Prions are infectious particles causing transmissible spongiform encephalopathies (TSEs). They consist, at least in part, of an isoform (PrPSc) of the ubiquitous cellular prion protein (PrPC). Conformational differences between PrPC and PrPSc are evident from increased beta-sheet content and protease resistance in PrPSc. Here we describe a monoclonal antibody, 15B3, that can discriminate between the normal and disease-specific forms of PrP. Such an antibody has been long sought as it should be invaluable for characterizing the infectious particle as well as for diagnosis of TSEs such as bovine spongiform encephalopathy (BSE) or Creutzfeldt-Jakob disease (CJD) in humans. 15B3 specifically precipitates bovine, murine or human PrPSc, but not PrPC, suggesting that it recognizes an epitope common to prions from different species. Using immobilized synthetic peptides, we mapped three polypeptide segments in PrP as the 15B3 epitope. In the NMR structure of recombinant mouse PrP, segments 2 and 3 of the 15B3 epitope are near neighbours in space, and segment 1 is located in a different part of the molecule. We discuss models for the PrPSc-specific epitope that ensure close spatial proximity of all three 15B3 segments, either by intermolecular contacts in oligomeric forms of the prion protein or by intramolecular rearrangement.

In dairy cattle in Switzerland, the prevalence of infection with Fasciola hepatica is over 16 per cent. Previous studies have suggested that even subclinical infections with liver fluke may induce significant reductions in the performance of cattle. The financial losses attributable to F hepatica were estimated using a simple spreadsheet model to sum the individual losses that have been suggested in the literature. Because there is substantial variability in these production losses, Monte Carlo sampling techniques were used to model this variability. Each cost item and each data item related to the prevalence of F hepatica was assigned a mathematical distribution which took account of the variability of the experimental data and/or the sample size of the data. A total of 10,000 simulations were undertaken, with each item randomly varied through its mathematical distribution on each simulation. The results suggest that the median financial loss due to bovine fasciolosis in Switzerland is approximately 52 million, with probable 95 per cent confidence limits ranging from 22 million to 92 million per annum, which represents a median loss of 299 per infected animal. Most of the losses arise from reduced milk yield and reduced fertility, and smaller losses are due to reduced meat production and the condemnation of livers.

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The purpose of this study was to determine the position, appearance and dimensions of the abomasum of 50 healthy cows by ultrasonography. The ventral abdominal region caudal to the xiphoid process was examined with a 3.5 MHz linear transducer. The abomasum could be visualised from both sides and from the ventral midline of 47 of the cows. The abomasum could be clearly differentiated from adjacent organs because of its contents, which appeared as a heterogeneous, moderately echogenic structure with echogenic stippling. However, the wall of the abomasum appeared, if at all, as a narrow echogenic line. Parts of the abomasal folds were visible occasionally as echogenic structures within the abomasum. Slow movement of the feed in the abomasum was also often visualised. The pylorus was positively identified in only one cow. The cranial margin of the abomasum was situated up to 15 cm caudal to the xiphoid process. The abomasum was between 7.4 and 42.9 cm long, and its maximal extent, measured from the ventral midline to the left, was from 5.0 to 26.0 cm in the cranial region and from 5.0 to 16.0 cm in the caudal region. From the ventral midline to the right, it was from 5.0 to 33.0 cm in the cranial region and from 28.0 to 36.0 cm in the caudal region. The minimal dorsoventral dimension of the abomasum ranged from 0.7 to 7.2 cm, and its maximal dorsoventral dimension ranged from 3.6 to 11.1 cm.

Ultrasonography is an ideal diagnostic tool for the investigation of bovine gastrointestinal disorders, the most common of which are traumatic reticuloperitonitis, left and right displacement of the abomasum, ileus of the small intestine, and dilatation and displacement of the cecum. An ultrasonographic examination is performed on nonsedated, standing cattle using a 3.5 MHz to 5.0 linear or convex transducer. When a tentative diagnosis has been made based on the clinical findings, often only the region in question is examined. For example, in cases with suspected traumatic reticuloperitonitis, the examination is performed in the sternal and parasternal regions, and in cattle suspected of having cholestasis, only the costal part of the abdominal wall on the right side is examined. Even experienced clinicians may not be able to pinpoint the organ affected and make a diagnosis in patients in which abdominal disease is suspected, however. In such cases, both sides of the abdomen are examined. Normally, the reticulum,1,2 spleen,1-4 rumen,2 and parts of the abomasum5,6 are seen on the left side, and the liver,7-9 omasum,10,11 parts of the abomasum,5,6 small intestine,12,13 large intestine,14,15 and right kidney16 are seen on the right. The uterus may be seen on either side depending on the stage of pregnancy. This article describes the ultrasonographic techniques used for examination of the reticulum, rumen, omasum, abomasum, small intestine, and large intestine. The normal findings are presented followed by a description of the most important diseases of these organs.Ultrasonography of the gastrointestinal tract in cattle AbstractUltrasonography is an ideal diagnostic tool for investigating gastrointestinal disorders in cattle. It is performed on standing non-sedated cattle using a 3.5 to 5.0 MHz linear or convex transducer. In animals with traumatic reticuloperitonitis, inflammatory fibrinous changes and abscesses can be imaged. Ultrasonography can be used to assess the size, position and contents of the abomasum. In left displacement of the abomasum, the abomasum is seen