論文 - 大澤 健司
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Association of inflammatory cytokine profiles in the cervical mucus with the mode of calving ease after induction of parturition in overdue cows 査読あり
Takuto Hashiguchi, Go Kitahara, Kazuyuki Kanemaru, Mizuho Uematsu, Takeshi Osawa
Animal 2025年12月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
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Dynamics of macrophages and inflammatory cytokine concentrations in the cervix of late pregnant cows 査読あり
Kanemaru K., Kitahara G., Hashiguchi T., Hemmi K., Kobayashi I., Osawa T.
Theriogenology 238 117357 2025年2月
担当区分：最終著者, 責任著者 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
Cervical ripening is associated with M1 macrophages and inflammatory cytokines in mice and rats, but its mechanism in cattle is unclear. In this study, to elucidate some of the mechanisms of normal cervical maturation in cows, we examined the expressions of M1 macrophages and mRNA of interleukin (IL)-1α, 1β, 6, 8, and 10, as well as TNFα in cervical tissue and the mRNA expressions and protein concentrations of these cytokines in cervical mucus from late pregnancy to parturition. Forty-one Japanese Black cows were sampled at 200, 230, and 260 d of gestation and then at 7 d intervals until parturition to obtain cervical mucus and tissue samples. The collected tissues were fluorescently immunostained with anti-Iba-1 antibodies, and the macrophage infiltration was checked. Cervical mucus was mixed with PBS, the concentrations of the above cytokines in the supernatant after centrifugation were measured, and the concentration per protein weight was used as the measurement. Total RNA was extracted from the cervical tissue and mucus, and the mRNA expression of various cytokines was analyzed using real-time PCR. In cervical tissue, macrophages stained with anti-Iba-1 antibody were observed from five to six weeks before calving until the week of calving. There was also a trend toward a concurrent increase in the mRNA expression of inflammatory cytokines, especially IL-6, three weeks before calving (P < 0.05). In cervical mucus, the concentrations of IL-1α, IL-1β, IL-8, and TNFα increased (P < 0.05) zero to three weeks before calving compared to 12–14 weeks before calving. In addition, IL-1α mRNA increased three weeks before and during the week of parturition, and IL-8 mRNA increased three weeks before and two weeks after (P < 0.05). These results suggest that cervical ripening in cows begins five to six weeks before calving when macrophages infiltrating cervical tissue may produce large amounts of IL-6, inflammatory cells infiltrate cervical mucus, and IL-1α, IL-1β, IL-8, and TNFα levels in the mucus increase toward calving.
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Profile of uterine flush lipid mediators in cows with subclinical endometritis: pilot study. 査読あり
Maehara T, Osawa T, Kitahara G, Satoh H, Murata T
The Journal of veterinary medical science advpub ( 0 ) 2024年3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：公益社団法人 日本獣医学会
Subclinical endometritis affects reproductive outcomes and causes economic losses in dairy cows, thus, it is important to understand disease progression mechanisms and develop diagnostic procedures for better disease management. We measured the levels of 146 lipid mediators in uterine flush samples using lipid chromatography-mass spectrometry. We detected 25 lipid mediators in the uterine flush of both the control and subclinical endometritis cows; 15 of the 25 lipid mediators were AA-derived metabolites. Among the AA-derived metabolites, cyclooxygenase (COX)-generated mediators were the most abundant. Specifically, levels of 11β-13,14-dihydro-15-keto prostaglandin (PG)F<sub>2α</sub>, PGE<sub>2</sub>, PGA<sub>2</sub>, 13-hydroxyoctadecadienoic acid, and PGD<sub>1</sub> were elevated in all the cows with subclinical endometritis. This study may provide new insights for the management of subclinical bovine endometritis.
DOI： 10.1292/jvms.23-0450
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Misaka M., Uematsu M., Hashimoto K., Kitahara G., Osawa T., Sasaki Y.
Preventive Veterinary Medicine 207 105716 2022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：Preventive Veterinary Medicine
Calf mortality severely affects productivity in the beef industry. The present study was conducted to assess the calf mortality risk (CMR) in Japanese Black calves and investigate potential associations between calf/cow information and the CMR. Records for calves born between April 2006 and March 2010 were extracted from an existing database, which included production data on commercial cow-calf operations in Miyazaki, Japan. The study group comprised 40,462 calves born to 15,600 cows on 908 farms. Because calves on the studied farms were weaned at approximately 4 months of age, the calf records were collected from birth to 120 days. The CMR was calculated as the number of dead calves divided by the number of surviving calves. Mixed-effect multivariable logistic regression modeling was used to determine potential associations between the CMR and the factors hypothesized to influence that risk. CMR analyses were performed separately for the following production stages: days 0–30, days 31–60, days 61–90 and days 91–120 after birth. Of the 40,462 calves, 1465 died during days 0–120 after birth, and the CMR was 3.6 %. Of the 1465 dead calves, 35.9 % died within 10 days after birth. During the 0–30-day period, the CMR was associated with dam parity, calving status, gestation length, sex, birth season and twin births (P < 0.05), but not with the number of inseminations to conception. Low parity, dystocia, gestation lengths < 280 days and > 301 days, male calves, calves born in autumn and winter and twin births yielded higher CMRs. Low dam parity also yielded higher CMRs during the 31–60-day, 61–90-day and 91–120-day periods (P < 0.05), but no other factors were associated with the CMR during these periods. Thus, various cow and calf factors were shown to be associated with CMRs in Japanese Black calves, and calves with these factors should be considered high-risk calves.
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Inflammatory changes and composition of collagen during cervical ripening in cows 査読あり
Yamanokuchi E., Kitahara G., Kanemaru K., Hemmi K., Kobayashi I., Yamaguchi R., Osawa T.
Animals 12 ( 19 ) 2022年10月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Animals
Dystocia and stillbirths in cows pose a high risk of loss of both dams and fetuses, thereby resulting in high economic losses. One of the causes of these problems is birth canal abnormalities. Thus, to prevent these occurrences, it is necessary to understand the mechanisms underlying cervical ripening. Although physiological inflammatory responses and changes in collagen composition have been reported in humans and mice, related information is scarce for cows. We observed inflammatory changes and changes in the collagen composition in the cervix from late pregnancy to parturition to clarify some of the physiological changes associated with cervical ripening during normal calving in cows. Cervical mucus and tissue samples were collected from 41 Japanese Black cows at 200, 230, and 260 days of gestation and at 7-day intervals thereafter until parturition. The percentage of polymorphonuclear neutrophils (PMN%) in the mucus was calculated, and interleukin (IL)-8 concentration was determined by enzyme-linked immunosorbent assay. Blood samples were collected from the jugular vein, and leukocyte counts were determined. Picrosirius red-stained cervical tissue specimens were observed under a polarizing microscope, and the percentage of type I and type III collagen areas in the cervical tissue were calculated. The PMN% in cervical mucus was lowest at 200 days gestation (12–13 weeks before delivery), significantly increased 5 weeks before (21.7 ± 0.04), and was highest 1 week before calving (50.9 ± 0.04). IL-8 levels were increased at 295 days compared with those at 200 days of pregnancy (p < 0.05). No significant changes were observed in the white blood cell counts. The percentage of type I collagen in the cervical tissue reached a maximum (91.4 ± 0.02%) on day 200, significantly decreased after 274 days (3 weeks before calving), and continued to decrease thereafter until the week of parturition. There was no significant change in type III collagen levels. The results suggest that cervical ripening progresses when PMNs begin to infiltrate the cervix at around 260 days of gestation (5–4 weeks before parturition), IL-8, which increases at the end of pregnancy, mobilizes PMNs, and enhances inflammation, and that type I collagen changes are useful as an indicator of cervical ripening.
DOI： 10.3390/ani12192646
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Maeda T., Kitahara G., Osawa T.
Reproduction in Domestic Animals 57 ( 9 ) 1029 - 1037 2022年9月
担当区分：最終著者, 責任著者 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
This study aimed to clarify the relationship between the maternal pelvis and calf size in normal and dystocia groups (Experiment 1) and to establish a method to predict dystocia due to physical imbalance between foetus and maternal pelvis before calving based on the parameters found in Experiment 1 (Experiment 2). In Experiment 1, 26 pairs of dams and their offspring were tested immediately after calving, and various parameters of offspring size and maternal pelvis were measured in normal and dystocia cases. The longitudinal diameter of the maternal pelvis was smaller (p <.01), and ratios of the offspring's birth weight and the width of the hoof crown (hoof width; measured using callipers) to the longitudinal diameter of the maternal pelvis were larger (p <.01) in the dystocia group than those in the normal group. In Experiment 2, 37 cows were tested, and in addition to the measurement items of Experiment 1, the inner pelvic diameter and the foetal hoof width were measured via ultrasonography at 285 days of gestation. The ratio of the internal diameter of the maternal pelvis (longitudinal diameter, transverse diameter and area) to the foetal hoof width was compared and was greater (p <.01) in the dystocia group than in the normal group. In conclusion, the risk of dystocia can be estimated by the ratio of the foetal hoof width to the longitudinal diameter of the maternal pelvis before calving.
DOI： 10.1111/rda.14169
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Association of herd size with stillbirth and dystocia rates in Japanese Black cattle 査読あり
Misaka M., Uematsu M., Kitahara G., Osawa T., Sasaki Y.
