首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
基于藏北高原的3个围栏与自由放牧试验样地,探讨了高寒草地牧草营养品质对放牧的响应机制。结果表明：在一个高寒草原化草甸冷季牧场,冷季放牧分别减少了24.29%和18.98%的杂草酸性洗涤纤维和中性洗涤纤维含量,并增加了41.05%的杂草粗灰分含量,从而增加了杂草营养品质;而没有改变群落和优势牧草营养品质。在一个高寒草原化草甸暖季牧场,暖季放牧分别减少了31.82%和27.45%的群落酸性洗涤纤维和中性洗涤纤维含量,并分别增加了137.35%和24.73%的群落粗灰分和粗脂肪含量,从而增加了群落营养品质;暖季放牧分别减少了22.04%和22.50%的优势牧草酸性洗涤纤维和中性洗涤纤维含量,并增加了202.19%的优势牧草粗灰分含量,从而增加了优势牧草营养品质;而没有改变杂草营养品质。在一个高寒草甸暖季牧场,暖季放牧分别减少了37.18%和25.10%的杂草酸性洗涤纤维和中性洗涤纤维含量,从而增加了杂草营养品质;增加了26.55%的优势牧草粗蛋白含量,从而趋于增加了优势牧草营养品质;而对群落营养品质无影响。植物群落营养品质与植物群落α和β多样性相关,优势牧草营养品质主要与土壤变量相关,杂草营养品质与土壤变量和杂草α多样性有关。因此,藏北高寒草地牧草营养品质对放牧的响应因草地类型和放牧季节的不同而不同,高寒草地应该采取分类放牧管理。  相似文献   

2.
河西走廊绿洲外围沙化草地固沙造林效果研究   总被引：1，自引：0，他引：1  
通过对流动沙丘固沙造林效果的对比研究,结果发现:未固沙造林的沙丘,丘间低地是以芦苇和赖草为优势种的原生群落,沙丘迎风坡植被稀疏,不形成植物群落,而实施固沙造林技术20年后的沙丘,虽丘间低地群落组成成分变化不大,但流动沙丘被完全固定,中下部形成以引入固沙灌木柠条锦鸡儿、花棒为优势种的人工植物群落,植物种类增加,生产力提高,草地生态系统得到有效恢复。固沙造林沙丘与未固沙造林沙丘相比,丘间低地群落高度增加51.6%,产草量增加12.6%,盖度增加4.7%,多度无变化,密度提高15%,物种丰富度指数提高25%,均匀度指数提高34.8%;迎风坡下部群落高度增加87.1%,产草量增加13%,多度提高一个等级,密度增加15%,物种丰富度指数提高228%,均匀度指数提高22.8%;迎风坡中部群落高度增加453.7%,产草量增加64.5%,多度提高一个等级,密度增加128.9%,物种丰富度指数提高616%,均匀度指数提高33.3%;迎风坡上部植被非常稀疏,不形成群落,植株平均高度25.3 cm,产草量增加206.8%,多度提高一个等级,密度增加550%,物种丰富度指数提高800%,均匀度指数提高66.7%。  相似文献   

3.
为了解不同杀虫剂对井上蛀果斑螟卵的触杀作用,采用浸渍法测定了辛硫磷、丙溴磷、乙酰甲胺磷、高效氯氟氢菊酯、杀虫双、除虫脲、噻嗪酮、阿维.哒螨灵、吡虫.三唑磷等9种药剂对井上蛀果斑螟卵的触杀效果。结果表明：2.5%高效氯氟氢菊酯EC 600倍液,对井上蛀果斑螟卵的触杀效果最高,校正死亡率达98.67％;40%辛硫磷EC 250和500倍液、30％乙酰甲胺磷EC 300倍液、37%噻嗪酮SC 250倍液、20％吡虫.三唑磷EC 150倍液处理,校正死亡率均在90%以上。此外,40%辛硫磷EC 1 000和1 500倍液、40%丙溴磷EC 2 000和2 500倍液、30％乙酰甲胺磷EC 600倍液、2.5%高效氯氟氰菊酯EC 800倍液、25%杀虫双AS 100和150倍液、25%除虫脲2 500倍液、8％阿维.哒螨灵EC 1 500倍液和20％吡虫.三唑磷EC 150倍液的触杀效果均高于80％。综合试验结果考虑,防治井上蛀果斑螟,可使用40％辛硫磷EC 500~1000倍液、30％乙酰甲胺磷EC 300~600倍液、2.5%高效氯氟氰菊酯EC 600~800倍液、37% 噻嗪酮SC 250倍液和20％吡虫.三唑磷EC 100~150倍液对该虫的卵期进行防治。  相似文献   

