著者

Fumiro KASHIWAMURA Avarzed AVGAANDORJ Keiko FURUMURA

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.12, no.1, pp.1-7, 2001 (Released:2001-10-27)

参考文献数

13

被引用文献数

3 16

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The body size and weight of 584 Banei draft racehorses at Obihiro Racing Stable in Hokkaido, Japan, was investigated. Almost all the animals (94.7%) were cross-breed heavy draft horses; there were a few Percheron and Percheron grade (4.8%) and a Belgian breed (0.5%). The ages of the animals ranged from 2 to 10 years. Males accounted for 80.3%, females for 17.5%, and 2.2% were castrated. The mean body measurements of 2-year-old Banei draft racehorses were significantly smaller than those of the 3-to 4-year-old or 5-to 10-year-old horses. Hip width, croup width, and rump length of females were greater than those of males. In contrast, males had greater chest width and cannon bone circumference than females. Significant relationships among almost all body measurements were observed. A high correlation was found between body weight and chest girth, croup width and body length. A principle component analysis were applied to investigate the effect of body conformation on racing performance in terms of earnings and the time on the performance test. Performance was significantly related to the principle components of general body size and weight of the horses. The cannon bone, body length, and rump length were suggested to have an effect on earnings per race in 2-year-old male horses. In terms of body size and conformation, the Banei draft racehorses, which are large in general size and well balanced, seemed to show high performance.

著者

Kousuke TANAKA Atsushi HIRAGA Toshiyuki TAKAHASHI Atsutoshi KUWANO Scott Edward MORRISON

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.26, no.2, pp.67-71, 2015 (Released:2015-07-02)

参考文献数

12

被引用文献数

2

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We applied aluminum hinged shoes (AHSs) to the club foot-associated contracted feet of 11 Thoroughbred yearlings to examine the effects of the shoes on the shape of the hoof and third phalanx (P III). After 3 months of AHS use, the size of the affected hooves increased significantly, reaching the approximate size of the healthy contralateral hooves with respect to the maximum lateral width of the foot, the mean ratio of the bearing border width to the coronary band width, and the mean ratio of the solar surface width to the articular surface width. These results suggest that the AHSs corrected the contracted feet in these yearling horses.

出版者

日本ウマ科学会

雑誌

Japanese Journal of Equine Science (ISSN:09171967)

巻号頁・発行日

vol.3, no.2, pp.207-212, 1993-03-30 (Released:2010-06-28)

著者

柏村 文郎

出版者

日本ウマ科学会

雑誌

Hippophile (ISSN:18836062)

巻号頁・発行日

vol.13, pp.19-28, 2002

著者

野崎 有以

出版者

日本ウマ科学会

雑誌

ヒポファイル (ISSN:18836062)

巻号頁・発行日

no.44, pp.11-24, 2011-04

著者

柏村 文郎

出版者

日本ウマ科学会

雑誌

Hippophile (ISSN:18836062)

巻号頁・発行日

vol.31, pp.21-27, 2008

著者

小島 亮

出版者

日本ウマ科学会

雑誌

Hippophile (ISSN:18836062)

巻号頁・発行日

no.47, pp.10-15, 2012-01

著者

Hajime OHMURA James H. JONES

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.28, no.3, pp.99-103, 2017 (Released:2017-09-20)

参考文献数

25

被引用文献数

15

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We investigated changes in heart rate (HR) and HR variability as a function of age in newborn foals to old Thoroughbred horses. Experiments were performed on a total of 83 healthy and clinically normal Thoroughbred horses. Resting HR decreased with age from birth. The relationship between age and HR fit the equation Y=48.2X-0.129(R2=0.705); the relationship between age and HR for horses 0–7 years old fit the equation Y=44.1X-0.179(R2=0.882). Seven-day-old horses had the highest HR values (106 ± 10.3 beat/min). The low frequency (LF) and high frequency (HF) powers increased with age in newborn to old horses. These changes in HR and HR variability appear to result from the effects of ageing. Three- to seven-year-old race horses had the lowest HR values (32.9 ± 3.5 beat/min) and the highest LF and HF powers except for the HF powers in the oldest horses. Race training may have contributed to these changes. Horses of ages greater than 25 years old had the highest HF powers and the lowest LF/HF ratios. In individual horses, 8 of the 15 horses over 25 years old had LF/HF ratios of less than 1.0; their HR variability appears to be unique, and they may have a different autonomic balance than horses of younger age.

