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1.
结缕草交播不同量高羊茅试验研究   总被引：10，自引：2，他引：8  
在已成坪的结缕草草坪上,按１０ｇ／ｍ２、２０ｇ／ｍ２、３０ｇ／ｍ２和４０ｇ／ｍ２播量在秋季交播高羊茅,连续３年按月测定群落中高羊茅和结缕草的密度、盖度和频度,进而探讨较为适宜的交播量和各种交播量的交播效果。４种交播量中以１０ｇ／ｍ２为最佳;增加交播高羊茅播量会显著增加高羊茅的密度（Ｐ＜０．０５）及程度不同的增加其盖度和频度（Ｐ＞０．０５）,但却明显地降低了结缕草的密度、盖度和频度（Ｐ＜０．０５）,使高羊茅的种群竞争能力加强而结缕草的竞争能力减弱,使草坪群落趋向于向高羊茅不同个体组成的单一草坪群落方向演替。  相似文献   

2.
河西地区碱茅属植物草地水盐动态的研究   总被引：3，自引：0，他引：3  
本文研究了河西地区２年生、３年生、４年生碱茅属植物人工草地及撩荒地的水盐动态。试验结果表明：１）土壤水分含量从表层到底层（０～１００ｃｍ）呈梯度形分布。上述四类草地分别分布在２１．６％～４４．２％、２５．９％～４４．０％、３５．０～４６．２％、３５．５％～４６．４％之间，在定期灌溉条件下，各草地２０ｃｍ以下土壤水分含量在相同层之间差异不显著。２）土壤表层（０～１０ｃｍ）盐分含量较高，１０ｃｍ以下盐分含量急剧下降。表层盐分含量以撩荒地最高，４年生、２年生及３年生碱茅草地分别次之，平均值依次为２．４６％、１．２１％、０．２３％、０．１８％。２０ｃｍ以下各层土壤盐分含量各草地均很小，不同草地的同一层及同一草地的不同层之间差异不显著。各草地在５月与９月有两个返盐期，其它各月（６月、７月、８月）盐分变化较平稳。３）土壤盐分含量与地下植物量无显著相关性，地上植物量的增大，使得草地以蒸腾为主的土壤水分散失量也大幅度增大，这揭示了碱茅草地治盐作用的内在机理。  相似文献   

3.
果洛地区“黑土滩”中秃斑地测定   总被引：9，自引：1，他引：8  
“黑土滩”中的秃斑地和原草地相比，毒草量增加６４．８％，优良牧草明显减少；地下根量（０—１０ｃｍ）减少２３７６．６ｇ／ｍ￣２；土壤趋于碱性、旱化，肥力下降，蓄水能力下降。以上差异均达到显著水平（Ｐ＜０．０５）。  相似文献   

4.
沈禹颖  赵银 《草业学报》1995,4(2):51-57
定位调查河西走廊三种盐化草地地下生物量随时空分布的规律表明：在垂直部面中，海韭菜、小灯心草和芦苇＋赖草草地根系均呈“Ｔ”型。海韭菜草地的根量在３０－４０ｃｍ处有一增大，与芦伟在该层产生水平根茎有关；小灯心草草地地表根系极丰富，０－１０ｃｍ与１０－２０ｃｍ层的根量比达５．０；而芦苇苇＋赖草草地的构成种简单，地下生物量较前两个草地为少；２）三种草地地下生物量随土壤深度的关系均可用非线性函数描述，其最佳  相似文献   

5.
天峻县草地土蝗种群结构调查与虫情预测   总被引：2，自引：1，他引：1  
天峻县草地土蝗种群结构调查与虫情预测侯秀敏，刘晓建，拉毛（青海省草原总站８１０００８）１调查区自然概况１９９４年８月２日至１２日我们在天峻县块尔玛乡及毗邻地区进行蝗虫种群结构调查，该地区海拔３２５０ｍ左右，年均气温为一１．２℃，最热月（７月）１０．２...  相似文献   

6.
在河西走廊地区建植碱茅（Ｐｕｃｃｉｎｅｌｌｉａｔｅｎｕｉｆｌｏｒａ－Ｐ．ｃｈｉｎｕｍｐｏｅｎｓｉｓ）人工草地，做收种和刈割兼用。撒播方式下，播量达２２．５ｋｇ／ｈｍ２时，种子落种数为２０００／ｍ２，田间出苗数７９４／ｍ２，出苗率为１３％，定苗数受地表积盐程度的影响（Ｐ＜０．０１），地表盐斑为５０％，９０％的幼苗数为９８８株／ｍ２和３０１株／ｍ２；碱茅草地盖度，种子产量和牧草产量均与土壤全盐含量呈负线性关系（ｒ－－０．８０５１，ｒ＝－０．８１５８，ｒ＝－０．９２９２），但种子发芽率和千粒重似乎不受立地土壤盐分的影响。由于受田间管理措施和碱茅自身发育节律的影响，生长第３年的草地盖度、种子产量和牧草产量均比第２年有不同幅度的下降，据此，适时灌水，加强施肥等田间管理措施对维持草地基况良好，获得高产有重要作用。  相似文献   

