Schwarze Wurzelfäule bei Blauen Lupinen – frühzeitige und spezifische Detektion des Erregers Thielaviopsis basicola

Black root-rot, caused by the soil-borne pathogen Thielaviopsis basicola leads to potential problems with a wide range of crops including grain legumes. During the 2007 growing season this pathogen was isolated from naturally infected narrow-leafed lupines (Lupinus angustifolius) in several areas. A first screening of disease resistance performed with a collection of L. angustifolius cultivars indicated a range from highly susceptible to moderate tolerant. In order to accelerate the screening procedure and to improve the identification of field samples a nested PCR-based detection was developed based on pathogen specific primers derived from the internal transcribed spacer regions (ITS) of T. basicola. Tests conducted on a wide range of potential lupin pathogens showed a high T. basicola specificity without any cross-reactions on other fungal pathogens. In more than 80% of the analysed field samples T. basicola-DNA was detected. For further resistance screenings the presented diagnostic test will contribute to an early and specific identification of T. basicola in plants.     

Risk factors for death and unwanted early slaughter in Swiss veal calves kept at a specific animal welfare standard

Calf losses (CL, mortality and unwanted early slaughter) in veal production are of great economic importance and an indicator of welfare. The objective of the present study was to evaluate CL and the causes of death on farms with a specific animal welfare standard (SAW) which exceeds the Swiss statutory regulations. Risk factors for CL were identified based on information about management, housing, feeding, and medication. In total, 74 production cohorts (2783 calves) of 15 farms were investigated. CL was 3.6%, the main causes of death were digestive disorders (52%), followed by respiratory diseases (28%). Factors significantly associated with an increased risk for CL were a higher number of individual daily doses of antibiotics (DDA), insufficient wind deflection in winter, and male gender. For administration of antibiotics to all calves of the cohort, a DDA of 14-21 was associated with a decreased risk for CL compared to a DDA of 7-13 days.     

Investigation of abortions and other animal health problems in relation to vaccination against Bluetongue virus in 2009

By the distribution of a questionnaire between all Swiss cattle practitioners it was possible to investigate abortions and other animal health problems related to Bluetongue vaccination 2009. The questionnaire helped to obtain plausibility and timely relation of the reported disorders. 58 abortions in cattle and different herd health problems could be examined. Because there is no possibility to show that a vaccination itself leads to an abortion the results of proven causes of abortions prior and after Bluetongue vaccination were compared regarding their diagnosis. Due to the fact that diagnosis and solving rate of abortions did not differ before and after vaccination, the vaccination itself cannot be responsible for the abortions. Evaluation of different herd health problems showed that Bluetongue vaccination was not responsible for these disorders which often existed already prior to vaccination. Herd health problems generally have multifactorial causes what makes it difficult to asses the effect of Bluetongue vaccination in some cases.     

The feeding ecology of elaterid larvae in central European arable land: New perspectives based on naturally occurring stable isotopes

To understand soil food webs, empirically generated data on the trophic connections and the feeding ecology of the major below-ground animal taxa are needed. Here we used stable isotope analysis to assess the trophic ecology of wireworms, the larvae of click beetles, in Central European arable land. Wireworms are amongst the major soil macroinvertebrates and are of practical importance in arable soils. Besides feeding on crops, they are thought to feed on weeds, soil organic matter (SOM), and even animal prey, but their feeding ecology is poorly studied under natural conditions. Elaterid larvae and their putative feeding substrates—plant roots, SOM, and litter—were sampled at 17 locations in Austria, Germany, and Italy and their isotope ratios of carbon (¹²C/¹³C) and nitrogen (¹⁴N/¹⁵N) measured to determine the wireworms’ trophic level, the importance of SOM and weeds within the diet of Agriotes larvae, as well as the individual diet variation in Agriotes obscurus larvae. δ¹⁵N signatures suggested that Agriotes larvae are predominately herbivorous, whereas the other wireworm species primarily fed on animal prey. In contrast to SOM, weeds were readily eaten by Agriotes larvae: their dietary contribution ranged between 28% and 67% in weedy maize fields. Most A. obscurus larvae fed on a mixed diet of weeds and maize, although ～15% of the larvae fed primarily on one of the two food sources only. δ¹⁵N signatures indicated that ～10% of the “herbivorous” A. obscurus larvae fed primarily on animal prey, revealing high intraspecific trophic plasticity in these soil insects. Wireworm feeding behaviour is apparently complex at the individual level: the population consists of types A and B generalists, a phenomenon which needs further assessment.     

Acid-base disorders in milk-fed calves with chronic indigestion.

Acid-base disorders were investigated in 50 calves with chronic indigestion and metabolic acidosis. In the calves that were unable to stand up, the acidosis was significantly more severe than in the calves that could stand up. The anion gap and four different components of the base excess were calculated by the method described by Fencl. The anion gap was high in more than half of the calves, and it was significantly associated with the base excess due to unidentified anions. However, in seven of the calves, the excess of unidentified anions would not have been detected without the calculations, which made it possible to measure the effect of sodium, chloride, plasma protein and unidentified anions on the acid-base balance. Twenty-four of the calves had a combination of hyperchloraemic and high anion gap metabolic acidosis. Changes in sodium and plasma protein concentrations had a minor impact on the calves' acid-base status.     

Demonstration of 16-Unsaturated C-19 Steroids ('Boar Pheromones') in Tissues of the Male Camel (Camelus dromedarius)

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Investigations into the role of pheromones in reproductive behaviour have been mainly limited to the boar, with 16-unsaturated C-19 steroids playing a major role. Similarities in the mating behaviour of the camel and pig suggest that pheromones may also be important in the camel. The aim of this study was to determine the concentrations of 16-unsaturated steroids in camel testes and other tissues. Samples of testicular tissue were obtained by castration from six male camels (9–15 years) and 16-unsaturated steroid content was measured by gas–liquid chromatography (GLC). In addition, samples of the glandula occipitalis ('poll gland'), g. parotis, g. submandibularis and the palatal flap ('dulaa') were obtained from a 10-year-old camel and also analysed for steroid content. Results were confirmed by GC-MS (gas-chromatography-mass spectrometry) in selected testicular samples. 5α-androst-16-en-3-one could be detected in all testicular specimen (range 0.05–1.28  μ g/g tissue) as well as in all the other tissues analysed, with highest concentrations in the glandula occipitalis. 5α-androst-16-en-3β-ol was present in most tissues, whereas 5α-androst-16-en-3α-ol was detectable at 0.75  μ g/g only in one testes which also had the highest level of 5α-androst-16-en-3-one. The similarities of these findings to the porcine species suggest a role of 16-unsaturated steroids as pheromones in the camel. Further experimental evidence however, is required to confirm these findings.     

III. Buchbesprechungen

Ohne Zusammenfassung