Animals 12 ( 15 ) 2022年8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：Animals
The objective of this study was to investigate the effect of herd size on stillbirth and dystocia rates; the relationships between herd size, calving season, parity, and gestation length in Japanese Black cattle were also explored. Data were collected for 41,184 calvings from 15,512 animals on 905 farms between 2006 and 2010. In this study, herds were classified into three groups based on size: small (1–10 cows), medium (11–50 cows), and large (≥51 cows). Herd size had an effect on the dystocia rate (p < 0.05) but not the stillbirth rate. Additionally, interactions between herd size and gestation length were associated with the dystocia rate (p < 0.05), and the dystocia rate was the highest in small herds, followed by medium and large herds for cows with a gestation length of 281–300 days, which is considered a pregnancy of normal duration. In summary, in Japanese Black cattle, there were different effects of herd size on the stillbirth rate and dystocia rates, as herd size was associated with the dystocia rate but not with the stillbirth rate.
DOI： 10.3390/ani12151994
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Elgendy O., Kitahara G., Taniguchi S., Osawa T.
Journal of Reproduction and Development 68 ( 4 ) 271 - 277 2022年
担当区分：最終著者, 責任著者 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 Reproduction and Development
High summer temperatures have deleterious effects on oocyte developmental competence. The antioxidant and autophagy-related properties of 5-aminolevulinic acid (5-ALA) gives the compound a broad range of biological activities. This study aimed to evaluate the effects of: 1) a high temperature-humidity index (THI) on the developmental competence of bovine oocytes, and 2) 5-ALA administration in combination with sodium ferrous citrate (SFC) during in vitro maturation (IVM) on bovine oocyte developmental competence evaluated at high THI. Bovine ovaries were collected from a local slaughterhouse at moderate environmental temperature (MT; THI of 56.2) and high environmental temperature (HT; THI of 76.7) periods; cumulus-oocyte complexes (COCs) were aspirated from medium-sized follicles, matured in vitro for 22 h, fertilized, and cultured for 10 days. For COCs collected during the HT period, 0 (control), 0.01, 0.1, 0.5, or 1 µM 5-ALA was added to the maturation medium in combination with SFC at a molar ratio of 1:0.125. The results showed that HT adversely affected blastocyst and hatching rates compared with MT. Adding 5-ALA/SFC (1 µM/0.125 µM) to the maturation medium of oocytes collected during the HT period improved cumulus cell expansion and blastocyst rates compared with the no-addition control. In conclusion, this study showed that high THI can disrupt bovine oocyte developmental competence. Adding 5-ALA to SFC ameliorates this negative effect of heat stress and improves subsequent embryo development.
DOI： 10.1262/jrd.2021-145
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Tani M., Tani C., Tasaki H., Harumoto S., Yoshimatsu R., Ito S., Koutaka T., Hattori N., Moritomo Y., Osawa T.
Australian Veterinary Journal 99 ( 11 ) 469 - 472 2021年11月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Australian Veterinary Journal
This study aimed to clarify the effectiveness of foetal body weight estimation by measuring foetal coronet width using transrectal ultrasonography in beef cows during near-term pregnancy. A characteristic ‘gull wing’ pattern was obtained from the foetal coronet cross-section from the dewclaw side using ultrasonography. This pattern was matched to the bone surface of the distal part of the middle phalanx. Then, the relationship between coronet width and body weight at birth of 22 Japanese Brown calves was analysed and a high correlation coefficient of 0.8965 (P < 0.001) was obtained. In conclusion, the coronet width of the fetus is depicted as a ‘gull wing’ hyperechoic structure and can be measured by ultrasonography per rectum during near-term pregnancy. This technique may be a useful tool to identify high-risk cows with dystocia before calving. High foetal coronet values may predispose cattle to dystocia.
DOI： 10.1111/avj.13112
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Osawa T.
Journal of Reproduction and Development 67 ( 5 ) 291 - 299 2021年10月
担当区分：筆頭著者, 責任著者 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 Reproduction and Development
A certain level of endometrial bacterial infection and inflammation is involved in bovine uterine involution during the puerperal period. Factors that hamper normal uterine involution expose the uterine environment to pathological conditions, causing different endometritis levels. The lack of proper diagnostic tools extends the time to conception. Efforts have been made to elucidate the postpartum uterine environment, including bacterial flora, changes in transient endometrial inflammation, and the pathophysiology of endometritis, to improve bovine reproductive performance. E. coli and Trueperella pyogenes in the uterus are likely to cause persistent infection, and Mycoplasma bovigenitalium infection is associated with dystocia and cytological endometritis in postpartum dairy cows. Due to the widespread use of cytobrush as a diagnostic tool for bovine subclinical endometritis (SE) that enables quantification of the degree of inflammation, we found that endometritis at week 5 postpartum was associated with delayed first ovulation. Approximately 30% of open cows have SE during the postpartum period, and cows with low blood glucose during prepartum have a high risk of developing SE. Additionally, cows with purulent vaginal discharge do not always have endometritis but only vaginitis and/or cervicitis. Intrauterine infusion of polyvinylpyrrolidone-iodine (PVP-I) improves fertility and promotes endometrial epithelial cell regeneration after inducing transient uterine inflammation, suggesting that PVP-I could be a good alternative to antibiotics. In conclusion, prepartum management to prevent glucose deficiency, prompt diagnosis to identify causative agents and intrauterine inflammation levels, and appropriate treatment to minimize antimicrobial resistance is beneficial for tackling endometritis and improving reproductive performance in bovine herds.
DOI： 10.1262/jrd.2021-052
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Wu X, Kitahara G, Suenaga T, Naramoto K, Sekiguchi S, Goto Y, Osawa T
Journal of Reproduction and Development 2021年10月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益社団法人 日本繁殖生物学会
The aim of this study was to clarify the influence of <i>Lactobacillus </i>spp. on the degree of endometrial inflammation in the postpartum period and the relationship between <i>Lactobacillus </i>spp. and pathogenic bacteria in the endometrium of postpartum dairy cows. Endometrial samples were collected from 41 Holstein-Friesian cows at 4 and 8 weeks postpartum using cytobrushes for polymorphonuclear neutrophil (PMN) count and bacterial culture to isolate <i>Lactobacillus </i>spp., <i>Escherichia coli</i>, and<i> Trueperella pyogenes</i>. The 4-week samples were divided into four groups (E + L +), (E + L −), (E − L +), (E − L −) according to whether endometritis was diagnosed (E +) and <i>Lactobacillus </i>spp. was isolated (L +). The diagnostic criterion for cytological endometritis was > 18% PMN. The average PMN% in the E + L + group was lower than that in the E + L-group (P < 0.05) at 8 weeks postpartum. There were no significant correlations between the number of colonies of <i>Lactobacillus</i> spp. and <i>E. coli</i> or between that of <i>Lactobacillus</i> spp. and <i>T. pyogenes</i>. <i>Lactobacillus </i>spp. could reduce PMN% in dairy cows with endometritis during the puerperal period. In conclusion, the intrauterine presence of <i>Lactobacillus </i>spp. may have a positive effect on uterine involution in postpartum dairy cows.
DOI： 10.1262/jrd.2021-023
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The effect of heat and cold stress on oxidative stress of follicular microenvironment in beef cattle 査読あり 国際共著
Kanada K., Elgendy O., Hemmi K., Kobayashi I., Sato R., Osawa T., Kitahara G.
Journal of Veterinary Medical Science 87 ( 11 ) 1336 - 1345 2025年11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
This study hypothesized that heat and cold stress affect the balance between oxidants and antioxidants (oxidative stress) of oocytes and follicular fluid (FF) in beef cattle and the oxidative stress between blood and FF is correlated. Thirty-two Japanese Black cattle that were divided into four seasonal groups [fall, winter (WG), spring (SpG), and summer (SmG) group]. Plasma and FF were measured diacron-reactive oxygen metabolites (d-ROMs), biological antioxidant potential (BAP), and oxidative stress index (OSI). Reactive oxygen species (ROS) were measured in oocytes. Temperature-humidity index was lower in WG and higher in SmG than in the other three groups (P<0.05). d-ROMs value was lower in FF than in plasma in all groups, BAP value was lower in FF than in plasma in WG, SpG, and SmG, and OSI was lower in FF than in plasma in WG and SpG (P<0.05). In FF, d-ROMs and BAP values were positively correlated in WG, SpG, and heifer groups (HG, P<0.05). d-ROMs or OSI values between plasma and FF were positively correlated in all animals and cow group (CG), SpG, CG, and HG (P<0.05). ROS levels in oocytes were higher in WG and SpG than in SmG (P<0.05). In conclusion, oxidative stress in the blood and FF are linked, and oxidative stress of oocytes increases in winter and spring in beef cattle that are kept on pasture, except in winter.
DOI： 10.1292/jvms.24-0323
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Kohigashi S.S., Uematsu M., Kitahara G., Osawa T.
Journal of Reproduction and Development 71 ( 3 ) 175 - 184 2025年5月
担当区分：最終著者, 責任著者 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 Reproduction and Development
This study aimed to clarify the association between the percentage of follicle number by size over antral follicle count (AFC) and subsequent reproductive performance. A total of 306 Japanese Black cattle underwent timed artificial insemination (TAI) 41–62 days postpartum; the AFC and numbers of small, medium, and large follicles were recorded 10 days before TAI. The cross-sectional and blood flow areas of the dominant follicle (DF) on the day of TAI and the corpus luteum (CL) six days after TAI were recorded. The total number of follicles ≥ 2 mm was defined as the AFC, and the percentages of follicle number by each size defined as small (S-AFC%; 2–2.9 mm), medium (M-AFC%; 3–8.4 mm), and large (L-AFC%; ≥ 8.5 mm) follicles. The AFC and S-, M-, and L-AFC% were further grouped into low, medium, and high tertiles, and the subsequent reproductive performance compared among the groups. Plasma anti-Müllerian hormone (AMH) levels were quantified on the day of AFC measurement. No differences were observed in reproductive performance between the AFC and L-AFC% groups. The high-S-AFC% group showed a 20.6% lower conception rate, 0.58 more AI numbers, and 21.9 longer days open than those of the low-S-AFC% group (P < 0.05). The low-M-AFC% group showed an 18.0% lower conception rate after TAI and 0.54 more AI numbers than those of the high-M-AFC% group (P < 0.05). DF and CL parameters did not differ among the AFC, S-, M-, and L-AFC% groups. Plasma AMH levels in the low-AFC group were the lowest in the tertile. In conclusion, the percentage of follicles by size could be used to estimate subsequent reproductive performance.
