河西走廊盐化草甸土壤水盐对植物群落数量特征的影响

采用通径及逐步回归方法分析了从河西走廊盐化草甸４３个样点收集的植物与土壤水盐资料。土壤水盐因子（包括土壤水分、盐分及与之显著相关的有机质、ｐＨ及地下水位）对群落及其优势种（芦苇与＊草）的数量特征均有显著影响，群落盖度主要取决于土壤盐分与有机质；芦苇与赖草盖度分别取决于土壤盐分与有机质，高度分别取决于地下水位及土壤水分；赖草频度及生物量与土壤ｐＨ有关。盖度与高度是受土壤水盐因子影响较大的两个群落特征，可作为群落优势度的构成要素。芦苇与赖草的群落特征受制于不同的土壤水盐生态因子，显示了二种土壤水盐生态位的分异，这可能是二种长期共存的生态学机制。     

河西走廓盐化草甸土壤水盐对植物群落数量特征的影响

采用通径及逐步回归方法分析了从河西走廓盐化草甸４３个样点收集的植物与土壤盐资料。土壤水盐因子对群落及其优势种的数量牡 征均有显著影响，群落盖度主要取决于土分与有机质；荒苇与赖草盖度分别取决于土壤分与有机质，高度分别取决于地下水位及土壤水分；赖草频度及生物量与土壤ＰＨ有关。     

川西北沙化草地生态恢复工程对沙地植被群落的影响

2007年7-8月在川西北若尔盖与红原的沙化草地区内,对生态恢复0、1、3、5、7、10和12年的样地植物群落指标进行调查。结果表明：生态恢复工程增加了样地内植物种类、多样性指数、群落总盖度以及地上部分生物量,而群落密度和高度变化表现出波动性,规律性不强。群落恢复演替中主要数量特征受优势种、次优势种、伴生种的控制,是群落演替较为典型的特征。该区生态恢复工程加快了沙化草地植被的恢复速度与群落正向演替的速度,但恢复演替需要较长的时间。因此,在对沙化草地采取围栏封育期间,禁止牲畜进入封育区;针对沙化草地的特点,采用合理的浇（保）水施肥措施,种植适宜植物及应用合理的种植技术和植被管理技术,才能使植被恢复的速度和效果达到一个理想的结果。     

草海水生植被演替系列的数量研究

采用双向指示种分析（ＴＷＩＮＳＰＡＮ）多元等级分划分类方法和无趋势对应分析（ＤＣＡ）排序方法，对草海湖泊水生植物群落的空间分布及演替动态进行了研究，并以分类结果为基础，计测了典型群落的群落位，用来探讨植物群落在水分梯度上的渐变过程。结果表明，草海湖相植物系列随着水分梯度的变化，呈现出有规律的替代性，群落带状分布十分明显；水生群落多为单优势种群落，组分种少，结构简单；内源性富氧化是水生群落演替的主要动力之一；人类活动对湖区景观格局和植物种群动态有着深刻的影响。     

土壤盐碱化对羊草草地植物多样性的影响

从群落物种丰富度，均匀度和多样性三个测度水平，采用八个指数和Ｚａｈｌ的大折刀法统计处理，探讨了松嫩平原羊草草地次生盐碱化梯度植物多样性的变化，结果表明，随着土壤盐碱化的加重，群落植物多样性单调衰减，并与土壤ｐＨ值和电导率呈显著指数负相关，与土壤水分呈指数正相关；其植物多样性的演替序列是：羊草－杂类草群落〉羊草群落〉羊草－星星草群落〉星星草群落〉朝鲜碱茅群落〉角碱蓬群落，结果与次生盐碱化演替序列一致     

藏中矿区植物种群生态位特征研究

本文采用样方法以藏中矿区的3种群落为研究对象,对样地的植物种群进行系统调查,并计算其主要植物的重要值、生态位宽度和生态位重叠值。结果表明,不同群落类型优势种非常明显,并且具有较高的生态位宽度和生态位重叠。高寒矿区各植物优势种群与其它种群之间竞争激烈,群落结构极不稳定,群落可能正处于正向演替和逆向演替的拐点。     

