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本文对放牧生态学中的一个基本概念一偏食性的涵义(属性)与维度等进行了相对全面地释义;并对比分析了与之密切相关的适口性概念。偏食性是指动物基于自身特性以及动物体状态(包括遗传特征、发育阶段、生理与营养状态等),在不受食物供给量限制的条件下,对所在生境中食物(或植物种类)表现出的采食程度差异,它具有动物依赖性、动态性及相对性。偏食性的测度能够一定程度地反映动物的食性选择趋向,或者体现动物对生境中不同食物的潜在采食或消耗量;对偏食性的分析还有助于解释动物的食性选择策略,有益于揭示动物的采食行为规律。偏食性的维度包括持续偏食性与即时偏食性,以及绝对偏食性与相对偏食性。持续偏食性是动物经过长期进化形成的、对某种食物表现出较长时间的稳定的采食强度,即时偏食性是动物在某一时间对食物的采食强度,即动物偏食性的瞬时度量;绝对偏食性是动物在面对某种单一食物、于自由采食状态下所度量的对该食物的采食强度,绝对偏食性可以被认为是动物最基本的偏食性维度,而相对偏食性是指同时提供2种或多种食物背景下,所度量的动物对某种食物的自由选择采食强度。深刻认识、理解动物的偏食性概念及涵义,并将之有效地应用于实际的草地放牧管理之中,对于发展动物采食理论,动、植物协同适应及进化理论,有效实施草地家畜管理都具有突出的科学价值和实践意义。 相似文献
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本文对放牧生态学中的一个基本概念一偏食性的涵义(属性)与维度等进行了相对全面地释义;并对比分析了与之密切相关的适口性概念。偏食性是指动物基于自身特性以及动物体状态(包括遗传特征、发育阶段、生理与营养状态等),在不受食物供给量限制的条件下,对所在生境中食物(或植物种类)表现出的采食程度差异,它具有动物依赖性、动态性及相对性。偏食性的测度能够一定程度地反映动物的食性选择趋向,或者体现动物对生境中不同食物的潜在采食或消耗量;对偏食性的分析还有助于解释动物的食性选择策略,有益于揭示动物的采食行为规律。偏食性的维度包括持续偏食性与即时偏食性,以及绝对偏食性与相对偏食性。持续偏食性是动物经过长期进化形成的、对某种食物表现出较长时间的稳定的采食强度,即时偏食性是动物在某一时间对食物的采食强度,即动物偏食性的瞬时度量;绝对偏食性是动物在面对某种单一食物、于自由采食状态下所度量的对该食物的采食强度,绝对偏食性可以被认为是动物最基本的偏食性维度,而相对偏食性是指同时提供2种或多种食物背景下,所度量的动物对某种食物的自由选择采食强度。深刻认识、理解动物的偏食性概念及涵义,并将之有效地应用于实际的草地放牧管理之中,对于发展动物采食理论,动、植物协同适应及进化理论,有效实施草地家畜管理都具有突出的科学价值和实践意义。 相似文献
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条件反射是动物出生后接触环境、训练后,在一定条件下建立起来的大脑机能活动,它没有固定的反射路径,容易受环境影响而发生改变或消失。条件反射可以分为自然条件反射和人工条件反射。如饲料的形状等属于自然条件反射;而通过人为的方法,如某种声音对鸡的采食形成的条件反射,就 相似文献
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内质网是蛋白质和脂质生物合成以及跨膜蛋白折叠的场所。生理和病理情况都可影响内质网的功能，导致内质网应激。长期和严重内质网应激可导致细胞的自噬和/或诱导细胞凋亡。多项研究表明，内质网应激是导致许多疾病的主要因素。因此，对内质网应激通路的调节已成为一个潜在的治疗靶点。槲皮素是属于黄酮类植物衍生的次生代谢物，具有一系列有益作用。近年来的研究发现，槲皮素可通过调控内质网应激信号，降低机体发生癌症、肝脏和胰腺疾病、心血管疾病、肠道疾病的风险，减少器官/组织损伤，进而维持动物机体健康。本文主要综述槲皮素调节动物内质网应激中的作用机制及研究进展，旨在为槲皮素的进一步开发利用和治疗动物内质网应激相关疾病方面提供参考。 相似文献
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本文综述了截止2015年国内外文献,分析了家畜放牧对啮齿动物的影响。放牧家畜的践踏和排泄物等引起土壤理化性质改变影响了啮齿类空间利用等,家畜采食影响了啮齿类食物资源及其丰度,采食还引起植物营养成分改变及次生防御化合物的产生,而植被高度变化导致了啮齿动物捕食风险的增加和生活史策略的改变。这些方面的影响与综合作用改变了啮齿动物的微栖息环境、分布、食性,以及领域、采食和挖掘等行为,繁殖和生活史特征;影响了啮齿动物的种群结构、种群数量消长及其调节过程;改变了啮齿动物的群落结构和种间相互作用,引起其群落演替。在综述上述各方面研究进展的基础上,提出放牧对啮齿动物影响的作用途径及其方式,放牧条件下草-畜-鼠耦合机制,不同放牧制度对啮齿动物的影响以及整合现代学科发展的相关探索是未来研究的重点。 相似文献
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研究啮齿动物的食性及其营养生态位特征不仅可以了解高寒草甸环境变化下物种的食性适应特征,还可探讨多种啮齿动物的种间关系。本研究采用粪便显微组织观察法,分析了甘南草原高原鼠兔（Ochotona curzoniae）、高原鼢鼠（Eospalax baileyi）和喜马拉雅旱獭（Marmota himalayana）3种啮齿动物的食性及营养生态位特征。结果发现：3种啮齿动物所采食的植物种类基本相同,但其比例各异;高原鼢鼠所采食的植物主要是珠芽蓼（Polygonum viviparum）和鹅绒委陵菜（Potentilla anserina）等杂类草,且对莎草科（Cyperaceae）植物的采食量显著高于其它两种动物,高原鼠兔主要采食禾本科（Poaceae）植物,喜马拉雅旱獭则主要采食禾本科和菊科（Asteraceae）植物;营养生态位宽度依次为喜马拉雅旱獭>高原鼢鼠>高原鼠兔,其中高原鼠兔与喜马拉雅旱獭的营养生态位重叠最大（0.52）。3种啮齿动物在食物上存在分化,营养生态位分离,是其共存的重要原因。 相似文献
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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
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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
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Tropical Animal Health and Production - 相似文献
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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
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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
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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
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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
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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
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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
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<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