4.
Book Reviews     
Book reviewed in this article:
Canine and Feline Behavioural Therapy Benjamin L. Hart and Lynette A. Hart. Published by Lea & Febiger, Philadelphia
Operationen and Hund und Katze Horst Schebitz and Wilhelm Brass. Published by Paul Parey
Reproduction in the Dog and Cat lb J. Christiansen. Published by Bailliere Tindall
Clinical Pharmacology & Therapeutics (The Thinking Veterinarian's Course) MacDiarmid et al. Published by the Post-graduate Committee in Veterinary Science
An Atlas of Canine Surgical Techniques Edited by P. G. C. Bedford
In Practice: The Small Animal Book Published by the British Veterinary Association
Quarterly Index. Information Access for the Small Animal Practitioner Edited by M. M. Mastin. Published by Veterinary Interface
Black's Veterinary Dictionary 15 th Edn Edited by Geoffrey West. Published by A & C Black
Acupuncture Points and Meridians in the Dog L. A. A. Janssens. Published by L. A. A. Janssens
Veterinary Anesthesia 2nd Edn William V. Lumb and E. Wynn Jones. Published by Lea & Febiger  相似文献   

5.
The pre-weaning production of ewes and lambs in spring on pastures grazed during the previous autumn and early winter by either weaner sheep, adult sheep, or cattle was investigated together with estimating the benefits of pre- and post-lambing drenches to ewes. These treatments were compared with one in which parasitism was uncontrolled in ewes lambing on pastures grazed previously by untreated weaner sheep, and another where parasitism was suppressed by 2-weekly drenching of the weaner sheep and also of the ewes and their lambs. Prior grazing by cattle effectively eliminated infection of pastures with intestinal Trichostrongylus and Nematodirus spp, but less so for Ostertagia spp. Worthwhile reductions in contamination were also achieved by grazing by adult sheep compared with grazing by undrenched weaners. Despite differences in the parasitological status of the pastures, there were no indications that pre-weaning growth rates of lambs were affected. However, wool growth in ewes was reduced by 10 to 20% by parasite infection. Wool growth of ewes on pastures grazed by cattle during the pre-experimental period exceeded that on any other treatment, and was significantly greater than that of ewes on pastures grazed by undrenched weaners. There was no production benefit in giving a pre-lambing drench to ewes on plots contaminated by weaners, or in giving the additional post-lambing drench to ewes grazing on plots contaminated by weaners, adult sheep or cattle.  相似文献   

6.
The average digestibility coefficients of feed mixture nutrients in pigs infected medium severely to severely by the helminths Ascaris suum and Oesophagostomum dentatum were lower in comparison with the post-dehelminthization condition (dry matter by 3.1%, crude protein by 6.7%, fat by 8.9%, nitrogen-free extracts and fibre by 2.2%, organic matter by 3.1%). The content of total digestible nutrients made 679 g in infected pigs and 708 g in dehelminthized pigs. In the period following the experimental infection of pigs by the helminths Ascaris suum, characterized by the formation of antibodies and adaptation after heavy injury of the organism, the digestibility coefficients of feed mixture nutrients were in comparison with the state prior to infection influenced positively. In two metabolism trials, on the 9th to 13th day after infection the digestibility coefficients increased as follows: of dry matter by 4.8% and 3.6%, crude protein by 8.2 and 4.2%, nitrogen-free extracts and fibre by 2.0 and 3.5% and organic matter by 3.0 and 3.3%. The decrease in fat digestibility coefficients was observed in both cases, by 12.4% and 9.9%. Prior to infection the content of total digestible nutrients was 712 g and 682 g, after infection 731 g and 707 g.  相似文献   

