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Contents Some anatomical characteristics of 507 Belgian Blue (BB) cattle, withers height (WH), heart girth (HG), the distance between the two tubera coxae (TcTc) and the distance between the two tubera ischiadica (TiTi), were compared with the internal pelvic measurements of width, height and area. Mean values were 58.9 ± 6.2 cm for TcTc, 14.6 ± 2.3 cm for TiTi, 15.2 ± 2.1 cm for pelvic width (PW), 18.8 ± 1.9 cm for pelvic height (PH) and 288.5 ± 60.9 cm 2 for pelvic area (PA). Cows that calved per vaginam had larger WH (p < 0.05), TcTc (p < 0.05) and TiTi (p < 0.001) and internal pelvic measurements [PH and PA (p < 0.001)] compared with those whose parturition was managed by caesarean section (CS): Correlations between internal pelvic measurements and TcTc were higher (r = 0.58–0.63) than TiTi (r = 0.22–0.28). Correlations between other external body measures such as HG and WH with the internal pelvic measurements were even higher for HG (r = 0.69–0.74) and for WH (r = 0.67–0.74). HG and WH, together with internal pelvic measures, may be added to estimated breeding values (EBV’s) that should assist breeders in selecting cows that can calve per vaginam, thereby reducing the breed’s dependence on elective CS for maintaining its unique characteristics.

In 2 previous publications (Planta and De Meester, 2007; De Meester et al., 2008) the value of the socially acceptable behavior (SAB) test as a temperament test was examined. In this study, the postures and behavioral strategies of 171 dogs in the SAB test were analyzed. All dogs were tested by the same test team, on the same location, and with the same test materials. Factor analysis of the results revealed that 2 underlying factors, presence and absence of the owners, explained 64% of the total variance in the test scores. The significant correlation between the SAB scores in the different subsequent subtests indicates that in addition to the nature of the stimulus, the posture is also influenced by the preceding subtest. In a cluster analysis, the outcome with 5 different clusters turned out to be stable. This allows us to categorize dogs more precisely than that presented in a study by De Meester et al. (2008) with respect to their reaction in potentially aversive situations in the presence or absence of the owners. Most dogs that threaten or bite other dogs in the test will have a high posture, although a high percentage of dogs in a very low position will bite too. Most dogs that bite the doll or hand will have a low posture in the specific subtests, indicating that the emotion behind this action is fear. On the basis of the low predictive values we can state that it is not possible to obtain all information regarding bite and/or flight behavior later in the test, only from the strategies or SAB scores ≥5 of the dogs in the subtests. If all the information is to be obtained, we have to perform all subtests. As a consequence, some dogs will bite or panic and flee in the test. It will be important to manage these behaviors in such a way that the dog has neither learning experience for aggression, nor suffers too much from fear. A protocol for desensitization and counter-conditioning must be available and the test must be stopped immediately if it adversely affects the welfare of the dog. In a process of ethical balancing, the value of the test must be weighted against its possible negative influences on the dog.

Summary The purpose of this study was to perform temporary atrial pacing and to determine the atrial strength-duration (S-D) curve which displays the minimal pulse intensity necessary to achieve atrial capture. In 7 horses, atrial pacing was applied using a temporary pacing catheter and a pacemaker as electrical pulse generator. Using the stimulus reduction method, 3 approaches for atrial threshold determination were used. With the fixed pulse width method, at several pulse widths, the corresponding minimal amplitudes to achieve capture were determined, describing an S-D curve. With the fixed amplitude method, the corresponding threshold pulse widths were determined at several fixed amplitudes. The third method proved to be the best and was a combination of both aforementioned methods to determine 2 points of the S-D curve. From these 2 points the whole S-D curve was calculated using a mathematical equation. Temporary pacing can be used to terminate atrial flutter, to induce atrial arrhythmias or to obtain more information about the electrophysiological properties of the heart, such as the atrial refractory period, atrial vulnerability and atrioventricular conduction.

Live weight is an important trait in cattle farming. Weighing is not always feasible and therefore live weight is often estimated from easily accessible data. In this study, data on live weight, age and gender, and four body measurements, withers height (WH), heart girth (HG) and width of the shoulders (SW) and hind quarters (BcW) of double-muscled Belgian Blue beef (DM-BBB) farm animals were used to develop multivariable non-linear and linear regression models that predict live weight from these easily accessible data. The relationship between the logarithm of the live weight and the logarithm of time is adequately described by a general logistic function. The age period from 100 to 600 days of age is contained in the linear part of the logistic function. This region is of particular economic interest because it contains the yearling age and slaughter age that are important in DM-BBB breeding and management. Adding one of the body traits in the linear models that contain age and gender as fixed effects decreases the coefficient of variation. A model with withers height and shoulder width has the lowest coefficient of variation, with no further significant improvement when adding either heart girth or width of the hind quarters.

Time to infection data are often simultaneously clustered and interval-censored. The time to infection is not known exactly; it is only known to have occurred within a certain interval. Moreover, observations often occur in clusters. Consequently, the independence assumption does not hold. Here we propose an extension of the shared gamma frailty model to handle the interval censoring and clustering simultaneously. We show that the frailties can be integrated out analytically, allowing maximization of the marginal likelihood to obtain parameter estimates. We apply our method to a longitudinal study with periodic follow-up on dairy cows to investigate the effect of parameters at the cow level (e.g., parity) and also parameters that can change within the cow (e.g., front or rear udder quarter) on time to infection. Dairy cows were assessed approximately monthly for the presence of a bacterial infection at the udder-quarter level, thus generating interval-censored data. Obviously, the four udder quarters are clustered within the cow. Based on simulations, we find that ignoring the interval-censored nature of the data can lead to biased parameter estimates.