DOI： 10.1262/jrd.2024-075
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Fertility Traits in Japanese Black Cows in Farms Classified by Calving Intervals Using Epidemiological Methods. 査読あり
Suzuki O, Uematsu M, Kitahara G, Osawa T, Sasaki Y
Reproduction in domestic animals = Zuchthygiene 60 ( 4 ) e70058 2025年4月
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Profile of cytokine gene expression of the endometrium and its relationship to inflammation and fertility in postpartum dairy cows. 査読あり 国際共著
Naramoto K, Kitahara G, Nazhat SA, Yasuda M, Osawa T
The Journal of veterinary medical science 2024年12月
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Misaka M., Uematsu M., Kitahara G., Osawa T., Sasaki Y.
PLoS ONE 19 ( 6 June ) e0304867 2024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：PLoS ONE
We aimed to characterize the change in the incidence of stillbirth (IS) in Japanese Black cattle during and after animal movement restrictions and suspended insemination because of a foot-and-mouth disease (FMD) outbreak in Miyazaki Prefecture in 2010. Calving data from 2006 to 2018 were collected from approximately 900 farms. Post-FMD period was divided into three based on the median IS per month (1.80%): period 1 (May 2011 to February 2013), period 2 (March 2013 to August 2015), and period 3 (September 2015 to December 2018). The ISs were similar during the Pre-FMD period and Post-FMD period 1, then substantially decreased during Post-FMD period 2 (p < .05), before returning to the value before the FMD outbreak period during Post-FMD period 3. Compared with the Pre-FMD period, Post-FMD period 1 was associated with a higher proportion of calvings by primiparous cows and Post-FMD period 2 was associated with a smaller number of calvings per month (p < .05). There were high ISs in primiparous cows during the Pre-FMD period, Post-FMD period 1, and Post-FMD period 3 (p < .05), but not during Post-FMD period 2. In summary, after the animal movement restrictions and suspended insemination introduced because of the FMD outbreak, the IS temporarily decreased and consequently returned to the pre-FMD level.
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Comparison of serum concentrations of pregnancy-associated glycoproteins and estrone sulphate during pregnancy in eutocia and dystocia beef cattle. 査読あり
Maeda T, Kitahara G, Osawa T
The Veterinary Journal (London, England : 1997) 106147 2024年5月
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Use of platelet lysate for in-vitro embryo production and treatment of repeat breeding in cows 査読あり 国際共著
Hassaneen A.S.A., Rawy M.S., Yamanokuchi E., Elgendy O., Kawano T., Wakitani S., Kitahara G., Osawa T.
Theriogenology 210 199 - 206 2023年10月
担当区分：責任著者 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
Platelet-rich plasma (PRP) is a biological hemocomponent derived from blood after the complete removal of red blood cells and the partial or complete removal of white blood cells to concentrate platelets in an appropriate volume of plasma. Platelets have important growth factors, cytokines, and active metabolites that improve the endometrial environment and positively affect implantation. This study evaluated the effect of the addition of activated PRP (platelets lysate; PL) on in vitro bovine oocyte maturation and embryonic development and the effect of intrauterine (IU) infusion of autologous PL in repeat breeder (RB) cows. Experiment 1 examined the effects of allogeneic PL, fetal calf serum (FCS), mixed PL + FCS, or platelet-poor plasma (PPP) supplementations to in vitro maturation and development media on in vitro oocyte maturation and embryo development in good- and poor-quality oocytes of Japanese Black cows. Experiment 2 examined the IU infusion of autologous PL, 24 h post-insemination, in 21 RB Holstein-Friesian dairy cows. The cleavage rate of good-quality oocytes was higher in the PL group (85.93 ± 2.50%) than in the PPP group (67.16 ± 3.41%) (P < 0.05), while the cleavage rate of the poor-quality oocytes was higher in the PL alone (76.13 ± 4.04%) and mixed PL + FCS treated (73.59 ± 4.22%) groups than in the PPP group (54.64 ± 2.93%) (P < 0.05). The blastocyst rate of the good-quality oocytes was higher in the PL group (40.97 ± 3.03%) than in the FCS (27.97 ± 3.31%) and PPP (25.33 ± 2.15%) groups (P < 0.05). The blastocyst rate of poor-quality oocytes and the hatching rates of both good and poor-quality oocytes showed no significant differences among all groups. The conception rate in the autologous PL-treated group was 41.67% (5/12), while it was 11.11% (1/9) in the control group. The platelets' count in the pregnant PL-treated cows (n = 5; mean ± SEM, 1.07 ± 0.10 × 109/mL) was higher than in the non-pregnant ones (n = 7; 0.67 ± 0.10 × 109/mL) (P < 0.05). In conclusion, allogeneic PL was effective in stimulating the in vitro oocyte maturation and embryonic development in both good and poor-quality bovine oocytes, and post-insemination IU infusion of autologous PL derived from high platelets’ count-PRP would be recommended for the treatment of RB cows.
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Elgendy O., Kitahara G., Yamada K., Taniguchi S., Osawa T.
Journal of Reproduction and Development 69 ( 5 ) 261 - 269 2023年
担当区分：最終著者 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 Reproduction and Development
A high temperature-humidity index during summer has deleterious effects on mitochondrial function, reducing oocyte developmental competence. 5-Aminolevulinic acid (5-ALA) and sodium ferrous citrate (SFC) are both known to support mitochondrial function and have strong anti-oxidant and anti-apoptotic activities. This study aimed to determine the mechanism of action of 5-ALA/SFC on oocyte quality. Bovine oocytes were collected from medium-sized follicles during summer (July–September, temperature-humidity index:76.6), cultured with 0, 1, 2, 4, and 8 µM 5-ALA with SFC at a molar ratio of 1:0.125, fertilized, and cultured for 10 days. The addition of 8/1 µM 5-ALA/SFC had a deleterious effect on oocyte cleavage rate in comparison with control oocytes, but did not affect the blastocyst rate, while 1/0.125 µM 5-ALA/SFC had a significantly higher increase in blastocyst rate than 8/1 µM 5-ALA/SFC. The addition of 1/0.125 and 2/0.25 µM 5-ALA/SFC improved oocyte quality by increasing the mitochondrial distribution pattern and metaphase-II oocytes, reducing reactive oxygen species and upregulating nuclear factor erythroid-2-related factor 2, heme oxygenase-1, and superoxide dismutase-1 in oocytes, and nuclear factor erythroid-2-related factor 2 and mitochondrial transcription factor A in cumulus cells. These results indicate that 1/0.125 and 2/0.25 µM 5-ALA/SFC may support oocyte quality and developmental competence and provide anti-oxidant actions in cumulus-oocyte complexes.
DOI： 10.1262/jrd.2023-038
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Tanimura K., Uematsu M., Kitahara G., Osawa T., Sasaki Y.
Theriogenology 189 177 - 182 2022年9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
Repeat breeding (RB) has been defined as failure to conceive from three or more regularly spaced services in the absence of detectable abnormalities, and cause economic loss on the farm owing to a declining conception rate. This study aimed to evaluate the reproductive characteristics of RB in Japanese Black cattle by assessing the longitudinal effect of RB at a low parity on subsequent fertility raised in commercial cow–calf operations. Data used in this study were collected from 764 farms in Miyazaki. Data from 2005 until 2014 comprised 158,945 AI records with 80,453 parity records for 22,565 cows. The effect of RB at heifers and parities 1 and 2 cows on subsequent fertility and survival on four consecutive parities was investigated. The results showed that cows with the number of inseminations to conception (INS) of ≥4 at a low parity had a higher probability of being RB again at subsequent parities compared with cattle with INS 1 or 2. Additionally, the degree of the negative effect of an INS ≥4 on fertility and survival increased as they became older. On the other hand, cows with an INS of 2 had similar fertility and survival with those with an INS of 1. In summary, this study suggests that repeat breeders at a low parity have a higher probability of RB again at subsequent parities compared with cattle with INS 1 or 2, and the negative effect of an INS ≥4 increases as parity increases.
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妊娠末期の褐毛和種牛における胎子蹄冠部幅測定による胎子体重の推定 査読あり
谷 峰人，谷 千賀子，田﨑穂菜美，春本沙由梨，吉松稜司，大澤健司
産業動物臨床医学雑誌 12 ( 4 ) 181 - 187 2022年1月
担当区分：最終著者 記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Usefulness of computed tomography for cryptorchidism in bulls 査読あり 国際共著
Goda Y., Mizutani S., Mizutani Y., Kitahara G., Siswandi R., Wakabayashi K., Torisu S., Kaneko Y., Hidaka Y., Osawa T., Asanuma T., Sato R., Satoh H.