7.
A plaque assay procedure was used successfully for studying the viruses of infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis (IPV), and rinderpest. The plaques produced by the IBR and IPV viruses were indistinguishable, but differed from those of rinderpest. The viruses were neutralized by their respective antisera as indicated by plaque inhibition. Plaques formed by the IBR and IPV viruses were inhibited by homologous and heterologous antisera but not by rinderpest antisera, while those of rinderpest were inhibited by the rinderpest antisera only.  相似文献   

8.
BooK Reviews     
Book reviewed in this article:
Veterinary Toxicology, 2nd Edn Myra L. Clarke, D. G. Harvey and D. J. Humphreys. Published by Bailliere Tindall
Veterinary Biology and Medicine of Captive Amphibians and Reptiles L. C. Marcus. Published by Bailliere Tindall
Interrelations between People and Pets Edited by B. Fogle. Published by Charles C. Thomas
Caged Bird Medicine C. V. Steiner and R. B. Davis. Published by Bailliere Tindall
Parrots W. de Grahl. Published by Ward Lock Ltd.
The Dog Directory, 6th Edn Edited by Joe and Liz Cartledge. Published by the Ryslip Group Ltd., Binfield Park, Bracknell, Berks
Veterinary Laboratory Data B. Rushton. Published by BVA Publications
Dealing with Data Diana M. Sard. Published by BVA Publications
Recent Advances in the Study of Raptor Diseases (The Proceedings of the International Symposium on Diseases of Birds of Prey held in July 1980.) Edited by J. E. Cooper and A. G. Greenwood  相似文献   

9.
In young chickens plasma concentrations of growth hormone (GH) are depressed by prostaglandins (PG) E1 and E2, epinephrine, norepinephrine, alpha 2 and beta agonists or thyroid hormones. A primary culture of chicken adenohypophyseal cells was used to examine the direct effects of these agents at the level of the pituitary as evaluated by GH release in the presence and absence of growth hormone releasing factor (GRF). Following collagenase dispersion and culture (preincubation, 48 hr) cells were exposed (incubation, 2 hr) to test agents, except for thyroid hormones which were added during the preincubation, and incubation period. Growth hormone release was increased (P less than .05) in the presence of PGE1 (10(-8)M by 34%; 10(-7)M by 54%), PGE2 (10(-8)M by 29%; 10(-7)M by 29%), PGF2 alpha (10(-8)M by 28%), and the beta agonist isoproterenol (10(-7)M by 46%). Basal GH release from chicken pituitary cells was not affected by dopamine, norepinephrine, epinephrine, thyroxine (T4), triiodothyronine (T3), or alpha adrenergic agonists. Growth hormone releasing factor stimulated GH release was not affected by the presence of prostaglandins E1, E2 or F2 alpha in the incubation media. However, GRF stimulated GH release was reduced by high doses of catecholamines: dopamine (10(-6)M by 34%), norepinephrine (10(-6)M by 74%), epinephrine (10(-8)M by 47%; 10(-7)M by 41%; 10(-6)M by 89%), and by the alpha 1 adrenergic agonist, phenylephrine (10(-7)M by 52%), the alpha 2 agonist, clonidine (10(-8)M by 34%; 10(-7)M by 83%) and the beta agonist, isoproterenol (10(-7)M by 64%).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Responses to selection for number of piglets born alive (NBA) by the total number of piglets born (TNB), the NBA, and the NBA plus number of piglets born dead (NBD) were compared using the accuracy of selection and expected genetic gain calculated from the selection index with family information and the real response to selection, using data generated by Monte Carlo computer simulation. The accuracy of selection for NBA selected by TNB was higher than that by NBA only if the genetic correlation between TNB and NBA was close to 1.0, or the value of heritability for the TNB was much larger than that for the NBA. The accuracy of selection for the NBA selected by the combination of the TNB and the NBA was generally highest in the three selection methods in each family structure. Selection by the TNB resulted in the greatest expected genetic gain for the TNB among the selection methods. In the best linear unbiased prediction (BLUP) selection, the genetic gain for the NBA accumulated by the NBA tended to be similar to that accumulated by the combination of the NBA and the NBD, and both genetic gains at generation 10 were significantly larger than that by the TNB (P < 0.001). The accumulated responses selected by the two‐trait animal model BLUP estimated from genetic parameters with errors were similar to those estimated from the true parameters, and there was no significant difference between them. These results indicate that selection by the NBA or by the NBA and the NBD gives more genetic improvement in the NBA than that by the TNB.  相似文献   