The efficacy of an injectable formulation of florfenicol (300 mg/mL) as metaphylactic control of naturally occurring bovine respiratory disease (BRD) was evaluated in two double-blind randomly controlled field studies on two Dutch veal calf herds (A and B). Cattle aged not older than 3 months and in the direct presence of calves with clinical respiratory disease were randomly allocated to treatment with 40 mg/kg florfenicol subcutaneously (s.c.) a positive control treatment (12.5 mg/kg tilmicosin p.o. twice daily for five consecutive days in herd A, and 12.5 mg/kg doxycycline p.o. twice daily for five consecutive days in herd B), or a negative control (one placebo saline s.c. administration on D0). The predominant respiratory pathogens present in pretreatment respiratory samples from affected animals were Mycoplasma bovis and Pasteurella multocida in outbreaks A and B, respectively. Metaphylactic administration of florfenicol resulted in a statistically significant weight gain, decreased rectal temperature for five consecutive days after treatment and decreased metaphylactic failure percentages compared with both positive and negative control groups. In summary, these studies demonstrated that a single s.c. injection of florfenicol is effective and practical for control of the bacterial component of BRD in veal calves.

Summary In veterinary epidemiology, we are often confronted with hierarchical or clustered data. Typically animals are grouped within herds, and consequently we cannot ignore the possibility of animals within herds being more alike than between herds. Based on a serological survey of bovine herpes virus type 1 in cattle, we describe a method for the estimation of herd-specific rates at which susceptible animals acquire the infection at different ages. In contrast with the population-averaged force of infection, this method allows us to model the herd-specific force of infection, allowing investigation of the variability between herds. A random-effects approach is used to account for the correlation in the data, allowing us to study both population-averaged and herd-specific force of infection. In contrast, generalized estimating equations can be used when interest is only in the population-averaged force of infection. Further, a flexible predictor model is needed to describe the dependence of covariates appropriately. Fractional polynomials as proposed by Royston and Altman offer such flexibility. However, the flexibility of this model should be restricted, since only positive forces of infection have a meaningful interpretation.

It has been demonstrated that pigs that have been double vaccinated with an E2 sub-unit marker vaccine and that are infected with classical swine fever virus (CSFV) through a natural contact infection may react positive in a CSFV detecting RT-nPCR test, whereas no virus could be isolated by using the conventional virus isolation (VI) technique. To evaluate whether these vaccinated and infected pigs may spread the virus, three experiments were set up. In the first, susceptible pigs were inoculated with serum originating from vaccinated RT-nPCR positive pigs. In the second, vaccinated RT-nPCR positive pigs were brought into contact with sentinel animals. In the third, vertical transmission was evaluated in RT-nPCR positive vaccinated pregnant gilts. In the first two experiments, no proof of virus transmission was found, whereas in the third vertical transmission was observed. The conclusion is that in vaccinated pigs that are positive in RT-nPCR but negative in VI, the level of circulating virus is probably not high enough for horizontal transmission, whereas vertical transmission of the virus is possible.

A report of the Scientific Committee on Animal Health and Animal Welfare of the European Commission (CEC, 1999.) includes recommendations for setting up monitoring programmes for classical swine fever (CSF) infection in a wild-boar population, based on the assumption that one would detect at least 5% prevalence in a CSF-infected wild-boar population. This assumption, however, is not science based. We propose an alternative method to provide evidence for a wild-boar population being free of CSF and evaluate the efficiency of a surveillance programme that was implemented in Belgium in 1998. In our study, the probability of freedom of CSF-virus was estimated based on 789 samples; these were collected from wild-boars within the surveillance programme (within the three provinces which include 95% of the Belgian wild-boar population) and examined by three diagnostics methods (antibody detection, virus detection and virus RNA detection). A Bayesian framework was used for the estimation, accounting for the diagnostic test characteristics without the assumption of the presence of a gold standard. The median probability of freedom of CSF-virus was estimated at 0.970, with a 95% credibility interval of 0.149–1.000. Independent on the choice of the prior information, the posterior distributions for the probability of freedom of CSF-virus were always skewed close to the upper boundary of 1. This represents a big gain of knowledge since we did not use any prior information for the probability of freedom of CSF-virus and took the uncertainty about the accuracy of the diagnostic methods into account.

Classical swine fever (CSF) is one of the most important viral pig diseases. Basic measures to control epidemics of CSF comprise eradication of infected herds and preventive emptying of herds at risk. Identification of these herds at risk is based on knowledge of the different transmission routes of the virus. Direct transmission of CSF is undoubtedly the most efficient way of CSF virus transmission. Data on indirect transmission are variable and often equivocal. Various indirect transmission routes like swill feeding, wild boar and artificial insemination are well described, and the importance is beyond discussion. Mechanical transmission via vehicles and persons are categorized as very important based upon epidemiological research, whereas in experiments they can only be reproduced under worst case conditions. The role of arthropods, birds, rodents, and other animals in the spread of CSF virus remains doubtful. Active transmission by these has never been demonstrated and also very sparse indications for mechanical transmission are available. Also the role of airborne transmission remains debated. However epidemiological as well as experimental data indicate that airborne spread over short distances is probable.

At present, two types of vaccines against classical swine fever (CSF) virus are commercially available: E2 sub-unit marker vaccines and the conventional attenuated live C-strain vaccines. To evaluate the reduction of the horizontal virus transmission, three comparable experiments were carried out in which groups of weaner pigs (vaccinated with a marker vaccine or a C-strain vaccine) were challenged with CSF virus at 0, 7, and 14 days post-vaccination (dpv). Virus transmission was prevented totally when the challenge occurred at 14 dpv with an E2-marker vaccine (0/12 contact pigs positive in virus isolation (VI); R = 0 (0; 1.5)). At 7 dpv, transmission was reduced slightly (5/12 contact pigs positive in VI; R = 1.0 (0.3; 3.0)), whereas at 0dpv, vaccination had no effect on transmission (10/12 contact pigs positive in VI; R = 2.9 (1.5; 10.8)). In the C-strain-vaccinated pigs, no virus transmission was detected even when the challenge was performed at the same day as the vaccination (0/12 contact pigs positive in VI; R = 0 (0; 1.5)).

