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forage and breed effects on behavior and temperament of pregnant beef heifers

Journal of Animal Science and Biotechnology 2013年第3期4卷 165-169页

作者： Angela R Mays Michael L Looper Benjamin C Williamson Kenneth P Coffey Wayne K Coblentz Glen E Aiken charles f rosenkrans jr Department of Animal Science University of ArkansasFayetteville AR 72701 USA Department of Agricultural Sciences Morehead StateUniversity327 Reed Hall Morehead KY 40351 USA USDA-ARS US Dairy Forage Research CenterMarshfield WI 54449 USA USDA-ARS Forage Animal Production Research UnitLexingtonKY 40546 USA

Background： Integration of behavioral observations with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle production ***-influenced（BR;n = 64） and Gelbvieh × Angus（GA;n = 64） heifers consumed either toxic endophyte-infected tall fescue（E＋） or one of two nontoxic endophyte-infected tall fescue（NT） cultivars during two *** were weighed at midpoint and termination of *** behavior（grazing,resting in the shade,lying,or standing without grazing） was recorded（n = 13 visual observations per yr in June and July） for each *** yr 2,exit velocity（EV） and serum prolactin（PRL） were ***： Grazing behavior was influenced（P 0.05） by an interaction between fescue cultivar and breed *** × Angus heifers assigned to E＋ pastures had the lowest percentage of animals grazing and the largest percentage of animals resting in the ***-influenced heifers had faster EV（P 0.001） than GA heifers（0.52 vs.0.74 ± 0.04 s/m,respectively）.Body weight（BW） was affected（P 0.01） by an interaction of tall fescue cultivar and d,and an interaction of tall fescue cultivar and breed *** grazing NT pastures were heavier（P 0.01） than heifers grazing E＋ pastures at midpoint and *** × Angus heifers grazing NT pastures were heavier（P 0.01） than GA and BR heifers grazing E＋ and BR heifers grazing NT *** interaction of forage cultivar and breed type occurred on serum PRL（P 0.01）.Conclusion： Collectively fescue cultivar,EV,and concentrations of serum PRL were associated with grazing *** grazing NT pastures were observed to be grazing more than heifers assigned to E＋ pastures,regardless of breed type,which may have contributed to changes in BW and average daily gain（ADG） in *** of behavioral observations along with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle prod

关键词： Cattle Endophyte-infected tall fescue Grazing behavior Prolactin Temperament

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Liver cytochrome P450 system as affected by endophyte-infected tall fescue seed extracts and ergot alkaloids

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Agricultural Sciences 2012年第1期3卷 1-4页

作者： Ali S. Moubarak Zelpha B. Johnson charles f. rosenkrans jr. Department of Animal Sciences University of Arkansas Fayetteville USA

Endophyte infected tall fescue (E+) is the base diet for nearly all beef cattle in the southern USA. It has been linked to a variety of toxicological conditions due to the presence of large numbers of ergot alkaloids. This study was designed to investigate the effects of E+ seed extract and selected ergot alkaloids on the detoxification pathway by cytochrome P450 (CYP3A4) enzyme system. Tests were performed using the P450- Glo CYP3A4 enzyme activity kit (Promega, WI), according to the manufacturer’s manual. Luminescence was measured using a single tube TD20/20 luminometer. Endophyte infected tall fescue seed was extracted with 50/50 methanol/25 mM ammonium carbonate, cleaned and concentrated on Strata-X reversed phase column (Phenomenex). The extracts were evaluated on an HPLC, and then tested using a serial dilution method. Commercially available ergonovine (EN), ergocorine (ER), bromocryptine (BC) and ergocryptine (EC) were tested individually using 0 to 44 nM concentrations. Seed extract of E+ produced a significant (P P followed by ER, BC, and then EN (70%, 40%, 30% and 10% at 44 nM concentration). The similarity of the inhibition curves of seed extract to that of the commercially available ergot alkaloids suggests a related mode of action and that the use of such ergot alkaloids and CYP3A4 assay is a good model to study the toxicity of tall fescue. furthermore, it provides the foundation to identify the individual toxic components of purified endophyte infected tall fescue extract.