Journal of Veterinary Medical Science 84 ( 10 ) 1430 - 1436 2022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：Journal of Veterinary Medical Science
Cryptorchidism is defined as the failure of the testis to descend into the scrotal position. Bulls with cryptorchidism have problems in both meat quality and husbandry management; thus, it is greatly important to accurately identify the retained testis and remove it during the early stage. Abdominal computed tomography (CT) was performed under general anesthesia in 34 bulls aged 3–9 months with cryptorchidism. All bulls underwent laparoscopic or incision approach for cryptorchidectomy, and 40 testes were dissected. The detection rates of retained testes were 64.5% in the abdominal cavity and 100% in the subcutaneous inguinal region, and the total detection rate was 72.5%. Furthermore, all cases in this study were suspected to have intra-abdominal cryptorchidism in primary care, but CT revealed that 22.5% of cases had cryptorchidism in the subcutaneous inguinal region. The CT value (mean ± standard deviation) of the retained testes was 20.96 ± 7.54 Hounsfield Unit, and the CT value and size of the retained testes showed a positive weak correlation with bovine age. Therefore, there is the demerit that general anesthesia and a huge device are necessary; nevertheless, CT is suggested to be useful in identifying the location of retained testes and selecting an appropriate surgical approach in bulls with cryptorchidism. Moreover, CT findings suggested that the maturation of the retained testes might depend not on the descending process but on age.
DOI： 10.1292/jvms.22-0124
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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
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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。
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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）
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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）
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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
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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
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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）
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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.
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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%；<i>p</i> < 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（<i>p</i> < 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
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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。
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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
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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）
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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
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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
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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
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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
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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 F<sub>2α </sub>[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% <i>vs</i>. 87.0% and 89.2% <i>vs</i>. 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
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El-Sheikh Ali, H., Kitahara, G., Takahashi, T., Mido, S., Sadawy, M., Kobayashi, I., Hemmi, K., Osawa, T.
Biology of Reproduction 97 ( 1 ) 153 - 161 2017年7月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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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
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IRSHAD Abdul Razaq, SASAKI Taihei, KUBO Tomoaki, ODASHIMA Naoyuki, KATANO Keiji, OSAWA Takeshi, TAKAHASHI Toru, IZAIKE Yoshiaki
Journal of Reproduction and Development 61 ( 5 ) 485 - 488 2015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：THE SOCIETY FOR REPRODUCTION AND DEVELOPMENT
The objectives of the present study were to develop a programmable piggyback syringe pump for bovine superovulation and to evaluate the effects of a four-times-a-day injection regimen using the pump. Non-lactating Holstein cows were treated with a total of 30 armour units of porcine FSH by injection four times a day with the pump (study, n = 9) or injection twice a day manually (control, n = 9) for four consecutive days from D10 of the estrous cycle. The pump-driven program successfully induced superovulation in all cows tested. The numbers of small (3– < 5 mm in diameter) and large (≥ 10 mm in diameter) follicles were greater in the study group on D11-13 and D14, respectively. There were fewer unovulated follicles detected on D21 (7 days after estrus) in the study group than in the control group (1.2 ± 0.4 and 3.2 ± 0.6, respectively).
DOI： 10.1262/jrd.2015-047
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EL-SHEIKH ALI Hossam, KITAHARA Go, TAMURA Youji, KOBAYASHI Ikuo, HEMMI Koichiro, ZAABEL Samy, OSAWA Takeshi
日本繁殖生物学会 講演要旨集 108 ( 0 ) P - 21-P-21 2015年
記述言語：英語 掲載種別：研究論文（その他学術会議資料等） 出版者・発行元：日本繁殖生物学会
During summer, the cow is 3.7 times more likely to lose embryo in comparison to winter. The present study aimed to investigate the effect of heat stress on the thermal environment of different portions of the female genital tract in comparison to winter and spring. Three non-pregnant Japanese Black cows were investigated using a digital thermometer with special design to record the temperature of vagina (VT), cervix (CT), uterine body (UBT) and uterine horns (UHT) on D0 (D0 = heat), 1, 2, 3 and 8 of the estrous cycle (between 0630–0800 h), D0 and D8 was selected to represent the day of artificial insemination (AI) and embryo transfer (ET), respectively, under field condition. Moreover, D1, 2 and 3 were selected to represent the process of fertilization and early embryogenesis. During the experiment, temperature humidity index (THI) was recorded. This experimental design was carried out in winter, spring and summer in Miyazaki, Japan. The THI in summer was higher than the alert THI (i.e. THI > 74), indicating heat stress and was significantly higher (P ˂ 0.001) than winter and spring (78.45 ± 0.32 <i>vs</i>. 60.26 ± 1.20 and 68.51 ± 0.80, respectively). The VT, CT, UBT and UHT were significantly (P < 0.001) elevated during summer in comparison to winter and spring. Moreover, THI was positively correlated (P < 0.001) with VT, CT, UBT and UHT. Based on this correlation, we developed a mathematical model to predict the temperature of different portions of the female genital tract based on THI. In conclusion, heat stress compromises the thermal environment of different portions of the female genital tract which could passively affect gametes and/or embryo with subsequent reduction of pregnancy rate in the cow.
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Persistence of uterine bacterial infection, and associations with endometritis and ovarian function in postpartum dairy cows 査読あり
Ghanem ME, Tezuka E, Devkota B, Izaike Y, Osawa T
Journal of Reproduction and Development 61 ( 1 ) 54 - 60 2014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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Effects of stillbirth and dystocia on subsequent reproductive performance in Japanese Black cattle
Sasaki Y., Uematsu M., Kitahara G., Osawa T., Osawa T., Sueyoshi M., Sueyoshi M.
Veterinary Journal 200 ( 3 ) 462 - 463 2014年6月
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：Veterinary Journal
The objective of this study was to determine the effects of stillbirth and dystocia on subsequent reproductive performance in Japanese Black cattle. Data were collected for 34,763 calvings from 13,186 animals on 826 farms. Stillbirth was associated with a decreased first service conception rate compared to cows with a normal calving (44.4 versus 54.0%, respectively, P < 0.001). Cows with a normal calving required fewer artificial inseminations per conception and had a lower stillbirth rate at subsequent parity than those with stillbirth and dystocia (P < 0.001). Japanese Black cows with stillbirth and dystocia had inferior subsequent reproductive performance compared with those with a normal calving. © 2014 Elsevier Ltd.
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Effect of postbreeding intramuscular administration of deslorelin acetate on plasma LH and progesterone concentrations and conception rate in mares 査読あり
Kino Satoshi, Osawa Takeshi, Mizuno Shuji, Watanabe Gen, Taya Kazuyoshi, Izaike Yoshiaki
Journal of Equine Science 25 ( 1 ) 23 - 27 2014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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International perspectives on the impacts of reproductive technologies on food production in Asia 招待あり
Takeshi Osawa
Advances in Experimental Medicine and Biology 752 213 - 228 2014年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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EL-SHEIKH ALI Hossam, KITAHARA Go, NIBE Kazumi, YAMAGUCHI Ryoji, OSAWA Takeshi
日本繁殖生物学会 講演要旨集 107 ( 0 ) P - 26-P-26 2014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
The current study aimed to evaluate the diagnostic value of plasma anti-Müllerian hormone (AMH) as a biomarker for sex cord-stromal tumors (SCST) in cattle in comparison to immunoreactive inhibin (ir-INH), estradiol-17β (E<sub>2</sub>) and testosterone (T). Therefore, we conducted two experiments. In experiment 1, four clinically healthy Japanese Black cows had blood samples taken daily over one estrous cycle to characterize their AMH profiles throughout the normal estrous cycle. Additionally, single blood samples were collected from 21 cyclic cows to clarify the physiological range of AMH. In experiment 2, animals with histologically confirmed SCST (SCST group, n = 10) and cows affected with cystic ovarian disease (COD group, n = 8) had one blood sample taken before extraction of SCST or treatment of COD. Blood samples (n = 105) from cyclic cows (n = 25) in experiment 1 were assigned as a physiologically cyclic group (PC group). Plasma AMH, ir-INH, E<sub>2</sub> and T concentrations were assayed in all samples. Plasma AMH concentrations did not show substantial fluctuation throughout the estrous cycle. Only plasma AMH, ir-INH and E<sub>2</sub> were significantly elevated in SCST group in comparison to PC group. The area under the receiver operating characteristic curve (AUC<sub>ROC</sub>) of AMH for diagnosis of SCST was 0.99 and was significantly (P < 0.01) higher than that of ir-INH and E<sub>2</sub>. Plasma AMH at a cutoff point of ≥ 0.36 ng/mL had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.1%) compared with ir-INH and E<sub>2</sub>. In conclusion, unilateral ovarian enlargement accompanied with plasma AMH concentrations ≥ 0.36 ng/mL is considered diagnostic for bovine SCST.
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Effect of Postbreeding Intramuscular Administration of Deslorelin Acetate on Plasma LH and Progesterone Concentrations and Conception Rate in Mares.
Kino S, Osawa T, Mizuno S, Watanabe G, Taya K, Izaike Y
Journal of equine science 25 ( 1 ) 23 - 7 2014年
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Plasma anti-Mullerian hormone as a biomarker for bovine granulosa-theca cell tumors: comparison with immunoreactive inhibin and ovarian steroid concentrations 査読あり
El-Sheikh Ali Hossam, Kitahara Go, Nibe Kazumi, Yamaguchi Ryoji, Horii Yoichiro, Zaabel Samy, Osawa Takeshi
Theriogenology 90 940 - 949 2013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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El-Sheikh Ali H., Kitahara G., Nibe K., Yamaguchi R., Horii Y., Zaabel S., Osawa T.
