研究者詳細 - 大澤　健司

Intra-abdominal mass containing controlled internal drug release (CIDR) devices detected by CT in a Japanese Black cow 査読あり国際共著

Sato R., Satoh H., Okada S., Goda Y., Sueun K., Kuroda K., Inoue Y., Kitahara G., Osawa T.

Journal of Veterinary Medical Science 84 ( 8 ) 1088 - 1092 2022年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Veterinary Medical Science

This report describes an intra-abdominal mass caused by progesterone-containing controlled internal drug release (CIDR) devices in the abdominal cavity of a 28-month-old Japanese Black heifer presenting with infertility. Rectal examination revealed a mass containing a cartilage-like object in the pelvic cavity. Computed tomography revealed a mass containing two T-shaped foreign bodies. Laparotomy was performed to remove the mass containing the foreign bodies. The heifer was healthy at discharge seven days post-surgery. This case adds CIDR device as a new etiology for intra-abdominal masses. Furthermore, it highlights the usefulness of CT in diagnosing deep abdominal lesions.

DOI： 10.1292/jvms.22-0180

黒毛和種経産牛の正常分娩に伴う子宮頸管熟化におけるコラーゲン組成に関連した変化

山之口瑛悟, 北原豪, 小林郁雄, 邉見広一郎, 菱川善隆, CHOIJOOKHUU Narantsog, 山口良二, 大澤健司

日本繁殖生物学会　講演要旨集 114 ( 0 ) OR - 32-OR-32 2021年9月

担当区分：責任著者記述言語：日本語掲載種別：研究論文（その他学術会議資料等）出版者・発行元：公益社団法人日本繁殖生物学会

【目的】分娩に伴う頸管熟化には生理的な炎症反応を伴うこと，さらにⅠ型コラーゲンの変化が頸管熟化に関連することがヒトやマウスでは示唆されているが，牛では不明である。牛の臨床現場では長期在胎や陣痛微弱による難産と死産が問題となっており，このような問題を防ぐために頸管熟化を促進させる方法の開発と応用が期待される。そこで，本研究では牛における正常な子宮頸管熟化機構と関連する変化の一端を明らかにすることを目的として，妊娠後期から分娩までのコラーゲンの変化に注目した試験を実施した。【材料と方法】宮崎大学農学部附属牧場の2～14産目の黒毛和種経産牛14頭を供試した。人工授精から分娩までの日数は293±4（平均±SD）日であった。人工授精後200（±3）日，260（±3）日，274（±3）日，288（±3）日，以降7日間隔で分娩直前（0～6日前）まで子宮頸管組織をパンチ生検で採取，さらに子宮頸管粘液を用手で採取した。頸管組織はピクロシリウスレッド染色し，偏光顕微鏡で観察と撮影を行い，得られた画像を用いⅠ型コラーゲンを示す領域が組織の総面積に占める割合を画像処理ソフト（ImageJ）で算出した。頸管粘液はディフクイック染色で有核細胞400個に対する多形核好中球の割合（PMN％）を算出した。【結果】Ⅰ型コラーゲンの組織に対する割合は，初回採材（分娩の12～13週間前）時点で94.8%から最終採材時では72.5％と低下した（p<0.05）。頸管粘液中のPMN％は初回採材時に最も低く（0.01％），分娩4～5週間前までに22.0％と上昇（p<0.05）し，分娩1週間前までに最高値（50.9％）を示した。【考察】以上の結果より，牛の頸管熟化には頸管組織におけるⅠ型コラーゲンの減少が関与していることが示唆された。また，頸管粘液中のPMNの増加の後にコラーゲンが変化し始めていることから，PMNによる炎症とPMNが分泌するコラゲナーゼが頸管熟化に影響することが推察された。

DOI： 10.14882/jrds.114.0_OR-32

黒毛和種牛の正常産と難産における母牛骨盤と産子サイズ比の比較招待あり

前田　崇史, 北原　豪, 大澤健司

畜産技術 796 9 - 15 2021年

担当区分：最終著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）

Intrauterine infusion of povidone-iodine: Its effect on the endometrium and subsequent fertility in postpartum dairy cows 査読あり

