Dispersal of vascular plants by game in northern Germany. Part I: Roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis>) and wild boar (<Emphasis Type="Italic">Sus scrofa</Emphasis>)

The endozoochorous and epizoochorous dispersal of vascular plant species by roe deer (Capreolus capreolus) and wild boar (Sus scrofa) was investigated in forest areas of Schleswig-Holstein and Lower Saxony, Germany. The primary aim of this study was to learn about which plant species and in what numbers diaspores are dispersed by the two wild ungulate species. In particular, the significance of zoochory for species composition and biodiversity of forests was evaluated. Fresh faecal pellets were collected from April–November 2001 in the forests of the two study areas. In addition, the coats and hooves of shot roe deer and wild boar were brushed out. The number of viable seeds was determined by greenhouse germination (seedling emergence method). The samples were spread in trays over sterilized soil from the study forests and were kept under controlled conditions in the greenhouse for 12 months. A total of 2,473 individuals from 77 vascular plant species were recorded. While roe deer exceeded wild boar concerning seed contents in the faeces, the significance of roe deer for epizoochorous dispersal was relatively low compared with wild boar. An analysis of the habitat preference of the vascular plant species dispersed by the two ungulate species revealed a high proportion of species growing in forests as well as in the open landscape, and also of non-forest species, while woody plants and herbaceous species closely tied to forest habitats were severely underrepresented. We also discuss consequences for forest ecology and nature conservation.     

A method to provide improved dose-response estimates for airborne pathogens in animals: an example using porcine reproductive and respiratory syndrome virus

This paper describes a method to provide improved probability estimates that exposure to a specific dose of an airborne infectious pathogen will result in animal infection. Individual animals were exposed to a specific dose of airborne pathogen. Following exposure, animals were individually housed and monitored for evidence of infection. The detection of specific antibodies and/or the pathogen in diagnostic specimens was evidence that the exposure dose resulted in infection. If replicated over a range of doses, the results can be used to derive a dose-response curve for a variety of animal species and infectious pathogens. This information is useful in estimating the likelihood of infection associated with exposure to airborne infectious microorganisms. Applications include predicting the risk of transmission associated with exposure to airborne pathogens, modeling the transmission of airborne pathogens, and determining requirements for effective exposure doses for vaccines delivered in aerosols.     

Sensitivity and specificity of cytologic evaluation in the diagnosis of neoplasia in body fluids from dogs and cats

Sensitivity and specificity were determined for the cytologic detection of malignant tumors in canine and feline body cavity effusions. In a prospective study, 424 body cavity effusions from dogs and cats were collected and evaluated, including 70 pleural and 163 peritoneal effusions from dogs, and 77 pleural and 114 peritoneal effusions from cats. Final diagnoses were confirmed in 339 of the 424 cases by clinical follow-up, necropsy, and in the case of malignant tumors, Histopathology. Malignant tumors were found in 18% of canine and 25% of feline body cavity effusions. Approximately one-half of tumors in both dogs and cats were carcinomas. Discrete cell tumors accounted for 56% of feline neoplastic effusions. The sensitivity of cytologic evaluation for the detection of malignant tumors in body cavity effusions was 64% for dogs and 61% for cats. Specificity was 99% for canine and 100% for feline effusions. Sensitivity and specificity were comparable to those obtained with cytologic evaluation of human samples.     

BHV-1 eradication program in Bavaria: a marker-independent strategy

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.     

Instrumented treadmill for measuring vertical ground reaction forces in horses

OBJECTIVE: To develop and validate a novel instrumented treadmill capable of determining vertical ground reaction forces of all 4 limbs simultaneously in horses. SAMPLE POPULATION: Data obtained while a horse was walking and trotting on the treadmill. PROCEDURE: 18 piezo-electric force transducers were mounted between the treadmill frame and supporting steel platform to measure the actual forces at the corresponding bearing points. Each of the 18 sensor forces is equal to the sum of the unknown hoof forces weighted with the transfer coefficients of the corresponding force application points. The 4 force traces were calculated, solving at each time point the resulting equation system, using the Gaussian least-squares method. System validation comprised the following tests: determination of the survey accuracy of the positioning system, determination of the natural frequencies of the system, linearity test of the force transfer to the individual sensors, determination of superimposed forces with the treadmill-integrated force measuring system (TiF) in a static configuration, and comparison of vertical ground reaction forces determined simultaneously by use of TiF and force shoes mounted on the forelimbs of a horse. RESULTS: Comparison between static test loads and TiF-calculated forces revealed deviations of < 1.4%. Force traces of TiF-calculated values and those recorded by use of the force shoes were highly correlated (r > or = 0.998). CONCLUSIONS AND CLINICAL RELEVANCE: This instrumented treadmill allows a reliable assessment of load distribution and interlimb coordination in a short period and, therefore, is suitable for use in experimental and clinical investigations.     

Analytical sensitivity of air samplers based on uniform point-source exposure to airborne Porcine reproductive and respiratory syndrome virus and swine influenza virus

Research and surveillance activities involving airborne pathogens rely on the capture and enumeration of pathogens suspended in aerosols. The objective of this study was to estimate the analytical sensitivity (detection threshold) of each of 4 air samplers for Porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). In a 5-min sampling period under controlled conditions, the analytical sensitivity of the AGI-30 (Ace Glass, Vineland, New Jersey, USA), AGI-4 (Ace Glass), SKC BioSampler (SKC, Eighty Four, Pennsylvania, USA), and Midwest Micro-Tek sampler (Midwest Micro-Tek, Brookings, South Dakota, USA) was calculated at 1 × 10^1.1, 1 × 10^1.3, 1 × 10^1.1, and 1 × 10^1.2 median tissue culture infectious dose (TCID₅₀) equivalents for PRRSV and 1 × 10^1.4, 1 × 10^1.1, 1 × 10^1.6, and 1 × 10^1.2 TCID₅₀ equivalents for SIV [per 60 L (5-min sampling period)]. Despite marked differences in sampler design, no statistically significant difference in analytical sensitivity was detected between the samplers for collection of artificially produced aerosols containing cell-culture-propagated PRRSV or SIV.     