Theriogenology 80 ( 8 ) 940 - 949 2013年11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
Granulosa-theca cell tumors (GTCTs) are the most frequently reported ovarian tumors in cattle. Clinically, GTCTs could be confused with other ovarian abnormalities; therefore, the only definitive diagnosis for such tumors is histopathology of a biopsy from the affected ovary. However, this is an invasive technique and unsuitable for farm conditions. As a result, the key aim of this study was to evaluate the diagnostic value of anti-Müllerian hormone (AMH), a glycoprotein hormone that is synthesized exclusively by ovarian granulosa cells, as a sensitive noninvasive biomarker for diagnosing GTCTs in cattle. To achieve this aim, we conducted two experiments. In experiment 1, four clinically healthy Japanese Black cows had blood samples taken daily over one estrous cycle to characterize their AMH profiles throughout the estrous cycle. Additionally, single blood samples were collected from 21 cyclic cows to clarify the physiological range of AMH. In experiment 2, cows with histologically confirmed GTCT (GTCT group, n = 9) and cows affected with cystic ovarian disease (COD group, n = 8) had one blood sample taken before extraction of the tumorous ovary or therapeutic treatment for the COD. Blood samples (n = 105) from cyclic cows (n = 25) in experiment 1 were assigned as a physiologically cyclic group (PC group). Plasma AMH, immunoreactive inhibin (ir-INH), estradiol-17β (E 2 ), testosterone (T), and progesterone (P 4 ) concentrations were assayed in all samples. In experiment 1, the mean plasma AMH concentration was 0.09 ± 0.003 ng/mL and did not show substantial fluctuation throughout the estrous cycle. In experiment 2, plasma AMH, ir-INH, and E 2 concentrations were significantly elevated in the GTCT group in comparison with the PC group; among these parameters, only the AMH concentrations were significantly higher in the GTCT group than in the COD group. The area under the receiver operating characteristic curve of AMH for diagnosis of GTCT was 0.99 and was significantly higher than that of ir-INH (P < 0.001) and E 2 (P < 0.01). Moreover, the AMH at a cutoff point of ≥0.36 ng/mL had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.1%) compared with the other tested parameters. In conclusion, plasma AMH concentration is probably a more reliable and sensitive biomarker for bovine GTCTs than the concentrations of ir-INH or ovarian steroids. © 2013 Elsevier Inc.
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Risk factors for stillbirth and dystocia in Japanese Black cattle 査読あり
Uematsu Mizuho, Sasaki Yosuke, Kitahara, Go, Sameshima Hiroshi, Osawa Takeshi
The Veterinary Journal 198 212 - 216 2013年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Prevalence of antibodies against Parainfluenza virus type 3, Respiratory syncitial virus and bovine Herpesvirus type 1 in sheep from Northern Prefectures of Japan 査読あり
Massimo Giangaspero, Giovanni Savini, Riccardo Orusa, Takeshi Osawa, Ryô Harasawa
Veterinaria Italiana 49 ( 3 ) 285 - 289 2013年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Fluctuation in plasma bone metabolic markers in multiparous and primiparous Holstein cows during early to peak lactation 査読あり
Devkota, B., Takahashi, M., Sasaki, K., Osawa, T., Izaike, Y., Yamagishi, N.
Journal of Veterinary Medical Science 2013年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Giangaspero, M., Orusa, R., Savini, G., Di Gennaro, A., Takeshi Osawa, T., Harasawa, R.
Clinical Microbiology 2013年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： 10.4172/cmo.1000104
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Serological survey to determine the occurrence of malignant catarrhal fever infection in the Japanese small ruminant population from northern districts 査読あり
Giangaspero, M., Savini, G., Osawa, T., Harasawa, R.
Journal of Veterinary Medical Science 2013年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Epidemiological survey for Toxoplasma gondii, Chlamydia psittaci var. ovis, Mycobacterium paratuberculosis, Coxiella burnetii, Brucella spp., Leptospirosis, and orf virus among sheep from northern districts of Japan 査読あり
Giangaspero, M., Bonfini, B., Orusa, R., Osawa, T., Harasawa, R.
Journal of Veterinary Medical Science 75 ( 5 ) 679 - 684 2013年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Epidemiological survey for Toxoplasma gondii, Chlamydia psittaci var. ovis, Mycobacterium paratuberculosis, Coxiella burnetii, Brucella spp., leptospirosis and Orf virus among sheep from northern districts of Japan.
Giangaspero M, Bonfini B, Orusa R, Savini G, Osawa T, Harasawa R
The Journal of veterinary medical science 75 ( 5 ) 679 - 84 2013年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Fluctuation in plasma bone metabolic markers in multiparous and primiparous Holstein cows during early to peak lactation.
Devkota B, Takahashi M, Sasaki K, Osawa T, Izaike Y, Yamagishi N
The Journal of veterinary medical science 75 ( 9 ) 1257 - 60 2013年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Serological survey to determine the occurrence of malignant catarrhal fever infection in the Japanese small ruminant population from northern districts. 査読あり
Giangaspero M, Savini G, Osawa T, Harasawa R
The Journal of veterinary medical science 75 ( 6 ) 815 - 8 2013年
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Experimental infection of pregnant cows with noncytopathogenic bovine viral diarrhea virus between days 26 and 50 postbreeding 査読あり
57 Tsuboi, T., Osawa, T., Hirata, T-I., Kawashima, K., Kimura, K., Haritani, M.
Research in Veterinary Science 94 ( 3 ) 803 - 805 2012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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Serological screening of Coxiella burnetii (Q fever) and Brucella spp. in sheep flocks in the northern prefectures of Japan in 2007 査読あり
Giangaspero, M., Osawa, T., Bonfini, B., Orusa, R., Robetto, S., Harasawa, R.
Veterinaria Italiana 48 ( 4 ) 357 - 365 2012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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Mycoplasma infection in the uterus of early postpartum dairy cows and its relation to dystocia and endometritis 査読あり
Ghanem E. M., Higuchi H., Tezuka E., Ito H., Devkota B., Izaike Y., Osawa T.
Theriogenology 79 ( 1 ) 180 - 185 2012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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Serological screening of Coxiella burnetii (Q fever) and Brucella spp. in sheep flocks in the northern prefectures of Japan in 2007.
Giangaspero M, Osawa T, Bonfini B, Orusa R, Robetto S, Harasawa R
Veterinaria italiana 48 ( 4 ) 357 - 65 2012年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of a single intrauterine administration of recombinant bovine interferon-τ on day 7 of the estrous cycle on the luteal phase length and blood profile in dairy cows 査読あり
Matsunaga, S., Osawa, T., Geshi, M., Takahashi, H., Inumaru, S., Yokomizo, Y., Miyake, Y-I.
Research in Veterinary Science 93 ( 1 ) 381 - 385 2012年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Relationship between sex hormone fluctuations and biomarkers of bone resorption in bovine plasma during the oestrous cycle 査読あり
Devkota, B., Itagaki, K., Kim, D., Sasaki, K., Osawa, T., Furuhama, K., Yamagishi, N.
Veterinary Journal 194 ( 2 ) 256 - 258 2012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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Association between energy status early postpartum and subsequent embryonic mortality in high-yielding recipient cows 査読あり
Senosy, W., Zain, A. E., Abdel-Razek, A.-R., K., Uchiza, M., Tameoka, N., Izaike, Y., Osawa, T.
Animal Science Journal 83 284 - 290 2012年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Evaluation of reproductive tract infection during early post-partum period and its relationship with subsequent reproductive performance in high milk producing dairy cows 査読あり
Senosy, W.S., Uchiza, M., Tameoka, N., Izaike, Y., Osawa, T.
Reproduction in Domectic Animals 47 203 - 207 2012年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Association between energy status early postpartum and subsequent embryonic mortality in high-yielding recipient cows.
Senosy W, Zain AE, Abdel-Razek AR, Uchiza M, Tameoka N, Izaike Y, Osawa T
Animal science journal = Nihon chikusan Gakkaiho 83 ( 4 ) 284 - 90 2012年4月
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Seroepidemiological survey of sheep flocks from Northern Japan for Mycoplasma ovipneumoniae and Mycoplasma agalactiae 査読あり
Giangaspero, M., Ibata, G., Savini, G., Osawa, T., Tatami, S., Takagi, E., Moriya, H., Okura, N., Kato, Kimura, A., Harasawa, R.
Tropical Animal Health Production 44 395 - 398 2012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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Seroepidemiological survey of sheep flocks from Northern Japan for Mycoplasma ovipneumoniae and Mycoplasma agalactiae. 査読あり
Giangaspero M, Nicholas RA, Hlusek M, Bonfini B, Osawa T, Orusa R, Tatami S, Takagi E, Moriya H, Okura N, Kato K, Kimura A, Harasawa R, Ayling RD
Tropical animal health and production 44 ( 3 ) 395 - 8 2012年3月
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Epidemiological survey of Border disease virus among sheep from northern districts of Japan 査読あり
Giangaspero, M., Ibata, G., Savini, G., Osawa, T., Tatami, S., Takagi, E., Moriya, H., Okura, N., Kimura, A., Harasawa, R.
Journal of Veterinary Medical Science 73 1629 - 1633 2011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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Reproductive tract defence and disease in postpartum dairy cows 査読あり
LeBlanc, S., Osawa, T., Dubuc, J.
Theriogenology 76 1610 - 1618 2011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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Epidemiological survey of Border disease virus among sheep from northern districts of Japan.
