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41.
In Bavaria a BHV-1 eradication program was initiated in 1986 and was changed to a compulsory program in 1998. The eradication success increased progressively from < 50% in 1986 to 87% of the farms in 2002. BHV 1-free farms are controlled by bulk milk serology twice a year along with blood serology in animals that are negative but from herds where positive field virus infected animals are present. All serological tests are performed with an indirect ELISA test, all positive results are confirmed by a gB ELISA. Currently about 100.000 virus infected cattle are in Bavarian herds, approximately 80% of these animals are in heavily infected herds (> 10 infected animals). These herds comprise about 5% of all Bavarian herds. The eradication of the virus in these heavily infected herds is the most diifficult, whereas the prevention of new infections appears controllable. In this review current problems in BHV1 eradication are named and possible improvements are discussed.  相似文献   
42.
Seven field isolates of German origin and the type strain WVU 1853 of Mycoplasma synoviae (MS) were experimentally investigated for their virulence in mycoplasma-free broiler chickens. Two groups of birds were inoculated at 6 days of age with each isolate, one group into the thoracic air sac and the other group intravenously and all surviving birds were examined at necropsy 17 days post inoculation (pi). Groups of negative control birds received sterile Frey's broth medium by intravenous and intra-air sac inoculation, respectively. Variation in virulence was evaluated on the basis of significant differences in incidence, severity and extend of MS-induced airsacculitis and synovitis as well as isolation rates of MS especially from parenchymous organs. All the strains tested were pathogenic but varied in their virulence for broiler chickens. Based on differences of the virulence, the isolates were classified to the categories: (1.) highly virulent, (2.) virulent, (3.) moderately virulent and (4.) slightly virulent. (1) Strains WVU 1853 and 246-91 induced a systemic disease associated with multiple synovitis and bilateral airsacculitis (2) Strains 93-92 and 151-77 induced bilateral airsacculitis similar to WVU 1853 and 246-91 but rarely a systemic disease after exposure by intra-thoracic airsac inoculation. (3) In comparison, strains 27-79, 76-93 and 513-83 caused less frequently airsacculitis and even if, then only at the side of intra-airsac exposure. (4) Strain 91-93 has been found to differ significantly from all the other isolates in its capacity to produce disease independently from the inoculation route. After intravenous inoculation, findings gave no indications for strains with selective tropism to the epithelial membranes of the lower respiratory tract or to those of the joints, tendon sheaths and bursae. However, the presented data of the experiments suggest that the MS strains tested differ in their potential capacity to invade systemically and produce acute septicaemia.  相似文献   
43.
In 2001 and 2002, two field trials were performed by the Plant Protection Service (PPS) of the Landwirtschaftskammer Weser-Ems in Oldenburg and the Institute for Plant Protection of the Bavarian State Research Center for Agriculture (LfL) in Freising respectively to examine the transmission of the bacterial ring rot pathogen of potato (Clavibacter michiganensis ssp. sepedonicus) by haulm cutting. In the experiment conducted by the PPS in Oldenburg a lawn-trimmer was used to simulate haulm cutting, before a bacterial suspension was sprayed on the ends of the cut haulms. Two cultivars (early and late) were tested and also the effect of an additional chemical measure for haulm destruction on the transmission of the pathogen was determined. In the trial performed at the LfL in Freising plots with infected plants for the contamination of the haulm cutter were treated immediately prior to plots with healthy plants. Infections of stems (re-growth) and tubers of the plants were determined by polymerase chain reaction (PCR) and indirect immunofluorescence antibody staining (IFAS). In the trials conducted with the haulm cutter, ring rot could be detected in the re-growth of 60% of the plants derived from healthy tubers 4 weeks after haulm cutting. It was confirmed in a bioassay, that the isolated pathogens were viable and virulent. Although the ring rot pathogen was transmitted to a great extent to the leaf material, no infection of progeny tubers occurred in a total of 450 tested plants. However in general a migration of the transmitted pathogen to the tubers cannot be excluded. Therefore further on it is advisable to clean and disinfect the haulm cutter before each use.  相似文献   
44.
From 1999 to 2001, field trials were carried out to find out weather there is a risk of the causal agent of Bacterial Ring Rot of potato (Clavibacter michiganensis ssp. sepedonicus) to be transmitted to the leaves of healthy potato plants via contaminated machinery and equipment during the vegetation period and if so weather the bacteria are transported into the newly formed tubers. Two methods were chosen. Firstly, a sharp-edged metal bar contaminated with a bacterial suspension was drawn through the leaves of potato plants up to 6 times during the vegetation period. Secondly, a suspension of the pathogen was directly injected into the stems of potato plants. The harvested tubers were tested in all trials, leaves were additionally tested in the trial with the contaminated metal bar. The pathogen was not found in any trial. Therefore the risk for the transmission of the Ringrot agent to the leaves of potato plants with contaminated machinery might be very low.  相似文献   
45.
