首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   16篇
  免费   3篇
林业   1篇
综合类   2篇
农作物   1篇
水产渔业   4篇
畜牧兽医   11篇
  2019年   1篇
  2017年   2篇
  2015年   1篇
  2013年   3篇
  2011年   2篇
  2010年   2篇
  2007年   1篇
  2006年   1篇
  2003年   2篇
  1999年   1篇
  1994年   1篇
  1986年   1篇
  1983年   1篇
排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
A total of 315 cattle were tested for infection with Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) at three consecutive samplings, using the interferon-gamma (IFN-gamma) test on whole blood and bacteriological culture of faecal samples. Of 205 cattle from 10 infected herds 99 (48%) were positive in the IFN-gamma test on at least one sampling using "IDEXX-criteria" for interpretation, and of 110 cattle from five non-infected herds three (3%) were positive. Forty-four animals from infected and one from non-infected herds tested positive at all three samplings. Although support for the specificity of the IFN-gamma test was provided by these results, they also indicate problems with false positives. Approximately half of the positive animals did not give the same result at all three samplings, indicating that repeated testing increases the chance of detecting reactors. Changing, or fluctuating, IFN-gamma test results occurred most frequently in animals younger than 1 year, indicating that the IFN-gamma test should be applied only to animals 1 year and older. M. paratuberculosis was isolated from 16 (4%) of 371 cattle, all from infected herds. Fifteen culture-positive cattle tested positive at least once in the IFN-gamma test. It was not possible to predict from the IFN-gamma test result the number of animals that would eventually develop disease. However, the test may be useful to detect animals that have been exposed to M. paratuberculosis earlier in their lives, and the testing of young cattle could be included in a control program to check for the effectiveness of preventing transmission of infection to calves and to identify animals at risk of developing disease later in their lives.  相似文献   
2.
In just two decades, round goby Neogobius melanostomus (Pallas) has dispersed throughout most of the Baltic and the North American Great Lakes. It thrives in shallow sheltered areas, where it is impacting native fauna. In Denmark, researchers, governmental institutions and fishers have joined in an effort to establish a sustainable round goby fishery. To do so, basic information about the movement of round goby is essential, so the movements of 50 round gobies were tracked using acoustic telemetry. The results revealed that activity took place mainly at night and seasonal migrations were common. The most frequent migration behaviour observed was a seaward return migration during winter, which was further confirmed by a snorkel survey. Tracking data also revealed riverine upstream dispersal. The results demonstrate that the round goby can be mapped using telemetry, and it is suggested that fishing for round goby may improve efficiency by targeting seasonal migration corridors.  相似文献   
3.
A newly studied interplanetary dust particle contains a unique set of minerals that closely resembles assemblages in the refractory, calcium- and aluminum-rich inclusions in carbonaceous chondrite meteorites. The set of minerals includes diopside, magnesium- aluminum spinel, anorthite, perovskite, and fassaite. Only fassaite has previously been identified in interplanetary dust particles. Diopside and spinel occur in complex symplectic intergrowths that may have formed by a reaction between condensed melilite and the solar nebula gas. The particle represents a new link between interplanetary dust particles and carbonaceous chondrites; however, the compositions of its two most abundant refractory phases, diopside and spinel, differ in detail from corresponding minerals in calcium- and aluminum-rich inclusions.  相似文献   
4.
In mares, pneumovagina develops because of perineal malconformation. This condition may aggravate to cause vaginitis, cervicitis, and endometritis. In animal models, visceral pain has been associated with genital infections causing hyperalgesia and allodynia in the affected organs. The pain from genital infections may be referred to dermal areas of the hindquarter.The aim of the current clinical case study was to determine whether performance problems attributable to hypersensitivity in dermal areas of the hindquarter, a classic symptom of nymphomania in the mare, may be caused by visceral pain resulting from irritative processes in the reproductive organs. Vulvoplastic surgery (Caslick operation) is a well-known treatment of mares in which poor perineal conformation is the underlying factor of genital infections. The current study is based on clinical examinations and performance of mares with hypersensitivity in dermal areas of the hindquarters before and after Caslick operation.Fourteen mares exhibiting performance problems such as kicking against the rider's legs, bolting, or refusing to move forward were selected for this study. Performance problems or stereotypic behavior were observed either permanently or intermittently during estrus. In 12 of 14 mares (86%), the performance problems were totally eliminated or diminished within 6 months after Caslick operation.The clinically observed performance improvement in the treated mares supports the hypothesis that problems attributable to hypersensitivity in dermal areas of the hindquarters may be caused by irritative processes in the labia vulvae, vestibulum, and vagina of the mare.  相似文献   
5.

