.05). Age was negatively correlated with SDNN and RMSSD (p < 0.05), indicating that older horses felt more anxiety to the novelty than younger horses. Thoroughbreds and females had distinct correlations between behavioral and HRV variables in comparison with other groups (p < 0.05), implying that escape duration might be a good indicator of stress, especially in these two groups. These results are expected to improve equine welfare, safety and utility, by providing insights into the temperament of particular horse groups, to better match reactivity levels with specific functions.

• Journal of Animal Science and Technology
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• v.50 no.6
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• pp.857-864
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• 2008

This study was conducted to identify various habits of stable vices and its occurring frequency in racing horses, currently managed in Korea, through categorizing the total 1,386 head of racing horses in Seoul Racing Park into sex, age and years of stabling. Among the 1,386 horses, 524 heads(37.8%) have shown habits of stable vices and its appearances rate according to each category is as following; While 40.7% of stallions showed the highest appearances rate of stable vices by sex, it was 50%, 44.2%, and 53% for the age of 2, 6 and 4, respectively by age, it was 41%, 40.6% and 39.1% for the years of stabling of 2, 4 and 3, respectively. For the appearances rate of individual stable vices, 7.0% of mares showed the highest appearances rate of ‘kicking at walls’, 12.9% of stallions showed ‘biting habit’ and 5.7% of castrated horses showed ‘weaving’ when grouped by sex. According to age, 8.3%, and 6.1% of horses of age 2 showed ‘kicking at walls’, ‘wind-sucking’ and ‘pawing’, respectively while 4.9% of horses of age 3 showed ‘pawing’, 6.4% of horses of age 4 showed ‘kicking at walls’, 6.8% of horses of age 5 showed ‘kicking at walls’ and ‘biting habit’ and 8.7% of horses of age 6 showed ‘weaving’ and ‘biting habit’. By the year of stabling, 6% of horses for 1 year had ‘pawing habit’, 7% og horses for 2 years had ‘kicking at walls’, 7.4% of horses for 3 years had ‘biting habit’ and it was 6.9% and 10.6% for ‘weaving’ for 4 and 5 years of stabling, respectively. In conclusion, the racing horses in Korea seemed to show high rate of appearance rate of stable vices and it is considered to be necessary to improve stable equipments and management skills to reduce the appearance rate of stable vices.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.417-426
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• 1998

During the 5 years period(93-197) of Seoul racecourse Thoroughbred racing, 2i963 holies took an active part in Seoul Racecourse and 61,181 horses entered the racing.400 horses(305 : 1 time, 76 :2 times, 19 :3 times, total : 514 cases) had bled(EIPH) from their nostils after their races. Incidence of bleeding horses from the 21963 racehorses was 13.5%, and incidence of bleeding cases from the 61,181 horses was 0.84%. The average racing frequence (1.05 times/1 month) of bleeders was more than that(0.8 times/1 month) of total race-horses. There was tendency to higher incidence of bleeding at older in age, female in sex, England/ Ireland horses in origin, higher grade in performances heavier in body weight increased, larger in weight to be carried, mid or longer in racing distance, handicap race, spring in season. Relationship did not exist between bleeding and respiratory disease. These results suggested that frequent entering into the race should be controlled. And body weight regulation with conditioning is recommended far reducing incidence of EIPH. It is supposed to prevent bleeding that decrescent performance horses should not be entering long distance or handicap race.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.66.1-66.8
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• 2022

Background: Prospective clinical study of blood lactate concentration in horses undergoing colic surgery is needed to determine utility in outcome prediction. Objectives: To evaluate venous lactate measurements in horses following colic surgery, including immediately after anesthetic recovery and daily throughout hospitalization, as well as to determine if lactate concentrations were significantly higher in horses that developed postoperative complications or did not survive to hospital discharge. Methods: Horses > 1 year of age undergoing surgery for colic and recovered from general anesthesia were sampled. A portable lactate meter was used to measure venous samples collected immediately following anesthetic recovery and daily throughout hospitalization. Complications arising during hospitalization and survival to hospital discharge were recorded. Results: Fifty one horses were enrolled, ranging in age from 2 to 29 years. Lactate concentration immediately following anesthetic recovery was higher in horses that developed complications during hospitalization (p = 0.046). The odds of developing complications postoperatively were doubled for horses with a venous lactate concentration > 5 mmol/L. Lactate measurements in non-survivors were significantly higher compared to survivors by 96 h postoperatively (p < 0.006). Conclusions: Higher venous lactate concentrations in the postoperative colic period were associated with an increased risk of complications and death. Results suggest horses with higher venous lactate measurements in recovery are more likely to have postoperative complications, with the odds of developing complications doubled for horses with a venous lactate > 5 mmol/L. Evaluation of venous lactate could provide information on prognosis in the postoperative period for horses with surgical colic.