Effects of humus content,farmyard manuring,and mineral‐N fertilization on yields and soil properties in a long‐term trial

Investigations carried out at Field F3 of the Halle long‐term fertilization trials using data from 1974 to 1983 showed that with adequate supply of mineral N‐fertilizer soil organic matter (SOM) had no significant effects of yield. Similarly enhanced SOM did not justify a reduction of mineral N (Stumpe et al., 2000). The studies presented here examine the effects of the SOM differences existing after the termination of those trials in 1986 up until 1997 (then mainly differences of hardly decomposable SOM) in comparison to farmyard manuring with enhanced mineral N application (3‐factor‐experiment). As with total SOM, hardly decomposable SOM did not directly affect yields. The effects of FYM treatment observed at lower mineral‐N levels were compensated for by enhanced mineral‐N supply. The direct effect of FYM (40 t ha^—1) corresponded to a mineral‐N supply of about 60 kg ha^—1 and the residual effect to about 20 kg ha^—1. The differences of the C‐content in the soil at the beginning of the present studies continued throughout the experimental period of 12 years. In addition, significant differentiation has been caused by FYM and N fertilization in comparison to unfertilized treatments. The major finding is that differences in SOM content do not lead to yield differences on physically good soils (chernozem‐like soils) if appropriate compensation by mineral‐N fertilization takes place.     

Changes in the subsoil of long‐term trials in Halle (Saale), Germany,caused by mineral fertilization

Four long‐term mineral fertilization trials (50 years) on a Haplic Phaeozem derived from sandy loess were conducted. Fertilization caused changes to the plough layer (0—25 cm) and to the undisturbed subsoil. Without lime, most remarkable acidification occurred in the plough layer, but only slight effects were evident in the subsoil. Where lime was applied, a considerable amount of Ca‐sulphate was formed. This leached out of the plough layer and accumulated throughout the profile, especially in dry years. Where fertilization was not adequate, there was a substantial contribution of K and P from the subsoil (mainly of its upper parts). Where the supply of these two elements continously exceeded their removal, a distinct increase of available K and P at depths of about 50 cm indicated transfer of both elements to the subsoil. Due to the high fixing capacity of both P and K in layers beneath 50 cm, leaching out of the rooting zone can be ignored. Mg and especially Na, applied with some of the fertilizers, were more mobile than K.     

Verbleib des 15N nach einmaliger Verabreichung von markiertem Düngerstickstoff im Dauerversuch Ewiger Roggenbau Halle

Fate of ¹⁵N after one single application of labelled N fertilizer in the long-term experiment Eternal Rye Cropping Halle To elucidate the fate of N in the long-term field experiment with continuous rye cropping in Halle, Germany (Haplic Phaeozem derived from sandy loess; mean annual precipitation: 466 mm) micro plots (9 m²) were established within the NPK main plot in 1993 and 1994 and the routine N dose (60 kg N ha^—1 a^—1) was once applied as ¹⁵N labelled fertilizer. In the subsequent four years each micro plot was analyzed for the ¹⁵N withdrawn with grain and straw and that remaining in the soil after harvest. Parallel to this, micro plots on the unfertilized main plot received a single dose of 5 kg ha^—1 of high-label ¹⁵N in order to achieve labelling of the annual N input from the air (˜40 kg ha^—1 a^—1) and to follow its fate. — In the NPK treatment about one third of the labelled fertilizer N applied (= *N) was taken up by the rye in the first year, while nearly half of it remained in the soil (0—100 cm), and 10—15% was not recovered (most likely lost via leaching). During the following three years the amount of *N remaining in the soil decreased from 32.7 kg ha^—1 to 21.5 kg ha^—1. However, less than half of the remobilized *N had been taken up by the crop. On the unfertilized plot the uptake of *N was lower at the end of the experiment compared to the NPK plot, while the loss exceeded the comparative figure correspondingly.     

Untersuchungen zur Charakterisierung des pflanzenverfügbaren Phosphats in Thüringer Carbonatböden

Investigations on the characterization of plant available phosphate in Thuringian calcareous soils Phosphate availability in Thuringian calcareous soils and its characterization by CAL‒, NaHCO₃-, H₂O- and CaCl₂-soil tests was investigated in laboratory and pot experiments. Soil CaCO₃ contents > 10% increase the pH value of CAL solution and thus decrease phosphate extractability. The increase of pH also causes an inadequate assessment of plant available phosphate by H₂O- and CaCl₂-soil tests. The CAL soluble P content of the soil corrected by the pH value of the extraction solution was most suitable for the forecast of P uptake of corn in a pot trial. From both parameters P availability indices for calcareous soils can be calculated which are comparable with those in soils containing < 5% CaCO₃. The equation, which still has to be verified in field experiments, reads as CAL-P_corrected = CAL-P_measured · (1 + 0.83·〈pH-value_{CAL solution} — 4.1〉).