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桑树的遗传变异特点及在品种选育中的应用 总被引：1，自引：0，他引：1
我国具有悠久的桑树栽培历史,拥有3 000余份桑树种质资源,分属15个桑种和4个变种,并逐渐形成适应不同生长环境的8个生态类型。依据已有的研究结果,综述桑树遗传变异的特点包括:广泛分布、自然有性杂交和异花授粉以及缺乏稳定性选择等,促进了桑树的突变发生,形成遗传变异的多样性;无性繁殖方式产生了丰富的无性系变异;性状遗传值中非加性效应占有较大比例;无性系品种间杂种一代存在复杂的多样性分离和经济性状的普遍退化;存在丰富的多倍体系列和普遍的混倍现象等。对桑树品种选育研究提出建议:基于桑树的高度杂合习性,不仅要重视研究不同品种中加性效应在遗传值中所占比率,更要研究非加性效应所占比率及充分利用的方法;基于桑树遗传变异的多样性和丰富的无性系变异,加强无性系和田间选优育种;利用桑树混倍现象,将培育多倍体特别是三倍体品种作为一条有效的多倍体育种途径。 相似文献
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Ismail Saidi Selemani Lars Olav Eik Øystein Holand Tormod Ådnøy Ephraim Mtengeti Daniel Mushi 《Livestock Science》2013,157(1):173-183
The study was conducted to assess the effects of seasonal variation in the quality and quantity of pasture and management of livestock exclosures (ngitili) on the grazing behavior of cattle and goats. The study was 2×2×2 factorial design with three independent variables: season (Dry or Rainy), ngitili management (Private or Communal) and animal species (Cattle or Goats). Focal and scan observation methods were used to record different behavioral activities. Vegetation attributes from the study areas were measured in two consecutive seasons. Most key forage species had significant higher crude protein (CP) content and in vitro organic matter digestibility (INVOMD) in rainy than in dry season (P<0.05), but Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) did not vary significantly with season (P>0.05). ADF and NDF were significantly higher in species from communal ngitili than those from private ngitili (P<0.05). Above-ground herbaceous biomass and bulk density (BD) were significantly higher in the rainy season and in the private ngitili than in the dry season and in the communal ngitili respectively. Cattle and goats spent considerably more time grazing and browsing respectively in the rainy season than in the dry season (P<0.05). Cattle foraging activities did not vary significantly (P>0.05) with ngitili management, but goats found to spend considerably more time browsing in the communal ngitili and more time grazing in the private ngitili (P<0.05). Despite the merits of stocking cattle and goats together in the heterogeneous pasture, seasonal variation in forage resources requires investigation of other strategies such as use of multipurpose trees and treatment of crop residues to improve livestock production. 相似文献
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胰腺周围脂肪组织和腺泡坏死被认为是急性胰腺炎(Acute pancreatitis,AP)的主要病理特征。胰腺炎轻者不累及其他器官,无并发症,为自限性疾病;重者胰腺出血、坏死、多器官功能衰竭,出现并发症,危及生命。近年来,胰腺炎在犬和猫中发病率非常高,而且病程一般是由急性期转至慢性期,由轻微转至严重。对其发病原因及其发病机制知之甚少,国内外兽医相关文献鲜有报道。论文参考大量研究文献并结合临床经验,综述该病的发病原因和发病机制,以期为临床预防和治疗提供思路。 相似文献
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The study deals with the situation regarding housing of dogs and cats in Swiss shelters and kennels. In shelters, dogs were mainly held inside a cubicle with a small outside yard. In kennels, housing of dogs took place mainly in inside rooms. Usually two or three dogs were kept together. Cats were held in rooms, with or without outside yards, mainly in groups; no establishment preferred exclusively the housing in cubicles. Shelters received on average 183 dogs and 262 cats each year. Among them, about a third were lost animals while the remaining ones were relinquished. The study highlights some possibilities for improvements and the great diversity of the establishments regarding their size, infrastructure, housing conditions and aims. 相似文献
