Reproductive efficiency of Iceland sheep     

Ó.R Dýrmundsson  S Hallgrímsson 《Livestock Production Science》1978,5(2):231-234

Iceland sheep are found to be relatively early maturing and the level of reproductive efficiency in the flock is raised by breeding from ewe lambs. Ram lambs are normally used for mating. Ewe prolificacy is progressively being increased by genetic selection for a higher lambing rate in conjunction with improvements in feeding. Lamb mortality is kept at a relatively low level by close supervision at lambing and disease control.  相似文献   

First record of Trichinella pseudospiralis in the Slovak Republic found in domestic focus   总被引：4，自引：0，他引：4  

Hurníková Z  Snábel V  Pozio E  Reiterová K  Hrcková G  Halásová D  Dubinský P 《Veterinary parasitology》2005,128(1-2):91-98

Infection of Trichinella spp. is widespread among wildlife in Slovakia and the red fox (Vulpes vulpes) is the main reservoir of Trichinella britovi. Trichinella spiralis has been rarely documented in sylvatic and domestic animals of this country. During routine examination of domestic pigs at the slaughter, Trichinella larvae were detected by artificial digestion in a domestic pig of a large-scale breeding farm in Eastern Slovakia. The parasite has been identified by molecular (PCR) and biochemical (allozymes) analyses and by the morphology of the nurse cell as the non-encapsulated species Trichinella pseudospiralis infecting both mammals and birds. The epidemiological investigation carried out at the farm level revealed the presence of the same parasite species in other three pigs of 192 examined (2.1%), in 3 of 14 (21.4%) examined synanthropic rats (Rattus norvegicus) and in a domestic cat. The farm was characterized by inadequate sanitary conditions, insufficient nutrition, cannibalism and the presence of rat population. A different profile has been observed at the phosphoglucomutase locus in T. pseudospiralis isolates from Slovakia in comparison with the T. pseudospiralis reference isolate from the Palearctic region. This is the first documented focus of T. pseudospiralis from Central Europe. The detection in domestic pigs of a non-encapsulated parasite infecting both mammals and birds stresses the need to avoid the use of trichinelloscopy to detect this infection at the slaughterhouse.  相似文献   

The breakup of a main-belt asteroid 450 thousand years ago     

Nesvorný D  Vokrouhlický D  Bottke WF 《Science (New York, N.Y.)》2006,312(5779):1490

Collisions in the asteroid belt frequently lead to catastrophic breakups, where more than half of the target's mass is ejected into space. Several dozen large asteroids have been disrupted by impacts over the past several billion years. These impact events have produced groups of fragments with similar orbits called asteroid families. Here we report the discovery of a very young asteroid family around the object 1270 Datura. Our work takes advantage of a method for identification of recent breakups in the asteroid belt using catalogs of osculating (i.e., instantaneous) asteroid orbits. The very young families show up in these catalogs as clusters in a five-dimensional space of osculating orbital elements.  相似文献   

金钱槭果实化学成分分析     

石亚娜  王跃虎  郭蓉  张金渝  王元忠  金航  龙春林 《云南农业大学学报(自然科学版)》2012,27(4):600-604

 为研究金钱槭果实中的化学成分,利用各种波谱技术从金钱槭果实乙醇提取物中共分离得到4个三萜类成分（1-4）和一个甾体化合物（5）,利用波谱技术及化学方法将它们分别鉴定为高根二醇 (1)、28-羟基-12-齐墩果烯-3-酮 (2)、高根二醇3-O-棕榈酸酯 (3)、羽扇豆烯酮 (4)和豆甾-4-烯-3-酮 (5),所有化合物均首次从该植物中发现。  相似文献   

Isolation and Functional Analysis of the bZIP Transcription Factor Gene TaABP1 from a Chinese Wheat Landrace     

CAO Xin-you  CHEN Ming  XU Zhao-shi  CHEN Yao- feng  LI Lian-cheng  YU Yue-hua  LIU Yang- na  MA You-zhi 《中国农业科学(英文版)》2012,(10):1580-1591