1981-2005年松嫩平原羊草草地植被生态对比分析

对比2次不同时间相同地点的植被调查,从植物分布区型、物种重要值、频度和物种多样性等方面入手分析了松嫩平原羊草草甸的时间尺度变化。结果表明,现群落有植物92种,隶属28科71属,与原群落相比减少1科5属18种。分属14个分布区型,其中东北分布区型为后增类型。群落上层以羊草和芦苇占优势,中层和下层分别以虎尾草和蔓委陵菜占优势,在植被划分上属羊草-虎尾草-蔓委陵菜群丛。频度分析则显示目前群落频度分布为A>B>C>D=E→0,暗示群落均匀程度增加。在物种多样性变化上,优势群落羊草群落物种多样性降低,而杂类草和盐生种类群落多样性增加。综上表明,本区植被的变化主要是种类减少,外来成分入侵,优势群落多样性降低,杂类草和盐生种类群落地位上升,群落有可能进一步发生退化,向次生植被演替,而这种退化主要是气候变化及人类不合理活动所致。     

放牧对草原植物的影响

从退化演替与恢复演替、植物群落的物种多样性、种群繁殖特性、生殖分配对策、植物组织养分分配和氮素循环以及生产力等方面综述了放牧对草原植物的影响,指出了草原生态学研究中不仅杨研究放牧影响下群落的演替过程及演替方向，而且还应加强对放牧影响下草原植物的生态对策的研究。     

天祝高寒草甸高原鼢鼠鼠丘植被演替调查

高原鼢鼠鼠丘植被演替是反映草地恢复的重要指标之一。以定点标记的方法对天祝高寒草甸高原鼢鼠鼠丘植被演替进行了调查。结果表明,鼠丘植被在不同演替阶段外貌特征及植物组成差异较大。随演替的进行,1~2年生植物和多年生杂类草比例呈递增趋势,禾本科和莎草科植物也伴随出现,但在群落中所占比例相对较低。α多样性表明,鼠丘植物的丰富度指数随演替进行呈显著递增趋势,但都低于原生植被。Shamon-wiener指数表明,形成4年的鼠丘植被群落达到演替后期,物种组成接近原生植被。植物功能群组成显示,演替各阶段1~2年生植物生物量在各自群落中的比例显著高于原生植被。     

青藏高原多年冻土地区公路建设对植被类型的影响

在查阅相关资料的基础上,采用常规草地调查的方法进行了实地调查.结果显示:随着生态因子发生变化和人类活动的加剧,该区公路沿线高寒草甸类草地群落结构表现出了较强的稳定性,中旱生耐旱的根茎型禾草比重有所增加;高寒草原植物群落稳定性相对较差,草地群落为适应新的生境而发生了自然演替;沼泽化草甸亚类草地植物群落中群落伴生种的种类增加,优势种嵩草属植物在群落中的比重有所下降.     

Effects of straw treatment and nitrogen supplementation on digestibility,intake and physiological responses of water intake as well as urine and faecal characteristics

This study investigates the effects of feeding diet based on untreated (UT) or ensiled alkali‐treated (ET) barley straw with either urea or casein supplementation, on feed intake, digestibility, ruminal pH, water intake and faecal and urinary characteristics. Four sheep fitted with ruminal cannulas were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Barley straw was treated by the dry (spraying) method in pH adjusted of hydrogen peroxide (pH 11.5), ensiled for 6 weeks and included at 65% of the diet dry matter (DM). The results showed that straw pH reduced from 11.58 to 8.60 after 6 weeks of ensilage. The ET diet increased average DM digestibility and intake by 19% and 43% respectively. Total water intake was similar across treatments, while the water/DM intake ratio was 23% higher with the UT diet than with the ET one. Ruminal (6.73 vs. 6.84) and faecal (8.67 vs. 9.05) pH decreased but urinary pH (6.14 vs. 8.13) increased as a result of feeding animals on the ET diet compared with the UT diet. Compared with the UT diet, the ET one decreased faecal fibre (12%), moisture (32%) and water holding capacity, while it increased faecal ash (10%) and density (20%). The volume of urine excreted by the sheep fed with the ET diet increased by 67%, but their urine specific gravity (SG) decreased. No significant effects were observed for the dietary N supplementation and interactions between straw type × N supplementation with regard to any of the measured characteristics except for DM intake, which reduced due to the casein supplementation in the ET diet. These results indicate that the alkali treatment and ensilage of barley straw increased digestibility, intake, faecal consistency and urinary pH and dilution but decreased straw alkalinity as well as ruminal and faecal pH.     

