Short communication: reference values for blood parameters in Holstein dairy cows: effects of parity, stage of lactation, and season of production

Confidence intervals for blood parameters used for nutritional and metabolic profile testing in cattle were calculated for clinically normal lactating Holstein cows, taking into account the effects of parity, stage of lactation, and season. Blood samples were collected from 740 cows in 33 Italian dairy herds according to a predefined protocol. Herds were visited during summer and the following winter, sampling 12 lactating cows at each visit (4 primiparous and 8 multiparous). Six cows were selected from the early-lactation group (days in milk: 10 to 89) and the other 6 were selected from the mid-lactation group (days in milk: 90 to 215). Cow selection criteria excluded animals clinically exposed to periparturient diseases as well as animals not considered in good health by a veterinary clinical examination. For each blood variable, outliers were identified and discarded. Data were then analyzed for their Gaussian distribution and variables with not normal distribution were log-transformed to adjust for lack of normality. Herd mean values were calculated for each blood parameter according to 3 main classification factors: parity (primiparous vs. multiparous), stage of lactation (early vs. mid) and season of production (summer vs. winter). The resulting data set was statistically analyzed using a mixed model with the fixed effects of these factors, their interactions, and the random effect of herd. General 95% confidence intervals were calculated for blood variables that showed a relevant herd variance component such as albumin, triglycerides, aspartate, urea, glucose, alanine aminotransferase, lactate dehydrogenase, direct and total bilirubin, calcium, magnesium, and potassium. For the remaining parameters, specific confidence intervals were calculated for each level of the significant main factors. Parity affected blood concentration of total protein, globulin, creatinine, alkaline phosphatase, gamma glutamyl transferase, creatinine kinase, and phosphorus. Blood nonesterified fatty acids, aspartate aminotransferase, gamma glutamyl transferase, creatinine kinase and cholesterol were influenced by stage of lactation. The season of production had a significant effect on total protein, globulin, creatinine, alkaline phosphatase, phosphorus, sodium, and chlorine. The outcomes of this work will improve the accuracy of the biochemical profile as a tool for dairy practitioners to assess the metabolic status of lactating Holstein cows.     

上海中心大厦日照温差效应分析

计算了上海地区施工历时较长的超高层混合结构上海中心大厦在施工阶段的温度作用:季节温差和日照温差,给出温度作用的两种工况和构件计算温度,考虑太阳的照射角度、日照时间及构件之间的遮挡情况,选取合理的日照温差作用范围,选用考虑重力二阶效应的有限元分析软件模型,分析结构在两种工况下代表位置处的整体变形特点和伸臂构件的受力情况,并比较两种工况下的结构效应。结果表明:日照温差作用对结构影响较大,结构在两种工况下竖向位移较大,季节温差作用下水平位移很小,日照温差下水平层间位移角相对较大;日照温差工况下,向阳面位置处相邻竖向构件相差较大,由于竖向构件的差异变形和结构整体弯曲效应,使得伸臂在此工况下的内力较季节温差有很大差别。     

太阳能热泵系统制热季节性能系数的分析

介绍了太阳能热泵（空气源＋水源热泵）供热系统的流程。选取单纯空气源热泵运行模式（运行模式1）、太阳能热泵运行模式（运行模式2）,在室外温度-10～7℃范围内,对两种运行模式制热量、设备功耗的计算式进行了拟合。计算比较了两种运行模式下的制热季节性能系数,运行模式1、2的制热季节性能系数约为2．56、3．48。     

高温季节混凝土施工如何防止裂缝的产生

根据高温季节混凝土施工的实际情况,从温度应力的形成、裂缝产生的原因等方面作了分析,通过分析给出了防止裂缝产生的一系列措施,以期保证高温季节混凝土施工质量。     

长江临堤复杂深基坑工程设计与施工

武汉时代广场临长江干堤仅60m,基坑开挖面积1.4万m2,开挖深度达19.45m,场地地质条件及周边环境复杂;基坑设计采取综合支护方案,通过精心策划与信息化施工管理,在长江汛期前完成全部地下室工程,成功地化解了深基坑安全与工期风险。     

短期降雨预报在汛限水位动态控制中的应用

以丹江口水库为例,根据考虑降雨预报的水库汛期限制水位控制的新理念,研究了利用短期降雨预报信息进行水库汛限水位动态控制的调度方式;同时分析了在发生降雨预报误差时,汛限水位动态控制的风险率以及大坝所能抗御洪水标准的变化,概化计算了抬高汛限水位增加的发电效益。结果表明,在不增加丹江口水库及其上下游防护对象风险的前提下,抬高汛限水位可以为丹江口水库带来较大的经济效益。     

含小水电分布式电源的配网线路串联补偿优化

以小水电接入电网为例进行分析研究,深入分析小水电给电网带来的不利影响,重点分析对变压器损耗和线路损耗这两方面的影响。最后,举例某地区小水电接入配电网进行分析研究,对丰水期的小水电加入串联补偿装置后线路电压的变化情况展开研究。     

基于Elman网络的黄河源区枯期径流预报

采用反馈Elman网络,对黄河唐乃亥水文站及上游玛曲站近45年(1959～2003年)年降雨及径流流量进行分析,建立了基于反馈神经网络的黄河源区枯季径流预报模型.利用Matlab7 神经网络工具箱对黄河源区唐乃亥水文站枯季径流量进行了预报.结果表明所建立的ANN(7,7,15,7)模型预报结果精度高,容错能力强,是枯季径流预报的有效手段.     

近10年浦东新区汛期雨情分析

通过对2002~2011年浦东新区汛期降水量的分析,对近10年汛期降水进行时间和空间分析,汲出汛期雨情的特征,为防汛排涝设施的设计和建设提供依据。     

大朝山水电站水库汛期运行水位动态控制研究

大朝山水库上游梯级为具有年调节能力的小湾水库，本次大朝山水库汛期运行水位动态控制研究仅针对小湾水库蓄水运行前。为了在小湾水电站投产前，合理利用大朝山水库调节库容，科学利用洪水资源，以不影响水库自身及上下游防洪安全、不增加水库淹没为前提，结合完善、可靠的水情测报系统，进行大朝山水库汛期运行水位动态控制研究，从水库泥沙淤积、水库淹没、能量指标、上下游防洪安全等方面综合分析比较，拟定大朝山水电站水库汛期运行水位动态控制方案，通过抬高水库汛期运行水位，以减少电站受阻容量，增加电站汛期出力，缓解云南电力供应紧张局面。