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低蛋白质饲粮中添加尿素对肉兔消化代谢的影响     

汪水平    杨志鹏  吴洪杰  张丽娜  陈艳青  田兴舟 《动物营养学报》2012,(5):961-967

本试验旨在研究低蛋白质饲粮中添加尿素对肉兔消化代谢的影响。采用单因子随机区组试验设计,选择 ９０只 ５０日龄体重相近的健康新西兰兔,随机分为 ３组,１个对照组和 ２个试验组,每组 １５个重复,每个重复 ２只。对照组饲喂粗蛋白质含量为 １１．１１％的基础饲粮,２个试验组分别饲喂在基础饲粮中以糊化淀粉缓释尿素的方式添加 １％、２％和 ３％尿素的试验饲粮。预试期为 １０ｄ,正试期为 ３０ｄ。正试期的第 １３～１８天收集试验兔排出的全部粪便和尿液。结果表明：与对照组相比,１％尿素组试验兔的有机物表观消化率、总能表观消化率及利用率、沉积氮、氮利用率和消化氮利用率显著或极显著升高（Ｐ＜０．０５或 Ｐ＜０．０１）,而 ２％尿素组试验兔的消化能、代谢能、沉积氮、氮利用率和消化氮利用率显著或极显著降低（Ｐ＜０．０５或 Ｐ＜０．０１）。对照组试验兔盲肠内容物脲酶活性和微生物蛋白浓度显著或极显著低于其余 ２组（Ｐ＜０．０５或 Ｐ＜０．０１）,而 ２％尿素组试验兔盲肠内容物氨氮和尿素氮浓度显著或极显著高于其余 ２组（Ｐ＜０．０５或 Ｐ＜０．０１）。由此得出,低蛋白质饲粮中添加 １％尿素可改善肉兔有机物、总能和氮的利用效率,提高盲肠内容物脲酶活性和微生物蛋白浓度;添加 ２％尿素则会降低肉兔氮的利用效率,提高盲肠内容物脲酶活性及微生物蛋白、氨氮和尿素氮浓度。  相似文献   

Limited genetic diversity of Aerococcus viridans strains isolated from clinical and subclinical cases of bovine mastitis in Slovakia     

Spaková T  Elecko J  Vasil M  Legáth J  Pristas P  Javorský P 《Polish journal of veterinary sciences》2012,15(2):329-335

The Aerococcus viridans isolates from bovine mastitis in Slovakia were isolated and characterized by classical microbiological and biochemical, and molecular techniques including IGS-PCR and rep-PCR, ARDRA and 16S rDNA gene sequencing. The substantial variability of antibiotic resistance patterns was observed. The majority of strains were resistant to beta-lactam antibiotics, the resistance to tetracycline was observed in 3 tested strains, resistance to lincomycin was found in 4 strains and practically all tested strains were sensitive to neomycin and ciprofloxacin. While variable at a phenotypic level, no significant genetic variability among A. viridans isolates was detected by molecular DNA based methods. The data obtained suggest that a few A. viridans strains spread among cow's population in Slovak farms.  相似文献   

Reports on establishing an ex situ site for ‘beautiful’ vavilovia (Vavilovia formosa) in Armenia     

Janna Akopian  Nune Sarukhanyan  Ivan Gabrielyan  Armen Vanyan  Aleksandar Mikić  Petr Smýkal  Gregory Kenicer  Margarita Vishnyakova  Andrey Sinjushin  Natalia Demidenko  Mike Ambrose 《Genetic Resources and Crop Evolution》2010,57(8):1127-1134

Vavilovia (Vavilovia Fed.) is one of the five genera in tribe Fabeae and consists of only one species, ‘beautiful’ vavilovia (Vavilovia formosa (Stev.) Fed.). The main centre of distribution is the Central and Eastern Caucasus, with a disjunct distribution among high alpine areas in the region, extending as far as West Turkey, Lebanon and Iran. In Armenia, in situ studies on Vavilovia started in the late 1930s. In July and August 2009, three expeditions were conducted to two locations: two to the Ughtasar Mountain and one to the Geghama Mountains. The first expedition to Ughtasar resulted in fresh plant collections and soil analysis for one of the sites. The expedition to Geghama established the existence of Vavilovia in the region of Lake Aknalitch. The second expedition to Ughtasar provided immature fruits and seeds. Collected plant material was transplanted into the Flora and Vegetation of Armenia plot of the Yerevan Botanic Garden established in 1940. Today, along with other plants the plot contains more than 200 species of wild relatives of cultural plants from 130 genera, including indiginous species of tribe Fabeae such as Vavilovia. The transplanted plants will continue to be monitored to see if the plants go on to successfully flower and set seed or whether further sites, possibly at higher altitudes might need to be tested to meet the long term conservation requirements of this iconic legume. These co-ordinated efforts provide a good example of an ex situ conservation strategy for Vavilovia formosa, which, if successful will improve access and utility for the whole legume research community.  相似文献   

