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Effects of Reduced <i>in Utero</i>and Post-Weaning Nutrition on Glucose Clearance Measures and Serum Metabolites

Agricultural Sciences 2018年第8期9卷 947-957页

作者： Richard Waterman Mark Petersen thomas geary Lance Vermeire USDA-ARS Fort Keogh Livestock and Range Research Laboratory Miles City MT USA

Lowering production costs while maintaining an optimal level of production is important to producers in extensive environments. Efforts that strive to match the environment to the nutritional requirements of the grazing animal will substantially improve economic returns to the producer. Therefore, a 3-yr study was implemented that evaluated glucose clearance and serum metabolites in primiparous beef heifers (n = 48;16/yr) from two different feeding regimes. Serum metabolites and glucose clearance measures were analyzed by fitting a repeated measure mixed model using the MIXED procedure of SAS 9.4 (SAS Inst., Inc., Cary, NC). Heifers dams received adequate 1.8 (ADEQ) or marginal 1.2 (MARG) kg/d winter supplementation for approximately 80 d prior to parturition and their heifer calves were then randomly assigned to heifer development treatments that provided ad-libitum (AL) or 80% of ad-libitum (LAL) feed post weaning. Heifers that received the AL treatment during the developmental period were then assigned the 1.8 kg/d winter supplementation for life, whereas heifers that received the LAL treatment during development were assigned the 1.2 kg/d winter supplementation for life. Peak glucose concentrations in response to a bolus dose of glucose changed in magnitude between ADEQ and MARG in utero treatments and decreased further removed from parturition (P = 0.05). However, these changes did not manifest along with other glucose clearance measures (P > 0.17) indicating that regardless of in utero treatment or heifer development treatment the reduction in feed input did not greatly influence glucose clearance measures or baseline serum metabolites throughout postpartum, first parity period.

关键词： Heifer Development Glucose Primiparous Beef Cow

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Economics of early weaning in northern great plains beef cattle production system

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Agricultural Sciences 2013年第5期4卷 219-223页

作者： John Travis Mulliniks Richard C. Waterman thomas W. geary Department of Animal Science University of Tennessee Crossville USA USDA-ARS Fort Keogh Livestock and Range Research Laboratory Miles City USA

Early removal of the calf from its dam reduces forage needs of the cow-calf enterprise and has been found to improve BW gain and pregnancy rates in the cow herd. However, early weaning may not always be economically viable for producers and the risk should be considered carefully. This study was conducted to evaluate the effect of early and normal weaning of steer and heifer calves on net income at weaning. Calves from Angus xHereforddams were randomly assigned to one of two weaning treatments. Calves were either early weaned (EW) at 80-d of age or remained with their dams until normal weaning (NW) at 213-d of age. Calves assigned to EW treatment received a 17.5% crude protein and 0.82 Mcal/kg net energy diet for approximately 130-d in a drylot. All economic analyses were conducted at normal weaning for both NW and EW calves. At normal weaning, price of steers ($US/kg) was lower (P = 0.003) and weaned steer value ($US/steer) was greater (P P = 0.18) was found in price of heifers ($US/kg) and weaned heifer value ($US/heifer) between NW and EW heifers. Feed cost was increased (P < 0.001) in EW steers and heifers compared to NW calves. Net revenue for both weaned steers and heifers was reduced (P < 0.001) in EW calves due to the feed cost of the growing diet. This study indicates that early weaning calves at 80-d of age decrease weaned calf value and net revenue for the cow-calf segment.

关键词： Age at Weaning Beef Cattle Production Economics

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比较研究——影响中美儿童计算能力差异的认知因素

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心理科学 1993年第1期16卷 22-27页

作者：刘凡 David C.geary Christine Bow-thomas 徐芬中央教育科学研究所密苏里大学心理系杭州大学心理系

本研究要确定中美儿童基本计算技能的差异是否与他们使用的解题策略和基本加工过程的速度有关。为此,对中美两国的一年级儿童进行了书面计算能力测验,以及一组计算机呈现的加法作业。中国儿童在计算能力测验上表现出3:1的操作优势。中... 详细信息

本研究要确定中美儿童基本计算技能的差异是否与他们使用的解题策略和基本加工过程的速度有关。为此,对中美两国的一年级儿童进行了书面计算能力测验,以及一组计算机呈现的加法作业。中国儿童在计算能力测验上表现出3:1的操作优势。中美儿童使用的解题策略种类一样,但是,中国儿童在策略综合运用的发展程度上超过美国儿童,检索策略的加工速度也超过美国儿童。显然,策略运用和加工速度的差异促成了中国儿童在计算能力测验上的优势.

关键词：计算技能解题策略认知儿童

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Comparison of estimators of variance for forest inventories with systematic sampling-results from artificial populations

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Forest Ecosystems 2020年第2期7卷 215-233页

作者： Steen Magnussen Ronald EMcRoberts Johannes Breidenbach thomas Nord-Larsen Göran Ståhl Lutz Fehrmann Sebastian Schnell 506 West Burnside Road VictoriaBC V8Z 1M5Canada Raspberry Ridge Analytics 15111 Elmcrest Avenue NorthHugoMN 55038USA Norwegian Institute of Bioeconomy Research Høgskolevegen 81431ÅsNorway Department of Geosciences and Natural Resource Management University of CopenhagenRolighedsvej 23DK-1958 Frederiksberg CDenmark Department of Forest Resource Management Swedish University of Agricultural SciencesUmeåSweden Forest Inventory and Remote Sensing Faculty of Forest SciencesUniversity of GöttingenBüsgenweg 5D37077GöttingenGermany Alfred-Möller-Straße 1 Haus 41-4216225 EberswaldeGermany.

Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this ***,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important *** better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi *** this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear *** compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance ***:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for *** latter always produced the greatest *** populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design ***:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow *** a strong or moderate linear trend,Matern’s estimator is *** large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.

关键词： Spatial autocorrelation Linear trend Model based Design biased Matern variance Successive difference replication variance geary contiguity coefficient Random site effects

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