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Pinard CL Weiss ML Brightman AH Fenwick BW Davidson HJ 《American journal of veterinary research》2003,64(1):104-108
OBJECTIVE: To evaluate lactoferrin and lysozyme content in various ocular glands of bison and cattle and in tears of bison. SAMPLE POPULATION: Tissues of ocular glands obtained from 15 bison and 15 cattle and tears collected from 38 bison. PROCEDURE: Immunohistochemical analysis was used to detect lysozyme and lactoferrin in formalin-fixed, paraffin-embedded sections of the ocular glands. Protein gel electrophoresis was used to analyze ocular glands and pooled bison tears by use of a tris-glycine gel and SDS-PAGE. Western blotting was used to detect lactoferrin and lysozyme. RESULTS: Immunohistochemical staining for lactoferrin was evident in the lacrimal gland and gland of the third eyelid in cattle and bison and the deep gland of the third eyelid (Harder's gland) in cattle. Equivocal staining for lactoferrin was seen for the Harder's gland in bison. An 80-kd band (lactoferrin) was detected via electrophoresis and western blots in the lacrimal gland and gland of the third eyelid in cattle and bison, Harder's glands of cattle, and bison tears. An inconsistent band was seen in Harder's glands of bison. Lysozyme was not detected in the lacrimal gland of cattle or bison with the use of immunohistochemical analysis or western blots. Western blots of bison tears did not reveal lysozyme. CONCLUSIONS AND CLINICAL RELEVANCE: Distribution of lactoferrin and a lack of lysozyme are similar in the lacrimal gland of cattle and bison. Differences in other tear components may be responsible for variability in the susceptibility to infectious corneal diseases that exists between bison and cattle. 相似文献
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试验系统探讨了猪卵母细胞的体外成熟和孤雌激活方法。结果表明:在成熟液中分别添加FSH(促卵泡素:0.1ng/mL)和hMG(人绝经期促性腺激素:0.01IU/mL)的卵母细胞成熟率差异显著,但2组间的分裂率和囊胚率差异不显著。在成熟液中添加0、10、30、50、70ng/mL或90ng/mL的EGF(表皮生长因子),50ng/mLEGF组的分裂率达到84.90%,囊胚率达到30.20%,显著高于其余各组。分别使用以TCM-199和NCSU-23为基础液的成熟液来成熟培养猪卵母细胞,NCSU-23组的分裂率,成熟率和囊胚率均高于TCM-199组。使用离子酶素激活方法和电激活方法进行对比,离子酶素激活后孤雌胚胎发育效果好,差异极显著(P<0.01)。 相似文献
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[目的]调查新疆奎屯地区7 个规模化牧场奶牛副结核病的感染情况,提供科学有效防控措施。[方法]2019—2021年持续对奎屯地区7 个规模化牧场长期、顽固性腹泻牛只采集血液分离血清,使用ELISA检测法进行副结核病的检测。[结果]2019年总阳性率为6.55%（636/9 715）,2020年总阳性率为6.80%（705/10 375）,2021年总阳性率为5.23%（615/11 753）。[结论]检疫加淘汰的方法对降低牧场副结核病的阳性率有较好效果。 相似文献
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喻明辉 《畜牧兽医科学(电子版)》2021,(5):169-170
目前肉制品的健康情况备受人们关注,而猪肉是人们餐桌上必不可少的肉制品之一,猪只的安全饲养对人类的生命健康有重要的影响。在饲养猪只中,可发生多种传染病,其中最主要的一种是非洲猪瘟,该传染病不仅具有高热性的特点,还具有高度接触性的特点,再加上目前对于该种疾病还没有特效的疫苗,以及有效的治疗措施,因此,做好该种疾病的预防工作至关重要。该文主要论述非洲猪瘟进行论述,并制定相应的防控措施。为减少猪只发病几率奠定良好的基础。 相似文献
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Siamudaala VM Bwalya JM Munang'andu HM Munag'andu HM Sinyangwe PG Banda F Mweene AS Takada A Kida H 《The Japanese journal of veterinary research》2006,54(1):15-23