Giangaspero M, Ibata G, Savini G, Osawa T, Tatami S, Takagi E, Moriya H, Okura N, Kimura A, Harasawa R
The Journal of veterinary medical science 73 ( 12 ) 1629 - 33 2011年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Reproductive tract defense and disease in postpartum dairy cows. 査読あり
LeBlanc SJ, Osawa T, Dubuc J
Theriogenology 76 ( 9 ) 1610 - 8 2011年12月
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Influences of metabolic traits on subclinical endometritis at different intervals postpartum in high milking cows 査読あり
Senosy, W.S., Izaike, Y., Osawa, T.
Reproduction in Domestic Animals 2011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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Validation of a direct time-resolved fluoroimmunoassay for progesterone in milk from dairy and beef cows 査読あり
Oku, Y., Osawa, T., Hirata, T-I., Kon, N., Akasaka, S., Senosy, W.S., Takahashi, T., Izaike, Y.
Veterinary Journal 190 244 - 248 2011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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Validation of a direct time-resolved fluoroimmunoassay for progesterone in milk from dairy and beef cows. 査読あり
Oku Y, Osawa T, Hirata T, Kon N, Akasaka S, Senosy WS, Takahashi T, Izaike Y
Veterinary journal (London, England : 1997) 190 ( 2 ) 244 - 8 2011年11月
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Epidemiological survey for visna-maedi among sheep in northern prefectures of Japan 査読あり
Giangaspero, M., Osawa, T., Orusa, R., Frossard, J-P., Naidu, B., Robetto, S., Tatami, S., Takagi, E., Moriya, H., Okura, N., Kato, K., Kimura, A., Harasawa, R.
Veterinaria Italiana 47 437 - 451 2011年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Impact of ovarian and uterine conditions on some diagnostic tests output of endometritis in post-partum high-yielding dairy cows 査読あり
Senosy, W.S., Uchiza, M., Tameoka, N., Izaike, Y., Osawa, T.
Reproduction in Domestic Animals 46 800 - 806 2011年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of follicular aspiration at the onset of progesterone-based timed artificial insemination protocol on the follicular dynamics and fertility in early postpartum Japanese black cows 査読あり
Hirata, T-I., Kon, N., Sugiyama, A., Sato, M., Osawa, T.
Journal of Reproduction and Development 57 613 - 619 2011年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of follicular aspiration at the onset of progesterone-based timed artificial insemination on the follicular dynamics and fertility of early postpartum Japanese black cows.
Hirata T, Kon N, Sugiyama A, Sato M, Osawa T
The Journal of reproduction and development 57 ( 5 ) 613 - 9 2011年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Epidemiological survey for visna-maedi among sheep in northern prefectures of Japan.
Giangaspero M, Osawa T, Orusa R, Frossard JP, Naidu B, Robetto S, Tatami S, Takagi E, Moriya H, Okura N, Kato K, Kimura A, Harasawa R
Veterinaria italiana 47 ( 4 ) 437 - 51 2011年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Fibrolipoma of the cryptorchid testis in a young bull 査読あり
Osawa, T., Miura, M., Yamagishi, N., Kim, D., Fukuda, N., Fukuoka, H., Sasaki, J., Goryo, M.
Journal of Veterinary Medical Science 73 1253 - 1255 2011年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Fibrolipoma of a cryptorchid testis in a young bull.
Osawa T, Miura M, Yamagishi N, Kim D, Fukuda N, Fukuoka H, Sasaki J, Goryo M
The Journal of veterinary medical science 73 ( 9 ) 1253 - 5 2011年9月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality 査読あり
Devkota, B., Takahashi, K-I., Matsuzaki, S., Matsui, M., Miyamoto, M., Yamagishi, N., Osawa, T., Hashizume, T., Izaike, Y., Miyake, Y-I.
Journal of Reproduction and Development 57 ( 3 ) 373 - 378 2011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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Basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality.
Devkota B, Takahashi K, Matsuzaki S, Matsui M, Miyamoto A, Yamagishi N, Osawa T, Hashizume T, Izaike Y, Miyake Y
The Journal of reproduction and development 57 ( 3 ) 373 - 8 2011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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Experimental infection of early pregnant cows with bovine viral diarrhea virus: Transmission of virus to the reproductive tract and conceptus 査読あり
Tsuboi, T, Osawa, T., Kimura, K., Kubo, M., Haritani, M.
Research in Veterinary Science 90 174 - 178 2011年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Association between evaluation of the reproductive tract by various diagnostic tests and restoration of ovarian cyclicity in high-producing dairy cows 査読あり
Senosy, W.S., Uchiza, M., Tameoka, N., Izaike, Y., Osawa, T.
Theriogenology 72 1153 - 1162 2009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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Plasma and fecal sex steroid hormone profiles during the estrous cycle in a Japanese serow (Capricornis crispus) 査読あり
Togashi, M., Tsujimoto, T., Yamauchi, K., Deguchi, Y., Hashizume, K., Kizaki, K., Honjou, S., Izaike, Y., Osawa, T.
Journal of Reproduction and Development 55 ( 4 ) 412 - 417 2009年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Plasma and fecal sex steroid hormone profiles during the estrous cycle in a Japanese serow (Capricornis crispus). 査読あり
Togashi M, Tsujimoto T, Yamauchi K, Deguchi Y, Hashizume K, Kizaki K, Honjou S, Izaike Y, Osawa T
The Journal of reproduction and development 55 ( 4 ) 412 - 7 2009年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Relationship between uterine morphology and peripheral concentrations of sex steroid hormone in wild Japanese black bears (Ursus thibetanus japonicus) 査読あり
Yamane, M., Yamamoto, Y., Tsujimoto, T, Osawa, T.
Animal Reproduction Science 113 251 - 262 2009年7月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Relationship between uterine morphology and peripheral concentrations of sex steroid hormone in wild Japanese black bears (Ursus thibetanus japonicus). 査読あり
Yamane M, Yamamoto Y, Tsujimoto T, Osawa T
Animal reproduction science 113 ( 1-4 ) 251 - 62 2009年7月
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乳牛のオブシンク処置におけるPGF2αから2回目GnRH投与までの間隔が定時授精後の排卵同期化率、授精後早期の胚生存率および妊娠率に与える影響 査読あり
高橋 純，大澤健司，洲鎌圭子，中坪競顧，松原和衛，三宅陽一
日本家畜臨床学会誌 32 ( 1 ) 1 - 7 2009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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Effect of synchronisation of ovulation on ovarian profile and days open in Holstein cows diagnosed as nonpregnant 26 days after timed artificial insemination 査読あり
Osawa, T., Honjou, S., Nitta, H., Uchiza, M., Tameoka, N., Moro, Y., Izaike, Y.
Journal of Reproduction and Development 55 ( 2 ) 163 - 169 2009年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of synchronisation of ovulation on ovarian profile and days open in holstein cows diagnosed as nonpregnant 26 days after timed artificial insemination.
Osawa T, Honjou S, Nitta H, Uchiza M, Tameoka N, Moro Y, Izaike Y
The Journal of reproduction and development 55 ( 2 ) 163 - 9 2009年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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CIDRを併用した過剰排卵処置に対するホルスタイン種未経産牛における卵巣の反応と回収胚の状態 査読あり
福田卓巳，大澤健司，打座美智子，爲岡奈々恵，遠藤 保，大井隆弘，荒屋孝一，下村則夫，広沢悠子，居在家義昭
日本家畜臨床学会誌 31 ( 3 ) 137 - 142 2008年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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乳用未経産牛の人工授精直後の陰唇刺激が受胎率に及ぼす効果 査読あり
小野 守，小関茂樹，斉藤康倫，泉 徳和，松井基純，大澤健司，三宅陽一
日本獣医師会雑誌 61 ( 10 ) 780 - 783 2008年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Effect of suckling on embryo production by repeated ovum pick-up before and after timed artificial insemination in early postpartum Japanese black cows 査読あり
Hirata, T-I., Sato, M., Sasaki, S-I., Sasaki, O., Osawa, T.
Journal of Reproduction and Development 54 ( 5 ) 346 - 351 2008年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of suckling on embryo production by repeated ovum pick-up before and after timed artificial insemination in early postpartum Japanese black cows.
Hirata T, Sato M, Sasaki S, Sasaki O, Osawa T
The Journal of reproduction and development 54 ( 5 ) 346 - 51 2008年10月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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ホルスタイン種経産牛における子宮蓄膿症を伴う非定型単胞性顆粒膜細胞腫の一例 査読あり
小宮誠子，大澤健司，三田能理子，植木淳史，清水祥子，加藤弘毅，阿南智顕，佐々木淳，御領政信，居在家義昭
日本家畜臨床学会誌 31 ( 1 ) 24 - 29 2008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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Applicability of a progesterone-based timed AI protocol after follicular fluid aspiration using OPU technique into suckled beef cows 査読あり
Hirata, T-I., Hoshina, T., Sasaki, S-I., Sasaki, O., Osawa, T.
Journal of Reproduction and Development 53 ( 2 ) 171 - 177 2007年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Applicability of a progesterone-based timed artificilal insemination protocol after follicular fluid aspiration using the ovum pick-up technique in suckled beef cows.