Colibacillosis appears to be of increasing significance in layer flocks, but there have been no studies of the risk factors associated with outbreaks. This study aimed to investigate the possible associations between risk factors of non-infectious nature and outbreaks of mortality due to colibacillosis in flocks of caged layer hens. Information on management, biosecurity measures and housing conditions was collected in 20 flocks suffering from the disease and in 20 clinically healthy control flocks. The data were processed using multiple logistic regression. The statistical analysis demonstrated that an increase in the distance to the nearest poultry farm by 1 km was associated with a six-fold decreased risk of an outbreak of colibacillosis (odds ratio=0.16). Furthermore, a 1 l increase in cage volume per hen was associated with a 33% decrease in the risk of an outbreak (odds ratio=0.75). It was concluded that the distance between poultry farms and the hen density in the cages are important risk factors for outbreaks of colibacillosis in flocks of layer hens.

This study aimed to examine the significance of interactions between Escherichia coli and various respiratory pathogens during outbreaks of colibacillosis-associated mortality in layer hen flocks under field conditions. For this purpose, a case-control study involving 20 control flocks with baseline mortality and 20 flocks with increased mortality due to E. coli septicaemia and polyserositis, was conducted. In each colibacillosis flock, blood samples were taken from 20 hens at the onset of clinical disease and three times thereafter at 2-week intervals. Control flocks of comparable ages were sampled in the same way. Pooled sera, taken at the first and last sampling, were examined for antibody titres against infectious bronchitis virus (IBV) and Newcastle disease virus (NDV), and the individual sera from all four samplings were examined for the presence and/or titres of antibodies against avian pneumovirus (APV), Mycoplasma gallisepticum, Mycoplasma synoviae and Ornithobacterium rhinotracheale. Titre increases were seen for IBV D274 (one control flock) and O. rhinotracheale (one control and one colibacillosis flock). An increase in per cent reactors was seen for APV (one control flock), and for M. synoviae (one control and two colibacillosis flocks). The study failed to detect any consistent interactions between E. coli and the aforementioned pathogens. These results indicate that, at least as observed in this study, outbreaks of increased mortality resulting from colibacillosis are not necessarily associated with IBV, NDV, APV, M. gallisepticum, M. synoviae or O. rhinotracheale infections.

To investigate the cardiopulmonary effects of a xylazine-guaiphenesin-ketamine infusion combined with inter-coccygeal extradural (lidocaine) anaesthesia in calves.Prospective study.Five Holstein Friesian calves (one steer, four heifers) aged 6 weeks weighing 65.2 +/- 2.7 kg.Calves were anaesthetized with isoflurane in oxygen for instrumentation. At least 12 hours later, xylazine (0.2 mg kg(-1) i.m.) was given. After 15 minutes, an infusion of xylazine hydrochloride (0.1 mg mL(-1)), guaiphenesin (50 mg mL(-1)) and ketamine (1 mg mL(-1)) (X-G-K) was infused at a rate of 1.1 mL kg(-1) hour-1 i.v. Oxygen (4 L minute(-1)) was delivered by nasotracheal tube 30 minutes later. Inter-coccygeal (Co1-Co2) extradural anaesthesia (lidocaine 2%, 0.18 mL kg(-1)) was administered 30 minutes later. Cardiopulmonary variables were obtained in the unsedated standing calves 10 minutes after xylazine, 15 and 30 minutes after X-G-K without O2, 15 and 30 minutes after X-G-K with O2 and 5, 15, 30, 45 and 60 minutes after extradural anaesthesia. Data were analysed using a repeated measurement analysis of variance including an autoregressive covariance structure of order 1 (correlations at different time intervals).Xylazine caused significant (p0.05) decreases in heart rate (HR), cardiac output (Qt) and index (CI), stroke volume and stroke index, mean, systolic and diastolic arterial blood pressure (MAP, SAP, DAP), left (LVWSI) and right ventricular stroke work index (RVWSI), mean, systolic and diastolic pulmonary arterial pressure (MPAP, SPAP, DPAP), arterial pH, arterial oxygen tension (PaO2), arterial base excess, arterial HCO3- concentration, arterial saturation, packed cell volume, arterial and venous oxygen content (CaO2, CvO2), O2 consumption and O2 delivery (VO2, DO2). Increases in systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were observed. During X-G-K infusion without O2, HR, Qt and CI increased gradually while SVR, PVR and MAP decreased. Left ventricular stroke work index and PaO2 remained constant, while O2 supplementation improved PaO2. Coccygeal extradural anaesthesia had little effect on cardiopulmonary variables. Respiratory rate (f) and PaCO2 significantly increased over the experiment.Xylazine caused adverse cardiopulmonary effects in calves. Improvement occurred during xylazine-guaiphenesin-ketamine infusion. Cardiac index and arterial blood pressure remained below baseline values while sustained increases in respiration rate and PaCO2 were observed. Inter-coccygeal extradural anaesthesia had only minor effects. Oxygen supplementation proved advantageous during guaiphenesin, ketamine and xylazine infusion in healthy calves in combination with coccygeal extradural anaesthesia induced persistent cardiopulmonary depression.

A high number of dairy heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes , one of the most widespread coagulase-negative staphylococci (CNS) in milk samples from freshly calved dairy heifers, was measured cross-sectionally in non-lactating heifers on eight commercial dairy farms in Belgium. The influence of age on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 heifers. The age of the heifers varied from 8 to 34 months. Overall, 20% of the heifers had at least one teat apex colonized with S. chromogenes . Of all teats sampled, 10% were colonized with S. chromogenes . The chance of having at least one teat apex colonized with S. chromogenes increased with age of the heifer. The presence of prepartum teat apex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the first few days of lactation from having somatic cell count ≥200,000 cells/ml milk, commonly accepted as the threshold for intramammary infection.

