Piet Deprez

Protection of just weaned pigs against infection with F18+Escherichia coli by non-immune plasma powder

The anti-colonization effect of porcine plasma powder against experimentally induced postweaning diarrhoea and oedema disease in just weaned piglets was examined. Piglets were infected with an Escherichia coli strain expressing F18ac fimbriae and producing SLTIIv- and LT-toxins. Reduced fecal excretion of the challenge strain and protection against clinical symptoms was obtained by daily supplementation of the feed with either 90 or 45 g of plasma powder. However, the piglets receiving 90 g of plasma powder a day showed diarrhoea and reduced weight gain compared to the piglets receiving 45 g of plasma powder a day. The diarrhoea was attributed to biogenic amines released from excessive protein in the diet.

Prospective study on quantitative and qualitative antimicrobial and anti-inflammatory drug use in white veal calves

OBJECTIVES To document and quantify drug use in white veal calves, an intensive livestock production system where multidrug resistance is abundantly present. METHODS Drug consumption data were prospectively collected on 15 white veal production cohorts (n = 5853 calves) in Belgium (2007-09). Treatment incidences (TIs) based on animal defined daily dose (ADD), prescribed daily dose (PDD) and used daily dose (UDD) were calculated. Risk factors were identified by linear regression. RESULTS The average TI(ADD) of antimicrobial treatments was 416.8 ADD per 1000 animals at risk. Predominantly, oral group antimicrobial treatments were used (95.8%). Of the oral group antimicrobial treatments, 12% and 88% were used for prophylactic or metaphylactic indications, respectively. The main indication for group and individual drug use was respiratory disease. The most frequently used antimicrobials (group treatments) were oxytetracycline (23.7%), amoxicillin (18.5%), tylosin (17.2%) and colistin (15.2%). Deviations from the leaflet dosage recommendations were frequently encountered, with 43.7% of the group treatments underdosed (often oxytetracycline and tylosin to treat dysbacteriosis). In 33.3% of the oral antimicrobial group treatments a combination of two antimicrobial preparations was used. Smaller integrations used more antimicrobials in group treatments than larger ones (P < 0.05); an integration is defined as a company that combines all steps of the production chain by having its own feed plant and slaughterhouse and by placing its calves in veal herds owned by producers that fatten these calves for this integration on contract. Producers used higher dosages than prescribed by the veterinarian in cohorts with a single caretaker (P < 0.01). CONCLUSIONS The present study provided detailed information on the intensive antimicrobial use in the white veal industry. Reduction can only be achieved by reducing the number of oral group treatments.

Chicken egg yolk antibodies against F18ab fimbriae of Escherichia coli inhibit shedding of F18 positive E. coli by experimentally infected pigs

F18ab and F18ac are antigenic variants of a colonizing fimbria commonly found on E. coli associated with postweaning diarrhea and edema disease in pigs. Chicken F18ab antibodies were obtained by immunising hens with purified F18ab fimbriae. For their in vitro characterisation antibodies were isolated from diluted egg yolks by ammonium sulfate precipitation. In vitro adhesion tests demonstrated that the chicken F18ab antibodies inhibited attachment of F18ab positive E. coli bacteria to the intestinal mucosa. Just weaned piglets were experimentally infected with an F18ab positive edema disease strain of E. coli, or with an F18ac positive postweaning diarrhea E. coli strain. The animals were infected on the second day of a period during which chicken F18ab antibodies were added to their feed. During the same period, pigs of the control group received commercial eggs in which no F18 antibodies were detected. In both experimental infections the excretion of the F18 positive strain was reduced in pigs that received the F18ab antibodies as compared to the control animals. The F18ab antibodies diminished the cases of diarrhea and death in animals infected with F18ac positive E. coli.

Risk Factors for Equine Postoperative Ileus and Effectiveness of Prophylactic Lidocaine

BACKGROUND Postoperative ileus (POI) is a frequent and often fatal complication of colic surgery. Reliably effective treatments are not available. OBJECTIVES To determine risk factors and protective factors associated with POI, and to assess the effect of lidocaine IV on short-term survival. ANIMALS One hundred and twenty-six horses that underwent small intestinal colic surgery and that survived for at least 24 hours postoperatively. METHODS Retrospective cross-sectional study. The association of 31 pre-, intra-, and postoperative variables with POI and the association of lidocaine treatment with short-term survival were investigated. Associations were evaluated with univariable logistic regression models, followed by multivariable analysis. RESULTS Significant associations of high heart rate (odds ratio [OR] = 1.05, 95% confidence interval [CI] 1.03-1.08), the presence of more than 8 L of reflux at admission (OR = 3.02, 95% CI 1.13-8.02) and the performance of a small intestinal resection (OR = 2.46, 95% CI 1.15-5.27) with an increased probability of POI were demonstrated. Prophylactic lidocaine treatment was significantly associated with a reduced incidence of POI (OR = 0.25, 95% CI 0.11-0.56). Lidocaine treatment was also significantly associated with enhanced short-term survival (OR = 0.30, 95% CI 0.09-0.98). CONCLUSIONS AND CLINICAL IMPORTANCE The variables associated with an increased risk of POI can be useful in identifying horses at risk of POI and in providing a more accurate prognosis. The results are supportive for lidocaine IV as an effective prokinetic treatment after small intestinal colic surgery.