7.
根据Ｉｗａｏ的抽样数模型，确定出门源草原毛虫（Ｇｙｎａｅｐｈｏｒａｍｅｎｙｕａｎｅｎｓｉｓ）的最适抽样数。当防治指标标为３０头／ｍ￣２时，序贯抽样的累积幼虫量界限公式为：Ｔ＿０（Ｎ）＝３０ｎ±２９．７１当ｔ＝１．６４，或Ｔ＿０（Ｎ）＝３０ｎ±３５．５１，当ｔ＝１．９６。在高寒草甸中，棋盘式抽样方法是随机取样幼虫和茧的最佳方式。  相似文献   

8.
高效液相色谱法检测泰乐菌素在肉鸡组织中的残留   总被引：4，自引：0，他引：4  
将肉鸡的肌肉、肝脏、肾脏和脂肪组织制成匀浆,用乙腈、石油醚和二氯甲烷萃取、净化后,用乙腈定容。以乙腈－ 甲醇－ ０．００５ ｍ ｏｌ／ Ｌ磷酸二氢铵溶液（６０∶３０∶１０）为流动相,用高效液相色谱检测。本法对溶解于乙腈中的泰乐菌素的最低检测限为 ０．０５ ｍ ｇ／ Ｌ,在肉鸡各种组织中的最低检测限为 ０．１０ ｍ ｇ／ Ｌ。标准曲线的线性范围为 ０．１０～６．４０ ｍ ｇ／ Ｌ。泰乐菌素质量浓度为 ０．１０、０．８０、６．４０ ｍ ｇ／ Ｌ 时的批间变异系数分别为（２．３±０．２）％ 、（１．９±１．３）％ 、（２．６±０．９）％ 。０．２０、０．４０、０．８０ ｍ ｇ／ Ｌ 的泰乐菌素在以上 ４ 种组织的回收率均符合残留检测的要求。结果表明,本法是一种灵敏、精密、可靠的检测肉鸡组织中泰乐菌素残留的分析方法。  相似文献   

9.
高寒草甸草地在全封育下的植物量变化   总被引：4，自引：0，他引：4  
用钢丝网封育高寒草甸类的高山嵩草－异针茅草地０．３６ｈｍ￣２，封育时间１９９０—１９９３年。对封育草地内地上及地下植物量测定结果：封育第一年优良牧草鲜草量增加明显，由原来的１７４．０ｇ／ｍ￣２增加到３２５．０ｇ／ｍ￣２（Ｐ＜０．０１），第２、３年产量变化不明显（Ｐ＞０．０５）；封育的第１、２年，优良牧草成份呈上升趋势，杂毒草成份呈下降趋势，封育的第３年优良牧草成份开始下降，杂毒草开始上升；地下植物总量（４０ｃｍ内），在封育的第１年下降明显，由原来的６４６９．５６ｇ／ｍ￣２下降到４７２１．６８ｇ／ｍ￣２（Ｐ＜０．０１），封育的第２、３年根量开始明显回升，至第３年上升为７３１０．０ｇ／ｍ￣２（Ｐ＜０．０１）。测定结果表明，高寒草甸草地封育时间以２年为佳。建议利用现有围栏，针对冬春草地采取冬季刮用枯草，早春禁牧（４—７月）的措施，封育退化草地两年，即可达到封育效果。  相似文献   

10.
巨型艾美耳球虫纯种鉴定和致病性研究   总被引：10，自引：1，他引：9  
采用单卵囊感染技术，从鸡球虫混合种中分离出一个纯种球虫，经鉴定为巨型艾美耳球虫（ＥｉｍｅｒｉａＭａｘｉｍａＴｙｚｚｅｒ，１９２９）。该种球虫卵囊为卵圆形，测２４０个的大小范围为２１．２５～３６．２５×１７．５～３０．０μｍ，平均为２８．８１±３．０７×２２．９８±２．７７μｍ，形状指数１．２５。卵囊内有一颗折光性极粒，位于窄端，无外残体。测１２０个孢子囊的大小范围为１５．５～１８．５×７．５～１０．０μｍ，平均为１７．３５±０．６６×８．７４±０．５１μｍ。最短孢子化时间为３０小时，潜伏期１４２小时。用此卵囊对鸡作致病性试验，挑选６０羽１３日龄伊莎（ＩＳＡ）公鸡分为１个不感染组和４个感染组，每羽口服感染１万、５万、１０万或２０万个孢子化卵囊。结果所有感染组与不感染组的平均增重差异达到显著（Ｐ＜０．０５）或极显著（Ｐ＜０．０１）水平，整个试验仅在２０万个的感染组出现１６．７％的死亡率，各感染组的肠道病变记分分别为１．３３、１．８３、２．４２和３．０８。  相似文献   

11.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

12.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

13.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

14.
The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.  相似文献   

15.
The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.  相似文献   

16.
Comparison of different tests to diagnose feline infectious peritonitis   总被引：1，自引：0，他引：1  
  相似文献   

17.
An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.  相似文献   

18.
Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein  相似文献   

19.
正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in  相似文献   

20.
Tropical Animal Health and Production -  相似文献   

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