著者

妹尾 俊彦 平山 八彦 明間 鯉一郎 呉 守一

出版者

日本ウマ科学会

雑誌

日本中央競馬会競走馬保健研究所報告 (ISSN:03685543)

巻号頁・発行日

vol.1965, no.3, pp.123-131, 1965-12-20 (Released:2011-02-23)

参考文献数

11

著者

Daisuke MIYAKOSHI Hiroyuki SENBA Mitsumori SHIKICHI Masaya MAEDA Ryo SHIBATA Kazuhiro MISUMI

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.27, no.2, pp.67-76, 2016 (Released:2016-06-21)

参考文献数

14

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This study aimed to evaluate the influence of radiographic abnormalities of 2-year-old Thoroughbred horses that were listed at in-training sales in Japan, on whether they started to race or not at 2–3 years of age. Radiographs of 850 2-year-old Thoroughbreds in the in-training sales repository from 2007 to 2010 were reviewed, and 26 categories of radiographic abnormalities were found. Forty-three horses (5.1%, 43/850) did not start a race at 2–3 years of age. In accordance with the racing results for this age category, as determined by Fisher’s exact test and multiple logistic regression analysis, none of the radiographic abnormalities were significantly related to failure to start a race. At 2 years of age, 198 horses (23.3%, 198/850) did not start a race. Horses with enlargement of the proximal sesamoid bones in the fore (9 of 19 horses) and hind limbs (5 of 9 horses) did not start a race at the age of 2 years, and fewer of these horses (fore, P=0.021; hind, P=0.030) started a race at the age of 2 years compared with the population of horses without these radiographic abnormalities. These results suggest that identification of radiographic enlargement of the proximal sesamoid bones during training sales could derail the racing debut of horses at the age of 2 years. However, this might not necessarily indicate a poor prognosis and resulting in retirement from racing at 2–3 years of age.

著者

Toshiyuki TAKAHASHI

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.26, no.2, pp.43-48, 2015 (Released:2015-07-02)

参考文献数

8

被引用文献数

1 17

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The running performance of Thoroughbred racehorses has been reported to peak when they are between 4 and 5 years old. However, changes in their racing speed by month or season have not been reported. The purposes of this study were to reveal the average racing speed of Thoroughbreds, and observe changes in their average speed with age. The surveyed races were flat races on turf and dirt tracks with firm or standard track conditions held by the Japan Racing Association from January 1st, 2002 to December 31st, 2010. The racing speed of each horse was calculated by dividing the race distance (m) by the horse’s final time (sec). Average speeds per month for each age and distance condition were calculated for each gender group when there were 30 or more starters per month for each age and distance condition for each gender group. The common characteristic change for all conditions was an average speed increase up until the first half of the age of 4 years old. The effect of increased carry weight on average speed was small, and average speed increased with the growth of the horse. After the latter half of the age of 4 years old, the horses’ average speed remained almost constant, with little variation. It is speculated that decreases in the weight carried; and the retirement of less well performing horses; are responsible for the maintenance of average speed.

著者

Kayo TERADA

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.11, no.4, pp.83-90, 2000 (Released:2001-08-16)