Different kinetic of antibody responses following infection of newly weaned pigs with an F4 enterotoxigenic Escherichia coli strain or an F18 verotoxigenic Escherichia coli strain.

To develop a vaccine against Escherichia coli-induced post-weaning diarrhea and edema disease, insights in the induction of the protective immune response following infection with these pathogenic E. coli is needed. Therefore, the fimbriae-specific antibody response of newly weaned pigs following infection with the Shiga-like toxin type II variant (SLT-IIv) producing F18(+) verotoxigenic E. coli (VTEC) (strain 107/86) was compared with the response following an infection with LT producing F4(+) enterotoxigenic E. coli (ETEC) (strain GIS 26). F4(+) ETEC were able to colonize the gut very soon after infection, as peak excretion of F4(+) E. coli bacteria was seen 2 days post-infection (dpi), but had already disappeared 7dpi. On the other hand, F18(+) VTEC infection resulted in a slower colonization of the gut as the peak excretion of F18(+) E. coli was observed between 3 and 5dpi, but this colonization remained longer as F18(+) E. coli were detected till 9dpi in feces. Furthermore, this fast colonization pattern of F4(+) ETEC is accompanied with the presence of F4-specific antibodies in mucosal tissues and serum from 4dpi onward, with maximal amounts of F4-specific IgA in the jejunal lamina propria and serum 7dpi. In contrast, F18-specific IgA was only readily detected in the jejunal lamina propria 15dpi and showed a maximum serum titer 21dpi. Besides this faster induction and higher antibody response, the switch from IgM to IgA and IgG was also earlier following the F4(+) ETEC infection.

Transcranial magnetic stimulation: review of the technique, basic principles and applications.

Transcranial magnetic stimulation is rapidly developing as a powerful, non-invasive tool for studying the descending motor tracts in humans. The applications of the test in animals are for the moment restricted to small animals. However, this non-invasive, sensitive and painless technique appears promising as a test of motor tract function in horses where the neurological examination is mainly restricted to clinical evaluation and some ancillary tests, such as radiography, cerebrospinal fluid analysis and electromyography. In this review, we want to discuss the history, basic principles, technique and applications of transcranial magnetic stimulation in humans and small animals and indicate the possibilities for its use in horses. Since the great portion of this review is based on human studies, it is worthwhile to mention that the reports being described are from humans unless otherwise specified.

Pharmacokinetics of Acyclovir after Intravenous Infusion of Acyclovir and after Oral Administration of Acyclovir and Its Prodrug Valacyclovir in Healthy Adult Horses

ABSTRACT The purpose of this study was twofold. The first aim was to evaluate the oral bioavailability and pharmacokinetics (PKs) of acyclovir in horses after intravenous (i.v.) administration and after oral administration of acyclovir and its prodrug, valacyclovir. Second, we aimed to combine these PK data with pharmacodynamic (PD) information, i.e., 50% effective concentrations (EC50 values) from in vitro studies, to design an optimal dosage schedule. Three treatments were administered to healthy adult horses: 10 mg of acyclovir/kg of body weight delivered as an i.v. infusion over 1 h, 20 mg of acyclovir/kg administered as tablets by nasogastric intubation, and 20 mg of valacyclovir/kg administered as tablets by nasogastric intubation. Total plasma concentrations were measured by a high-performance liquid chromatography method combined with fluorescence detection, while unbound plasma concentrations were determined by liquid chromatography-tandem mass spectrometry. The peak concentration of i.v. acyclovir was approximately 10 μg/ml for both the total and the unbound plasma concentrations. The mean half-life of elimination was between 5.05 h (total concentration) and 11.9 h (unbound concentration). Oral administration of acyclovir resulted in low maximum concentration in plasma (Cmax) and poor bioavailability. A 10-times-higher Cmax and an 8-times-higher bioavailability were achieved with oral administration of valacyclovir. The i.v. administration of 10 mg/kg acyclovir and the oral administration of 20 mg/kg valacyclovir achieved concentrations within the sensitivity range of equine herpesvirus type 1 (EHV-1). The higher bioavailability of valacyclovir makes it an attractive candidate for the prophylactic and/or therapeutic treatment of horses infected with EHV-1. The results from the PK/PD modeling showed that a dosage of 40 mg/kg valacyclovir, administered three times daily, would be sufficient to reach plasma concentrations above the EC50 values.

