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| Registros recuperados: 42 | |
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| KOBAYASHI, Shu-ichi; MIYAMOTO, Akio; 宮本, 明夫. |
| Luteal cells utilize lipoproteins (LIPs) for progesterone (P) synthesis. A luteolysin prostaglandin F2α (PGF 2α) has shown to prevent the LIPs utilization for steroidogenesis in bovine midcycle luteal cells. However, a luteolytic injection of PGF2α before Day 5 (Day 0=estrus) can not induce the regression of the corpus luteum (CL). This suggests that the intraluteal mechanism of PGF2 α action on the LIPs utilization in early CL is different from that of the mid luteal stage. Thus, this study aimed to investigate the interaction between PGF2 α and LIPs on the secretion of P and oxytocin (OT) from bovine early CL. An in vitro microdialysis system (MDS) was used as a model. Each bovine early CL (Days 3-4) was implanted with the MDS, and maintained in an organ... |
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Palavras-chave: PGF2α; Lipoproteins; Early CL; Cow. |
| Ano: 2000 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2972 |
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| OHTANI, Masayuki; OKI, Naoko; TANIMURA, Miyune; KOBAYASHI, Shu-ichi; ACOSTA, Tomas J.; HAYASHI, Kanako; MIYAMOTO, Akio; 宮本, 明夫. |
| It is well known that an injection of prostaglandin F2α (PGF2α) or its analogue during the mid luteal phase of the estrous cycle induces a rapid decrease in plasma progesterone (P4) concentration, followed by luteolysis in the cow. There is evidence that a potent vasoactive peptide, endothelin-1 (ET-1), is produced in the bovine corpus luteum (CL), and that it is directly involved in luteolysis. We previously found that ET-1 concentrations in the peripheral plasma increase during the period of luteolysis and ovulation in cows. However, it is not clear whether the elevation of peripheral plasma ET-1 concentration observed during luteolysis and ovulation originates exclusively from the ovary and/or CL. Such a profile of plasma ET-1 concentration may be... |
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Palavras-chave: Endothelin; Progesterone; Plasma; Calves; Cows. |
| Ano: 2001 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2973 |
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| KOBAYASHI, Shu-ichi; ACOSTA, Tomas J.; HAYASHI, Kanako; BERISHA, Bajram; OZAWA, Takahiro; OHTANI, Masayuki; SCHAMS, Dieter; MIYAMOTO, Akio; 宮本, 明夫. |
| It is well known that prostaglandin (PG) F2α and PGE2 are actively produced by bovine early corpus luteum (CL) at higher levels than in the CL of later stages. However, there is no in vivo information about the local secretion of PGs within bovine developing CL so far. Thus, the objective of the present study was to determine in detail the real-time changes in PGF2α and PGE2 secretion within developing CL. A microdialysis system (MDS) was surgically implanted into the newly formed CL of 6 cows on Day 3 after GnRH administration (about 1.5 days after ovulation) to induce superovulation following FSH treatment. Both PGF2α and PGE2 release were high during the first 24 h within developing CL but decreased thereafter. These profiles were well reflected in the... |
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Palavras-chave: PGF2α; PGE2; Developing CL; Cow; In vivo. |
| Ano: 2002 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2974 |
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| HAYASHI, Ken-Go; BERISHA, Bajram; MATSUI, Motozumi; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 宮本, 明夫. |
| Recent findings indicate that the changing profile of angiopoietins (ANPT) and their receptor Tie2 are closely associated with development and regression of the vascular network in the cyclic ovary. We previously reported that mRNA expression for the ANPT-Tie system in theca interna changes during bovine follicular development and atresia, and both ANPTs affect steroidogenesis in the preovulatory follicle. The aim of this study was to investigate mRNA expression for ANPT1, ANPT-2 and Tie2 in granulosa cells (GC) during follicular development in the cow. Bovine follicles were classified according to the estradiol-17β (E2) concentration in follicular fluid (FF) as follows: (1) E2<0.5, (2) 0.5<E2<5, (3) 5<E2<20, (4) 20<E2<180 and (5)... |
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Palavras-chave: Follicular development; Angiopoietin-Tie system; Granulosa cell; Cow. |
