論文 - 大澤 健司
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Nabenishi H., Kitahara G., Takagi S., Yamazaki A., Osawa T.
Domestic Animal Endocrinology 60 19 - 24 2017年7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：Domestic Animal Endocrinology
© 2017 Elsevier Inc. To use plasma anti-Müllerian hormone (AMH) concentrations as early-stage markers for donor cow selection, we investigated the relationship between plasma AMH concentrations in Japanese black heifers and subsequent embryo productivity following superovulation treatment. Plasma AMH and nonesterified fatty acid (NEFA) concentrations in 6 heifers were evaluated once per month from 3 mo before successful AI for primiparity to 3 mo postpartum. Following calving, embryo collection by superovulation treatment was performed at 3- to 4-mo intervals. There were no significant differences in plasma AMH concentrations between the time points throughout the study period. There were, however, significant inter-animal differences in plasma AMH concentrations (P < 0.05). These findings suggest that plasma AMH concentrations were stable over time and individually specific. There were significant positive correlations between plasma AMH concentrations before AI and embryo productivity variables, including the number of ova/embryos (number of transferable embryos, degenerated embryos, and unfertilized oocytes) and numbers/proportions of fertilized and transferable embryos. There was no significant correlation between plasma AMH and NEFA concentrations throughout the study period. These findings reveal that plasma AMH concentrations during the rearing period can be used to predict subsequent embryo productivity following superovulation treatment, suggesting that these concentrations are useful early-stage markers for selecting donor cows.
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黒毛和種牛における人工授精後のhCGとGnRHの2段投与による受胎率向上 査読あり
佐藤知広，北原 豪，大澤健司
家畜診療 64 ( 6 ) 335 - 344 2017年6月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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宮崎県における和牛繁殖農場の飼養管理の疫学調査および飼養規模と地域間における比較 査読あり
入倉 法子, 上松 瑞穂, 北原 豪, 大澤 健司, 佐々木 羊介
日本畜産学会報 88 ( 3 ) 303 - 313 2017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：公益社団法人 日本畜産学会
本研究では，宮崎県に所在する黒毛和種牛の繁殖農場を対象として，繁殖雌牛に対する飼養管理の実態を調査した．本研究に用いた農場数は331農場であり，母牛頭数の平均は21.3±1.8頭であった．農場の飼養規模に関して，母牛頭数が1～10頭である農場の割合は，44.3%と最も多かった．母牛の飼養頭数が1～10頭である農場を小規模農場，21頭以上である農場を大規模農場とした．分娩前後において，分娩予定牛を分娩房で飼養する農場割合は大規模農場が小規模農場に比べて高かったが（<i>P</i><0.05），繁殖雌牛をつなぎで飼養する農場割合は小規模農場が大規模農場よりも高かった（<i>P</i><0.05）．分娩時に敷料としてのこくずを使用する農場割合は，大規模農場で83.9%と最も高かった（<i>P</i><0.05）．発情確認の方法では，腟内温度センサーを使用する農場割合は，大規模農場が小規模農場に比べて高かった（<i>P</i><0.05）．結論として，本研究では黒毛和種繁殖雌牛に対する飼養管理が飼養規模で異なることを明らかにした．
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Sasaki Y., Uematsu M., Kitahara G., Osawa T.