Application of the restricted-access precolumn packing material alkyl-diol silica in a column-switching system for the determination of ketoprofen enantiomers in horse plasma.

The group of LiChrospher ADS (alkyl-diol silica) sorbents that make part of a unique family of restricted-access materials, have been developed as special packings for precolumns used in the LC-integrated sample processing of biofluids. The advantage of these sorbents lies in the direct injection of untreated biological fluids, that is without sample clean-up, the elimination of the protein matrix with a quantitative recovery together with an on-column enrichment. The present method is based on previous work applying UV detection at 260 nm for ketoprofen determinations. Plasma samples introduced to the ADS precolumn using a 0.1 M phosphate buffer, pH 7.0. After washing with the buffer the ADS column was backflushed with the mobile phase 0.01 M phosphate buffer-6% (v/v) 2-propanol-5 mM octanoic acid at a pH of 5.5, thus transporting the analytes to the chiral-HSA (human serum albumin) (100x4.0 mm) column where the separation of the ketoprofen enantiomers was achieved with a resolution factor of 1.4. The developed column-switching method was fully applicable to plasma injections.

Longitudinal study on morbidity and mortality in white veal calves in Belgium

BackgroundMortality and morbidity are hardly documented in the white veal industry, despite high levels of antimicrobial drug use and resistance. The objective of the present study was to determine the causes and epidemiology of morbidity and mortality in dairy, beef and crossbred white veal production. A total of 5853 calves, housed in 15 production cohorts, were followed during one production cycle. Causes of mortality were determined by necropsy. Morbidity was daily recorded by the producers.ResultsThe total mortality risk was 5,3% and was significantly higher in beef veal production compared to dairy or crossbreds. The main causes of mortality were pneumonia (1.3% of the calves at risk), ruminal disorders (0.7%), idiopathic peritonitis (0.5%), enterotoxaemia (0.5%) and enteritis (0.4%). Belgian Blue beef calves were more likely to die from pneumonia, enterotoxaemia and arthritis. Detection of bovine viral diarrhea virus at necropsy was associated with chronic pneumonia and pleuritis. Of the calves, 25.4% was treated individually and the morbidity rate was 1.66 cases per 1000 calf days at risk. The incidence rate of respiratory disease, diarrhea, arthritis and otitis was 0.95, 0.30, 0.11 and 0.07 cases per 1000 calf days at risk respectively. Morbidity peaked in the first three weeks after arrival and gradually declined towards the end of the production cycle.ConclusionsThe present study provided insights into the causes and epidemiology of morbidity and mortality in white veal calves in Belgium, housed in the most frequent housing system in Europe. The necropsy findings, identified risk periods and differences between production systems can guide both veterinarians and producers towards the most profitable and ethical preventive and therapeutic protocols.

Haemorrhagic diathesis in neonatal calves: an emerging syndrome in Europe.

In 2008 and 2009 a large number of cases of haemorrhagic diathesis (HD) in neonatal calves were reported in different European countries. In Flanders, 84 cases of neonatal HD in 30 herds were reported in this period. The disease typically affects calves younger than 1 month old from different breed and gender. Prominent clinical signs are cutaneous bleeding, petechiae on all mucosae, melena and often high fever. Early in the disease, the mental state of the animals is uncompromised. The typical haematological finding is pancytopenia, with severe to complete thrombocytopenia being the cause of the increased susceptibility to bleeding. In seven of the affected herds blood samples of calves of the same age group as the clinical case were collected and on six of those farms at least one subclinical case could be identified. Necropsy findings were generalized petechiae, ecchymoses or haemorrhages and variable lymphadenopathy. Histopathology of haemorrhagic lesions revealed multifocal extravasation of red blood cells (haemorrhage) with preservation of tissue architecture and absence of other abnormalities. Total bone marrow aplasia and depletion of all lymphoid tissue was the most prominent finding on histology. Activated macrophages and haemophagocytosis were seen on bone marrow cytology from two live calves. Polymerase chain reaction for bovine viral diarrhoea virus, bluetongue and epizootic haemorrhagic disease virus was negative. Several attempts to isolate a viral agent were unsuccessful.