Hirata T, Hoshina T, Sasaki S, Sasaki O, Osawa T
The Journal of reproduction and development 53 ( 2 ) 171 - 7 2007年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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血中プロジェステロン（P4）濃度からみた牛の卵胞嚢腫および卵巣静止における診断精度の評価 査読あり
三宅陽一，大澤健司，大津信一，鈴木一教，園中篤，田高恵，森田靖，太田大作，高橋正弘
日本家畜臨床学会誌 29 ( 2 ) 43 - 46 2006年11月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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顆粒膜細胞種に罹患した黒毛和種2例の内分泌学的検索 査読あり
猪熊道仁，大澤健司，原茂雄，懸田和子，渥美孝雄，渡辺元，田谷一善，三宅陽一
日本獣医師会雑誌 59 ( 11 ) 746 - 749 2006年11月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Immunoreactive insulin-like growth factor in plasma during pre- and post-partum periods of thoroughbred mares from which the newborn were removed: its pattern, physiological function and relation to other hormones 査読あり
Derar R. I., Haramaki, S., Hoque, SMD. S., Hashizume, T., Osawa, T., Taya, K., Watanabe, G. and Miyake, Y-I.
Journal of Equine Science 17 ( 3 ) 75 - 79 2006年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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繁殖性と産乳能力が低いホルスタイン種体細胞クローン牛の臨床所見ならびに病理所見 査読あり
高橋正弘，土屋秀樹，植木淳史，三田能理子，久保正法，御領政信，橋爪 力，大澤健司
日本獣医師会雑誌 59 ( 8 ) 540 - 543 2006年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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A nationwide survey on seroprevalence of Neospora caninum infection in beef cattle in Uruguay 査読あり
Bañales, P., Fernandez, L., Repiso, M.V., Gil, A., Dargatz, D.A., Osawa, T.
Veterinary Parasitology 139 15 - 20 2006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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A nationwide survey on seroprevalence of Neospora caninum infection in beef cattle in Uruguay.
Bañales P, Fernandez L, Repiso MV, Gil A, Dargatz DA, Osawa T
Veterinary parasitology 139 ( 1-3 ) 15 - 20 2006年6月
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動物園鳥類および野生鳥類におけるPCR法による雌雄判別法の検討（共著） 査読あり
安永千秋，豊坂加奈，辻本恒徳，斎藤靖史，大澤健司，三宅陽一
野生動物医学会誌 11 ( 1 ) 43 - 48 2006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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子牛における腸間膜の長軸捻転の1例 査読あり
山岸則夫，入江陽一，能登はる菜，浪岡徹，岡田啓司，大澤健司，内藤善久
日本家畜臨床学会誌 29 ( 1 ) 16 - 19 2006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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ホルスタイン種経産牛における子宮外膜部の巨大被包化膿瘍を伴う子宮蓄膿症の一例 査読あり
大澤健司，松田敬一，古宮久美，穂積愛美，山根正子，御領政信，岡田啓司，内藤善久
日本家畜臨床学会誌 29 ( 1 ) 10 - 15 2006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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Postnatal developmental changes in immunohistochemical localization of alpha-smooth muscle actin (SMA) and vimentin in bovine testes. 査読あり
Devkota B, Sasaki M, Takahashi K, Matsuzaki S, Matsui M, Haneda S, Takahashi M, Osawa T, Miyake Y
The Journal of reproduction and development 52 ( 1 ) 43 - 9 2006年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Postnatal development changes in immunohistochemical localization of α-smooth muscle actin (SMA) and vimentin in bovine testes 査読あり
Devkota, B., Sasaki, M., Takahashi, K-I., Matsuzaki, S., Matsui, M., Haneda, S., Takahashi, M., Osawa, T., Miyake, Y-I.
Journal of Reproduction and Development 52 ( 1 ) 43 - 49 2006年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Postnatal development changes in immunohistochemical localization of alpha-smooth muscle actin (SMA) and vimentin in bovine testes 査読あり
DEVKOTA Bhuminand, DEVKOTA Bhuminand, DEVKOTA Bhuminand, SASAKI Motoki, SASAKI Motoki, TAKAHASHI Ken−ichi, MATSUZAKI Shigenori, MATSUI Motozumi, MATSUI Motozumi, HANEDA Shingo, HANEDA Shingo, TAKAHASHI Masahiro, OSAWA Takeshi, OSAWA Takeshi, MIYAKE Yoh−ichi, MIYAKE Yoh−ichi
Journal of Reproduction and Development 52 ( 1 ) 43 - 49 2006年
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動物園鳥類および野生鳥類におけるPCR法による雌雄判別法の検討 査読あり
大澤 健司
Japanese Journal of Zoo and Wildlife Medicine 11 ( 1 ) 43 - 48 2006年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Insulin-like growth factor-I as a follicular growth promoter during early pregnancy in thoroughbred mares 査読あり
Derar R. I., Haramaki, S., Hoque, MD. S., Hashizume, T., Osawa, T., Taya, K., Watanabe, G. and Miyake, Y-I.
Journal of Veterinary Medical Science 67 ( 1 ) 19 - 23 2005年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Insulin-like growth factor-I as a follicular growth promoter during early pregnancy in thoroughbred mares.
Derar R, Haramaki S, Hoque S, Hashizume T, Osawa T, Taya K, Watanabe G, Miyake Y
The Journal of veterinary medical science 67 ( 1 ) 19 - 23 2005年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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人工授精後の黒毛和種牛に対する連続経腟採卵‐牛胚体外生産法の適用
大澤 健司
日本胚移植学雑誌 27 ( 3 ) 78 - 86 2005年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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鎖肛子牛の１症例
大澤 健司
岩手県獣医師会報 31 8 - 10 2005年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Effect of active immunization of pony mares against recombinant porcine inhibin α subunit on ovarian follicular development and plasma steriods and gonadotropins 査読あり
Derar R. I., Maeda, Y., Hoque, M. S., Osawa, T., Watanabe, G., Taya, K. and Miyake, Y-I.
Journal of Veterinary Medical Science 66 ( 1 ) 31 - 35 2004年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Effect of active immunization of pony mares against recombinant porcine inhibin alpha subunit on ovarian follicular development and plasma steroids and gonadotropins.
Derar RI, Maeda Y, Hoque SM, Osawa T, Watanabe G, Taya K, Miyake Y
The Journal of veterinary medical science 66 ( 1 ) 31 - 5 2004年1月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Comparison of the effectiveness of ovulation synchronization protocol in anestrous and cycling beef cows 査読あり
Osawa, T., Morishige, D., Ohta, D., Kimura, Y., Hirata, T-I. and Miyake, Y-I.
Journal of Reproduction and Development 49 ( 6 ) 513 - 521 2003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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Comparison of the effectiveness of ovulation synchronization protocol in anestrous and cycling beef cows.
Osawa T, Morishige D, Ohta D, Kimura Y, Hirata T, Miyake Y
The Journal of reproduction and development 49 ( 6 ) 513 - 21 2003年12月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Endocrinological changes before and after removal of the granulosa theca cell tumor (GTCT) affected ovary in 6 mares 査読あり
Hoque, M.S., Senba H., Tsunoda N., Derar R. I., Watanabe, G., Taya, K., Osawa, T. and Miyake, Y-I.
Journal of Veterinary Medical Science 65 ( 8 ) 887 - 891 2003年8月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Endocrinological changes before and after removal of the granulosa theca cell tumor (GTCT) affected ovary in 6 mares.
Hoque S, Senba H, Tsunoda N, Derar RI, Watanabe G, Taya K, Osawa T, Miyake Y
The Journal of veterinary medical science 65 ( 8 ) 887 - 91 2003年8月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Spontaneous repair of the atrophic contaralateral ovary without ovariectomy in the case of a granulosa theca cell tumor (GTCT) affected mare 査読あり
Hoque, M. S., Derar R. I., Osawa, T., Taya, K., Watanabe, G. and Miyake, Y-I.
Journal of Veterinary Medical Science 65 ( 6 ) 749 - 751 2003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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Origin of plasma insulin-like growth factor-I (IGF-I) during estrus in goats 査読あり
Nonaka, S., Hashizume, T., Horiuchi, M., Mikami, U., Osawa, T., Miyake, Y-I. and Hara, S.
Journal of Reproduction and Development 49 ( 3 ) 253 - 258 2003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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Localization of inhibin α-, βA- and βB-subunits and aromatase in the ovarian follicles with granulosa theca cell tumor (GTCT) in 6 mares 査読あり
Hoque, M.S., Derar R. I., Senba, H., Osawa, T., Kano, K., Taya, K. and Miyake, Y-I.
Journal of Veterinary Medical Science 65 ( 6 ) 713 - 717 2003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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Localization of inhibin alpha-, betaA- and betaB-subunits and aromatase in ovarian follicles with granulosa theca cell tumor (GTCT) in 6 mares. 査読あり
Hoque S, Derar RI, Senba H, Osawa T, Kano K, Taya K, Miyake Y
The Journal of veterinary medical science 65 ( 6 ) 713 - 7 2003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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Spontaneous repair of the atrophic contralateral ovary without ovariectomy in the case of a granulosa theca cell tumor (GTCT) affected mare. 査読あり
Hoque S, Derar RI, Osawa T, Taya K, Watanabe G, Miyake Y
The Journal of veterinary medical science 65 ( 6 ) 749 - 51 2003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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Origin of plasma insulin-like growth factor-I (IGF-I) during estrus in goats. 査読あり
Nonaka S, Hashizume T, Horiuchi M, Mikami U, Osawa T, Miyake Y, Hara S
The Journal of reproduction and development 49 ( 3 ) 253 - 8 2003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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Hoque S., Derar R., Senba H., Osawa T., Kano K., Taya K., Miyake Y.