| Ano: 2004 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2975 |
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| TANAKA, Jun; ACOSTA, Tomas J.; BERISHA, Bajram; TETSUKA, Masa; MATSUI, Motozumi; KOBAYASHI, Shuichi; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 宮本, 明夫. |
| Local angiogenesis and angiolysis in the corpus luteum (CL) relate to the luteal function. Recent studies indicate that angiopoietins (ANPT) and their receptors Tie regulate remodeling of microvasculature. We therefore examined 1) the relative changes in the expression of mRNA for ANPT-1, ANPT-2, Tie1 and Tie2 in bovine CL by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) during the estrous cycle and prostaglandin F2α (PGF2α)-induced luteolysis, and 2) the effect of ANPT-2 on progesterone (P4) release from CL at the late stage of the estrous cycle by an in vitro microdialysis system (MDS). The CLs were classified into 4 stages (early: Day 2-5, n=7, mid: Day 8-12, n=15, late: Day 15-17, n=9, regressing: Day >18, n=19). The... |
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Palavras-chave: Angiopoietin; Angiolysis; Luteolysis; Corpus luteum; Cow. |
| Ano: 2004 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2977 |
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| NOZAKI, Hirofumi; WIJAYAGUNAWARDANE, Missaka P.B.; KODITUWAKKU, Suranga P.; YOSHIDA, Takashi; NAKAMURA, Tadashi; ARAI, Ikichi; URASHIMA, Tadasu; MIYAMOTO, Akio; 中村, 正; 浦島, 匡; 宮本, 明夫. |
| N-acetylglucosaminyltransferase I (GnT I; EC 2.4.1.101), which catalyzes the first step in the conversion of oligomannose to complex or hybrid N-glycans of glycoproteins, was found in media cultured with bovine oviduct epithelial cells (BOEC) obtained from non-pregnant cows during the follicular phase. Combined treatment with specific hormones increased GnT I release from BOEC. Luteinizing hormone (LH; 10 ng/ml) alone slightly, but together with 17β-estradiol (E2; 1 ng/ml), synergistically increased GnT I activity. Vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF) α, which have been shown to have their highest activities in the bovine oviduct during the periovulatory period, also increased in GnT I activity. This study provides the... |
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Palavras-chave: Bovine; Luteinizing hormone (LH); N-acetylglucosaminyltransferase I; Oviduct; Tumor necrosis factor (TNF) α; Vascular endothelial growth factor (VEGF). |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2978 |
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| ACOSTA, Tomas J.; TETSUKA, Masa; MATSUI, Motozumi; SHIMIZU, Takashi; BERISHA, Bajram; SCHAMS, Dieter; MIYAMOTO, Akio; 松井, 基純; 清水, 隆; 宮本, 明夫. |
| The aim of the present in vivo study was to monitor real-time fluctuations of cortisol (Cr) in the wall of preovulatory follicles using a microdialysis system (MDS) implanted in the theca layer as well as changes in ovarian venous plasma (OVP) and jugular venous plasma (JVP). Seven cows were superovulated using FSH and prostaglandin F2α injections. Dialysis capillary membranes were surgically implanted into the theca layer of mature follicles and connected to a microdialysis system. Fractions of the perfusates were collected from Day -1 (Day 0=LH surge) to Day 3. No difference in the concentrations of Cr between JVP and OVP was detected throughout the experiment. Circulating concentrations of Cr ranged from 20 to 35 ng/ml 8 h after surgery in ovulatory and... |
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Palavras-chave: Bovine; Cortisol; Follicle; Ovary; Ovulation. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2980 |
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| HORI, Takuya; YAMSAARD, Thicomeporn; UETA, Yoshiko Yanagimoto; HARAKAWA, Shinji; KANEKO, Etsushi; MIYAMOTO, Akio; XUAN, Xuenan; TOYODA, Yutaka; SUZUKI, Hiroshi; 宮本, 明夫; 玄, 学南; 鈴木, 宏志. |
| It is well-known that there are considerable strain differences in the relative copulation rates between male and superovulated female mice. In particular, the C57BL/6J strain of mice has a lower rate of successful copulation. We examined the effect of exposure to an electric field on sexual behavior in C57BL/6J male mice. When C57BL/6J males were exposed to a 50 Hz, 45 kV/m electric field for 30 min per day for 11 days and placed in a cage with a superovulated female of the same strain, the successful copulation rates of males was significantly improved compared with unexposed males (P<0.05). These results suggest that the exposure of C57BL/6J male mice to an electric field improves their sub-fertility activity in mating with superovulated females. |