Rumika Yoshida, Go Kitahara, Takeshi Osawa

Journal of Veterinary Medical Science 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

Severe degenerative changes in cryptorchid testes in Japanese Black cattle 査読あり

Fuke N, Kitahara G, Ito S, Van Diep N, Ping Teh AP, Izzati UZ, Myint O, Hirai T, Torisu S, Kaneko Y, Sato H, Hidaka Y, Osawa T, Yamaguchi R

Veterinary Pathology 300985820906891 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）

DOI： 10.1177/0300985820906891

Endocrinological characterization of an ovarian sex cord-stromal tumor with a Sertoli cell pattern in a Japanese Black cow. 査読あり

El-Sheikh Ali H, Kitahara G, Nibe K, Osawa T

Reproduction in Domestic Animals = Zuchthygiene 54 ( 11 ) 1501 - 1504 2019年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

DOI： 10.1111/rda.13556

Daily calving frequency and preterm calving is not associated with lunar cycle but preterm calving is associated with weather conditions in Japanese Black cows 査読あり

Quantitative relationship between climatic conditions and the conception rate of Japanese Black cattle in commercial cow–calf operations 査読あり

Kino Erina, Uematsu Mizuho, Kitahara Go, Osawa Takeshi, Sasaki Yosuke

Livestock Science 228 170 - 176 2019年8月

記述言語：英語掲載種別：研究論文（学術雑誌）

Sasaki Y., Kitai N., Uematsu M., Kitahara G., Osawa T.

PLoS ONE 14 ( 7 ) e0220255 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PLoS ONE

© 2019 Sasaki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Several external factors including lunar cycle and weather conditions might be associated with calving conditions. Our objective here was to determine the effects of lunar cycle and weather conditions on calving frequency and the occurrence of preterm calving in Japanese Black cows. Calving records were obtained from 905 farms in Miyazaki Prefecture, Japan. Data were collected from 41,116 calvings. We conducted two studies: Study 1 investigated the effects of lunar cycle and weather conditions on daily calving frequency (DCF) with the observational unit of each day and Study 2 investigated those effects on the occurrence of preterm calving with the observational unit for each calving. Preterm calving was defined by whether or not a cow calving before 280 days of gestation, lower 10th percentile of gestation length of the collected data, and by whether or not a cow calving before 289 days of gestation, median of the gestation length. For Study 1, lunar cycle was not associated with DCF in all cows, in only primiparous cows and in only multiparous cows. As well as lunar cycle, weather conditions such as temperature, diurnal temperature variation, the temperature-humidity index, precipitation amount, barometric pressure, relative humidity and solar radiation, were also not associated with DCF. For Study 2, lunar cycle phases were not associated with the occurrence of preterm calving. However, preterm calving was associated with all of the weather conditions (P < 0.05) except for precipitation amounts and solar radiation. Temperature, the temperature-humidity index and relative humidity were positively associated with the occurrence of preterm calving. In contrast, diurnal temperature variations and barometric pressure were negatively associated with the occurrence of preterm calving. In conclusion, the lunar cycle was not associated with DCF and preterm calving, but the weather conditions were associated with preterm calving.

DOI： 10.1371/journal.pone.0220255

黒毛和種牛における発情発見方法と分娩率との関連性査読あり

紀野瑛里奈, 上松瑞穂, 北原豪, 大澤健司, 佐々木羊介

産業動物臨床医学雑誌 9 ( 0 ) 207 - 210 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：日本家畜臨床学会・大動物臨床研究会