Comparison of Thoracic Auscultation,Clinical Score,and Ultrasonography as Indicators of Bovine Respiratory Disease in Preweaned Dairy Calves

Background

The diagnostic tools for bovine respiratory disease diagnosis include clinical inspection, thoracic auscultation, and ultrasonography.

Hypothesis

Thoracic auscultation and clinical examination have limitations in the detection of lung consolidation in dairy calves.

Animals

Prospective cohort of 106 preweaned calves from 13 different dairy herds (10 with a history of active bovine respiratory disease (BRD) in calves and 3 without suspected BRD problems).

Methods

Each preweaned calf was clinically inspected using the Wisconsin calf respiratory scoring chart (CRSC) and treatment history was noted. Systematic thoracic auscultation and ultrasonography then were performed, the latter focusing on lung consolidation. Mortality was recorded over a 30‐day period.

Results

A total of 56 of 106 calves had ultrasonographic evidence of lung consolidation. The sensitivity of thoracic auscultation to detect consolidation was 5.9% (range, 0–16.7%). Only 41.1% (23/33) of calves with consolidated lungs had been treated previously by the producers. When adding CRSC and previous BRD treatment by the producer, sensitivity of detection increased to 71.4% (40/56). The area under the receiver operating characteristics curve was 0.809 (95% CI, 0.721–0.879) for the number of areas within the lungs with consolidation and 0.743 (95% CI, 0.648–0.823) for the maximal depth of consolidation as predictors of death within 1 month after examination. These were not significantly different (P = .06).

Conclusions and Clinical Importance

This study shows that thoracic auscultation is of limited value in diagnosing lung consolidation in calves. Ultrasonographic assessment of the thorax could be a useful tool to assess BRD detection efficiency on dairy farms.     

秸秆饲料化技术的研究进展

本文着重介绍了国内外提高秸秆饲用价值的方法、技术(主要包括物理处理、化学处理、生物处理及复合处理等)及其原理、效果和优缺点,指出其中存在的问题,并对其发展趋势作了展望。     

浅谈我省地方畜禽品种资源保护及开发利用

近年来，我省先后从国内外引进了20多个鸡种，10多个牛种、羊种和猪种等，因其高效而占领了我省市场。同时存在着盲目引种，品种多乱、杂等问题。伴随着少数高产畜禽品种的普及推广，使各地固有的许多品种资源迅速减少或消失。因此，针对陕西畜禽品种资源的现状问题，并结合近年来畜牧业生产中的实际状况，特就如何搞好地方畜禽品种资源的保护及开发利用提出建议与对策。     

猪的行为特征探讨与饲养管理的改善

猪的行为是猪的本质特征的外在表现，在很大程度上影响着养猪工艺的发展和养猪业的效益。本文概括的分析了猪一般的行为特点和在饲养管理过程中的利用与改善措施。并对相关遗传特征进行了探讨。随着人们对猪的行为性状重要性认识的不断深入，猪的行为特征将在科学和生产过程中得到更加广泛的利用。     

鮰爱德华菌外膜微孔蛋白ompN1、ompN2和ompN3基因生物信息学分析及截段基因的原核表达与其抗原性检测

根据GenBank中鮰爱德华菌(Edwardsiella ictaluri)外膜微孔蛋白N(outer membrane porin protein,OMP)基因序列(NC_012779.2)设计引物,以鮰爱德华菌Ms12基因组DNA为模板,经PCR扩增后克隆至pMD19-T载体,将阳性克隆菌送公司测序。测序结果通过生物信息学软件对ompN1、ompN2和ompN3序列的氨基酸序列相对分子质量、分子式、信号肽、跨膜区、亲/疏水性、B细胞表位进行预测,并构建系统发育树;根据去信号肽的B细胞表位相对集中区域设计特异性引物,经PCR扩增后,将截段序列克隆至pMD19-T载体,鉴定成功后克隆至原核表达载体pET32a(+)并转化至BL21(DE3)/Rosseta(DE3)进行IPTG诱导表达,最后用兔抗鮰爱德华菌血清对重组蛋白OmpN1、OmpN2和OmpN3进行免疫原性检测。结果显示扩增得到ompN1(1 143bp)、ompN2(1 056bp)和ompN3(1 053bp)的序列,获得的基因登录号分别为KJ831564、KJ831565和KJ831566。经生物信息学分析显示,OmpN1、OmpN2和OmpN3蛋白分子式分别为C1940H2993N543O622S7、C1817H2723N497O579S5和C1896H2843N519O563S7,相对分子质量大小分别为44 100、40 900和41 800,均为含有1个信号肽和跨膜区的疏水性蛋白,具有1个革兰阴性细菌OM_channels超家族结构域,是1种嵌入型的膜外蛋白;SDS-PAGE电泳检测发现,诱导表达的融合重组蛋白均以包涵体的形式出现在沉淀中,大小分别约为61 800、58 700和59 100;Western-blot分析表明,重组蛋白OmpN1、OmpN2和OmpN3均能与兔抗鮰爱德华菌全菌血清结合,表明鮰爱德华菌外膜微孔蛋白N具有亚单位疫苗开发的潜力。     

