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南方喀斯特地区放牧型人工草地开展划区轮牧,可有效地提高草地利用率且获得较高的放牧收益。确定科学的划区轮牧方案对于延长草地利用年限、降低杂草比例以及家畜增重等具有重要意义。本研究选择贵州灼圃多年生禾草/白三叶混播草地,以当地自由放牧为对照,开展了不同绵羊数量、放牧天数和轮牧频次对草地产草量、杂草比例和绵羊体重影响研究。2年试验结果显示,1）以草地总生物量、再生量、可食牧草生物量和禾豆比例为评价指标,6只绵羊,每个轮牧小区平均放牧12 d,轮牧频次3次效果最佳;2）以控制杂草生物量和杂草频度为评价指标,10只绵羊,每个轮牧小区平均放牧9 d,轮牧频次3次效果最佳;3）以绵羊月增重为评价指标,6只绵羊,每个轮牧小区平均放牧12 d,轮牧频次3次效果最佳。综合考虑划区轮牧对草地生产力、杂草控制和绵羊增重的影响,南方喀斯特地区禾草/白三叶混播人工草地建植初期实行划区轮牧以6只绵羊,每个轮牧小区放牧12 d,轮牧频次3次效果最佳。 相似文献
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为确定川西北地区高寒草甸的最佳放牧强度,根据牦牛的采食量和草地地上生物量,设置了轻度(0.71头·hm~(-2))、中度(1.19头·hm~(-2))、重度(1.60头·hm~(-2))3个放牧强度处理,进行连续3年的放牧,测定其对草地植物物种丰富度、地上生物量的影响。结果表明,随着放牧强度的增加,植物物种丰富度呈下降趋势;放牧第3年,中度放牧草地年度地上生物量最高,显著高于其它两处理(P0.05),轻度放牧次之,重度放牧最低;和放牧第1年相比,轻度放牧和中度放牧草地地上生物量中杂类草生物量比例显著减少(P0.05),禾草生物量比例显著增加(P0.05),而重度放牧草地杂类草生物量比例未变,禾草生物量比例显著下降(P0.05),但3个放牧处理中莎草占地上生物量的比例均显著增加(P0.05)。因此,川西北地区高寒草甸的最佳放牧强度为1.19头·hm~(-2),这利于草地高产和优良牧草禾草及莎草的生长。 相似文献
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禾草/白三叶(Trifolium repens)草地是中国南方喀斯特地区主要刈牧地之一,探究不同家畜放牧下禾草/白三叶草地植被构成和群落稳定性,可一定程度揭示其植被演替特征。本研究定量分析了多年放牧牛(grazing cattle pasture,GC)、放牧羊(grazing sheep pasture,GS)的禾草/白三叶草地群落特征、物种多样性、生物量构成及群落稳定性。结果显示:1)草地死物质量及植物物种数为GC>GS,植物物种Simpson指数为GS>GC;2)草地禾草[多年生黑麦草(Lolium perenne)、鸭茅(Dactylis glomerata)及原生禾草]、原生双子叶(马鞭草科、车前科、酢浆草科和十字花科)及适口性中等植物地上生物量组分为GC>GS,播种白三叶地上生物量组分为GS>GC;且GC草地地上生物量以禾草为主(77.20%),GS草地地上生物量以禾草(51.79%)和豆科(28.02%)为主;3)草地土壤K含量为GC>GS;4)GC草地植物种Raunkiaer频度直方图呈反J型,群落演替度(37.08)比GS草地(45.45)的低。研究认为,GC草地群落处于相对稳定状态,而GS草地群落处于更高演替阶段,牛放牧更利于禾草/白三叶草地群落稳定性和物种多样性的维持。因此,放牧时可实行牛、羊混牧制,或牛、羊轮牧制,以提高禾草/白三叶草地的稳定性和生产力。 相似文献
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羊茅黑麦草和无芒雀麦叶片再生动态及其与草地管理的关系 总被引：7，自引：0，他引：7
羊茅黑麦草和无芒雀麦刈割后叶片再生动态的试验结果表明，这两种禾草刈割后，不同再生期的叶伸长率，萎蔫率、净生长率及叶片发生率间存在着显著差异，刈割强度影响不显著，留茬高度在５ｃｍ与１０ｃｍ之间，上述各项参数相对稳定，叶片动态对草地管理有重要的实践意义，建议以叶片动态作为刈割和放牧的判断标准之一。 相似文献
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放牧强度对混播草地群落数量特征的影响(简报) 总被引：3，自引：1，他引：2
放牧强度对人工草地群落数量特征的影响,国内外学者已有报道[1~2],而有关青藏高原的研究则很少[3]。Reategui[4]认为,载畜量增大将使丛生禾草向矮生禾草演替,而导致草地退化。另外,放牧强度对植物群落组成和生物多样性也有很大影响,随着放牧强度的增加,一些适口性高、再生性强、不耐牧的种类减少,而适口性差、耐牧的种类增多[5]。本试验研究放牧强度对垂穗披碱草(Elymus nutans)/星星草(Puccinellia tenuflora)混播草地群落数量特征的影响,旨在为人工草地的放牧利用提供科学依据。 相似文献
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美国高尔夫球场狗牙根草坪杂草防除研究进展 总被引：8，自引：2，他引：6
根据文献报道,介绍了美国高尔夫球场狗牙根草坪杂草防除地进展,狗牙根草坪杂草防除的难点是禾本科杂草。用甲胂钠,阿特拉津或西玛津防除鼠尾粟,用费赛特及费赛特加灭草喹防除铺地黍,用甲胂钠及ｄｉｔｈｉｏｐｙｒ除草通,恶草灵,圃草定,黄草消防防马唐,用禾草灵,圃草定ｄｉｔｈｉｏｐｙｒ,除草通,恶草灵防除牛筋草;用灭草喹防除野草,供试狗牙根草坪品种为普通狗牙根,Ｔｉｆｗａｙ和Ｏｒｍｏｎｄ。还介绍了禾草灵,西玛 相似文献
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新孢子虫病是导致奶牛流产的主要原因之一，给奶牛业造成很大的经济损失。各国学者对新孢子虫病的诊断方法进行了大量的研究工作。本文对奶牛新孢子虫病的临床诊断、病原学诊断、血清学诊断及分子生物学诊断方法的研究进展进行了综述。 相似文献