Antimicrobial resistance may become a major problem in veterinary medicine as a consequence of the intensive use and misuse of antimicrobial drugs. Related problems are now arising in human medicine, such as the appearance of multi-resistant food-borne pathogens. Product characteristics, dose, treatment interval and duration of treatment influence the selection pressure for antimicrobial drug resistance. There are theoretical, experimental and clinical indications that the emergence of de novo resistance in a pathogenic population can be prevented by minimizing the time that suboptimal drug levels are present in the infected tissue compartment. Until recently, attention has been focused on target pathogens. However, it should be kept in mind that when antimicrobial drugs are used in an individual, resistance selection mainly affects the normal body flora. In the long term, this is at least equally important as resistance selection in the target pathogens, as the horizontal transfer of resistance genes converts almost all pathogenic bacteria into potential recipients for antimicrobial resistance. Other factors contributing to the epidemiology of antimicrobial resistance are the localization and size of the microbial population, and the age, immunity and contact intensity of the host. In livestock, dynamic herd-related resistance patterns have been observed in different animal species.

A new in vitro method was developed for analyzing the capacity of sperm to bind to oviductal epithelium to determine whether this binding capacity could be used to predict nonreturn rates (NRR). Sperm binding was evaluated by counting 5,59,6,69-tetrachloro-1,19,3,39-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1)-labeled spermatozoa attached to oviductal epithelium and by measuring the surface area of the oviduct explants by means of an image analysis program. Hepes 1 Tyrode albumin lactate pyruvate (TALP) was a more useful medium than in vitro fertilization (IVF)-TALP, TCM-199 medium 1 10% fetal calf serum, and TCM-199 medium alone for the investigation of sperm binding to oviductal explants. Oviduct explants with a surface area of ,20 000 mm2 provided more consistent results than did explants with a surface area of .100 000 mm2 . A positive association was found between the loge transformed number of spermatozoa bound to 0.1 mm2 oviductal epithelium and the NRR of the respective sires after 24 h of coincubation, provided that the membrane integrity of the sperm sample was .60%. Determination of the capacity of sperm to bind to oviductal explants could become a reliable in vitro method for predicting the NRR of a given sire.

This paper describes the epidemiological characteristics of the 1997 Classical Swine Fever (CSF) outbreak that occurred in the Limburg Province of Belgium, where there is a policy of non-vaccination, intensive surveillance and eradication. Between 30 June and 17 July 1997, eight herds, located in three different areas, were confirmed to be CSF-positive. CSF virus was transmitted from the primary infected herd of one area to another five herds in the same area and to one herd in a different area. The mode of virus introduction for this primary infected herd and for the one herd that was not infected by this primary herd could not be determined. Clinical, serological, and virological findings indicated that the CSF-infected herds were detected in an early stage of the infection. The early detection of the infection together with a preventive stamping out procedure resulted in a rapid elimination of the CSF virus. A total of 46,561 pigs were slaughtered to control the spread of the infection. Another 27,579 pigs were slaughtered in the framework of the market support. The total direct costs of the episode were estimated at [symbol: see text] 10,893,337.

The clinical and virological protection induced by an E2 sub-unit marker-vaccine against Classical Swine Fever (CSF) was examined during an experimental infection in vaccinated and non-vaccinated pigs. Forty-five pigs were equally distributed over three adjacent pens of an isolation unit, there was only indirect (airborne) contact between pigs in the different pens. In pen 3 all pigs were vaccinated twice with 4 weeks interval. Pigs in pens 1 and 2 were not vaccinated. Two weeks after booster vaccination, one randomly selected pig in the middle pen was experimentally inoculated with CSF virus. After the initial virus spread in the infected pen, all pigs in the non-vaccinated adjacent pen were infected. In the vaccinated pen, seven out of 14 pigs became infected during the experiment. Survival analysis showed that virus transmission by direct and indirect contact was significantly (p

The protective use of plasma powder from cattle and swine against experimentally induced neonatal E. coli diarrhoea in colostrum‐deprived calves was examined. Diarrhoea was induced with a strain expressing F5+ fimbriae and a strain expressing F17+ fimbriae. In all groups supplemented with bovine plasma powder, diarrhoea and fever were less severe than in the control groups. For the groups infected with the F5+ E. coli strain, a reduction in excretion of the challenge strain by 2–4 orders of magnitude and by 1–2 orders of magnitude was seen when supplemented with bovine plasma powder at a dose of 25 g/l milk and 10 g/l milk, respectively. The bovine plasma powder showed also beneficial effects in the F17+ infected groups. No mortality, no septicaemia and no severe clinical signs were observed. Concerning the excretion of the E. coli F17+ strain in the faeces, no significant difference with the control group was found. Swine plasma powder showed little beneficial effect on E. coli diarrhoea in calves in this study.

The spread of Classical Swine Fever (CSF) virus (strain Lorraine), originally isolated in the first CSF infected herd of the 1993-1994 Belgian epizootic, was examined in an isolation unit with three adjacent pens and 15 weaner pigs per pen. Virus was introduced through experimental inoculation of one weaner pig in the middle pen (pen 2). The experimentally inoculated pig became viraemic 4 days post-inoculation (dpi) and the pen mates at 12 (n = 9) and 14 dpi (n = 5). The first viraemia in pens 1 and 3 was observed 18 dpi. Pigs were found to be seropositive in pens 1, 2, and 3 from 24, 20, and 22 dpi onwards, respectively. The reproduction ratio (R0) for the pigs in pen 2, estimated according to the martingale method, was 81.3 (s.e. = 109.54). The rate ratio (Cox proportional hazard) of the first pigs to become viraemic in pen 3 (airborne contact plus contact via contaminated clothing and footwear with pen 2) versus pen 1 (airborne contact with pen 2 only) was 1.60 (P = 0.3342). Thus, the additional contact of contaminated clothing did not affect transmission of the CSF virus. The survivor function (Kaplan-Meier survival analysis) did not significantly differ per pen. The time from first detection of virus in plasma to death was not significantly different between pens. The mean rectal temperature of pigs in a pen increased 3 to 4 days prior to detection of virus. The proportion of seropositive pigs per pen (p) from the day the first weaner pig in a pen became viraemic (dpf) was examined as a function of time with a logistic regression model. The model parameter estimates did not differ between pens. Hence, the data from the three pens were pooled. The regression equation of the seroprevalence over time for the pooled data was p = 1/[1+e(4.65-0.39 *dpf)].