本研究の目的は，黒毛和種牛における発情発見方法と分娩率との関連性を分析することである．宮崎県に所在する黒毛和種牛の繁殖農場272 戸を対象として，発情発見方法に関するアンケート調査を実施し，各発情発見方法の実施手段と分娩率との関連性および複数の発情発見方法の組み合わせと分娩率との関連性を分析した．発情発見の各方法に関して，実施農場と非実施農場との間で分娩率を比較したところ，発情発見方法として鳴き声を用いている農場が用いていない農場よりも分娩率が高かった（53.1 ± 0.9% vs. 50.2 ± 0.9%；p < 0.05）．また，発情発見方法が「粘液のみ」であった農場は，「粘液＆行動＆鳴き声」または「粘液＆鳴き声」の組み合わせで実施している農場よりも分娩率が低かった（p < 0.05）．結論として，本研究では牛の鳴き声を発情発見の一つとして用いることが分娩率と関連しており，発情の見落としや遅れを防ぐために，個々の牛に対する観察に十分な時間をかけることが繁殖成績を向上させるうえで重要であることが示唆された．

DOI： 10.4190/jjlac.9.207

ホルスタイン種経産牛における悪露の色とその後の子宮内膜炎罹患との関係

末永哲也, 南野知也, 三栗野陽子, 堀井洋一郎, 北原豪, 大澤健司

日本繁殖生物学会　講演要旨集 112 ( 0 ) OR2 - 25-OR2-25 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本繁殖生物学会

【目的】乳牛における子宮内膜炎診断は分娩後5週以降での実施が一般的である。一方，より早期に罹患リスクを予測し，対策を講じることができれば，その後の繁殖成績を向上させることが期待できる。そこで本研究では産褥期の子宮内環境の指標として悪露を用い，悪露の色とその後の子宮内膜炎罹患との関係性を調査した。【材料と方法】大分県内の一酪農場にて繋養のホルスタイン種経産牛29頭を供試し，分娩後2日，5日，1週（分娩後11±3日）および2週（分娩後18±3日）の悪露を採取，デジタルカメラにて撮影し，その色をRGB解析した。RGB解析では，R値，G値，B値，計3つの値の二乗の和の平方値を濃淡指数（0〜441：0が黒，441が白）とし，255からR値を除した値，G値，B値の3つの値の二乗の和の平方値を赤色指数（0～441：0が赤）とした。また，分娩後2日における悪露の腟内貯留の有無で貯留群（n=22）と非貯留群（n=7）に分類した。なお，貯留群は赤色指数の中央値（182.7）を閾値とし，これより低いものを赤色群，高いものを非赤色群とした。分娩後2日に直腸温が39.3℃以上の個体を産褥熱と診断，分娩後5週（分娩後36±3日）にサイトブラシを用いて子宮内膜細胞診を行い，多形核好中球浸潤度（PMN%）が6以上の個体を子宮内膜炎と診断した。得られたデータより，悪露の色とPMN%および子宮内膜炎罹患との関係を解析した。【結果】赤色群の45.6%（5/11），非赤色群の9.0%（1/11）の個体が産褥熱と診断された。PMN%は貯留群が7.7±1.9（平均±SD）と，非貯留群の2.4±0.9より高かった（P<0.05）。また，分娩後2週における濃淡指数とPMN%は正の相関（r=0.538，P<0.05）を示した。【結論】分娩後2日における悪露の色や貯留の有無が分娩後5週の子宮内膜における炎症度と関係していることが示唆された。また，分娩後2週における悪露の濃淡指数とその後の子宮内膜炎罹患のリスクとの関連が示唆された。

DOI： 10.14882/jrds.112.0_OR2-25

Characterization of anti-Müllerian hormone in a case of bovine male pseudohermaphroditism 査読あり

Kitahara G., El-Sheikh Ali H., Teh A., Hidaka Y., Haneda S., Mido S., Yamaguchi R., Osawa T.