11.
放牧强度对夏季高寒草甸生物量和植被结构的影响   总被引：21，自引：0，他引：21  
讨论了放牧强度对高寒草甸夏季草地上生物量和植被结构的影响。结果表明 :轻牧组、中牧组及重牧组各放牧强度对草地优良牧草所占比例影响较大 ,其中 :禾本科牧草分别提高 2 0 .5 %、6.5 % ,减少1 3.5 % ;莎草科牧草分别提高 2 0 .3%、1 0 .4% ,减少 7.7% ;杂类草分别减少 2 0 .5 %、6.5 % ,提高 1 3.5 %。再从草地盖度看 ,优良牧草 (禾草 +莎草 )在轻牧组提高 1 .4% ,中牧和重牧组分别减少 2 .2 %和 6.4% ;杂类草盖度在轻牧和中牧组分别减少 2 1 .3%和 7.2 % ,而在重牧组则提高 3.2 %。  相似文献   

12.
In vitro susceptibility testing correctly predicted the outcome of ampicillin therapy in all 56 urinary tract infections (UTI) caused by coagulase-positive staphylococci (Staphylococcus aureus and S intermedius), in all 26 UTI caused by Proteus mirabilis, in 38 of 44 UTI caused by Escherichia coli, in 29 of 31 UTI caused by Streptococcus spp, in 8 of 10 UTI caused by Klebsiella pneumoniae, and in 16 of 20 UTI caused by other bacterial species. Thus, 173 of 187 (92.5%) isolates responded to ampicillin therapy in a manner predicted by in vitro susceptibility test results. In vitro susceptibility testing correctly predicted the outcome of therapy with trimethoprim-sulfa in 119 of 138 UTI caused by Escherichia coli, in 33 of 45 UTI caused by Klebsiella pneumoniae, in 38 of 43 UTI caused by Proteus mirabilis, in 21 of 25 UTI caused by Streptococcus spp, in 9 of 11 UTI caused by coagulase-positive staphylococci, and in 19 of 21 UTI caused by other bacterial species. Thus, 239 of 283 (84%) isolates responded to trimethoprim-sulfa therapy in a manner predicted by in vitro susceptibility test results.  相似文献   

13.
On the basis of FAO/WHO tolerance recommendations, slaughtered pigs were divided into groups with gamma-HCH residues ranging from 0.5 to 2.0 mg per kg and with DDT residues ranging between 0.5 and 5.0 mg per kg in fat. Groups with negative residue findings were formed for control. Some parameters of the biological value of lard were determined in pig back fat. The presence of DDT and gamma-HCH residues did not change the melting and congelation points of lard. The acid number was higher by 31%, the saponification number dropped by 2.6%, the iodine number by 7.6%, the level of palmito-oleic acid by 16%, linoleic acid by 15% and linolenic acid by 40% due to the presence of DDT residues in lard. In the lard containing gamma-HCH residues the acid number increased by 42%, the saponification number decreased by 3.6%, the number of 8.1%, the level of palmito-oleic acid by 14%, linoleic acid by 18% and linolenic acid by 30%. It has been inferred from the results that the presence of DDT and gamma-HCH residues in the organism of a pig reduces the biological value of lard owing to the probable alteration of fat metabolism.  相似文献   

