Analysis of risk factors for the occurrence of feather pecking in laying hen growers

1. Potential risk factors for the occurrence of feather pecking in laying hen growers raised under commercial conditions were investigated on Swiss farms with more than 500 rearing places. On-farm interviews were conducted on a sample of 64 flocks which represented 42.6% of all farms concerned. 2. All variables considered were dichotomised and their univariate correlation with the occurrence of feather pecking was tested for significance at P <0.20 using chi2 tests. Logistic regression with backward elimination was then used with the significant variables to identify the potentially most important factors influencing feather pecking. These variables included stocking density, light intensity, intensity of care, access to elevated perches, access to a roofed and littered outdoor area ('bad weather run'), time of access to the feeding facilities of the housing system, stocking density in the restricted area at the beginning of the rearing period, additional open feeding areas in the beginning and air quality. 3. The final model contained stocking density and access to elevated perches as significant factors (P<0.05). Flocks kept in high density (> or = 10 birds per m2) and with no access to elevated perches were 6.4 (95% Confidence interval 1.7 to 24.2) and 4.0 (95% Confidence interval 1.2 to 12.9) times more likely to be affected by feather pecking, respectively. 4. The study identified 2 risk factors for the occurrence of feather pecking in flocks of laying hen growers reared under commercial conditions. It is concluded that in order to reduce feather pecking chicks should be reared at low density and with access to elevated perches.     

The prevalence of salmonella, yersinia and mycobacteria in slaughtered pigs in Switzerland

Clinically healthy food animals can be reservoirs for various foodborne pathogens. In general, such animals do not have lesions that are visible during meat inspection. Pigs are considered to be carriers of salmonella, yersinia and mycobacteria, but the risk of transmission to humans is difficult to assess. The aim of this study was to estimate the actual prevalence of the three above mentioned pathogens in the Swiss pig population and to comment on their significance. A total of 570 samples each of tonsils and mesenteric lymphnodes, were collected at two slaughterhouses from carcasses of apparently healthy pigs and analyzed for the presence of salmonella, yersinia and mycobacteria. The prevalence of salmonella (0.9%) was found to be lower than--while that of yersinia (8.1%) and mycobacteria (12.8%) about equal to--results reported from other European countries. Yersinia typing showed that serotype O:9 of Yersinia enterocolitica (2.5%) was 6 to 7 times more frequent than serotype O:3 (0.4%)--formerly the most frequent serotype. Mycobacterium avium was the most frequent isolate (90.7%) among the mycobacteria isolated. Although all three pathogens are present in the Swiss pig population, we consider the risk of transmission to humans via consumption of pork as low. Appropriate preventive measures and quality management should contribute to keep the risk under control.     

Evaluation of a monitoring system for assessing animal health in dairy cattle

A monitoring system to assess animal health in dairy farms was developed and applied on 44 farms in an epidemiological study. The objective of the study was to evaluate the applicability of the system for long term monitoring of health data. For this purpose, the quality of the collected data and the acceptance of the system by farmers and veterinarians were investigated. Farmers recorded all health events using a form. Collected data was entered into a central database on a monthly basis. The recording of health data was easy to do and did not take a lot of time. Most of the farmers (89%) used less than 20 minutes per week for the recording. This time need was independent of the herd size. 66% of the farmers found it useful to record health data, especially for improving their overview on health of each single cow. Treatments were reported in 81% of the cases, inseminations and calving in 80% of the cases. All events were reported correctly and precise.     

Animal pneumocystosis: a model for man

Pneumocystis carinii is an important pulmonary pathogen responsible for morbidity and mortality in patients with AIDS. Apart from AIDS, cases of pneumocystosis have been reported in patients receiving immunosuppressive therapy associated with organ transplantation without chemoprophylaxis and in malignant blood diseases. In vitro models are only of limited interest because there is no continuous in vitro culture. The in vivo models have contributed a great deal to the understanding of human Pneumocystis carinii pneumonia. Indeed, animal models remain of prime interest for many purposes, principally comparative medicine, pathogenesis, epidemiology and immunology. Among animal models, the rabbit is a very susceptible host to P. carinii infection, and does not need glucocorticoid treatment. Moreover, antigenic and genomic data suggest that rabbit-derived Pneumocystis strains are more closely related to human Pneumocystis than those of mice or rats. We have therefore shown that the rabbit model permits the study of the pulmonary surfactant modification due to P. carinii infection. This model should be a very interesting model for pathogenesis or immune response studies in immunocompetent animals. The rabbit model could also be used for epidemiological studies. P. carinii transmission appears to be very rapid via contact of Pneumocystis-free rabbits with infected rabbits. These Pneumocystis-free animals could be helpful for characterizing the source and the reservoir and studying parasite transmission.     