Theriogenology 86 ( 9 ) 2156 - 2161 2016年12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：Theriogenology
© 2016 Elsevier Inc. The Japanese Black is the most common breed of beef cattle in Japan. However, only limited data are available on the associations of season, parity, and herd size with reproductive performance in Japanese Black cattle. Therefore, the objective of the present study was to determine the associations of these factors with reproductive performance parameters, such as the calving to first service interval (CFSI) and first service conception rate in Japanese Black cattle. Data were collected from 34,763 calvings in 13,186 animals from 826 commercial cow-calf operations in the Miyazaki prefecture, which is located on the south eastern coast of Kyushu, Japan. This region has a temperate climate with warm humid summers and cold winters. All cattle were reared intensively, and the animals were housed in free stalls throughout their lives. The mean number of cows per farm was 18 (range, 1–454). All animals were bred by artificial insemination. Herds were classified into three groups based on size: small (≤10 cows), intermediate (11–50 cows), and large (≥51 cows). The mean (±SD) parity, CFSI, and the first service conception rate were 4.9 ± 2.9, 80.0 ± 46.2 days, and 53.5 ± 49.9%, respectively. Cows that calved in the spring (March to May) and winter (December to February) had the longest CFSI (P < 0.05). The CFSI in first-parity cows was shorter than in cows at parity 7 or higher (P < 0.05). Cows in large herds had an approximately 10 days shorter mean CFSI than those in small herds (P < 0.05). Cows inseminated in the winter or spring had an approximately 5% points lesser first-service conception rate (FSCR) than those inseminated during the summer (June to August) or autumn (September to November; P < 0.05). As parity increased from 1 to 9, FSCR decreased from 60.0% to 43.1% (P < 0.05). Cows in small herds had a lesser FSCR than those in intermediate and large herds (P < 0.05). In summary, decreased reproductive performance in intensively reared Japanese Black cattle was associated with calving and artificial insemination during the winter and spring, greater parity, and small herd size.
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Kitahara G., Kamata R., Sasaki Y., El-Sheikh Ali H., Mido S., Kobayashi I., Hemmi K., Osawa T.
Domestic Animal Endocrinology 57 127 - 132 2016年10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：Domestic Animal Endocrinology
© 2016 Elsevier Inc.The aim of this study was to clarify the time-course of changes in anti-Müllerian hormone (AMH) and testosterone (T) concentrations in peripheral blood and to determine the relationships between blood AMH concentration and testicular development during the early postnatal and prepubertal periods in beef bull calves. A total of 17 Japanese Black bull calves were enrolled in this study. The wk in which the calf was born (within 6 d after birth) was defined as M 0. Blood samples were taken once in every mo from M 0 to M 6 from each bull calf, and plasma AMH and T concentrations were determined. Of the 17 calves, 10 were castrated at 6 mo of age (prepuberty) and the right testis was histologically examined. Plasma AMH concentration (means ± SE) at M 0, 1, and 2 were 123.5 ± 9.8, 189.6 ± 18.7, and 254.6 ± 14.1 ng/mL, respectively. From M 0 through M 2, plasma AMH concentration was significantly greater each mo than in the previous mo (P < 0.05); however, plasma AMH concentration significantly decreased over the last 3 mo of the study (P < 0.05). The average age at which plasma AMH concentration was the highest was 2.3 ± 0.1 mo of age. Plasma T concentration significantly increased from M 0 (0.18 ± 0.02 ng/mL) until M 6 (6.52 ± 1.41 ng/mL). Plasma AMH and T concentrations at M 4, 5, and 6 were significantly negatively correlated (P < 0.05). Linear regression did not reveal a significant relationship between Sertoli or Leydig cell numbers and plasma AMH or T concentrations, respectively. In conclusion, blood AMH concentration peaks at 2 mo of age and is negatively correlated with blood T concentration from 4 to 6 mo of age. Although prepubertal blood AMH or T concentrations did not reflect Sertoli or Leydig cell numbers at the end of the prepubertal period, blood AMH concentration may be indicative of abnormal Sertoli cells function.
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Correlation of blood metabolite concentrations and body condition scores with persistent postpartum uterine bacterial infection in dairy cows 査読あり
Ghanem, E. M., Tezuka, E., Sasaki, Takahashi, M., Yamagishi, N., Izaike, Y., Osawa, T.
Journal of Reproduction and Development 62 ( 5 ) 457 - 463 2016年6月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Serum selenium and liposoluble vitamins in Japanese Black cows that had stillborn calves 査読あり
Uematsu, M., Kitahara, G., Sameshima, H., Osawa, T.
Journal of Veterinary Medical Science 78 1501 - 1504 2016年5月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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産業動物分野の卒後教育に関する全国アンケート調査 査読あり
北原 豪，池田正浩，梅村崇志，末吉益雄，大澤健司，森田哲夫，村上 昇
獣医畜産新報 69 ( 5 ) 349 - 354 2016年5月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Mido S., Murata N., Rawy M., Kitahara G., Osawa T.