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随着规模化养猪业的发展,传染性疾病越来越多,混合感染或多重感染十分普遍,给疾病的诊断和预防带来很大困难。本文将我们实验室2010年分别采自福建、广西、河南、上海、内蒙、浙江、江苏和山西等地发病猪场的185份病料,通过RT-PCR和PCR方法对其进行猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus,PRRSV）、猪繁殖障碍的猪瘟病毒（Classical swine fever virus,CSFV）、猪圆环病毒2（Porcine circovirus type 2,PCV2）、猪细小病毒（Porcine parvovirus,PPV）、猪伪狂犬病毒（Pseudorabies virus,PRV）、细环病毒2（Torque teno virus 2,TTV2）等病毒检测。结果表明在所检的病料中PRRSV、PCV2和TTV2的阳性率比较高,分别为49.2%、62.2%和95.1%。有些地方TTV2的阳性率高达100%;同时,还存在很普遍的PRRSV与PCV2、PRRSV与TTV2、PCV2与TTV2等混合感染,混合感染率分别为27.6%、45.4%、58.4%;以及PRRSV、PCV2与TTV2的三重感染率为24.9%。同时对部分PRRSV阳性病料的PRRSV GP5和nsp2基因分别进行测序,分析测序结果表明病料中的PRRSV的GP5和nsp2序列与PRRSV HuN4株的相应序列的亲缘关系分别在98.2%和96.2%以上,且在nsp2区域都存在30个不连续氨基酸的缺失,说明现在临床中所流行的PRRSV可能仍是与高致病性PRRSV基因型相似的病毒。通过本文可以及时了解当前养猪场的病毒性疾病的流行情况,为猪场病毒性疾病的防控提供依据。 相似文献
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循化县岗察乡暖棚养羊试验浅析 总被引：1，自引：0，他引：1
通过示范户与对照户暖棚养羊试验,对养羊农户暖棚内进行温度、湿度、牲畜保膘、繁活率等指标的测定,并进行对比分析,其结果表明:暖棚饲养比敞棚饲养,绵羊的产肉量、产毛量有不同程度的提高,死亡率下降。 相似文献
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内蒙古自治区牛皮蝇蛆病的流行与防治 总被引：1，自引：0，他引：1
内蒙古自治区牛皮蝇蛆病主要分布于中、东部的锡盟、呼盟、通辽市等地区.侵袭牛的皮蝇主要有两个种,即纹皮蝇(Hypoderma lineatum)和牛皮蝇(H.bovis),纹皮蝇较多,占70%～80%.感染率一般在50%以上,多为80%～90%,不少地区高达100%.感染强度40～70个瘤包,最高达770个.牛皮蝇蛆病给内蒙古自治区的畜牧业生产造成非常严重的损失.四十余年来,未曾间断过对该病的防治,目前其方法主要采用倍硫磷注射或浇泼,收到一定效果,但并未得到安全控制. 相似文献
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刘春雷 《四川畜牧兽医学院学报》2007,5(4):100-102
宗教在社会生活中可以发挥重要影响。在构建社会主义和谐社会的系统工程中，我们应该用和谐思维正确认识宗教与和谐社会建设的关系，发挥宗教在社会生活中的积极作用，妥善处理宗教方面的矛盾，化解宗教的负面影响。 相似文献
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J. G. Allen 《Australian veterinary journal》1981,57(5):212-215
SUMMARY A retrospective study of cases of bovine lupinosis submitted to this Laboratory, and a trial in which 3 cows, 3 steers and 3 heifers were grazed together on toxic lupin stubbles, were carried out to determine further knowledge of this disease. It was found that what is presently recognised as bovine lupinosis can be divided into 2 distinct entities on the basis of liver pathology. Firstly, a fatty liver syndrome, which accounted for most outbreaks of the disease and most deaths, affected late-pregnant or recently calved cows, and is suggested to be a nutritional ketosis secondary to mild inappetance caused by lupinosis toxin. Secondly, a cirrhotic liver syndrome, which affected all classes of cattle, usually became apparent in winter and is considered to be the principal result of the direct action of lupinosis toxin. Cattle were less susceptible to lupinosis than sheep. Recommendations are made on grazing lupins by cattle. 相似文献
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陈文凯 《四川畜牧兽医学院学报》2006,4(2):286-287
随着信息时代的来临，高校图书馆服务内容、服务方式、服务理念都发生了深刻的变化。本文着重探讨了高校图书馆馆员角色定位向深层次发展问题，分析到图书馆馆员是最活跃最主动的因素，提出高校图书馆馆员的发展方向。 相似文献
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MARTINA FLOECK 《Veterinary radiology & ultrasound》2007,48(1):74-77
Nineteen cattle with pyelonephritis were examined sonographically. A 3.5- and 5.0-MHz convex transducer was used for percutaneous and a 5.5-MHz linear scanner for transrectal examination. Ultrasonographic changes included enlarged kidneys, echogenic material, and flocculent fluid within a dilated and deformed renal sinus and a poor cortical medullary differentiation. Azotemia was detected in 10 and hematuria and proteinuria in all animals. Microbial culture revealed Corynebacterium renale in eight and Escherichia coli in five cattle. Sonography supplemented the clinical examination and clinicopathological analysis by providing additional information on renal disease in these patients. 相似文献