Background

Coxiella burnetii is a well-known cause of placentitis and subsequent abortion in ruminants, but there are no reports on the relationship with perinatal mortality. The study was performed to determine the influence of level and change of bulk tank milk (BTM) antibodies to C. burnetii on two outcomes associated with parturition in cattle: a) stillbirth; and b) stillbirth and neonatal mortality combined (perinatal death).

Methods

Twenty-four Danish dairy herds were tested repeatedly for antibodies to C. burnetii in BTM using a commercial ELISA. Samples were collected monthly from July 2008 to July 2009. Information on the 2,362 calvings occurring in the study period was obtained from the Danish Cattle Database. Two multilevel logistic regression models were created for the two outcomes stillbirth and perinatal mortality. One model included the level of BTM antibodies in a specified period before or after the outcome had occurred. The other model included the change in antibodies over time. These predictors were included both at herd and animal level. Furthermore, all models included parity and breed.

Results

The individual monthly BTM antibody levels were highly correlated within herds. Consequently, changes in BTM antibody levels were not found to be associated with neither risk of stillbirth nor the risk of perinatal mortality. However, the risk of stillborn calves and perinatal death was higher with high level of BTM antibodies 8 to 9 months after the incident, but not outside this period.

Conclusion

We conclude that the level of antibodies to C. burnetii in BTM may be associated with perinatal mortality, but the association was not persistent and should be investigated further.  相似文献   
6.
The acute phase protein orosomucoid (ORM) has anti-inflammatory and immunomodulatory effects, and may play an important role in the maintenance of metabolic homeostasis in obesity-induced low-grade inflammation. Even though the pig is a widely used model for obesity related metabolic symptoms, the expression of ORM has not yet been characterized in such pig models. The objective of this study was to investigate the expression of ORM1 mRNA in liver, visceral adipose tissue, subcutaneous adipose tissue (SAT) from the abdomen or retroperitoneal abdominal adipose tissue (RPAT) and SAT from the neck, as well as the serum concentration of ORM protein in three porcine obesity models; the domestic pig, Göttingen minipigs and Ossabaw minipigs.No changes in ORM1 mRNA expression were observed in obese pigs compared to lean pigs in the four types of tissues. However, obese Ossabaw minipigs, but none of the other breeds, showed significantly elevated ORM serum concentrations compared to their lean counterparts. Studies in humans have shown that the expression of ORM was unchanged in adipose tissue depots in obese humans with an increased serum concentration of ORM. Thus in this respect, obese Ossabaw minipigs behave more similarly to obese humans than the other two pig breeds investigated.  相似文献   
7.
During recent years in Denmark higher rates of antibodies to Coxiella burnetii have been detected in animals and humans than previously reported. A study based on bulk tank milk samples from 100 randomly selected dairy herds was performed to estimate the prevalence and geographical distribution of antibody positive dairy herds. Using the CHEKIT Q-Fever Antibody ELISA Test Kit (IDEXX), the study demonstrated a prevalence of 59% antibody positive herds, 11% antibody intermediate herds and 30% antibody negative herds based on the instructions provided by the manufacturer. The geographical distribution does not indicate a relationship between the regional density of dairy farms and the prevalence of antibody positive dairy farms. The result supports the hypothesis of an increase in the prevalence of positive dairy herds compared to previous years.  相似文献   
8.
9.
Cotyledons (n=170) from dairy cattle were analysed for Coxiella burnetii by real-time (rt) PCR targeting the IS1111a and icd genes. Positive cases (n=90) and a random selection of negative cases (n=20) were examined by histology, immunohistochemistry and, if infection level was high, by fluorescence in situ hybridisation. PCR results were compared to bulk tank milk (BTM) antibody levels. Placental infection was detected in cows from herds at all BTM antibody levels. However the likelihood of placental infection was generally higher in herds with intermediate or high BMT antibody levels than in herds with low antibody levels. Histological examination revealed a range of mostly mild cotyledonary changes; C. burnetii infection was only rarely associated with inflammation. This may explain why bovine Q fever is usually not clinically apparent. Nevertheless, infected cattle will shed C. burnetii at calving and this can occur even in herds without BTM antibodies.  相似文献   
10.

Background  

Major changes in climate have been observed in the Arctic and climate models predict further amplification of the enhanced greenhouse effect at high-latitudes leading to increased warming. We propose that warming in the Arctic may affect the annual growth conditions of the cold adapted Arctic charr and that such effects can already be detected retrospectrally using otolith data.  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