14.
In the specialised rearing house for young cattle of all age groups the occurrence of endoparasites was followed. In the age group of 21 to 90 days, 56% of calves aged about 30 days eliminated oocysts of coccidia. On the whole, 49.3% of calves were infested by coccidia, 3% by enterohelminths. 90.3% of calves aged from three to six months were parasitised by coccidia, 7.4% by enterohelminths. Young cattle, aged from 6 to 12 months, were parasitised in 94.6% by coccidia and in 14.1% by enterohelminths. 86.6% of pregnant heifers at the age of 14 to 19 months had coccidia, 7.7% enterohelminths. The total farm capacity was about 950 animals. Throughout the year the number of examined animals amounted to 1,195, out of this number 958 animals, i. e. 80.2%, were infested by coccidia, 55.6% of animals by the species Eimeria bovis, 47.0% by E. zuernii, 43.3% by E. auburnensis, 39.4% by E. ellipsoidalis, 25.2% by E. cylindrica, 13.6% by E. subspherica, 3.1% by E. bukidnonensis, 1.7% by Isospora spp., 0.4% by E. brasiliensis, 0.08% by E. pellita. Enterohelminths were observed only in 96 animals, i. e. in 8.03%. Trichocephalus was found in 3.9% of animals, Cooperia in 2.4%, Ostertagia in 0.6%, Chabertia in 0.4%, Nematodirus in 0.3%, Capillaria in 0.2%, Oesophagostomum in 0.2%, Bunostomum in 0.1% and Trichostrongylus in 0.1%. The highest elimination of oocysts of coccidia was observed in August, January and February, of eggs of enterohelminths from August to October. In all age groups the most frequent was the occurrence of pathogenic species of coccidia.  相似文献   

15.
本研究采用室内盆栽实验,探讨了一种由适量的氮、磷和钠等元素组成的钠复合肥对多浆旱生植物霸王幼苗生长及抗旱性的影响。结果表明,干旱胁迫下施钠复合肥后,与对照和磷酸二铵肥相比,霸王幼苗的株高增加了30%和12%、叶面积增加了97%和40%、叶相对有机干重增加了10%和7%、叶干重增加了57%和38%、叶含水量增加了347%和55%,净光合速率增加了145%和24%、PSⅡ原初光能转换效率增加了6%和4%、电子传递速率增加了16%和8%、量子产额增加了14%和5%,而叶MDA含量下降了58%和18%、相对质膜透性下降了50%和26%。另外,与对照相比,施钠复合肥后霸王幼苗水分利用效率提高了4%。这些结果说明,钠复合肥能够促进干旱胁迫下霸王幼苗的生长、提高其抗旱性,并且效果优于磷酸二铵肥。  相似文献   

16.
中草药饲料添加剂对香猪生长性能和肉质的影响   总被引：2，自引：0，他引：2  
研究了添加不同剂量的中草药饲料添加剂(0.3%和0.4%)对香猪生产性能和肌肉营养组分的影响。结果表明:0.3%和0.4%中草药组的日增重比对照组分别提高了42.98%(P<0.05)和30.06%(P<0.05);料重比分别降低了14.69%(P<0.05)和13.73%(P<0.05)。中草药添加组肉质的pH24值、失水率、粗脂肪、粗蛋白、眼肌面积均显著高于对照组(P<0.05);0.4%中草药组的主要鲜味氨基酸和必需氨基酸含量含量分别较对照组提高了28.37%和28.75%;人体必需脂肪酸中,0.3%和0.4%中草药组较对照组分别提高2.18%和4.36%;不饱和脂肪酸各组中油酸、亚油酸含量最高,0.3%和0.4%中草药组的亚麻酸、亚油酸和花生四烯酸含量分别比对照组提高2.41%、2.67%、3.68%和5.12%、3.51%、19.12%。  相似文献   

