Jeju Pony Research Articles

Comparison Analysis of Metabolites by Exercise in Thoroughbred and Korean Native Jeju Pony

Comparison Analysis of Metabolites by Exercise in Thoroughbred and Korean Native Jeju Pony

Effect of the Time of Trot on Hematology and Blood Chemistry in Jeju Pony Crossbreed Horses

Effect of the Time of Trot on Hematology and Blood Chemistry in Jeju Pony Crossbreed Horses

Research Trends and Implications for Preservation and Improvement of Jeju Ponies (Review)

Research Trends and Implications for Preservation and Improvement of Jeju Ponies (Review)

Comparison of Hippological Differences Between Jeju Ponies and Jeju Pony Crossbreds: II. The Incidence of Innate Pacers in the Jeju Raceresource

Comparison of Hippological Differences Between Jeju Ponies and Jeju Pony Crossbreds: II. The Incidence of Innate Pacers in the Jeju Raceresource

말의 4족 보법에서 속도변화에 따른 전족 움직임의 운동능력 분석

Objective : The purposes of this study was to analyze the locomotive movement of forelimbs according to changes in velocities in the quadruped cadence of horses. Methods : Horses selected as subjects consisted of Jeju pony horses (heights of withers: 1.23±0.51). Two camcorders (HDR-HC7/HDV 1080i, Sony Corp, Japan) were used to capture the movement of the horses’ forelimbs at a rate of 60 frames/sec. Additionally, raw data was collected from Kwon3D XP motion analysis package ver 4.0 program (Visol, Korea) with DARTFISH (DFKREA., Korea) video software solution. The variables analyzed consisted of 1 step lengths, 1 stride lengths, stance time, swing time, 1 stride time, velocity while walking, and trot of the horses. A two-way ANOVA and paired t-test of the variables by velocity and phase were treated at .05 level of significant difference, statistically. Results : The time elapsed of walk(stance: 0.63 sec[63.86%], swing: 0.35 sec[36.14%], 1 stride time: 0.99 sec respectively) showed significant difference with more delay than that of trot(stance: 0.29 sec[45.73%], swing: 0.34 sec[54.27% ], 1 stride time: 0.63 sec respectively), and also showed significant difference at trot in interaction (stance time>tort swing>walk swing>walk stance). The 1 step lengths and stride lengths in trot showed significant difference with longer than that of walk. Velocity of Trot showed significant difference statistically with higher than that of walk Conclusion : The horses’ velocity during 1 step lengths and 1 stride lengths showed a proportional relationship, but the correlation between the horses’ velocity and stance time showed a negative relationship during the quadruped cadence.

Incidence of Wolf Teeth in Jeju Ponies and Jeju Pony Crossbreds

Incidence of Wolf Teeth in Jeju Ponies and Jeju Pony Crossbreds

Investigation of De Novo Unique Differentially Expressed Genes Related to Evolution in Exercise Response during Domestication in Thoroughbred Race Horses

Previous studies of horse RNA-seq were performed by mapping sequence reads to the reference genome during transcriptome analysis. However in this study, we focused on two main ideas. First, differentially expressed genes (DEGs) were identified by de novo–based analysis (DBA) in RNA-seq data from six Thoroughbreds before and after exercise, here-after referred to as “de novo unique differentially expressed genes” (DUDEG). Second, by integrating both conventional DEGs and genes identified as being selected for during domestication of Thoroughbred and Jeju pony from whole genome re-sequencing (WGS) data, we give a new concept to the definition of DEG. We identified 1,034 and 567 DUDEGs in skeletal muscle and blood, respectively. DUDEGs in skeletal muscle were significantly related to exercise-induced stress biological process gene ontology (BP-GO) terms: ‘immune system process’; ‘response to stimulus’; and, ‘death’ and a KEGG pathways: ‘JAK-STAT signaling pathway’; ‘MAPK signaling pathway’; ‘regulation of actin cytoskeleton’; and, ‘p53 signaling pathway’. In addition, we found TIMELESS, EIF4A3 and ZNF592 in blood and CHMP4C and FOXO3 in skeletal muscle, to be in common between DUDEGs and selected genes identified by evolutionary statistics such as FST and Cross Population Extended Haplotype Homozygosity (XP-EHH). Moreover, in Thoroughbreds, three out of five genes (CHMP4C, EIF4A3 and FOXO3) related to exercise response showed relatively low nucleotide diversity compared to the Jeju pony. DUDEGs are not only conceptually new DEGs that cannot be attained from reference-based analysis (RBA) but also supports previous RBA results related to exercise in Thoroughbred. In summary, three exercise related genes which were selected for during domestication in the evolutionary history of Thoroughbred were identified as conceptually new DEGs in this study.