Effects of Moringa oleifera leaves as a substitute for alfalfa meal on nutrient digestibility,growth performance,carcass trait,meat quality,antioxidant capacity and biochemical parameters of rabbits

This contribution reports the effects of Moringa oleifera leaves (MOLs) meal on the growth performances, nutrient digestibility, carcass trait, meat quality, antioxidant capacity and biochemical parameters of growing New Zealand white rabbits. The MOL was substituted for alfalfa meal at levels of 0, 10%, 20% and 30% to obtain respective diets MOL0, MOL10, MOL20 and MOL30. Each treatment was replicated five times with 10 rabbits per replicate. Results showed the average daily weight gain (ADWG) and feed conversion ratio (FCR) of rabbits fed MOL20 diet were significantly better (p < 0.05) than those of other three dietary groups. Liver and spleen index of rabbits fed MOL20 and MOL30 diets was significantly higher (p < 0.05) than that of the groups fed with lower M. oleifera leaves (MOL0, MOL10). The meat drip loss of rabbits fed with diet MOL10 was significantly lower (p < 0.05) than that of rabbits fed other diets. All rabbits fed MOL dietary groups had lower (p < 0.05) shear force of longissimus dorsi than the group without M. oleifera leaves. No significant differences were found in the digestibility of crude fibre (CF), crude fat (EE), ash, crude protein (CP) and nitrogen‐free extract (NFE) among the dietary groups. Moringa oleifera leaves also have a significant impact on serum albumin (ALB), low‐density lipoprotein cholesterol (LDLC), triiodothyroxine (T₃) and tetraiodothyroxine (T₄) values and the activity of superoxide dismutase (SOD) and catalase (CAT) in serum and liver. The results indicated that M. oleifera leaves could be developed as a good feed source, and it not only could substitute for alfalfa meal well but also has a significant effect on growth performance, meat quality, antioxidant and biochemical parameters of rabbits.     

解淀粉芽孢杆菌HZ-6-3的筛选鉴定及其防治番茄灰霉病效果的评价

采用平板对峙法,从银杏组织分离的内生细菌菌株中筛选对灰葡萄孢菌抑菌活性较好的菌株,其中菌株HZ-6-3的抑制作用最强,抑制率为79.06%。通过菌落形态观察、生理生化特征、16S rRNA基因序列和gyrA基因分析将菌株HZ-6-3鉴定为解淀粉芽孢杆菌。抑菌谱测定结果显示,该菌株对其他8种植物病原真菌均具有不同程度的拮抗作用。该菌株可产生蛋白酶、果胶酶、β-1,3-葡聚糖酶和淀粉酶;能够显著抑制病原菌的菌丝生长,使菌丝生长扭曲,细胞膨大、形成串状泡囊结构等畸变。利用盆栽试验测定了该菌株对番茄灰霉病的防控效果,结果显示1×10⁸ CFU·mL^-1的预防效果和治疗效果最高,可达81.12%和70.45%。上述结果显示菌株HZ-6-3具有作为生物制剂的潜能。     

以建立草原公园为抓手,推动牧区草原转型升级

草地不仅是构建"两屏三带"生态安全战略的重要部分,也是我国牧业发展的基础,我国草原保护在生态保护与牧民增收、草原利用管理、科技支撑能力等方面仍存在很多问题.文章阐述了草原自然公园的定义和草原资源的特点,分析了草原保护中存在的主要问题,并提出了从发展生态旅游、建立产学研相结合的技术创新体系、发展饲草产业、完善补偿机制4个...