17.
牛磺酸对马杜霉素中毒大鼠的保护作用   总被引：1，自引：1，他引：0  
观察牛磺酸对大鼠马杜霉素中毒时的保护作用。将试验大鼠每天灌服马杜霉素进行染毒,且染毒前1 h腹腔注射牛磺酸保护,染毒5 d,继续注射牛磺酸2 d后处死,测定血清、肝脏、腿肌和心肌的丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性、谷胱甘肽过氧化物酶（GSH-Px）活力和总抗氧化能力（T-AOC）。结果表明牛磺酸组的大鼠血清、肝脏、腿肌和心肌中SOD活性、GSH-Px活力、T-AOC均有所提高,MDA有所降低,与对照组、马杜霉素组比较,差异显著（P〈0.01,P〈0.05）。牛磺酸可以提高大鼠机体的抗氧化能力,对马杜霉素引起的脂质过氧化具有保护作用。  相似文献   

18.
The motor cortex was transcranially and peripheral nervous structures (motor roots, plexus, peripheral nerves) were percutaneously stimulated by magnetic pulses in awake dogs and in dogs awaking from general anesthesia. The compound muscle action potentials were recorded by surface or needle electrodes. The central motor conduction time as an information about central motor tracts was obtained by subtracting the peripheral latency from the corticomuscular latency. The peripheral latency was assessed by high voltage electrical and magnetic stimulation of motor roots and by the F-wave technique. The motor conduction velocity of the tibial nerve was measured by percutaneous magnetic and by electrical stimulation and the resulting values were compared.  相似文献   

19.
Because of its widespread use and potential adverse biological effects, bisphenol A (BPA) represents one of the most studied endocrine-disrupting compounds. Within the reproductive system, ovarian granulosa cells have been documented as a target of BPA action, but no consensus has been reached about functional modifications induced by BPA. On these bases, we studied the potential disrupting effects of BPA on the main granulosa cell functional activities, also taking into account a potential interference with the ovarian angiogenic process. Ovarian granulosa cells were isolated from porcine follicles and cultured in the presence or absence of BPA at different concentrations for 48 h. Cell proliferation was studied by measuring adenosine triphosphate content. Progesterone (P4) and estradiol 17β (E2) production was determined by radioimmunoassay. Vascular endothelial growth factor (VEGF) output was quantified by an enzyme-linked immunosorbent assay. Redox status was monitored by measuring superoxide anion and hydrogen peroxide, and by determining the activities of the scavenging enzymes superoxide dismutase, catalase, and peroxidase by colorimetric methods. Granulosa cell proliferation as well as redox status resulted unaffected by BPA. Concentrations of E2 were stimulated by the lower BPA concentration, whereas they were inhibited by the larger doses tested. P4 output was decreased by all BPA concentrations. To the contrary, VEGF production was stimulated. Data indicate that BPA can interfere with reproductive activity by affecting granulosa cell steroidogenesis in vitro; furthermore, BPA can exert a promoting effect on the ovarian angiogenic process by increasing VEGF output in pigs. A disruption of this finely tuned process seems particularly relevant because of the risk of uncontrolled neovascularization.  相似文献   

20.
猪精子RNA提取的初步研究   总被引：1，自引：0，他引：1  
实验采用Trizol一次法或试剂盒提取猪精子的总RNA,然后通过RT-PCR扩增的方法,检测精子和睾丸组织中鱼精蛋白(PRM-1)的mRNA;使用不同数量的精子,检测在本实验条件下能扩增出PRM-1带所需要的最小精子数量;通过OD260/280的测算,判断不同提取方法所得RNA的纯度;通过琼脂糖电泳得到精子RNA与睾丸、卵巢组织RNA的电泳图。实验结果表明:在使用RNA沉淀剂时,1.51×107精子可检测到PRM-1的mRNA,不使用沉淀剂则需要3.02×107精子才检测到;使用Trizol一次法提取的精子总RNA纯度较常规Mini试剂盒(W6221)高;本实验首次得到猪精子总RNA的普通琼脂糖凝胶电泳图。初步研究的结果表明,Trizol一次法可用来提取精子总RNA供进一步研究;猪精子RNA的28S和18S片段与睾丸、卵巢组织无明显差异。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号