Journal of Veterinary Medical Science 78 ( 4 ) 551 - 556 2016年4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
© 2016 The Japanese Society of Veterinary Science.Endometritis is one of the major diseases causing infertility in the cow. Intrauterine infusion of povidone-iodine (PVP-I) is a common treatment. However, the optimal concentration of PVP-I for treating endometritis effectively remains unknown. We tested concentrations of 2.0% or 0.5% PVP-I for treating clinical endometritis in dairy cattle. In Experiment 1, bacteria isolated from the uterus were incubated with either 2.0% or 0.5% PVP-I, and the numbers of bacterial colonies were counted. In Experiment 2, 18 cows with clinical endometritis were treated with either 2.0% or 0.5% PVP-I (n=9 in each group). Cytology samples and bacteria were collected using a cytobrush on weeks 0 (W0), 1 (W1) and 2 (W2) after treatment. Subsequent reproductive performance was compared between the two groups. In Experiment 1, both concentrations had a similar antiseptic outcome. In Experiment 2, the percentage of polymorphonuclear neutrophils (PMN%) in the endometrial epithelium at W2 in the 2.0% group was significantly lower (P<0.05) than in the 0.5% group, although the PMN% decreased significantly from W0 to W2 (P<0.01) in both groups. Decreases in bacterial infection rates from W0 to W2 were similar in both groups. The first service conception rate was higher, numbers of services per conception were fewer, and time to conception was shorter in the 2.0% group than in the 0.5% group. Thus, an intrauterine infusion of 2.0% PVP-I was better than 0.5% in treating clinical endometritis in these dairy cattle.
DOI： 10.1292/jvms.15-0412
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Ghanem M., Ghanem M., Tezuka E., Sasaki K., Takahashi M., Yamagishi N., Yamagishi N., Izaike Y., Osawa T., Osawa T.
Journal of Reproduction and Development 62 ( 5 ) 457 - 463 2016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 Reproduction and Development
© 2016 by the Society for Reproduction and Development.To analyze the relationship of blood metabolite concentrations and body condition score (BCS) with persistent bacterial uterine infection, specifically that caused by Trueperella pyogenes and anaerobic bacteria, uterine bacteriological swabs (n = 128) were collected from 64 Holstein cows at 5 (W5) and 7 (W7) weeks postpartum, and the percentage of neutrophils in the endometrium was evaluated. Blood glucose, total cholesterol (T-cho), blood urea nitrogen (BUN), non-esterified fatty acid (NEFA), and β-hydroxybutyric acid concentrations were analyzed at 3 weeks (W-3) and 1 week (W-1) prepartum and W3, W5, and W7 postpartum. BCS were evaluated at W-3, W3, and W7. Blood glucose concentrations at W-3 and W-1 in cows with persistent bacterial infection were lower (P = 0.05) than in the rest of the cows. Total BUN concentrations in cows with persistent bacterial infection were lower (P < 0.01) than those in other cows, although the association between the pre or postpartum time and status of infection was not significant. Total NEFA concentrations in cows with persistent bacterial infection were similar to those in uninfected cows and cows positive for infection at W5 but not W7. Total BCS in cows with persistent bacterial infection were lower (P < 0.01) than those in cows positive for infection at both W5 but not W7 and W7 but not W5; however, the association between the pre or postpartum time and status of infection was not significant. Glucose concentrations at W-3 and W-1 negatively correlated with persistent bacterial infection at W5 and W7 (P < 0.01). BUN concentrations at W3 (P < 0.01), W5 (P < 0.05), and W7 (P < 0.05) and BCS at W3 (P < 0.01) negatively correlated with persistent postpartum bacterial infection. Decreased prepartum blood glucose concentrations might be an important risk factor for persistent postpartum bacterial uterine infection in dairy cows.