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Palavras-chave: Mice; Male; Electric field; Copulation; Superovulation; Sexual behavior. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3021 |
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| ACOSTA, Tomas J.; HAYASHI, Ken-Go; MATSUI, Motozumi; MIYAMOTO, Akio; 松井, 基純; 宮本, 明夫. |
| Increase in the blood supply to individual follicles appears to be associated with follicular growth rates and the ability to become the dominant follicle, while reduced thecal vascularity appears to be closely associated with follicular atresia. Therefore, this study aimed to determine the real-time changes in the vascularity of the follicle wall during the first follicular wave in cycling Holstein cows. Normally cycling and lactating cows (n=5) were examined by transrectal color Doppler ultrasonography (the sensitivity for velocity: > 2 mm/sec) to determine the changes in the vasculature of the follicle wall (presence or absence of blood flow) and the diameter of follicles. A new follicular wave and ovulation were induced by GnRH injection at 48 h... |
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Palavras-chave: Blood flow; Follicular wave; Selection; Deviation; Cow. |
| Ano: 2005 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2979 |
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| SHIMIZU, Takashi; AKIYAMA, Hirotada; ABE, Yasuyuki; SASADA, Hiroshi; SATO, Eimei; MIYAMOTO, Akio; UCHIDA, Takafumi; 清水, 隆; 宮本, 明夫. |
| Protein phosphorylation on certain serine or threonine residues preceding proline (Ser/Thr-Pro) is a pivotal signaling mechanism in diverse cellular processes. Pin1 is a highly conserved enzyme that isomerizes only the phosphorylated Ser/Thr-Pro bonds in certain proteins, thereby inducing conformational changes. Although much protein is phosphorylated in the ovary, the role of Pin1 in the ovary is still unknown. The purpose of this study is to investigate the effects of gonadotropins on protein and mRNA expression of Pin1 in mice ovaries. Quantitative PCR analysis showed that the expression of Pin1 mRNA significantly increased in the ovaries of equine chorionic gonadotropin (eCG)-treated mice compared with those of untreated mice (P<0.05). However,... |
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Palavras-chave: E2F; Follicle development; Gonadotropin; Ovary; Pin1. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4056 |
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| KAWASHIMA, Chiho; KANEKO, Etsushi; AMAYA MONTOYA, Carlos; MATSUI, Motozumi; YAMAGISHI, Norio; MATSUNAGA, Nobuyoshi; ISHII, Mitsuo; KIDA, Katsuya; MIYAKE, Yoichi; MIYAMOTO, Akio; 川島, 千帆; 松井, 基純; 石井, 三都夫; 木田, 克弥; 三宅, 陽一; 宮本, 明夫. |
| The aim of this study was to investigate the relationship between the first ovulation within 3 weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cattle in Hokkaido, Japan. In Experiment 1, 110 cows (44 primiparous and 66 multiparous) were used to determine the effects of the first ovulation within 3 weeks postpartum on subsequent ovarian cycles. Milk samples were collected twice weekly from 7 to 100 days postpartum. The first ovulation was identified by an increase in milk progesterone (P4) to more than 1 ng/ml within 3 weeks postpartum. The numbers of cows showing ovulation and anovulation within 3 weeks postpartum were 31 (70.5%) and 13 (29.5%) in the primiparous cows and 35 (53.0%) and 31 (47.0%) in the multiparous... |
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Palavras-chave: Dairy cow; First ovulation; Postpartum; Resumption of ovarian cycle. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/916 |
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| MIYAMOTO, Akio; SHIRASUNA, Koumei; HAYASHI, Ken-Go; KAMADA, Daichi; KAWASHIMA, Chiho; KANEKO, Etsushi; ACOSTA, Tomas J.; MATSUI, Motozumi; 宮本, 明夫; 白砂, 孔明; 川島, 千帆; 松井, 基純. |
| Ultrasonography (US) has been applied to the ovary and the uterus of domestic animals from the late 1980s, and established in 1990s as a practical tool for animal production. US made it possible to detect pregnancy at a very early stage and, most importantly, to observe the real-time dynamics of follicular development and hence the discovery of follicular waves. This has greatly contributed to our understanding of ovarian physiology and helped us to develop several "pin-point" protocols for hormonal treatment. While US may not seem to fit preconceived ideas of a "green" technology, it does not contravene environmental priorities, and it is non-invasive ("ethical") and non-hormonal ("clean"). Using the US technology that is now commercially available at a... |
