多機能超音波画像診断によるセラピーホースに適した馬の妊娠および胎子検査

• Material Type: 博士論文
• Title: 多機能超音波画像診断によるセラピーホースに適した馬の妊娠および胎子検査
• Author/Editor: 高, 遠之
• Author Heading: 高, 遠之
• Publication, Distribution, etc.: 帯広畜産大学
• Publication Date: 2023-09-29
• Publication Date (W3CDTF): 2023-09-29
• Alternative Title: Multifunctional ultrasound examination of pregnancy mare and fetal in pony for Equine- Assisted Therapy
• Degree grantor/type: 帯広畜産大学
• Date Granted: 2023-09-29
• Date Granted (W3CDTF): 2023-09-29
• Dissertation Number: 甲第137号
• Degree Type: 博士（獣医学）; Doctor of Veterinary Medicine
• Text Language Code: jpn
• Alias of Author: GAO, Yuanzhi
• NDC: 649
• Target Audience: 一般
• Note (General): application/pdf; 北海道和種馬は日本において重要な動物である。保有数が年々減少する現状の中で、如何に保護するのが重要な課題の1つである。生産性向上の要として、流産防止は馬繁殖効率向上の一番の課題である。そのため、本研究は北海道和種馬妊娠馬に関する研究に着目し、第1章から第3章までの実験を行った。この研究を通じて、より効率的な北海道和種馬の生産を可能とすることを目標とした。第1章では、北海道和種馬の正常妊娠時の胎子健康指標を計測した。妊娠時胎子のFEO、CTUP、FHR、FGL、FKL並びに妊娠馬の血中ホルモン測定は胎子評価の大事の指標である。後程の第3章においてもその重要性を表してる。また本実験における最大の発見は胎子性腺の大きさと母体E2濃度の相関が発見したことである。この結果から妊娠中の妊娠維持のためのE2産生メカニズムと胎子性腺との関係が更に明らかになった。第2章では、初めて馬を用いて3D超音波検査を使用し、妊娠早期胎子性別判断を行った。馬においての生前胎子性別判断は従来ほとんど2D超音波検査を使用したが、本実験から、2D超音波検査より3D超音波検査は性別判断が容易になり、更に2D超音波検査より10日早めに性別判断が出来ることが判明した。将来3D超音波検査はより有用な胎子性別判断法として期待できる。第3章は馬胎子巨大膀胱の症例報告である。馬の巨大膀胱は非常に稀な症例であり、この章では、馬胎子巨大膀胱の妊娠全期間の経過、胎子指標および母体ホルモン変化を詳細に記録した。この症例から得られたデータは将来馬胎子巨大膀胱の診断に有用と思われる。また本症例の観測はほとんど経腹壁超音波検査のみ可能であるため、改めて妊娠後期の経腹壁超音波検査の重要性も重視すべきと思われる。最後に以上の実験から、更に北海道和種馬の妊娠に関する知見が深まり、将来的な北海道和種馬の生産に役立つこと、また、この知見を他の保有数の少ない馬でも応用できることが期待される。; The Hokkaido Native Pony is one of the eight native Japanese Native horse breeds that live in Japan. The Hokkaido Native Pony is 120-130 cm in height and has a mild temperament, making it suitable for horse-assisted therapy. However, the number of Hokkaido Native Pony is decreasing year by year. In addition, little research has been conducted on the breeding of Hokkaido Native Pony.Ultrasound imaging is an important tool in the examination of equine reproduction. In order to improve the breeding efficiency of Hokkaido Native Pony, this study was conducted to investigate fertility in Hokkaido Native Pony using multifunctional ultrasound technology by conducting Experiments 1-3.Experiment 1 measured fetal well-being parameters in normal Hokkaido Native Pony for the whole gestation period.Embryo transplants were performed on 5 Hokkaido Native Pony and crossbreds from 2018-2020, totaling 7 gestational periods. Examinations were performed every week using an ultrasound imaging system to measure uteroplacental thickness (CTUP); fetal eye orbital length (FEO); gonadal length (GL); and fetal heart rate (FHR) through the rectal or abdominal wall using linear and convex probes.FHR reached a peak of 180 ± 6.3 beats/min from 9-13 weeks of gestation and then decreased until full-term; FEO could be measured from 10 weeks gestation and increased until full-term, reaching 35 ± 2.5 mm before delivery; CTUP could be measured from 13 weeks of gestation and increased until fullterm, reaching 8.6 ± 0.6 mm before delivery; and GL was measured from 9 weeks of gestation and increased until full-term. GL was measurable from 16 weeks of gestation to full term and was peaked at 27-37 weeks of gestation, then decreased until full term.FHR has the ability to detect fetal abnormalities such as fetal acid deficiency and cardiovascular system stunting, CTUP was used for ascending placentitis, and FEO was reported to be useful as a simple indicator of fetal development. In addition, GL was found to be consistent with estradiol secretion dynamics, which is important for the maintenance of pregnancy. This experiment will enable early detection of pregnancy abnormalities in Hokkaido Native Pony and is expected to improve equine productivity.Experiment 2 used 3D ultrasound to determine the fetal gender of pony in early pregnancy.A total of 9 pregnancies of 5 Hokkaido Native Pony were performed from 2020 to 2023. Fetal gender determination was performed once every 5 days between 50 and 100 days of gestation. At the time of examination, the fetal