DOI： 10.1262/jrd.2015-103
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黒毛和種雄子牛の精巣におけるニードルバイオプシーがその後の発育に及ぼす影響
池田 泰彦, 北原 豪, 邊見 広一郎, 小林 郁雄, 大澤 健司
日本繁殖生物学会 講演要旨集 109 ( 0 ) OR2 - 29-OR2-29 2016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：日本繁殖生物学会
【目的】種雄牛の供用開始には6年以上かかり，その選抜および育成には多くの労力と経費を要する。種雄牛候補牛の精巣における将来の不可逆的異常が早期に予測できれば，それ以降の選抜から除外することで，経費軽減が可能となる。ニードルバイオプシーは侵襲性が低い生検法として知られているものの，春機発動前のウシ精巣におけるニードルバイオプシーがその後の発育に及ぼす影響を検証した報告は見当たらない。そこで本実験では，その影響を超音波検査，サーモグラフィー検査，および組織学的検査により検証した。【方法】宮崎大学住吉フィールドにて飼養の黒毛和種雄子牛3頭を供試，採材は生後6日以内を0週齢とし4週齢，8週齢でニードルバイオプシーを行い，その後の発育に及ぼす影響を4週間後（8週齢）に検査した。鎮静後直ちに精巣の超音波検査を行いエコー輝度の変化を観察，陰嚢周囲長を測定，陰嚢を剃毛，消毒後に14Gバイオプシーニードルを用い右側精巣から組織を採取した。採取後，サーモグラフィーを用いて左右陰嚢の表面温度を比較した。採取した組織を10%ホルマリンで固定し，パラフィン包埋後4 μmで切片を作成，HE染色にて精細管15本あたりの直径の平均を計測した。【結果】8週齢においてエコー輝度の変化，陰嚢表面温度の左右非対称は認められず，陰嚢周囲長（10.66±0.23 cm : 平均±SD）および精細管直径（60.95±3.11 μm）ともに同週齢の無処置精巣と比較して差は認められなかった。以上より，ウシにおける生後4週齢でのニードルバイオプシーは，その後4週間の精巣組織の発育に影響を及ぼさないことが示唆された。
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Effects of intrauterine infusion of povidone-iodine on endometrial cytology and bacteriology in dairy cows with clinical endometritis 査読あり
Mido, S., Murata, N., Rawy, M.S., Kitahara, G., Osawa, T.
Journal of Veterinary Medical Science 78 ( 4 ) 551 - 556 2015年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Persistence of uterine bacterial infection, and its associations with endometritis and ovarian function in postpartum dairy cows 査読あり
Ghanem, E. M., Tezuka, E., Devkota, B., Izaike, Y., Osawa, T.
Journal of Reproduction and Development 61 ( 1 ) 54 - 60 2015年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1262/jrd.2014-051
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高齢雌牛における卵巣活動の長期観察
平田統一，赤坂 茂，千田広幸，佐々木修一，佐々木 修，桃田優子，杉山あかね，昆 直樹，佐藤麻衣，南雲鮎美，伊藤悠紀，山中 芽，高橋愛衣，大澤健司，佐々木 淳，岩田尚孝
日本胚移植学雑誌 37 ( 3 ) 89 - 97 2015年11月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Evidence of spontaneous recovery of granulosa-theca cell tumour in a heifer: A retrospective report 査読あり
El-Sheikh Ali H, Kitahara G, Torisu S, Nibe K, Kaneko Y, Hidaka Y, Osawa T
Reproduction in Domestic Animals 2015年6月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1111/rda.12555
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Development of a programmable piggyback syringe pump and four-times-a-day injection regimen for superovulation in non-lactating Holstein cows 査読あり
Irshad AR, Sasaki T, Kubo T, Odashima N, Katano K, Osawa T, Takahashi T, Izaike Y
Journal of Reproduction and Development 2015年6月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows 査読あり
Devkota B, Takahashi M, Sato S, Sasaki K, Ueki A, Osawa T, Takahashi M, Yamagishi N
Journal of Veterinary Medical Science 2015年3月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Laparoscopic cryptorchidectomy in standing bulls 査読あり
Kaneko Y, Torisu S, Kitahara G, Hidaka Y, Satoh H, Asanuma T, Mizutani S, Osawa T, Naganobu K
Journal of Veterinary Medical Science 77 ( 5 ) 631 - 635 2015年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.1292/jvms.14-0587