• Journal of Veterinary Science
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• v.23 no.3
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• pp.44.1-44.10
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• 2022

Background: The equine temporomandibular joint (TMJ) has a complex anatomical structure that makes diagnosis of TMJ disorders difficult. Computed tomography (CT) is now available in equine medicine; hence, TMJ evaluation has become more convenient. Objectives: The objectives of this study were to describe the CT features of the TMJ in Jeju horses and to compare these features with those of Thoroughbreds. Methods: In this report, the TMJs of 10 Jeju horses (mean age: 4.5 ± 1.9 yr; mean body weight: 282.6 ± 40.3 kg) and 6 Thoroughbreds (mean age: 7.3 ± 1.6 yr; mean body weight: 479.7 ± 44.0 kg) were examined using CT. After CT scanning, the Hounsfield units (HU) and height to width ratio (H:W) of the mandibular condyle were measured. Results: The mean H:W in Jeju horses was significantly lower than that in Thoroughbreds. The mean HU in Jeju horses was lower than that in Thoroughbreds; however, the difference was not significant. The most frequent CT finding was an irregular medial margin of the mandibular condyle in both breeds. Conclusions: In this study, the shape of the mandibular condyle in Jeju horses was flatter than that in Thoroughbreds. This report could be useful in evaluating the TMJ in Jeju horses. Moreover, CT could be a pragmatic choice for the examination of the TMJ in horses.

• Journal of Animal Science and Technology
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• v.59 no.1
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• pp.2.1-2.6
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• 2017

Background: This study aimed to analyze the on heart rate, blood lactate concentration, packed cell volume (PCV) and hemoglobin (Hb) response after conducting exercise in endurance horses. Methods: A total of 20 healthy 3-9-years-old Jeju crossbreed mares ($5.95{\pm}2.24$ year) of age and $312.65{\pm}13.59kg$ of weight) currently participating the endurance competition were used. The field tests selected for the experiment was gallop (approximately 8.3 m/s) along the selected 2.5 km course (a natural forest trail, not artificial road; a closed loop course). The horses were divided into three groups according to their age; 3-4 years of age (G1, $3.29{\pm}0.49$ year), 6-7 years of age (G2, $6.42{\pm}0.53$), and 8-9 years of age (G3, $8.50{\pm}0.55$). The measurements times for the heart rate, blood lactate concentration, PCV, and Hb analysis were conducted before exercise (T0), shortly after exercise (T1), 15 min after exercise (T2), and 30 min after exercise (T3), respectively. Data was analyzed using an analysis of covariance (ANCOVA) for repeated measures with times and groups. Results: The results of the comparison depending on the passage of rest time after exercise suggest that the heart rate and blood lactate concentration of three groups at T2 significantly decreased compared to T1 (p < 0.001). PCV of the G2 and G3 groups were significantly decreased at T2 compared to T1 (p < 0.01). Hb values at G2 (p < 0.01) and G3 (p < 0.001) groups were significantly decreased at T2 as compared to T1. However, heart rate, blood lactate concentration, PCV and Hb level at T1 showed no difference in the comparison of horses from different age groups with the exception of G3 group in terms of heart rate. Conclusion: The physiologic and hematological responses of horses during recovery time after 2,500 m exercise with gallop were no significant difference among the groups. These data are useful as a response evaluation method for training of endurance horses.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.81.1-81.12
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• 2023

Background: The incidence of colic and the outcomes of colic surgery have not been surveyed in racetracks in Korea. Objectives: This study examined the incidence, mortality, and case fatality of colic and investigated the effects of age and sex after an exploratory celiotomy on the long-term survival rate (return to racing), subsequent racing performance, and career longevity. Methods: The incidence, mortality, and case fatalities of colic were examined over an 11-year period. The records of 40 horses that had undergone a celiotomy, after participating in at least one race and 75 race-matched control horses were analyzed. The racing performance and career length of the horses that returned to racing post-surgery were compared with a control group. Results: The annual incidence, fatality rate of colic, and annual mortality rate at Seoul Racecourse were 6.5, 2.8 per 100 horse-years, and 0.2 deaths cases per 100 horse-years, respectively. Of the 40 horses that underwent colic surgery, 26 (65%) returned to racing. The likelihood of returning to racing decreased with increasing age of the horses, and geldings had a lower probability of returning. While the performance in the five preoperative races between the two groups was not significantly different, a significant decrease in racing performance was observed after the surgery date (p < 0.01). Horses that underwent colic surgery did not show a significant decrease in career length. Conclusions: Surgical treatment for colic at the age of three and four years had a negative impact on the racing performance. On the other hand, there was no significant difference in career longevity between the two groups.