关键词： Seed Extract Tall fescue CYP3A4 Ergot Alkaloid

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Bovine Sperm Motility as Affected by Alpha Tocopherol and Ascorbic Acid during Storage

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Advances in Reproductive Sciences 2019年第2期7卷 39-49页

作者： Ryan Page charles rosenkrans jr. Department of Animal Science Division of Agriculture University of Arkansas System Fayetteville AR USA

Our purpose was to determine the impact of ascorbic acid and α-tocopherol on bovine sperm motility following short-term storage or cryopreservation. Semen was collected from mature Angus bulls (n = 4). The experimental design was a randomized complete block, with bull serving as block, and treatments were structured as a 4 × 4 factorial with four concentrations of ascorbic acid (0, 5, 10, 20 mM) and four concentrations of α-tocopherol (0, 0.05, 0.5, 5 mM). Sperm motility characteristics were evaluated using computer assisted sperm analyses at 0, 4, and 8 h of incubation (39?C) and post-cryopreservation. Initial sperm motility was (79.6% ± 1.6) and decreased to (6.1% ± 1.6%) after cryopreservation. Cryopreserved spermatozoa had lower (P P > 0.1) by α-tocopherol. Addition of 20 mM ascorbic acid to storage media decreased (P P α-tocopherol. Stepwise regression models predicted (P α-tocopherol was not beneficial for short-term storage of spermatozoa;however, our results were inconclusive with regards to inclusion of ascorbic acid and α-tocopherol in egg yolk-based cryopreservation media.

关键词： Bull Spermatozoa Antioxidants Cryopreservation

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Ergot Alkaloid Effects on Bovine Sperm Motility <i>In Vitro</i>

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Advances in Reproductive Sciences 2019年第1期7卷 7-15页

作者： Ryan Page Toby Lester Rick Rorie charles rosenkrans jr. Department of Animal Science Division of Agriculture University of Arkansas System Fayetteville Arkansas USA

Cattle in some parts of the world graze pastures that consist of tall fescue that may contain ergot alkaloid contamination. Those ergot alkaloids are associated with reduced reproductive rates in cattle. Our objective was to determine if ergot alkaloids [dihydroergotamine (DHET), ergonovine (EN), and ergotamine (ET)] directly affect bovine sperm characteristics. Spermatozoa were collected from mature Angus (n = 2) and Balancer (n = 4) bulls. Within bull, treatments were structured as a 3 × 5 factorial with three alkaloids (DHET, EN, and ET) and five concentrations of each alkaloid (0, 33, 66, 100, or 200 μM). Spermatozoa (25 × 106) were incubated (39?C) in 1 mL of modified sperm medium. Sperm motility characteristics were evaluated using CASA (Hamiliton Thorne IVOS, Beverly, MA) at 0, 3, and 6 h after initial alkaloid exposure. Initial sperm motility was (69% ± 1.1%) and declined (P = 0.01) to (35% ± 2.6%) at 6 h. Sperm motility decreased (P P f how ergot alkaloids may hinder cattle reproductive rates.

关键词： CASA Bull Spermatozoa Toxins

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Interaction of ergotamine with liver Cytochrome P450 3A in rats

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Agricultural Sciences 2012年第6期3卷 795-798页

作者： Ali S. Moubarak Hehai Wang Zelpha B. Johnson charles f. rosenkrans Department of Animal Science University of Arkansas Fayetteville AR 72701

This study was conducted to investigate the effect of the ergot alkaloid, ergotamine (ET), on the induction of CYP3A and the interaction in vivo and in vitro with ET. Sprague-Dawley rats were treated intraperitoneally for 4 days as follows: control (injecting with 0.5 ml of only corn oil);dexamethasone treatment (injecting with 100mg/kg of dexamethasone in corn oil);and ergotamine treatment (injecting with 100mg/kg of ergotamine in corn oil). Liver tissues were collected from each group (n = 5, total of 30 rats) and liver microsomes were prepared. Cytochrome CYP3A activity was evaluated using ET and its isomer as substrates in medium containing liver microsomes and NADPH at 37℃ for 30 min. HPLC was used to measure the disappearance of the substrate and the appearance of the metabolites. Liver microsomes from rats pretreated with dexamethasone were five times more (P 0.05) in activity of CYP3A when compared to the control group (5.2 vs. 7.0 nM ET/min/mg protein;SE = 4.83) or ET isomer (1.5 vs. 4.7 nM ET isomer/ min/mg protein;SE = 1.70). When ketoconazole was used as specific inhibitor of CYP3A, ergotamine metabolisms were inhibited in a dose dependent fashion reaching a maximum at an inhibitor to substrate ratio of greater than one and LD50 at 0.5 nM of ketoconazole/mg protein. The data presented in this study suggest that although the ergot alkaloids ergotamine and its isomer are ideal substrates for the isozyme CYP3A, these compounds have no effect on the induction of CYP3A after 4 days of treatment.