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Palavras-chave: Color Doppler ultrasound; Blood flow; Ovary; Reproduction; Cow. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2983 |
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| HAYASHI, Ken-Go; MATSUI, Motozumi; ACOSTA, Tomas J.; KIDA, Katsuya; MIYAMOTO, Akio; 松井, 基純; 木田, 克弥; 宮本, 明夫. |
| Luteinizing hormone (LH) surge and follicle rupture act as trigger to start corpus luteum (CL) formation. Thus, we aimed to investigate whether a dominant follicle that has not been exposed to an LH surge can become a functional CL. For this purpose, follicular fluid from the dominant follicles (DF) of cows was aspirated before or after a GnRH-induced LH surge, and subsequent CL formation was observed. Holstein cows were divided into four groups as follows: Luteal phase, a DF was aspirated 7 days after GnRH injection; Pre-LH surge, a DF was aspirated 42 h after PGF2α injection during the mid luteal phase; Post-LH surge, a DF was aspirated 24 h after GnRH injection following PGF2α; and Intact follicle, ovulation was induced by GnRH injection after PGF2α.... |
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Palavras-chave: Corpus luteum formation; Cow; Follicle aspiration; LH surge. |
| Ano: 2006 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2982 |
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| SHIMIZU, Takashi; JAYAWARDANA, Barana C.; TETSUKA, Masafumi; MIYAMOTO, Akio; 清水, 隆; 手塚, 雅文; 宮本, 明夫. |
| Vascular endothelial growth factor (VEGF) isoforms (VEGF 120 and VEGF 164) secreted by granulosa cells are involved in thecal angiogenesis during follicular development in the bovine ovary. However, whether the transcript of the VEGF120 and VEGF164 isoforms differs during follicular development in the ovary is still unknown. We first examined the gene expression of VEGF120, VEGF164, fms-like tyrosine kinase (Flt-1), and fetal liver kinase (Flk-1) in the granulosa cells (GCs) and theca cells (TCs) of pre-selection and post-selection follicles (PRF and POF respectively) from the bovine ovary. Then we examined the effects of FSH and estradiol (E2) on these factors in cultured bovine GCs. Messenger RNA (mRNA) expression was quantified using real-time PCR... |
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Palavras-chave: Estradiol; Fetal liver kinase (Flk-1); Fms-like tyrosine kinase (Flt-1); Follicle-stimulating hormone (FSH); Granulosa cell; Vascular Endothelial Growth factor (VEGF). |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4057 |
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| KAWASHIMA, Chiho; KIDA, Katsuya; HAYASHI, Ken-Go; AMAYA MONTOYA, Carlos; KANEKO, Etsushi; MATSUNAGA, Nobuyoshi; SHIMIZU, Takashi; MATSUI, Motozumi; MIYAKE, Yoh-Ichi; SCHAMS, Dieter; MIYAMOTO, Akio; 川島, 千帆; 木田, 克弥; 清水, 隆; 松井, 基純; 三宅, 陽一; 宮本, 明夫. |
| The aim of the present study was to investigate the changing profiles of plasma metabolic hormones during the ovarian cycles of beef and dairy cattle. We used 16 non-pregnant, non-lactating Japanese Black beef cattle (6 heifers and 10 cows; parity=2.3 ± 0.8) and 12 multiparous Holstein dairy cows (parity=3.0 ± 0.3). Blood samples for hormonal analysis (growth hormone, GH; insulin-like growth factor-I, IGF-1; insulin; and progesterone, P4) were obtained twice weekly for 40 days before artificial insemination for Japanese Black cattle and from 50 to 100 days postpartum for Holstein cows. Luteal phases were considered normal if the P4 concentrations for at least 3 time points over the course of 7 days remained above 1 ng/ml and at least 2 of the time points... |
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Palavras-chave: Cattle; Insulin-like growth factor-I; Ovarian cycle; Progesterone. |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2984 |
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| SHIMIZU, Takashi; BERISHA, Bajram; SCHAMS, Dieter; MIYAMOTO, Akio; 清水, 隆; 宮本, 明夫. |