In a companion paper a logistic regression model of seroprevalence over time was developed on the basis of data obtained during an experimental infection of weaner pigs with classical swine fever (CSF) virus. The model was applied to seroprevalence data from three outbreaks of the 1993-1994 epizootic to test whether the model could predict correctly the day of virus introduction into the herd. It was concluded that the logistic regression model has potential as a tool to estimate in retrospect the day CSF virus was introduced into a pig herd, which in turn may assist in identification of risk factors implicated in the further spread of the disease.

This study examines the influence of parity, stage of lactation, and single isolations (i.e., the isolation of a microorganism that could not be reisolated in the same quarter in the next sampling) of staphylococci other than Staphylococcus aureus (coagulase-negative staphylococci), Corynebacterium bovis, or esculin-positive cocci other than Streptococcus uberis (referred to as esculin-positive cocci throughout) on the monthly log(e)-transformed somatic cell count (SCC) for 180 first, second, and third parity cows that were observed over a whole lactation. Repeated measures ANOVA was used to analyze the data. No significant effect was found for the infection variable. However, the results indicated that even single isolations of coagulase-negative staphylocci, C. bovis, or esculin-positive cocci resulted in a numerical or statistically significant increase in SCC. Least squares mean SCC (log(e)-transformed) for bacterio-logically negative cows and cows with single isolations of coagulase-negative staphylococci, C. bovis, or esculin-positive cocci were 3.90, 3.97, 4.08, and 4.17, respectively. Significant effects of parity, stage of lactation, and the interaction of parity and stage of lactation could not be found when only bacteriologically negative cows were considered. Least squares mean SCC for first, second, and third parity cows were 3.80, 3.93, and 3.97, respectively. However, the effects of parity, stage of lactation, and the interaction of parity and stage of lactation were significant when all 180 cows were included. Therefore, these effects must be due to factors that were present in the infected groups.

At calving, purebred animals of the Belgian Blue (BB) breed are compromised by the incompatibility in size and shape of the dam and her calf, resulting in a very high incidence of dystocia problems. To clarify which body parts of the calf are of decisive importance to allow natural delivery and to investigate both the mean value as well as the variation among these body sizes within this breed (variation being an important condition for selection), measurements of nine body parts (body weight at birth (BW), body length (BL), length of the head (LH), shoulder width (SW), hip width (HW), heart girth (HG), withers height (WH) and the circumference of the fetlock of both the front (CFF) and the hind leg (CFH)) were assessed in 147 newborn purebred BB calves on 17 farms. Simple and partial correlations were assessed and we examined whether environmental factors (gender of the calf, parity of the cow, type of calving, season of birth and time of measurement after birth) were significantly associated with these specific calf measurements. The mean BW was 49.2 ± 7.1 kg. The average BL was 56.4 ± 4.5 cm and the mean LH was 24.4 ± 2.3 cm. Measurements obtained for SW and HW were 22.4 ± 2.2 and 22.9 ± 2.1 cm, respectively, whereas the mean WH was 71.1 ± 4.7 cm. Measurements of circumferences revealed a CFF of 17.9 ± 1.1 cm, a CFH of 18.0 ± 1.0 cm and a mean HG of 78.0 ± 5.4 cm. Partial correlations of the BW with eight body measurements were significant (P < 0.01) and ranged between 0.17 and 0.85; 0.42 and 0.88; and 0.24 and 0.88 when corrected for gender, parity and type of calving, respectively. BL (P < 0.01) and the CFF and CFH (P < 0.001) are larger in bull calves than in heifer calves. Calves born through caesarean section had broader SW (P < 0.01) and HW (P < 0.01) when compared with calves born after natural calving (defined as bornper vaginam without assistance or with slight traction). Sizes of calves born out of multiparous cows were generally larger than of calves born out of heifers (SW:P < 0.001; HW:P < 0.05). As SW and HW are the broadest points of a BB calf, they are both candidates for being the limiting measures for calving ease, but the difference between HW and SW for the total data set was not different from zero (P > 0.05). In contrast to male calves in which no significant difference (between HW and SW) could be found, female calves show the difference between HW and SW that was significantly different from zero (P < 0.001); thus, in female calves, the HW is the most limiting factor of the calf’s body. The significant variation in some body measures between the calves and the strong correlation within these sizes raises the possibility of selection towards smaller calves aiming to limit the dystocia problem in the BB breed. Furthermore, on the basis of our results, we were able to build equations for the farmer to use at the moment of calving containing the LH, the CF and the calf’s gender to estimate SW and HW, the limiting body parts of the calf to be born naturally. Together with the knowledge of the pelvic size of the dam, this information gives the obstetrician or the farmer a more accurate prediction of the probability of natural calving at parturition.

Coagulase-negative staphylococci from cases of bovine mastitis were identified to species level by using an identification scheme based on a three-plate test system which tested for DNase on DNA agar, for protease on calcium caseinate agar, and for the organism's sensitivity to novobiocin, desferrioxaminine (deferoxamine) and fosfomycin by agar diffusion tests. Testing for the inhibition of Staphylococcus delta haemolysin (Skalka 1991) can replace the protease tests.

Udder infections in dairy cows are observed at udder quarter level. Therefore, the best strategy to study infection dynamics of particular bacteria causing mastitis is to follow up and model individual udder quarter infection times. Udder quarter infection times, however, are not independent as they are clustered within a cow and herds. Another challenge in modelling infection times is that the exact infection time is unknown; it is only known that the infection has taken place in the interval between the last negative and the first positive sample. We applied a technique based on the gamma frailty model which handles the clustering and interval censoring simultaneously. Parameter estimates can be obtained analytically and their variance is obtained by the inverse of the hessian matrix. The proposed technique was applied to udder quarter infection times for Corynebacterium bovis, Staphylococcus aureus and Streptococcus uberis. Multiparous cows were more likely to get infected earlier in lactation with C. bovis or S. uberis than primiparous cows. The times to infection of all three bacteria were highly clustered at cow level and the results of a stratified model on a subset of herds suggested a high clustering on herd level for C. bovis and S. uberis.