was first determined by transrectal examination with a linear type probe. Then, the probe was replaced with a 3D probe of the convex type, and the subabdominal region of the fetal was moved to the center of the screen. The fetal 3D volume was scanned three times when mares were at rest and then analyzed posteriorly.Results showed that all 2D and 3D examination results were consistent with postpartum fetal sex. The gestational age at which fetal gender could be determined by 2D and 3D ultrasound ranged from 50 to 80 days of gestation. For 2D ultrasound, the highest detection rate was at 70 days gestation (66.7%). For 3D ultrasound, the highest detection rate was 60 days (55.6%).Fetal gender determination in pregnant horses is a technique of enormous benefit. This experiment was the first study to evaluate the utility of 3D ultrasound fetal gender determination in pony. In this experiment, all fetal 3D ultrasound images from gestation 50 to 100 days were feasible. The advantage of 3D ultrasound is that it can scan the fetus without changing the angle of the probe during the examination, which is considered to be more accurate than 2D ultrasound.Experiment 3 was a case report of early detection of fetal enlarge bladder by transabdominal ultrasound prenatal diagnosis.The pregnant mare in this case was an 8-year-old Hokkaido Native Pony whose embryo was transferred from a Kiso-pony in Nagano on June 10, 2021, and arrived at Obihiro University of Agriculture and Veterinary Medicine on the same day. At 215 days of gestation, a low-intensity ultrasound image of a fetal abdominal abnormality was observed for the first time during transabdominal ultrasound examination. Subsequently, at 229 days of gestation, it was determined that the abnormal image was the bladder, based on its position in relation to the other organs. Thereafter, the abnormal bladder was visible until delivery, and its volume increased as the pregnancy progressed.Since the fetus did not appear to give birth until 30 days past the due date, delivery was induced at 363 days of gestation, and a live foal was born. The foal was euthanized without treatment due to congenital defects other than a enlarge bladder.This was the first case in which a giant bladder in a fetal was observed during prenatal diagnosis, and the fetal was subsequently born alive. In this case, the fetal enlarge bladder was found to have no effect on other health parameters. Surprisingly, the fetal was born alive without bladder rupture. Thus, the enlarge bladder in equine fetal can be detected by ultrasonography even at the gestational stage. Compared to the fatal that not be examined prenatally, the treatment can be performed more quickly and precisely. On the other hand, in the clinical enlarge bladder can also be associated with hydronephrosis. In the present case, the kidneys were not abnormal until delivery. Further studies are required to clarify the mechanism of enlarge bladder complications. Finally, although there are still many unclear issues regarding equine congenital diseases, widespread prenatal examination of equine fetal can be expected to increase the survival rate of equine fetal by identifying the condition of the fetal at the gestational stage and preparing for treatment of fetal abnormalities before delivery.The data collected in this study is expected to be fundamental research that can contribute to improving the productivity of Hokkaido Native Pony in the future.; 博士学位論文; 大学院畜産学研究科 獣医学専攻; Doctoral Program of Veterinary Science
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• Collection (Materials For Handicapped People:1): テキストデータ
• Collection (particular): 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文; https://dl.ndl.go.jp/collections/A00014
• Acquisition Basis: 博士論文（自動収集）
• Date Accepted (W3CDTF): 2023-12-15T22:13:23+09:00
• Format (IMT): application/pdf
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• Periodical Title (URI): https://obihiro.repo.nii.ac.jp/records/2000048
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