Anthrax is endemic in Western and North-western Provinces of Zambia. The disease occurs throughout the year and impacts negatively on the economy of the livestock industry and public health in Zambia. During 1989-1995, there were 1626 suspected cases of anthrax in cattle in Western province and of these 51 were confirmed. There were 220 cases of human anthrax cases in 1990 alone and 248 cases during 1991-1998 with 19.1% and 7.7% case fatality rates, respectively. Interplay of the ecology of affected areas and anthropogenic factors seem to trigger anthrax epidemics. Anthrax has drawn considerable attention in recent years due to its potential use as a biological weapon. In this paper, the history, current status and approaches towards the control of the disease in Zambia are discussed. Quarantine measures restrict trade of livestock and exchange of animals for draught power resulting in poor food security at household levels. Challenges of anthrax control are complex and comprise of socio-political, economical, environmental and cultural factors. Inadequate funding, lack of innovative disease control strategies and lack of cooperation from stakeholders are the major constraints to the control of the disease. It is hoped that the information provided here will stimulate continued awareness for the veterinary and medical authorities to maintain their surveillance and capabilities against the disease. This may lead to a culminating positive impact on livestock and human health in the southern African region. 相似文献
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b. bengtsson s-o. jacobsson j. luthman & a. franklin 《Journal of veterinary pharmacology and therapeutics》1997,20(4):258-261
Concentrations of penicillin-G in serum were determined after single intravenous doses of potassium penicillin-G (10 mg/kg body wt) to ewes and cows in late pregnancy and in early lactation. Penicillin-G in serum was analysed by a microbiological method and pharmacokinetic parameters were calculated by model-independent methods. Serum concentrations were lower in early lactation than in late pregnancy in both ewes and cows. The differences were statistically significant at most sampling times in ewes but only during the first hour in cows.
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug. 相似文献
Weight corrected values of clearance and volume of distribution were significantly higher in early lactation than in late pregnancy in both ewes and cows. Mean residence time and elimination-half life were shorter in lactating than in pregnant ewes, however for the latter parameter the difference was not statistically significant. Neither of these parameters changed in cows.
It is concluded that in both ewes and cows pharmacokinetic parameters of penicillin-G are altered from late pregnancy to early lactation but that these changes have little practical impact and do not call for a revised dosage regime of the studied drug. 相似文献
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内生真菌在我国部分国产和引进禾草品种的幼苗及成株中的分布 总被引：6，自引：0，他引：6
对已知种带内生真菌的部分国产和引进的禾草品种通过盆栽及幼苗检验，确定了内生真菌的生产力，同时调查了内生真菌在兰州市城区部分草坪绿地中的分布。结果表明，采自我国新疆阿勒泰地区的布顿大麦草种子中的内生真菌具高活力，幼苗侵染率为８１．５％，而其余受检国产禾草种的种子均已丧失发芽力，未能进行幼苗检验。自美国引进的黑麦草品种的种样中的内生真菌均具生活力，已全部在幼苗中检出，侵染率为５．６％￣５０％。调查的兰 相似文献
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兰州地区苜蓿和红豆草根际溶磷菌筛选及菌株部分特性研究 总被引：6，自引：1，他引：5
利用溶磷圈法对苜蓿和红豆草根际不同部位溶磷细菌进行了分离,共获得分离物386个,其中137个具有溶磷能力.苜蓿和红豆草根际不同部位溶磷菌数量分布有差异.其数量为RS>RP>NRS>HP.对筛选获得的12株溶磷圈较大的菌株进行菌落形态特征观察发现,大多数菌落呈灰白色或乳白色、不规则、半透明、边缘不整齐、突起、无光泽、无色素.进一步利用钼蓝比色法对菌株分解磷矿粉能力测定显示,各菌株分解磷矿粉能力差异较大,溶磷量最大为338.4mg/ml,最小为25.9mg/ml,这与其自身溶磷机制有关.溶磷量与菌株培养液pH值之间存在显著相关性.12株菌株大部分具有分泌IAA的能力,其中LM6和LH9分泌IAA能力较强. 相似文献
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