Modeling infectious diseases data is a relatively young research area in which clustering and stratification are key features. It is not unlikely for these data to have missing values. If values are missing completely at random, the analysis on the complete cases is valid. However, in practice this assumption is usually not fulfilled. This article shows the effect of ignoring missing data in modeling the force of infection of the bovine herpesvirus-1 in Belgian cattle and proposes the use of weighted generalized estimating equations with constrained fractional polynomials as a flexible modeling tool.

Background Diarrhea and mortality resulting from infections with enteropathogenic Escherichia coli (EPEC) are of major economic importance in the rabbit meat industry. There is a growing need for an effective vaccine to cope with these problems and to reduce the use of antibiotics. EPEC are characterized by an attaching and effacing virulence mechanism. This is partly mediated by the intimate binding between an adhesin, called intimin, and a translocated receptor (Tir) of prokaryote origin. We constructed an intimin deletion mutant of the rabbit EPEC (REPEC) wild-type strain 97/241.6 (bio-/serogroup 3-/O15) and examined its protective capacity. Results After verifying its complete loss of virulence, we used the attenuated strain in vaccination-challenge experiments in which complete protection against a homologous, but virulent, strain was observed. The attenuated strain was able to persist in the intestinal lumen, where it elicited an immune response against EPEC-related virulence proteins, as was shown using an EspB-specific ELISA. Despite the priming of an immune response and the generation of specific antibodies, the intimin mutant was not able to fully protect rabbits against challenges with REPEC strains of other bio-/serogroups. Conclusion These data indicate that protection against REPEC infections is at least partly bio-/serogroup dependent and a multivalent vaccine may be needed for protection against the full range of REPEC types. Such a combination vaccine may be developed using intimin null mutants, as the latter were clearly shown to be safe and effective against homologous infections.

Colibacillosis appears to be of increasing importance in layer flocks. The aim of this study was to determine characteristics of avian pathogenic Escherichia coli associated with the occurrence of colibacillosis outbreaks at flock level. Forty E. coli strains originating from layers from healthy flocks (‘control isolates’), consisting of 25 caecal and 15 extra-intestinal isolates, were compared with 40 strains isolated from layers originating from colibacillosis-affected flocks (‘outbreak isolates’), consisting of 20 caecal and 20 extra-intestinal isolates. The examined characteristics were adhesins, invasivity in T84 cell culture, serum resistance, iron uptake, colicin production, and toxinogenicity. The following traits were significantly more often detected in the outbreak isolates than in the control isolates: tsh, iss, iucA, iutA, irp2, fyuA, iroC, cvaC, colicin and colicin V production. A comparison of the extra-intestinal outbreak isolates and the caecal control isolates yielded the same results as when the caecal isolates, extra-intestinal isolates and total number of isolates of the outbreak and the control group were compared. When comparing the caecal and extra-intestinal isolates within the control and within the outbreak group, no significant differences were detected. The O78 and O2 groups showed significant differences with other O-types and NT strains for prevalence of most of the same characteristics. The combination of type 1 fimbriae, tsh, serum resistance, iss, traT, iucA, fyuA, iroC and colicin or colicin V production was significantly more often present in extra-intestinal outbreak isolates than in extra-intestinal control isolates. Only the combination of serum resistance, fyuA and colicin production was present in all outbreak isolates, with a significantly lower prevalence in the control isolates. None of the characteristics or combinations examined were exclusive to the outbreak isolates.

In Europe, outbreaks of acute mortality in layer flocks due to colisepticaemia have frequently been observed since the mid-1990s. The aims of this study were to describe the disease, to identify the serotypes of the avian pathogenic Escherichia coli (APEC) present in these outbreaks, and to detect the presence of F11 fimbriae and flagella in the isolates. For this purpose, 20 flocks with APEC-associated increased mortality and 20 control flocks matched for age were examined. Weekly mortality rates in the colibacillosis-affected flocks reached 1.71%, versus 0.30% in the control flocks. The maximum cumulative mortality over an entire colibacillosis outbreak reached 9.19%. The disease was often flock and hen house associated, with recurrent outbreaks within one round and in successive rounds in the same house. Disease was usually acute without clinical symptoms. Peritonitis with yolk material deposited in the peritoneal cavity and polyserositis were the main lesions at necropsy. O78 strains were isolated in 15 of the 20 colibacillosis flocks, and in only one of the control flocks. The majority of strains from the control flocks could not be serotyped by the 28 O-antisera used. In general, F11 fimbriae and flagella were present in the majority of the strains. F11 fimbriae were significantly more often found in O78 isolates than in the other serotypes, and are thus more often present in isolates from colibacillosis flocks. Strains positive for F11, and for F11 and flagella, were more frequently present in heart and liver of the colibacillosis-affected flocks.

A higher milking frequency, as a consequence of milking with an automated milking system, incorporates a threat to teat condition. To study the effect of transition from conventional to automated milking on teat skin and teat end condition, 40 lactating Holstein-Friesian cows and heifers from a high yielding dairy herd were randomly allocated to either a conventional or an automated milking system group. In the latter group, automated milking was initiated during the study period, while conventional milking was continued in the control group. Teat skin and teat end condition were evaluated weekly on quarter level for all animals from 5 wk before until 8 wk after transition. A high emollient iodine teat dip was used on all cows during the study period. Teat skin condition of the animals in the automated milking system group was consistent from before and during milking with the automated milking system. Rear teats had a better skin and end condition than front teats. Evolution of teat end condition over time between the automated and conventional milking groups was not statistically different. Heifers, however, seemed to be more sensitive to the change than multiparous cows, as their teat end condition slightly decreased.

Summary In this experiment transmission of classical swine fever (CSF) virus via excretions of infected pigs was investigated under experimental conditions. Five pairs of pigs were experimentally infected with CSF virus. Eight days after experimental infection, when all pigs were viraemic for at least 3 days, the pens were depopulated and 20 h later, restocked with five pairs of susceptible pigs which stayed in these pens for 35 days. During the first 3 weeks of the experiment, the pens were neither cleaned nor disinfected. During the observation period, none of the susceptible pigs became infected. This result indicates that CSF virus spread via excretions is of minor importance in the early stages of infection. For extrapolation of these findings to the field situation and to increase the validity of the conclusions further research is needed to evaluate the effect of factors like virus strain, interval, ... , that may influence the outcome of the experiment.