Journal of Veterinary Medical Science 65 ( 6 ) 713 - 717 2003年6月
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
To clarify the morphological and immunohistochemical characteristics in mares with granulosa theca cell tumor (GTCT), the localization of inhibin subunits (α, βA, βB) and aromatase in the granulosa cell layers and theca layers in the ovarian follicles were determined by immunohistochemical staining. The follicles were obtained from the ovaries of 6 mares with GTCT and 4 normal mares as controls. Immunohistochemically, inhibin α-subunit was localized in the granulosa cells of all follicles showing different sizes in all GTCT cases and βA- subunit was localized in two GTCT cases in all sized follicles. But inhibin βB- subunit and aromatase were not localized in GTCT cases. On the other hand, inhibin α-, βA-, and βB- subunits and aromatase were localized in the large and medium sized follicles, but inhibin βA- and βB-subunits and aromatase were not stained in the small sized follicles in normal cases. These findings suggest that some mares with GTCT can secrete dimeric inhibin (inhibin A), but all GTCT cases cannot secrete inhibin B. By the results of aromatase staining it is clear that testosterone is not converted into estradiol due to the lack of aromatase in the GTCT follicles.
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Application of timed artificial insemination protocols to grazing Japanese Black cattle with long open period 査読あり
Osawa, T., Morishige, D., Ohta, D., Kimura, Y. and Miyake, Y-I.
Journal of Veterinary Medical Science 65 ( 4 ) 459 - 464 2003年4月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Application of timed artificial insemination protocols to grazing Japanese black cattle with long open period.
Osawa T, Morishige D, Ohta D, Kimura Y, Miyake Y
The Journal of veterinary medical science 65 ( 4 ) 459 - 64 2003年4月
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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乳牛の嚢腫卵胞を伴う繁殖障害の３症例 –超音波画像およびプロジェステロン値による経過観察–
大澤 健司
岩手県獣医師会報 29 ( 3 ) 87 - 91 2003年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Seroprevalence of Neospora caninum infection in dairy and beef cattle in Paraguay 査読あり
Osawa, T., Wastling, J., Acosta, L., Ortellado, C., Ibarra, J. and Innes, E. A.
Veterinary Parasitology 110 17 - 23 2002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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Seroprevalence of Neospora caninum infection in dairy and beef cattle in Paraguay. 査読あり
Osawa T, Wastling J, Acosta L, Ortellado C, Ibarra J, Innes EA
Veterinary parasitology 110 ( 1-2 ) 17 - 23 2002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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Clinical findings before and after the removal of ovaries affected with granulosa theca cell tumor (GTCT) in 16 mares 査読あり
Hoque MD. Shafiqul, Derar R. I., Tsunoda, N., Senba, H., Osawa, T. and Miyake, Y-I.
Journal of Equine Science 13 ( 3 ) 75 - 81 2002年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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The peripheral levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), immunoreactive (ir-) inhibin, progesterone (P) and estradiol-17β (E2) at the time of control of ovulation with gonadotropin releasing hormone (GnRH) agonist (Deslorelin) in pony mares. 査読あり
Derar R. I., Maeda, Y., Tsunoda, N., Hoque, M. S., Osawa, T. and Miyake, Y-I.
Journal of Equine Science 13 ( 3 ) 83 - 87 2002年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Derar R., Maeda Y., Tsunoda N., Hoque M., Osawa T., Miyake Y.
Journal of Equine Science 13 ( 3 ) 83 - 87 2002年1月
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 Equine Science
Control of ovulation in mares obviously has many advantages in a breeding program. Two pony mares were challenged against synthetic Gonadotropin Releasing Hormone (GnRH) agonist (Deslorelin) for six consecutive cycles. Clinical and endocrinological findings after treatment (n=6) with GnRH agonist were compared with those of the control findings before treatment (n=3) of the same mares. The time interval from administration of the GnRH agonist till ovulation (43.5 ±4.0 hr) and the length of the estrous cycle (19.5 ±1.0 days) at the time of treatment were significantly (p < 0.05) shortened as compared with those of the control. A preovulatory sharp rise in plasma luteinizing hormone (LH) and folliclestimulating hormone (FSH) was also noticed 24 hr from the time of GnRH agonist injection and one day prior to ovulation in the studied mares, but there were no significant differences before and after treatment with GnRH agonist on the levels of ir-inhibin, progesterone (P) and estradiol-l7β (E 2 ). It seems likely that GnRH agonist is beneficent in reducing the number of matings needed for conception in a natural mating program and that ovulation in mares may be induced by a sharp preovulatory rise in LH and FSH.
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Pituitary chromophobe carcinoma with a low level of serum gonadotropin and an aspermatogenesis in a dog 査読あり
Sato, J., Sato, R., Kinai, M., Tomizawa, N., Osawa, T., Nakada, K., Yano, A., Goryo, M. and Naito, Y.
Journal of Veterinary Medical Science 63 ( 2 ) 183 - 185 2001年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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放牧牛を対象とした排卵同期化と定時授精法による受胎促進の試み
大澤 健司
岩手県獣医師会報 27 ( 4 ) 135 - 138 2001年
記述言語：日本語 掲載種別：研究論文（学術雑誌）
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Endocrinological studies of mares with granulosa-theca cell tumor 査読あり
Yoshida, G., Tsunoda, N., Miyake, Y-I., Hoque MD. S., Osawa, T., Nagamine, N., Taniyama, H., Nambo, Y., Watanabe, G. and Taya, K.
Journal of Equine Science 11 ( 2 ) 35 - 43 2000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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Changes in peripheral follicle stimulating hormone (FSH), luteinizing hormone (LH), inhibin, estradiol-17β, progesterone, and testosterone levels before and after the administration of equine chorionic gonadotropin (eCG), human chorionic gonadotropin (hCG) and gonadotropin releasing hormone analogue (GnRH-A) in three cases of bovine gonadal hypoplasia (XY female) 査読あり
Miyake, Y-I., Hirata, T-I., Osawa, T., Watanabe, G. and Taya, K.
Journal of Reproduction and Development 46 ( 6 ) 381 - 386 2000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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Effects of dystocia, retained placenta and body condition on plasma β-endorphin profile in periparturient dairy cows 査読あり
Osawa, T., Nakao, T., Moriyoshi, M. and Nakada, K.
Journal of Reproduction and Development 46 23 - 30 2000年1月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Miyake Y., Hirata T., Osawa T., Watanabe G., Taya K.
Journal of Reproduction and Development 46 ( 6 ) 381 - 386 2000年1月
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
To clarify the endocrinological characteristics of bovine gonadal hypoplasia (XY female), peripheral FSH, LH, inhibin, estradiol-17 β (E 2 ), progesterone (P) and testosterone (T) levels were measured before and after the administration of eCG, hCG and GnRH-A in the 3 bovine XY females without the Sry gene. Before the administration of hormonal drugs, the concentrations of FSH and LH were higher than in adult bulls, cows in the luteal phase and castrated bulls. On the other hand, the concentrations of inhibin and E 2 were lower than those observed in the follicular phase during the estrous cycle. Concentrations of P and T were much lower than those observed in the luteal phase during the estrous cycle and in bulls. Gonads of our XY females did not respond to eCG or hCG stimulation, whereas the pituitary was highly responsive to GnRH-A in LH secretion.
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A multiple antigen ELISA to detect Neospora-specific antibodies in bovine sera, bovine foetal fluids, ovine and caprine sera 査読あり
Osawa, T., Wastling, J., Maley, S., Buxton, D. and Innes, E.A.
Veterinary Parasitology 79 19 - 34 1998年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Plasma β-endorphin around parturition and its relationship to cortisol level and resumption of pituitary and ovarian functions in dairy cows 査読あり
Osawa, T., Nakao, T., Moriyoshi, M. and Nakada, K.
Animal Reproduction Science 52 27 - 38 1998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 β-endorphin around parturition and its relationship to cortisol level and resumption of pituitary and ovarian functions in dairy cows. 査読あり
OSAWA T, NAKAO T, MORIYOSHI M, NAKADA K
Animal Reproduction Science 52 ( 1 ) 27 - 38 1998年
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Postpartum plasma PGF metabolite profile in cows with dystocia and/or retained placenta, and effect of fenprostalene on uterine involution and reproductive performance 査読あり
Nakao, T., Gamal, A., Osawa, T., Nakada, K., Moriyoshi, M., Kawata, K.
Journal of Veterinary Medical Science 59 ( 9 ) 791 - 794 1997年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Postpartum adrenal, pituitary and ovarian functions in dairy cows 査読あり
Torres, E., Nakao, T., Osawa, T., Moriyoshi, M., Kawata, K., Nakada, K.
Journal of Veterinary Medicine Series A 44 ( 3 ) 133 - 142 1997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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Pituitary response to exogenous GnRH on day 7 postpartum in high-producing dairy cows 査読あり
Osawa, T., Nakao, T., Nakada, K., Moriyoshi, M., Kawata, K.
Reproduction in Domestic Animals 31 343 - 347 1996年9月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Fertirelin and Buserelin compared by LH release, milk progesterone and subsequent reproductive performance in dairy cows treated for follicular cysts 査読あり
Osawa, T., Nakao, T., Kimura, M., Kaneko, K., Takagi, H., Moriyoshi, M., Kawata, K.
Theriogenology 44 835 - 847 1995年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Response of serum LH and milk progesterone to two GnRH agonists, feritrelin and buserelin, in cows with ovarian follicular cysts.
OSAWA Takeshi
Bovine Practitioner 29 58 - 59 1995年
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Identification of serovar of Mycobacterium avium-intracellulare-scrofulaceum complex strain isolated from swine by thin-layer chromatography using glycopeptido-lipid
OSAWA Takeshi
食品衛生研究 42 ( 5 ) 57 - 64 1992年
記述言語：日本語 掲載種別：研究論文（学術雑誌）