参考文献数

17

被引用文献数

13 52

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The aim of this study was to see if differences in proficiency exist between advanced-and novice-level horseback riders with regard to head movement and EMG activity. Three advanced-and three novice horseback riders rode a horse at a walk, sitting trot and canter whilst their head acceleration and the EMG activity of their rectus abdominis muscle (M. rectus abdominis), erector spinae muscle (M. erector spinae) and abductor magnus muscle (M. adductor magnus) were recorded simultaneously. All results were conducted with Frequency Analysis by the Maximum Entropy Method. At walk, the novice rider showed a frequency distribution dispersion (P<0.1) of the head in the proximal-distal direction which was not observed in the advanced rider, but no distinct primary factors were observed in the muscular discharge frequency distributions-perhaps due to the novice rider's level which was not completely inexperienced. At a sitting trot, unstable movements of the novice rider's upper body were observed in the cranial-caudal direction (P<0.05), mirroring the horse's violent rocking movements. The electromyogram frequency distributions at this gait suggest that the novice rider was unable to balance the erector spinae and rectus abdominis muscles, and therefore unable to cope with the unstable movement. It also suggests that there was instantaneous muscular activity of the adductor magnus muscle in order to stabilize the ill-balanced body. At a canter, there were no significant differences in the dispersion of acceleration frequency distribution or in the electromyogram frequency distribution, but although there were no "significant" differences, the results obtained from the advanced rider at this gait showed a dispersion of acceleration frequency distribution that was slightly greater than that of the novice rider. This situation was only observed at a canter. In conclusion, differences exist in the degree of difficulty of coordination between horse and rider according to the gait. In addition, from the results of this study, we can clearly see that differences also exist in the rider's own skill and ability to "maintain posture".

著者

Yusuke HORI Takatoshi OZAKI Yoshimitsu YAMADA Teruaki TOZAKI Heui-Soo KIM Ayaka TAKIMOTO Maiko ENDO Noboru MANABE Miho INOUE-MURAYAMA Kazuo FUJITA

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.24, no.3, pp.31-36, 2013 (Released:2013-09-30)

参考文献数

15

被引用文献数

2 12

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Genetic polymorphisms in genes related to neurotransmitters or hormones affect personality or behavioral traits in many animal species including humans. In domestic animals, the allele frequency of such genes has been reported to be different among breeds and it may account for breed differences in behavior. In this study, we investigated breed differences in horses in the dopamine receptor D4 gene (DRD4), which has been reported to affect horse personality. We collected samples from seven horse breeds including those native to Japan and Korea, and compared the sequence of the DRD4 exon3 region among these breeds. We found that there were two types of polymorphisms (VNTR and SNPs) in the exon3 region, and some of them seemed to be breed-specific. In addition, we found that the allele frequency of G292A, reported to be associated with horse personality, differed greatly between native Japanese horses and Thoroughbred horses. The frequency of the A allele which is associated with low curiosity and high vigilance, was much lower in native Japanese horses (Hokkaido, 0.03; Taishu, 0.08) than in Thoroughbreds (0.62). This difference may account for breed differences in personality or behavioral traits. Further studies of the function of these polymorphisms and their effect on behavior are indicated.

出版者

日本ウマ科学会

巻号頁・発行日

vol.(39);2010・1, 2010-01

著者

江藤 大介 羽田 哲朗 草野 寛一 甲斐 眞 楠瀬 良

出版者

日本ウマ科学会

雑誌

Journal of equine science = Continuation of Japanese Journal of Equine Science and Bulletin of Equine Research Institute (ISSN:13403516)

巻号頁・発行日

vol.15, no.3, pp.61-65, 2004-09-01

参考文献数

12

著者

天田 明男 栗田 晴夫

出版者

日本ウマ科学会

雑誌

日本中央競馬会競走馬保健研究所報告 (ISSN:03685543)

巻号頁・発行日

vol.1975, no.12, pp.89-100, 1975

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競走馬における発作性心房細動の発症の実態を知る目的で,レースで1着馬から大差で遅れてゴールインした馬について心電図学的調査を実施した。調査は,1973年4月から11月までの8カ月間,京都,阪神,中京の各競馬場における出走馬を対象として行った。その結果,サラブレッド競走馬5例に発作性心房細動を認めた。心房細動は,いずれの症例もレース中に発症したが,23時間以内に洞調律に自然に復帰した。5例のうち2例において,,洞調律復帰後の心電図に心房性期外収縮が認められた。<BR>いずれの症例も,洞調律復帰後ただちにトレーニングを再開し,心房細動発症以前と同様の競走成績をあげ得た。しかし,5例のうち1例は,5カ月後に心房細動の再発が認められた。<BR>これらの症例の観察から,競走馬における発作性心房細動の病因,臨床的意義などについて考察した。

著者

永田 雄三

出版者

日本ウマ科学会

雑誌

日本中央競馬会競走馬保健研究所報告 (ISSN:03685543)