A new in vitro method was developed for analyzing the capacity of sperm to bind to oviductal epithelium to determine whether this binding capacity could be used to predict nonreturn rates (NRR). Sperm binding was evaluated by counting 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1)-labeled spermatozoa attached to oviductal epithelium and by measuring the surface area of the oviduct explants by means of an image analysis program. Hepes + Tyrode albumin lactate pyruvate (TALP) was a more useful medium than in vitro fertilization (IVF)-TALP, TCM-199 medium + 10% fetal calf serum, and TCM-199 medium alone for the investigation of sperm binding to oviductal explants. Oviduct explants with a surface area of20 000 micro m(2) provided more consistent results than did explants with a surface area of100 000 micro m(2). A positive association was found between the log(e) transformed number of spermatozoa bound to 0.1 mm(2) oviductal epithelium and the NRR of the respective sires after 24 h of coincubation, provided that the membrane integrity of the sperm sample was60%. Determination of the capacity of sperm to bind to oviductal explants could become a reliable in vitro method for predicting the NRR of a given sire.

Fifty randomly selected fattening pig herds were studied to investigate the epidemiological characteristics of infections with Actinobacillus pleuropneumoniae serovars 2, 3 and 9, and to identify risk factors for their within-herd seroprevalences. Information about 13 farm characteristics was obtained by means of a questionnaire and used to assess potential risk factors for the percentage of slaughter pigs with antibodies against each of the three serovars. The presence of antibodies was measured with an indirect ELISA. The median within-herd seroprevalence for serovar 2 was 58 per cent (range 0 to 100 per cent), for serovar 3, 53 per cent (range 10 to 95 per cent), and for serovar 9, 35 per cent (range 5 to 100 per cent). All but one farm tested positive for A pleuropneumoniae serovar 2, and all the farms were positive for A pleuropneumoniae serovars 3 and 9. There was a positive association (P

Supraphysiological oxygen tension during embryo culture can generate reactive oxygen species (ROS), which can induce apoptosis. Antioxidants such as thiol compounds (cysteine, cysteamine) can be used to prevent ROS damage to the embryo. The purpose of this study was to evaluate the prevalence of apoptosis during bovine embryo development and to evaluate the effect of the presence or absence of cysteine 0.6 mM in modified synthetic oviduct fluid (mSOF) on in vitro produced cattle embryos cultured under two different oxygen tensions (5% O2 versus 20% O2). Effects were assessed by checking embryo development at Days 7, 8 and 9 and by evaluating Day 9 hatched blastocysts for differentiation by means of differential staining and for apoptosis by means of TUNEL-assay. Apoptotic cells were present in 94% of Day 7 blastocysts and in 100% of Days 8 and 9 blastocysts. Cysteine addition affected Day 8 blastocyst rates in a negative way (P < 0.05) regardless of the oxygen tension. In fact, cysteine addition to the mSOF culture medium had a negative effect upon embryo development in terms of blastocyst rates, hatching rates and apoptotic cell ratio. Embryos cultured under 5% O2 in the presence of cysteine, however, possessed significantly higher numbers of ICM cells. This finding corroborates the theoretical assumption that antioxidants are beneficial for ICM development.

The cardiopulmonary effects of different levels of carbon dioxide insufflation (3, 5 and 2 mm Hg) under two-lung ventilation were studied in six sevoflurane (1.5 minimum alveolar concentration; MAC) anaesthetized dogs during left-sided thoracoscopy. An arterial catheter, Swan-Ganz catheter and multianaesthetic gas analyser were used to monitor the cardiopulmonary parameters during the experiment. Baseline data were obtained before intrathoracic pressure elevation and the measurements were repeated at intervals after left lung collapse induced by insufflation with carbon dioxide gas. The intrapleural pressure levels used were 3, 5 and 2 mm Hg. Arterial blood pressures, cardiac index, stroke index, left and right ventricular stroke work index, arterial haemoglobin saturation, arterial oxygen tension and systemic vascular resistance decreased significantly during hemithorax insufflation, whereas heart rate, right atrial pressure, mean, systolic and diastolic pulmonary arterial pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance and arterial carbon dioxide tension significantly increased during intrapleural pressure elevation. Although carbon dioxide insufflation into the left hemithorax with an intrapleural pressure of 2-5 mm Hg compromises cardiac functioning in 1.5 MAC sevoflurane anaesthetized dogs, it can be an efficacious adjunct for thoracoscopic procedures. Intrathoracic view was satisfactory with an intrapleural pressure of 2 mm Hg. Therefore, the intrathoracic pressure rise during thoracoscopy with two-lung ventilation should be kept as low as possible. Additional insufflation periods should be avoided, since a more rapid and more severe cardiopulmonary depression can occur.

The purpose of this study was to investigate the cardiopulmonary influences of sevoflurane in oxygen at two anaesthetic concentrations (1.5 and 2 MAC) during spontaneous and controlled ventilation in dogs. After premedication with fentanyl-droperidol (5 μg/kg and 0.25 mg/kg intramuscularly) and induction with propofol (6 mg/kg intravenously) six dogs were anaesthetized for 3 h. Three types of ventilation were compared: spontaneous ventilation (SpV), intermittent positive pressure ventilation (IPPV), and positive end expiratory pressure ventilation (PEEP, 5 cm H 2 O). Heart rate, haemoglobin oxygen saturation, arterial blood pressures, right atrial and pulmonary arterial pressures, pulmonary capillary wedge pressure and cardiac output were measured. Find tidal CO 2 %, inspiratory oxygen fraction, respiration rate and tidal volume were recorded using a multi-gas analyser and a respirometer. Acid-base and blood gas analyses were performed. Cardiac index, stroke volume, stroke index, systemic and pulmonary vascular resistance, left and right ventricular stroke work index were calculated. Increasing the MAC value during sevoflurane anaesthesia with spontaneous ventilation induced a marked cardiopulmonary depression; on the other hand, heart rate increased significantly, but the increases were not clinically relevant. The influences of artificial respiration on cardiopulmonary parameters during 1.5 MAC sevoflurane anaesthesia were minimal. In contrast, PEEP ventilation during 2 MAC concentration had more pronounced negative influences, especially on right cardiac parameters. In conclusion, at 1.5 MAC, a surgical anaesthesia level, sevoflurane can be used safely in healthy dogs during spontaneous and controlled ventilation (IPPV and PEEP of 5 cm H 2 O).