Reproduction in Domestic Animals 53 ( 3 ) 809 - 813 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Reproduction in Domestic Animals

© 2018 Blackwell Verlag GmbH The current report aimed to characterize plasma anti-Müllerian hormone (AMH) in bovine male pseudohermaphroditism. The blood AMH concentration in a Japanese Black male pseudohermaphrodite calf was compared with pre- and post-pubertal male and female calves and castrated calves. The concentration in the case was higher than in post-pubertal males, castrated males, and pre- and post-pubertal female calves (p <.05), but similar to that in pre-pubertal male calves. After extraction of the testes, the concentration in the case dropped to a certain extent. The extracted testes expressed AMH, as detected by immunohistochemistry. This study is the first to show the characterization of AMH in a male pseudohermaphrodite calf. AMH levels in peripheral blood might be useful to diagnose male pseudohermaphroditism in cattle.

DOI： 10.1111/rda.13149

Association of interservice interval with conception rate in Japanese Black cattle 査読あり

Irikura N, Uematsu M, Kitahara G, Osawa T, Sasaki Y

Reproduction in Domestic Animals 53 ( 4 ) 1020 - 1023 2018年4月

記述言語：英語掲載種別：研究論文（学術雑誌）

Effect of exogenous estradiol Benzoate on uterine blood flow in postpartum dairy cows 査読あり

Rawy M, Mido S, El-Sheikh Ali H, Derar D, Megahed G, Kitahara G, Osawa T

Animal Reproduction Science 192 136 - 145 2018年3月

記述言語：英語掲載種別：研究論文（学術雑誌）

DOI： 10.1016/j.anireprosci.2018.03.001

Different prostaglandin F₂α secretion in response to oxytocin injection between pregnant and non-pregnant cows: effect of the day of oxytocin challenge test for determining the difference 査読あり

Kubo T., Iga K., Fukuju N., Kizaki K., Osawa T., Izaike Y., Takahashi T.

Animal Science Journal 89 ( 2 ) 332 - 339 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Animal Science Journal

© 2017 Japanese Society of Animal Science The present study was conducted to determine the difference in plasma prostaglandin F 2 α metabolite concentrations following oxytocin (OT) challenge between pregnant and non-pregnant cows. Experiment 1: cows were subjected to the OT challenge test on days 12, 14 or 16 (day of estrus = day 0) with or without prior insemination and plasma 13,14-dihydro-15-keto prostaglandin F 2 α (PGFM) concentrations were measured from −30 to 180 min after OT injection. On day 16, the increment of plasma PGFM concentrations in response to OT injection was significantly smaller in pregnant than that in cyclic cows. On days 12 and 14, there was little OT-induced PGFM secretion and no difference in PGFM increase between the pregnant and cyclic cows. Experiment 2: cows were inseminated on day 0 and subjected to the OT challenge test on day 16. Cows were classified into non-pregnant/early embryonic death (NP/EED), late embryonic death (LED) and pregnant (PREG) groups. The increment of PGFM concentrations in response to OT injection was less in both PREG and LED groups than that in the NP/EED group. In conclusion, plasma PGFM secretion induced by OT is suggested as the base of pregnancy diagnosis prior to returning estrus in cows.

DOI： 10.1111/asj.12952

Associations of periparturient plasma biochemical parameters, endometrial leukocyte esterase and myeloperoxidase, and bacterial detection with clinical and subclinical endometritis in postpartum dairy cows 査読あり

Nazhat S., Kitahara G., Kozuka N., Mido S., Sadawy M., Ali H., Osawa T.

Journal of Veterinary Medical Science 80 ( 2 ) 302 - 310 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Veterinary Medical Science

© 2018 The Japanese Society of Veterinary Science. This study was aimed at demonstrating associations between peripheral biochemical parameters, endometrial leukocyte esterase (LE) and myeloperoxidase (MPO), and bacterial detection with the degree of endometrial inflammation, and determining the best time postpartum for diagnosing endometritis to predict subsequent fertility in dairy cows. Plasma albumin, blood urea nitrogen (BUN), total cholesterol (T-cho), NEFA, and BHBA concentrations were analyzed in 43 Holstein cows at 3, 5 and 7 weeks postpartum (W3, W5 and W7). Endometrial samples were collected at W3, W5 and W7 to examine LE and MPO activities, bacterial detection rates, and PMN% profiles. The 43 cows were divided into healthy (HE), subclinical endometritis (SE), and clinical endometritis (CE) groups, classified differently at W3, W5 and W7 based on the definitions of SE and CE for each of the three weeks pp. LE level had an association with PMN% in all weeks pp (P < 0.05). Albumin and BUN levels had weak negative associations with endometrial PMN% at W3. Pathogenic bacterial detection rates were higher in the cows with endometritis at W3 and W5. Conception rate at first artificial insemination tended to be lower (P=0.057) in the cows diagnosed with endometritis at W3 than in the healthy cows. In conclusion, associations were found between endometrial LE and endometritis, but not for MPO and endometritis. Diagnosing endometritis in W3 may be the best moment to predict subsequent fertility.