巻号頁・発行日

vol.1971, no.8, pp.91-99, 1971

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競走馬用に作成した完全配合飼料を一定量摂取することによって得られるエネルギー量が,Medium Trainingに耐えられるものであるかどうかを血糖値の変動を尺度として検討した。 競走馬は牝の3才馬で育成期を終えたものを使用し,本実験期間中いわゆる競走調教法を実施した。また,実験の最初と中間と最後に日本における慣例的な競走馬の能力検査を行った。競走調教法には試作処方によるインタバルトレーニング法を採用した。血糖値の定量は,朝飼付後3時間目を運動前の安静値とし,その後運動開始し,そして運動後5分値と60分値を測定した。 摂取した可消化エネルギー量は約23,700Kca1,体重1kg当り52,6Kca1と算出された。実験期間1カ月の前半15日間に馬の体重は2.3~4.5%減少したが,その後15日間はほとんど体重の変動はなかった。 3回の能力検査の際の運動負荷においては,最終800mの全力疾走時間が60秒以上のときは,馬の血糖値は運動後二過性の上昇または下降をし,その増減の割合は運動前の30%以内であった。そして,60分後にはいつれもほぼ安静値に回復した。一方,一例だけ最終800mを56秒で走った馬は,運動後34 mg/100 mlまで血糖値が下がり,グルコースの組織内とりこみがかなり大きかったことをものがたっていた。しかしながら,このケースも60分後には安静値に回復したところから,馬の肝臓中にはかなりのグリコーゲが貯蔵されていたものと推定される。 インタバルトレーニングによる運動負荷の場合,血糖値の変動は能力検査の場合よりもやや大きく上昇または下降した。その増減の割合は運動前の値の70%以内であった。しかし,もっとも下ったのは48mg/100mlであった。能力検査の場合に比して,インタバルトレーニングを負荷したときの血糖値の変動は増減がかなり大きかったが,これは運動の強度が質的・量的にかなり異なり,強くそして複雑であったことによるものと推察される。いつれにせよ,運動後の血糖値の激減がみられなかったこと,また,60分後には安静値に近い値に回復していることから,インタバルトレーニングによる運動負荷量約6,800Kcalに対して・完全配合飼料8.5kg摂取による栄養は大体収支がつぐなわれていたと思われる。

著者

富岡 義雄 兼子 樹広 及川 正明 兼丸 卓美 吉原 豊彦 和田 隆一

出版者

日本ウマ科学会

雑誌

日本中央競馬会競走馬総合研究所報告 (ISSN:03864634)

巻号頁・発行日

vol.1985, no.22, pp.22-29, 1985

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競走馬の中手骨 (Mc) における骨塩含量 (BMC/BW; g/cm²) の部位および左右肢間の差を明らかにするとともに, BMC/BWに影響を与える因子を検討するため, ボーンミネラルアナライザー (BMA) を用いて競走馬15頭28肢のMcを測定した. 放射性アメリシウム (²⁴¹Am) を線源としたBMAの測定値は精度ならびに再現性に優れていた. このBMAを用いて水槽内に保定したMcを内外側方向で, 遠位関節面から1cmごとに20cm近位まで20個所のBMC/BWを測定したところ, その測定値を図示すると一定のパターンを示した. それは遠位関節面より1cmならびに17cm近位部にピークをもち, 遠位関節面より近位5cm部を最低値とするものであった. また左右Mc間に差はみられなかった. 緻密骨からなる骨幹中央部のBMC/BWは出走回数, 出走期間ならびに馬体重と有意の正の相関を示し, またこの値は59か月齢まで加齢にともない上昇した. 一方, 海綿骨のBMC/BWは遠位関節面から1cm近位部で極めて高値を示した. またこの値は出走回数出走期間ならびに加齢と有意の正の相関を示した.

出版者

日本ウマ科学会

巻号頁・発行日

1998

出版者

日本ウマ科学会

雑誌

Japanese Journal of Equine Science (ISSN:09171967)

巻号頁・発行日

vol.4, no.1, pp.97-100, 1993-09-30 (Released:2010-06-28)