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1.
研究了格姆滩高寒草甸不同草地植被地上生物量及物种多样性,结果表明：地上总生物量为藏嵩草沼泽化草甸〉山生柳灌丛草甸〉小嵩草草甸（P〈0.05）。藏嵩草沼泽化草甸由24种植物组成,隶属13科22属;小嵩草草甸由36种植物组成,隶属16科31属;山生柳灌丛草甸草层由42种植物组成,隶属13科31属。不同草地类型植物群落多样性指数、物种丰富度指数、均匀度指数、生态优势度指数均为山生柳灌丛草甸草层〉小嵩草草甸〉藏嵩草沼泽化草甸,植被盖度山生柳灌丛草甸草层〉藏嵩草沼泽化草甸〉小嵩草草甸。  相似文献   

2.
研究了格姆滩高寒草甸不同植被类型草地生物量.结果表明:不同植被类型草地生物量差异比较明显(P<0.05).地上、地下生物量均为藏嵩草沼泽化草甸>山生柳灌丛草甸>小嵩草草甸.地上植物量按不同功能群组成变化为:莎草类地上生物量藏嵩草沼泽化草甸>山生柳灌丛草甸>小嵩草草甸,禾草和杂类草均为山生柳灌丛草甸>藏嵩草沼泽化草甸>小嵩草草甸.各样地地下生物量均随土层深度的增加而减小.  相似文献   

3.
黄河源区山生柳灌丛草甸植物群落多样性及植物量组成   总被引：4，自引：2，他引：2  
对黄河源区山生柳灌丛草甸物种组成、结构及其植被生产力进行了调查.结果表明,该类植被由45种植物组成,隶属于14科33属.其中,灌木层由3种灌木组成,隶属于3属2科,优势度为:山生柳Salix oritrepha(57.28%)>金露梅Potentilla fruticosa(28.19%)>高山绣线菊Spiraea alpina(14.53%).草本层由42种植物组成,隶属于13科31属,优势种为垂头菊Cremanthodium spp.、黄芪Astragalus spp.、线叶嵩草Kobresia capillifolia和小金莲花Trollius pumilus.草本层的Shannon-Wiener多样性指数为3.42,Simpson优势度指数为0.96,Pielous均匀度指数为0.92.群落地上干物质量为296.4 g/m2,地下植物量为3 185.6 g/m2.地下植物量主要分布在0～10 cm土层,为2 272.0 g/m2,占0～30 cm土层植物量的71.3%,根冠比为10.8.阔叶草类、莎草类和禾草类植物分别占总鲜质量的73.4%、20.1%和6.5%;占总干质量的57.1%、30.6%和12.3%.根据该灌丛物种、生产力构成及现状分析,黄河源区山生柳灌丛目前处于中度利用状态.  相似文献   

4.
黄河源区高寒草甸不同植被生物量及土壤养分状况研究   总被引：3，自引：1，他引：2  
为了给黄河源区原生草地植被的科学管理及退化草地的治理提供理论依据,对青海省玛沁县藏嵩草(Kobresia tibetica)沼泽化草甸,山生柳(Salix oritrepha)灌丛草甸及小嵩草(Kobresia pygmaea)草甸物种多样性、生物量及土壤养分状况进行比较研究。结果表明:不同植被类型植物群落多样性指数、物种丰富度指数、均匀度指数、生态优势度指数均为山生柳灌丛草甸>小嵩草草甸>藏嵩草沼泽化草甸。各群落生物量差异明显,地上、地下总生物量均为藏嵩草沼泽化草甸>山生柳灌丛草甸>小嵩草草甸(P<0.05)。藏嵩草沼泽化草甸土壤养分含量最高。小嵩草草甸和山生柳灌丛草甸各土壤层养分含量随土壤深度的增加呈下降趋势,pH值呈上升趋势,而藏嵩草沼泽化草甸却表现出相反的趋势,即随土壤深度的增加各层养分含量呈上升趋势,pH值呈下降趋势。  相似文献   

5.
通过对青海湖地区中度退化嵩草型草地地下植物量的研究,结果显示:线叶嵩草型中度退化样地地下植物量季节变化动态为升高—降低的“单峰”曲线;在牧草生长季的不同时期,随着土壤深度的增加,地下植物量的分布呈明显递减趋势;地下85.53%的植物量分布在0~20 cm深的土层中;在地下0~40 cm土层内,其根系的年净生产量及周转值分别为787.13 g/m2、26.08%;地下/地上植物量的值为24.61。  相似文献   