Identification of reference genes for normalization of gene expression in thoroughbred and Jeju native horse(Jeju pony) tissues

Quantitative analysis of horse gene expression profiles under diverse experimental conditions is limited by the lack of reliable reference genes for normalization of mRNA levels. Therefore, in this study, the expression of potential reference genes was compared between thoroughbred and Jeju native horse (Jeju pony). We compared the expression of nine genes by quantitative real-time RT-PCR in fourteen tissues between the two horse breeds and analyzed their stability using the geNorm and NormFinder programs. The data obtained in this study suggest that the UBB gene could serve as a reference gene in gene expression analysis of thoroughbred and Jeju native horses.

국내 경주마의 주파기록에 대한 품종별 비교 분석

Horse Science Research Center, Pusan National University, Miryang, Gyeongnam, 627-706, KoreaABSTRACTThis study was conducted to provide basic information for the improvement of racing performance of Jeju pony & Halla horse, using the 85,732 racing records collected from Jeju & Kwacheon racecourses from January 1, 2005 to December 31, 2009. During the last 5 years, a total of 2,892 heads of horses were racing at the Jeju racecourse and 11.7%(338 heads) of them were Jeju ponies. The average body weight of Jeju pony and Halla horse were 267kg & 287kg, respectively, which were 58% and 62% of that of Thoroughbred(460kg). The repeatabilities of Jeju pony, Halla horse and Thoroughbred for finishing time were estimated in the range of 0.26-0.66(average, 0.54), 0.34-0.68(average, 0.56) and 0.37-0.60(average, 0.50), respectively, and as the racing distance increased, the repeatabilities decreased. In the racing distance of 1,000 m, the differences in the finishing times between Thoroughbred & Jeju pony, Thoroughbred & Halla horse, and Jeju pony & Halla horse were 24.33 seconds, 10.81 seconds and 13.52 seconds, respectively. The racing performance of Halla horse was improved by 55.6% than that of Jeju pony at the 1,000 m race.(Key words :Jeju pony, Halla horse, Thoroughbred, Finishing time, Repeatability)

Age of the Jeju pony (Equus caballus) at first reproduction: potential costs for foals and mothers that first reproduce early in life

In a related paper, we showed that mares that reproduced early in life tended to have higher fecundity because of a decrease in the duration of inter-birth intervals relative to mares that reproduced later in life. However, we know that young mares are subordinate to older mares. Hence, costs associated with low dominance rank might offset the benefits of earlier reproduction. We compared harassment of foals of female Jeju ponies that first reproduced at three years of age with that of foals of females that first reproduced at five years of age. As a consequence of their positions in the linear dominance hierarchy, foals born to and guarded by young mares were harassed more frequently than foals whose mothers were older when they first reproduced. A mare that reproduced early in life guarded her offspring more closely and intervened between her foal and neighboring mares more frequently than those mares which first reproduced when older. This need to guard their foals and the harm that might ensue from frequent harassment might counter-balance selection towards earlier reproduction in mares.