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Laurent Blond Jacques Dupuis Guy Beauregard Luc Breton Maxim Moreau 《Veterinary radiology & ultrasound》2005,46(3):210-216
Canine elbow incongruence is believed to be the consequence of underdevelopment of the radius. The purpose of this study is to determine the sensitivity and specificity of radiography to detect elbow incongruence in an in vitro model and to assess the optimal elbow angle and radiographic beam position. Five normal cadaveric canine left forelimbs were used. A four-pin, type 1 external fixator with a linear motor side bar was fixed to the cranial part of the radius of each limb and a 1 cm segment of bone was removed from the mid-diaphysis to allow radial shortening. Each elbow was subjected to the same protocol. They were radiographed at two different angles (90 degrees and 135 degrees) of flexion, with 10 different radiographic beam positions (centered on the humeral condyle, 3 cm cranial, 3 cm caudal, 3 cm distal, 3 cm proximal, 3 cm cranio-proximal, 3 cm cranio-distal, 3 cm caudo-proximal, 3 cm caudo-distal and on the shoulder joint) and at four different level of radial shortening (0, 1, 2 and 3 mm). In addition, a radiographic view centered on the elbows flexed at 135 degrees was made after simulating weight bearing. The acquired digital images were independently evaluated by three evaluators unaware of the elbows status. The elbows were judged normal, incongruent or borderline based on specific criteria. The sensitivity for detection of elbow incongruence at and beyond 2 mm was excellent at 90 degrees (median = 100% for all views) and good at 135 degrees (median = 80%) of flexion with no difference between examiners. The sensitivity at 1 mm of incongruence was unchanged at 135 degrees but was reduced at 90 degrees of flexion (median = 60%) with a significant difference between the evaluators. The specificity was significantly different between the evaluators and ranged from 70% to 90% at 90 degrees of flexion and from 50% to 80% at 135 degrees. The lowest specificities at 90 degrees were obtained with the proximal displacements of the X-ray beam. Simulating weight bearing significantly decreased the sensitivity at 1 mm (from 80% to 50%) and 3 mm (from 100% to 80%) of incongruence and slightly increased the specificity (from 55% to 65%). Radiography is a sensitive and specific test to detect moderate-to-severe radio-ulnar incongruence (2 mm and over) if the elbow is flexed at a 90 degrees angle regardless of the radiographic beam position. Finally, canine elbow incongruence appeared reduced after an in vitro weight-bearing simulation. 相似文献