关键词： Microsomes Liver Rat

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Marketing / Dalian :

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丛书名：世界财经与管理教材大系i市场营销系列

1998年

作者： charles W. Lamb jr. Joseph f. Hair jr. Carl Mc

Rev. ed. of: Principles of marketing, 1993.

ISBN: (纸本)7810442112

Rev. ed. of: Principles of marketing, 1993.

关键词： Marketing.

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fundamentals of logic design : :5th ed. / 5th ed.

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丛书名：经典原版书库

2003年

作者： Roth charles H. jr.

本书详细地阐述了理解逻辑设计基本概念所必需的理论, 同时又不过多地讨论开关理论的数学证明, 全书共分20个单元, 包括布尔代数、逻辑门设计、触发器、状态机等基本概念。

ISBN: (纸本)7111123514

关键词： Logic design.

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美国在CIMT2003展出的主要产品及其特点

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世界制造技术与装备市场 2003年第2期 179-181页

作者： charles f.Carter jr. 美国AMT前副主席

美国机械制造技术协会(AMT)是美国机床工业的贸易组织.AMT的前身就是成立于1902年的美国机床制造者协会(NMTBA).

关键词： CIMT2003 美国机械制造技术协会 AMT 展览会

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机床的技术发展趋势

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世界制造技术与装备市场 1998年第1期 73-74页

作者： charles f.Carter jr.,延祐美国制造技术协会技术副总裁

本文将分几个段落来对90年代后半期的技术发展趋势对机床工业的影响作一些评述。控制器,特别是那些基于计算机的控制器,其日益增长的重要性,是机床设计考虑中的一个主要因素。当然,对机械设计也不可忽略。一种全新的,基于STEWART平台... 详细信息

本文将分几个段落来对90年代后半期的技术发展趋势对机床工业的影响作一些评述。控制器,特别是那些基于计算机的控制器,其日益增长的重要性,是机床设计考虑中的一个主要因素。当然,对机械设计也不可忽略。一种全新的,基于STEWART平台的结构的出现,就是机械设计革新的例子。

关键词：机床轴承 DN 陶瓷滚珠直线电机

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养鸡场规模大小与肉用仔鸡生产效益的关系

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国外畜牧学(猪与禽) 1983年第4期 36-37页

作者： f.charles jr.Strong 孙志远佐治亚大学佐治亚大学家禽科学推广员

最近几十年中农业生产的趋势是生产机构集中为越来越大的单位,结果有效的农场数减少。这种趋势在肉鸡业中尤为明显,现在拥有十万只或以上肉用仔鸡的鸡场已经不稀奇了。现已提出若干种原因来解释肉用仔鸡场规模的扩大,但最常被引述的原... 详细信息

最近几十年中农业生产的趋势是生产机构集中为越来越大的单位,结果有效的农场数减少。这种趋势在肉鸡业中尤为明显,现在拥有十万只或以上肉用仔鸡的鸡场已经不稀奇了。现已提出若干种原因来解释肉用仔鸡场规模的扩大,但最常被引述的原因是提高了现有资源的利用率,包括劳动力(主要是饲养工人和管理人员)的集中和运输工具更为有效的使用(饲料运输、上门服务和提鸡运鸡等)。大家都知道,鸡场规模扩大会使生产率产生一定的损失。但据认为,因资源利用率的提高而引起的成本降低可弥补这种生产损失。遗憾的

关键词：养鸡场料肉比养禽场产肉性能肉用仔鸡

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