Sex Preferences in Jeju Pony Foals (Equus caballus) for Mutual Grooming and Play-Fighting Behaviors

We investigated mutual grooming by Jeju pony (Equus caballus) foals to determine whether male foals preferentially interact with potential future sexual partners or competitors. We predicted that relative to female foals, male foals would exchange grooming more frequently with young mares and that in general, foals would mutually groom more frequently with the opposite sex rather than the same sex. Observing 53 foals between April and October 1998, we recorded 113 mutual grooming events. Male foals exchanged grooming with yearling mares more frequently than with their mother, while female foals exchanged grooming with their mother more frequently than with yearling mares. Contrary to the prediction, foals were not more likely to mutually groom with a foal of the opposite sex than with a foal of the same sex. In our study, 21 instances of play-fighting behavior followed mutual grooming between peers. Relative to intersexual grooming events, play-fighting was more likely to follow intrasexual mutual grooming, and male foals were much more likely to play fight than female foals. These results provide evidence that Jeju pony foals develop and maintain social relationships at the earliest stage of their lives. We suggest that early social experiences might influence social bonding later when the male foal begins to form a harem after separation from its mother.

Gender Differences in Maternal Intervention in Jeju Ponies (Equus caballus)

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 (<TEX>$2\sim11$</TEX> years old) were as likely to intervene as those in the elder age class (<TEX>$17\sim25$</TEX> 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.

Behavioral ecology of the Jeju pony (Equus caballus): Effects of maternal age, maternal dominance hierarchy and foal age on mare aggression

On Jeju Island, Korea, dominance hierarchy and maternal care according to maternal age were studied in a herd of Jeju ponies (Equus caballus), consisting of 73 mares, their foals and one stallion. Dominance ranks were nearly linear and increased significantly with the age of mares. Most aggressive encounters involved mares under 5 years old. Mares under the age of 5 years have apparently not established their rank. The mean frequency of aggressive actions of mares per hour increased significantly as the day of parturition approached. Aggressive actions of mares with foals decreased significantly as their foals aged. The overall frequency of aggression of mares with foals also decreased significantly with the age of the mares. Our results suggest that the cost of maternal care is lower for older, more dominant mares than for subordinate ones.

Age-specific fertility rates of the Jeju pony ( Equus caballus )

Age-specific fertility is an essential parameter of life history. Here we report age-specific fertility rates, measured as the number of foals per mare per year, for Jeju ponies aged 2–28 years. The total sample consisted of 545 foals produced by 178 mares from 1988 to 2002. The mean fertility rate across all ages of the mares was 0.65 foals/mare per year (±0.24 SD). The fertility rates were above average for the 7- to 8- and 19- to 20-year-old mares, whereas they were relatively low for mares under 4 years old. The fertility rates tended to increase with the age of the stallion, but the relationship was not significant (n =15, P =0.09). The incidence of inter-birth interval was not associated with the age that the mare first reproduced (n =64 mares, P =0.99). However, mares that reproduced later in life tended to have a reduced fertility rate due to an increase in the duration of inter-birth intervals relative to mares that reproduced earlier (n =4 years of first reproduction, P =0.068). The fertility rates of Jeju ponies were lower than for other horses, perhaps because only one stallion was introduced to a relatively large herd every year. We suggest that the introduction of more stallions to the herd each year would increase fertility rates.

Difference of early experience of foals according to dominance ranks of their mothers in the Jeju pony (Equus caballus)

In order to determine whether foals of more 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.

Diurnal activity patterns of Jeju ponies (equus caballus)

We investigated seasonal variation of diurnal activity patterns in Jeju ponies (Equus caballus). The data were collected from a semi‐natural herd during daylight hours from March to September 1998. Over all months, the mean proportion of time spent grazing was 83.7% (±29.7 S.D.); that resting was 15.7±17%, grooming 0.7±1.2%, and moving 0.56±5.4% Activity patterns varied with the seasons. The mean proportion of grazing mares peaked during late winter and early spring (March), when there was not enough food, and declined during other seasons (between May and September), when food was abundant. The mean proportion of mares that were resting and mutual grooming peaked in spring (April and May), at which time the weather was warm and food became abundant. During other seasons when grasses started to grow and the weather was mildly cool, these activities were less common. The mean proportion of mares that were moving peaked in June, although it was a small proportion of the total activity. For those mares witho...