6.
通过对2016年度青海湖流域自然区域5个草地类植被进行草地生态监测结果分析:草层平均高度为7.4cm,其中,优势种平均高度为6.6cm,草地植被覆盖度平均为69%,其中优势种覆盖度为31%;平均鲜草总产草量为3026.02kg/hm~2,其中高寒草甸类平均鲜草总产草量最高为3960.89kg/hm~2,高寒草甸草原最低为1426.70kg/hm~2;各类草地地下生物量以高寒草甸类草地最高为57946.70kg/hm~2。  相似文献   

7.
对海北定位站地区分布的金露梅灌丛草甸、矮嵩草草甸和沼泽化藏嵩草草甸3种高寒植被类型群落及土壤环境因子的观测结果表明:3种植被类型地上年净生产量依次为矮嵩草草甸(339.594 g/m2)＞沼泽化藏嵩草草甸(339.358 g/m2)＞金露梅灌丛草甸(278.299 g/m2);光能利用率为矮嵩草草甸(0.099%)＞沼泽化藏嵩草草甸(0.091%)＞金露梅灌丛草甸(0.075%);植被群落的种类组成为矮嵩草草甸(54种)＞金露梅灌丛草甸(47种)＞沼泽化藏嵩草草甸(24种).观察矮嵩草草甸和金露梅灌丛草甸0～20 cm土壤温湿度表明,矮嵩草草甸土壤温度＞金露梅灌丛草甸,土壤湿度则相反,其中矮嵩草草甸土壤温度较高,土壤湿度较低,金露梅灌丛草甸则是高土壤湿度和低土壤温度,而沼泽化藏嵩草草甸土壤湿度达饱和甚至超饱和状态,土壤温度显得更低.  相似文献   

8.
围栏封育对昭苏马场春秋草场植被恢复的影响   总被引：2，自引：3，他引：2  
对昭苏马场未封育与封育春秋草场植被进行了调查分析,结果表明:未封育草地植物优势种是亚洲百里香和草原苔草,封育草地植物优势种是针茅和草原苔草;未封育草地植物种类为28种,群落盖度为62.8%,地下植物量1 452.7 g/m2;封育后草地植物种类为31种,群落盖度和地下植物量分别增加了41.0%和34.5%;禾本科草类的重要值由未封育的17.6%增加到封育后的35.2%,豆科和菊科草类基本保持稳定,封育后藜科和杂类草的重要值比未封育时减小了13.5%;封育草地的丰富度指数和多样性指数均大于未封育草地,而均匀度指数则相反。  相似文献   

9.
通过对大武地区小嵩草草甸的研究,分析了不同程度退化草地群落结构和地上、地下植物量的变化。结果表明:随着退化程度的加重,群落的组成和优势种发生了很大的变化,植物群落从以莎草科为主,向以杂类草为主的群落演替;地上、地下植物量均呈现下降趋势,而杂类草的地上生物量则表现出逐渐增加的趋势。几种不同程度退化草地的地下植物量主要分布在0~10cm的范围内,且显著高于其它层;物种多样性、均匀度指数有下降趋势。  相似文献   

10.
高寒草甸退化草地—“黑土滩”植物量测定   总被引：5，自引：0，他引：5  
依据高寒草甸草地秃斑地的多少和距居民点的远近划分为轻度退化草地(极少量秃斑地)、中度退化草地(少量秃斑地)、重度退化草地(大量秃斑地)和极度退化草地(全部秃斑地)四个退化草地等级。对各等级退化草地进行了植物量测定。结果表明:草地植物量(地上和地下)及土壤含水量,随着草地退化程度的加剧明显下降(P<0.01),毒杂草量则明显上升(P<0.01)。其中极度退化草地较轻度退化草地植被中嵩草属牧草优势度减少38,可食鲜草量减少219.2g/m~2,而毒杂草则增加99.6g/m~2,植物活根量(干物质)减少2390.6g/m~2,土壤含水量(0—10cm)减少10.02％,并对高寒草甸退化草地(黑土滩)的成因及治理途径提出了看法和意见。  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
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   

14.
Tropical Animal Health and Production -  相似文献   

15.
Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.  相似文献   

16.
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   

17.
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   

18.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

19.
The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.  相似文献   

20.
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   

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