DOI： 10.1292/jvms.17-0478

Effects of service number on conception rate in Japanese Black cattle 査読あり

Irikura N., Uematsu M., Kitahara G., Osawa T., Sasaki Y.

Reproduction in Domestic Animals 53 ( 1 ) 34 - 39 2018年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Reproduction in Domestic Animals

© 2017 Blackwell Verlag GmbH The conception rate (CR) of Japanese Black cattle has been decreasing since 1990. The objectives of this study were to compare CR by artificial insemination (AI) number, and to assess the interaction between AI number and possible factors related to CR in Japanese Black cattle. Records of 11,182 AI records for 6,741 heifers and 61,302 AI records for 13,139 cows on 977 farms were analysed. The average CR of heifers was 47.0%, and CR at the first, second and third AI was higher than at the fourth or subsequent AI (p < 0.05). The average CR of cows was 47.8%, and their CR at first and second AI was higher than the fourth or subsequent AI (p < 0.05). Data analysis with CR as the dependent variable revealed significant interactions of AI number with interval from calving to first AI and AI season. Cows first serviced at ≤48 days post-partum had lower CR than those at ≥90 days at first AI (p < 0.05), but the interval from calving to first AI did not affect CR at second AI. Cows serviced in the autumn had a higher CR at first AI than those serviced in the spring and winter (p < 0.05); however, there was no seasonal difference in CR at the second AI. In summary, CR began to decrease from the fourth AI in heifers and the third AI in cows. The AI season and the interval from calving to first AI significantly affected CR only at the first AI.

DOI： 10.1111/rda.13049

Validation of a novel timed artificial insemination protocol in beef cows with a functional corpus luteum detected by ultrasonography. 査読あり

Funakura H, Shiki A, Tsubakishita Y, Mido S, Katamoto H, Kitahara G, Osawa T

The Journal of reproduction and development 2018年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：日本繁殖生物学会

This study aimed to clarify the feasibility of a novel timed artificial insemination (TAI) protocol using ultrasonography, and to determine the associations between the ovarian component and fertility. In Experiment 1,272 Japanese Black cows with a corpus luteum (CL) ≥ 18 mm in diameter were divided randomly into either the TRT group (134 cows that were administered gonadotropin-releasing hormone [GnRH] 56 h [day 2] after prostaglandin F2α [PGF] administration [day 0], followed by TAI 16–20 h later) or the CN-1 group (138 cows that were administered PGF followed by AI after estrus detection). In addition, the CN-2 group was designated for 306 cows given PGF and inseminated after estrus detection in the past two years at the same farms. In Experiment 2, 38 cows had the same treatment as the TRT group, and the sizes of follicles and CL were video-recorded on days 0 and 2. In Experiment 1, the AI and ovulation synchronization rates were higher in the TRT group than those in the CN-1 group (100% vs. 87.0% and 89.2% vs. 33.3%, respectively) (P < 0.01). The pregnancy rate in the TRT group (60.4%) was higher than that in the CN-2 group (45.1%) (P < 0.05). In Experiment 2, cows with a larger CL diameter and greater CL volume on day 0 had a higher pregnancy outcome (P < 0.05). In conclusion, this protocol was effective for improving pregnancy rates in beef herds, and fertility was associated with the CL size at the time of PGF administration.

DOI： 10.1262/jrd.2017-135