| The aim of the present study was to examine the messenger RNA expressions of the endothelin and angiotensin systems during the periovulatory phase in gonadotrophin releasing hormone (GnRH)-treated cows. Ovaries were collected by transvaginal ovariectomy (n=5 cows/group), and the follicles (n=5, one follicle/cow) were classified into the following groups: before GnRH administration (control, before LH surge), 3-5 h after GnRH (during LH surge), 10 h after GnRH; 20 h after GnRH, 25 h after GnRH (peri-ovulation), and early corpus luteum (CL) (Days 2-3). Expression of mRNA was investigated using quantitative real-time PCR. The expression of angiotensin converting enzyme (ACE) mRNA significantly decreased immediately after onset of the LH surge and remained at... |
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Palavras-chave: Angiotensin; Bovine; Endothelin-1; Gonadotrophin releasing hormone (GnRH); Ovulation. |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2987 |
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| SHIRASUNA, Koumei; WATANABE, Sho; NAGAI, Kaya; SASAHARA, Kiemi; SHIMIZU, Takashi; RICKEN, Albert M.; SPANEL-BOROWSKI, Katharina; MIYAMOTO, Akio; 白砂, 孔明; 清水, 隆; 宮本, 明夫. |
| Cell-to-cell interaction via cell contact-dependent pathway is essentially important for maintenance and regulation of corpus luteum (CL) integrity and its physiological actions. The objective of the present study was to evaluate the mRNA expression of the cell adhesion molecules (CAMs) that are constituent factors of gap junctions [connexin (Cx) 43] and adherence junctions (VE-, E-, N-cadherin) in two types of endothelial cells from the mid CL and in CL tissue during the estrous cycle and PGF2α-induced luteolysis in the cow. Specific mRNA expression for Cx43 and N-cadherin was detected in cytokeratin-positive (CK+) and cytokeratin-negative (CK-) luteal endothelial cells (EC) and fully luteinized granulosa cells (LGC). E-cadherin mRNA was expressed in... |
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Palavras-chave: Cadherin; Connexin; Corpus luteum; Cow; Luteolysis. |
| Ano: 2007 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2988 |
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| ISHII, Mitsuo; KOBAYASHI, Syuichi; ACOSTA, Tomas J.; MIKI, Wataru; YAMANOI, Takahiro; MATSUI, Motozumi; MIYAKE, Yoh-Ichi; MIYAMOTO, Akio; 石井, 三都夫; 松井, 基純; 三宅, 陽一; 宮本, 明夫. |
| The aim of this study was to clarify the relationship between circulating oxytocin (OT) and PGF2α metabolite (PGFM) in mares at the third stage of labor and placental expulsion time in order to investigate a cause of retained placenta of which the incidence increase in a heavy draft mare. Blood was sampled every 5 min from foaling to expulsion of the placenta in 18 heavy draft mares to evaluate circulating OT and PGFM. The relationships between OT and PGFM concentration and recorded placental expulsion times were investigated. The results were as follows (1) The highest level of OT concentration was observed close to foaling in 15 mares. (2) The OT concentrations close to foaling were variable with a large difference from the lowest concentration, 22.1... |
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Palavras-chave: Heavy draft mare; Oxytocin; 15-keto-dihydro prostaglandin F2α (PGFM); Placental expulsion. |
| Ano: 2008 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3089 |
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| KAWASHIMA, Chiho; KIDA, Katsuya; MATSUHASHI, Miki; MATSUI, Motozumi; SHIMIZU, Takashi; MATSUNAGA, Nobuyoshi; ISHII, Mitsuo; MIYAKE, Yoh-Ichi; MIYAMOTO, Akio; 川島, 千帆; 木田, 克弥; 松井, 基純; 清水, 隆; 石井, 三都夫; 三宅, 陽一; 宮本, 明夫; 松長, 延吉. |
| The aim of our study was to investigate the effects of suckling on reproductive performance and metabolic status of obese (mean body condition score of more than 4.0 on a scale of 1-5) maternal Japanese Black cows during early postpartum period. We used 7 postpartum Japanese Black cattle. Four cows were suckled ad libitum (suckled) until completion of their first artificial insemination (AI), while 3 cows were not suckled at all because they were separated from their calves immediately after parturition (non-suckled). Body weight and plasma concentrations of metabolites and hormones were measured from wk 1 to 9 postpartum. Ovarian activity was detected using plasma progesterone concentration, and all cows received their first AI after application of the... |
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Palavras-chave: Japanese Black cattle; Metabolic status; Obesity; Reproductive performance; Suckling. |
| Ano: 2008 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/2991 |
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| Registros recuperados: 42 | |
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