共查询到20条相似文献，搜索用时 296 毫秒
1.
2.
本试验在内蒙古呼伦贝尔市草甸草原,针对划区轮牧和自由放牧对植物群落及主要植物种群的影响进行做了比较研究．分析结果表明：（1）羊草的高度、盖度和密度在划区轮牧区较在自由放牧区高,说明划区轮牧有利于多年生根茎禾草的繁殖,对一年生植物的生长起到了一定的抑制作用。（2）Margalef指数、Shannon-wiener指数、Simpson指数和Pielou指数划区轮牧区均高于自由放牧区,说明划区轮牧较自由放牧更有利于提高物种的多样性和丰富度。（3）植物群落总的地上现存量划区轮牧较自由放牧高,说明划区轮牧较自由放牧能够保持群落具有更高的地上现存量。 相似文献
3.
4.
通过对长芒草 杂草草场暖季划区轮牧、自由放牧及围栏封育3种处理方式的研究，结果表明：划区轮牧区植物群落种建群的质量百分比显著高于自由放牧区和围栏封育区。划区轮牧十分有利于长芒草草场的恢复，对今后草地资源可持续利用有着十分重要的意义。 相似文献
5.
6.
放牧制度对荒漠草原优势植物种和土壤生态化学计量学特征的影响 总被引：2，自引：0，他引：2
本文以短花针茅荒漠草原为研究对象,对荒漠草原优势植物种和土壤的生态化学计量学特征进行研究。结果表明,短花针茅划区轮牧区和对照区C含量分别为409.28g/kg和387.46g/kg,略低于自由放牧区,而N、P含量高于自由放牧区。短花针茅划区轮牧区C∶P、N∶P高于自由放牧区和对照区。对照区碱韭C、P含量高于划区轮牧区和自由放牧区,其值分别为394.19g/kg和2.35g/kg,自由放牧区碱韭C、N、P含量均高于划区轮牧区。土壤C∶N值分布在6.99-11.06之间,低于我国土壤C∶N平均值(10∶1-12∶1之间),且低于全球C∶N平均值(13.33)。土壤的C∶P值分布在12.1-30.30之间,低于我国平均值105。 相似文献
7.
8.
9.
10.
《中国草地学报》2019,(4)
为研究暖温性草原区植物群落特征和草地生产力对不同放牧模式的响应,探讨草地生产力和多样性指数的关系,选择内蒙古和林格尔县暖温性草原区短花针茅群落作为样地,采用划区轮牧、自由放牧Ⅰ(载畜率3.48只羊/hm~2)、自由放牧Ⅱ(载畜率4.00只羊/hm~2)和围栏禁牧4种放牧方式,2017年连续6个月进行草地健康监测。结果显示:不同放牧方式对草地群落特征及α多样性均存在显著影响(P0.05),围栏禁牧表现最好;划区轮牧的草地群落特征及α多样性显著高于其他两种放牧方式;8月围栏禁牧下的草地生产力虽高于其他放牧方式,但10月份4种放牧制度下草地生产力差异较8月份小。综上,和林格尔县暖温型草地可以支持放牧行为,划区轮牧可保证草地可持续发展。 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.
Tropical Animal Health and Production - 相似文献
14.
Rassnick KM Gieger TL Williams LE Ruslander DM Northrup NC Kristal O Myers NC Moore AS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2001,15(3):196-199
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
15.
H Hayashi T Yoshimura J Y Chen 《Comparative immunology, microbiology and infectious diseases》1985,8(2):73-87
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.
Davis MS Willard MD Nelson SL Mandsager RE McKiernan BS Mansell JK Lehenbauer TW 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(3):311-314
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.
B. Cinar Kul N. Bilgen J.A. Lenstra O. Korkmaz Agaoglu B. Akyuz O. Ertugrul 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2015,132(6):449-453
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
18.
Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects 总被引：1，自引：0，他引：1
Johansson AM Gardner SY Levine JF Papich MG LaFevers DH Fuquay LR Reagan VH Atkins CE 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(6):887-895
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
19.
Ling GV Thurmond MC Choi YK Franti CE Ruby AL Johnson DL 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(6):817-823
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.
<正>1.INTRODUCTION Ensuring transportation network security is one Of the most daunting challenges confronting homeland security agencies today.Significant research has been dedicated.To model and analyze the vulnerability of transportation systems,while notably fewer studies propose specific strategies for deploying defensive technologies to safeguard these systems. 相似文献