Stable isotopes and gut contents indicate differential resource use by coexisting asp (Leuciscus aspius) and pikeperch (Sander lucioperca)          下载免费PDF全文

Mojmír Vašek  Antti P. Eloranta  Ivana Vejříková  Petr Blabolil  Milan Říha  Tomáš Jůza  Marek Šmejkal  Josef Matěna  Jan Kubečka  Jiří Peterka 《Ecology of Freshwater Fish》2018,27(4):1054-1065

Differential use of habitat and prey resources is an important mechanism that may allow coexistence of sympatric species. Unlike interactions between smaller cyprinid and percid fishes, the resource use by coexisting predatory asp (Leuciscus aspius) and pikeperch (Sander lucioperca) is relatively unknown. Here, gut content and stable isotope analyses were used to study ontogenetic dietary shifts and interspecific trophic niche overlap between asp and pikeperch coexisting in two reservoirs. The hypothesis that both species show an ontogenetic dietary shift from small invertebrates to large fish prey, but at the same time use different prey resources to reduce potential competitive interactions, was validated. The isotopic niches of the two predators showed no, or only a moderate, degree of overlap (0%–65%). The ontogenetic changes in the degree of interspecific isotopic niche overlap were different in the two reservoirs, suggesting that trophic segregation can be dynamic and variable among systems. Gut contents revealed that small (<100 mm standard length) asp consumed mostly terrestrial invertebrates and emerged aquatic insects, whereas small pikeperch foraged on zooplankton, larval and pupal stages of aquatic insects and fish. Larger individuals (>100 mm) of both species were predominantly piscivorous, with asp consuming more cyprinid prey and pikeperch more percid prey. Coexisting asp and pikeperch populations are able to utilise different prey resources, thereby reducing potential negative competitive interactions.  相似文献   

Detection of enzootic nasal tumor virus (ENTV) in a sheep flock in southern Brazil     

de Cecco  Bianca Santana  Lorenzett  Marina Paula  Henker  Luan Cleber  Weber  Matheus Nunes  Moséna  Ana Cristina Sbaraini  Baumbach  Letícia  Canal  Cláudio Wageck  Driemeier  David  Pavarini  Saulo Petinatti  Sonne  Luciana 《Tropical animal health and production》2019,51(7):2095-2098

Enzootic nasal tumor (ENT) is a contagious neoplasm associated with enzootic nasal tumor virus (ENTV), which may induce disease in sheep (ENTV-1) and goats (ENTV-2). This study aimed to describe the occurrence of ENT in two Texel sheep (Ovis aries) from a 75-sheep flock, located in the city of Gravataí, southern Brazil. Animals used to be purchased from different origins, and no specific tests for disease monitoring or quarantine procedure were performed. Affected animals presented respiratory distress, anorexia with severe weight loss, and mucopurulent unilateral nasal discharge. Necropsy was performed in both animals and nasal cavity masses were observed. Histopathological analysis demonstrated an epithelial neoplasm compatible with nasal adenocarcinoma. PCR using a protocol that amplifies a 591 bp sequence of 5’LTR-gag region of ENTV1 was performed followed by DNA sequencing. Both samples were positive, and the sequences obtained presented highest identity (97%) with ENTV strain TN28 (GenBank accession number MH899613) detected in a Texel sheep from Scotland. This is the first report of ENTV-1 leading to enzootic nasal tumor in sheep in Latin America, which confirms the presence of the retrovirus in sheep flocks in the Brazilian territory.

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