The determination of minimum inhibitory concentrations by broth microdilution is recommended as method of choice for susceptibility testing of veterinary bacterial pathogens. Accordingly, broth microdilution is used in veterinary routine diagnostic laboratories at a progressive rate. To reduce the costs of susceptibility testing, it is reasonable to develop widely accepted uniform microtitre plate layouts that are produced in large quantities. Such microtitre plate layouts have already been developed and published for the susceptibility testing of pathogens from food-producing animals. However, a microtitre plate layout, especially designed for the testing of bacteria from dogs and cats, should be available, too. The choice of the antimicrobial agents or combinations of antimicrobial agents to be included in a suitable layout should be based on the following criteria: (1) the approval and availability of an antimicrobial agent or combination of agents, (2) known cross-resistances, and (3) availability of approved clinical breakpoints. The latter point is of particular importance for the choice of the numbers of concentrations per antimicrobial agent tested and the range of test concentrations. Taking into account these aspects, a science-based layout proposal for microtitre plates, which are suitable for routine testing of bacteria from dogs and cats, is presented and discussed.  相似文献   
46.
Precision farming technologies allow for collection of large amounts of data from producers' fields. This study used grid-sampling techniques and factor analysis to investigate relationships between several site variables and corn (Zea mays L.) yields on five producer's fields. Sampling positions (112 to 258) were at the intersecting points of grid lines spaced 15 m. Variables measured were soil organic matter, pH, P, K, and NO3-N; residue cover; broadleaf and grass weed control; corn height at two dates, plant population, and grain yield. Correlation and multiple regression analyses showed that some variables were related to corn yields but the variables involved in significant relationships varied among fields. Moreover, the site variables often were highly correlated and the correlations varied among fields. In these conditions multiple regression would be an unreliable analysis tool. Study of covariance relationships among the variables using factor analysis showed that some of the variables measured could be grouped to indicate a number of underlying common factors influencing corn yields. These common factors were soil fertility, weed control, and conditions for early plant growth. Their importance in explaining the yield variability differed greatly among fields. Application of factor analysis to data generated by precision-farming technologies has potential for describing and understanding relationships between measured variables.  相似文献   
47.
Since 1987 penis-inflammation and -prolapse were observed in north-german breeder-geese. Up to 28% of the ganders showed local symptoms. In the females no clinical signs of cloaca-inflammation were seen. The general condition of the birds was good and there was no increased mortality. Egg production and fertility were not influenced. Bacteriological examinations of the altered penis-tissues revealed in different frequency microorganisms belonging to the genera Mycoplasma, Candida, Bacteroides, Clostridium, Streptococcus, Micrococcus, Staphylococcus, Corynebacterium, Escherichia, Proteus and Pseudomonas. Within 70 days only one third of the diseased ganders recovered completely, the others still showed penis-necrosis or -deformation. It is recommended to examine all ganders prior to each sexual season and to eliminate affected birds.  相似文献   
48.
Results of post-mortem and laboratory examinations of broilers sampled randomly or selected by clinical symptoms were compared. The male:female-ratio was in all cases nearly equal for randomly sampled and selected birds. Regarding post-mortem findings, differences dependent on selection criteria were observed: in randomly-sampled birds the frequency of breast-blisters and plantar inflammations was higher than in selected broilers, whereas in the latter osteodystrophy and bursal atrophy were seen more frequently. Alterations of joints and tendon-sheaths caused by a reovirus-arthritis in one flock were seen in same frequency in randomly sampled and selected birds, respectively. Parasitological examinations revealed the highest coccidial lesion scores in selected birds with lameness or slightly retarded growth but when dwarfism birds were included into calculations, there was no significant difference among both groups. Results of bacteriological and serological examinations showed no differences between the groups.  相似文献   
49.
The almost simultaneous initial detections of avian influenza A H5N1 viruses in central Europe in February 2006, at a time devoid of migratory bird activity, raised the question of the origin of these viruses. This report presents molecular data from Europe providing evidence for multiple and spatially overlapping H5N1 introductions into Bavaria, Germany.  相似文献   
50.
Maturation and spawning of blue shrimp Penaeus stylirostris were obtained in hypersaline and turbid water. Results indicate that number of spawnings per female and percentage of viable spawnings are similar to those reported under "standard" conditions by other investigators. However, the number of nauplii produced was 50 to 75% less. A significant correlation was observed between reproductive activity and lunar cycles, showing peak activity at three to four days following new moon. Additionally, working with records of individual females, the number of spawnings per female was found to be extremely variable, with intervals between consecutive spawnings non-uniform. Instead, they tended to group in pairs with less than six days between spawnings, followed by a variable period of time (usually more than 12 days) before the paired spawnings were repeated.  相似文献   
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