Use of quantitative two-dimensional color tissue Doppler imaging for assessment of left ventricular radial and longitudinal myocardial velocities in dogs

OBJECTIVE: To determine left ventricular free wall (LVFW) radial and longitudinal myocardial contraction velocities in healthy dogs via quantitative 2-dimensional color tissue Doppler imaging (TDI). ANIMALS: 100 dogs. PROCEDURE: TDI was used by a single trained observer to measure radial and longitudinal myocardial movement in the LVFW. Radial myocardial velocities were recorded in segments in the endocardial and epicardial layers of the LVFW, and longitudinal velocities were recorded in segments at 3 levels (basal, middle, apical) of the LVFW. RESULTS: LVFW velocities were higher in the endocardial layers than in the epicardial layers. Left ventricular free wall velocities were higher in the basal segments than in the middle and apical segments. Radial myocardial velocity gradients, defined as the difference between endocardial and epicardial velocities, were (mean +/- SD) 2.5 +/- 0.8 cm/s, 3.8 +/- 1.5 cm/s, and 2.3 +/- 0.9 cm/s in systole, early diastole, and late diastole, respectively. Longitudinal myocardial velocity gradients, defined as the difference between basal and apical velocities, were 5.9 +/- 2.2 cm/s, 6.9 +/- 2.5 cm/s, and 4.9 +/- 1.7 cm/s in systole, early diastole, and late diastole, respectively. A breed effect was detected for several systolic and diastolic TDI variables. In all segments, systolic velocities were independent of fractional shortening. CONCLUSIONS AND CLINICAL RELEVANCE: LVFW myocardial velocities decreased from the endocardium to the epicardium and from base to apex, thus revealing intramyocardial radial and longitudinal velocity gradients. These indices could enhance conventional echocardiographic analysis of left ventricular function in dogs. Breed-specific reference intervals should be defined.     

Comparison of intraosseous and intravenous infusion of technetium Tc 99m pertechnate in the distal portion of forelimbs in standing horses by use of scintigraphic imaging

OBJECTIVE: To describe and compare the distribution of technetium Tc 99m (99mTc) pertechnate following intraosseous or i.v. injection (with or without use of a tourniquet) in the distal portion of the forelimb in standing horses. ANIMALS: 4 horses. PROCEDURE: Each horse received 4 forelimb treatments in random sequence: intraosseous infusion with tourniquet application (IOT), intraosseous infusion without tourniquet application, i.v infusion with tourniquet application (IVT), and i.v. infusion without tourniquet application. Dynamic nuclear scintigraphic imaging of the third metacarpal bone, proximal and middle phalanges, and distal phalanx was performed from the start of each treatment until 1 hour after infusion was completed. Radionuclide activity was compared within and between treatment groups. RESULTS: Tourniquet application was necessary to maintain high levels of radionuclide activity in the distal portion of the forelimb after intraosseous or i.v. infusion with 99mTc pertechnate; IVT and IOT treatments resulted in similar radionuclide activity in the proximal and middle phalanges and distal phalanx. Of the 4 treatments, there was significantly higher radionuclide activity in the distal aspect of the third metacarpal bone after the IOT treatment. CONCLUSIONS AND CLINICAL RELEVANCE: By use of a tourniquet, radionuclide administration via the intraosseous or i.v. routes resulted in effective perfusion of the distal portion of the forelimb and similar distribution of the agent in the phalanges of horses. Further studies are required to ascertain whether these findings apply to delivery of therapeutic agents in infected tissues via IOT or IVT.     

Effect of marbofloxacin on cardiovascular variables in healthy isoflurane-anesthetized dogs

OBJECTIVE: To study the hemodynamic effects of marbofloxacin (MBF) in isoflurane-anesthetized dogs. ANIMALS: 6 healthy 8-month-old Beagles. PROCEDURE: Anesthesia was induced with sodium thiopental and maintained with isoflurane. Cardiovascular variables were monitored throughout anesthesia. Marbofloxacin was administered by an IV bolus at 2 mg/kg, followed 10 minutes later by an infusion at a rate of 40 mg/kg/h for 30 minutes (total dose, 20 mg/kg). Plasma MBF concentrations were measured by high-performance liquid chromatography. RESULTS: The mean peak concentration during MBF infusion was 34.2 +/- 6.4 microg/mL. The IV administration of the MBF bolus did not alter any cardiovascular variable in isoflurane-anesthetized dogs. Significant changes were found during infusion when a cumulative dose of 12 mg/kg had been given. The maximal decreases observed at the end of the infusion were 16% in heart rate, 26% in systolic left ventricular pressure, 33% in systolic aortic pressure, 38% in diastolic aortic pressure, 29% in cardiac output, and 12% in QT interval. All dogs recovered rapidly from anesthesia at the end of the experiment. CONCLUSIONS AND CLINICAL RELEVANCE: MBF may safely be used at 2 mg/kg IV in isoflurane-anesthetized dogs, and significant adverse cardiovascular effects are found only when 6 to 8 times the recommended dose is given.