An experimental infection with classical swine fever (CSF) virus in 12 conventional gilts, housed in a sow-box housing system, was conducted in order to evaluate horizontal transmission, clinical, virological and serological response, and the effect on gestation. Two of the 12 gilts, of which 10 were pregnant, were experimentally inoculated. They became viraemic for the first time 6 days post-inoculation (dpi). The contact gilts became viraemic between 18 and 21 days post inoculation. On the basis of virological findings and the martingale estimate of R0 (13.0) it was concluded that the two experimentally inoculated gilts infected all contact gilts, although random contacts between gilts were not possible. The prescence of CSF infection could be diagnosed earlier and during a longer period when the leucocyte count or polymerase chain reaction were used in comparison with virus isolation in whole blood (P < 0.05). The observed clinical symptoms were atypical and highly variable between the gilts, which hampered clinical diagnosis. The pregnant gilts became infected between day 43 and 67 of gestation. In all cases vertical virus transmission occurred and this resulted partially in abortion and/or mummification.

In the present study the influence of three volatile agents (halothane, isoflurane and sevoflurane) in oxygen at two concentrations [1.5 and 2 minimum alveolar concentration (MAC)] on non-invasive cardio-respiratory parameters (heart and respirators rates, non-invasive blood pressures at 15, 30, 60 min and after extubation) and on the recovery times (appearance of the first eyelid reflex, emergence time) after clinical anaesthesia was studied. After premedication with fentanyl-droperidol (5 microg/kg and 0.25 mg/kg, intramuscularly) and induction with propofol (5 mg/kg, intravenously) six dogs were randomly anaesthetized for 1 h for a standard neurologic stimulation test. A wide individual variation in respiration rate (induced by an initial hyperpnea) was observed in the 1.5 MAC protocols, without significant differences. Heart rate was significantly lower during 1.5 and 2 MAC halothane when compared to isoflurane and sevoflurane. An increase from 1.5 to 2 MAC induced significant decreases in diastolic (DAP) and mean arterial blood pressure in all groups without significant changes in the systolic arterial pressures. Only DAP in sevoflurane protocol was significantly different at 1.5 and 2 MAC compared to halothane. Time had no significant influences in the non-invasive blood pressures in all protocols. Extubation induced a significant increase of all parameters in all protocols. The time for a first eyelid reflex was significantly longer after 2 MAC compared to the 1.5 MAC protocol. There was no significant difference between the three anaesthetic agents. Although emergence time was longest for halothane at both anaesthetic concentrations, no significant difference in emergence time was observed for the three volatile agents.

International audience; This cross-sectional epidemiologic study was conducted in 150 randomly selected farrow-to-finish pig herds to investigate descriptive epidemiological characteristics of infections with three different serovars of Actinobacillus pleuropneumoniae, and to identify risk factors for the within-herd seroprevalences of these serovars. Different farm characteristics ($n = 28$) were examined as potential risk factors for the percentage of pigs with antibodies against serovars 2, 3 and 9. The presence of antibodies was measured using an indirect ELISA. Logistic regression analyses were used to assess the associations between the potential risk factors and the proportion of seropositive pigs. The median within-herd seroprevalences were 95% (range: 0-100% ), 100% (range: 10-100% ), and 35% (range: 0-100% ) for serovars 2, 3, and 9, respectively. There was a positive association ($P < 0.001$) between each of these serovars. The within-herd seroprevalence of serovar 2 was significantly higher in farms that purchased gilts from $\geq$ 2 origin herds (OR = 2.33; $P < 0.05$) and in farms with poor biosecurity measures (OR = 4.62; $P < 0.05$). The proportion of pigs seropositive for serovar 3 was significantly higher when tested pigs were slaughtered in May-August and in November-December (OR = 5.96; $P < 0.001$), in herds without a growing unit (OR = 2.63; $P < 0.01$), and in herds with a direct air-entry into the finishing unit (OR = 1.92; $P < 0.05$). The within-herd seroprevalence of serovar 9 increased significantly in herds with poor biosecurity measures (OR = 1.76; $P < 0.05$). The study documented that infections with A. pleuropneumoniae serovars 2, 3, and 9 were very common in the selected herds, and that the sero-epidemiological characteristics and risk factors showed some variation depending on the serovar. The purchase policy of gilts and biosecurity measures are risk factors that can be improved fairly easily on pig farms.; Facteurs de risque associés à la séroprévalence d'Actinobacillus pleuropneumoniae serovars 2, 3 et 9 chez le porc charcutier provenant d'élevages naisseurs-engraisseurs. Une étude transversale séro-épidémiologique vis-à-vis de trois sérovars (2, 3 et 9) d'Actinobacillus pleuropneumoniae a été conduite chez des porcs charcutiers à l'abattoir. Ces animaux provenaient de 150 élevages naisseurs-engraisseurs sélectionnés au hasard. Il s'agissait d'identifier les principaux facteurs explicatifs de la variation de la séroprévalence intra-troupeau pour ces trois sérovars. Différentes caractéristiques d'élevages ($n = 28$) ont été étudiées comme étant susceptibles d'expliquer la séroprévalence. La présence d'anticorps a été évaluée par ELISA indirect. Les associations entre ces facteurs ont été calculées par régression logistique. La prévalence médiane intra-élevage d'animaux séroréacteurs était respectivement de 95 % (étendue : 0-100 % ), 100 % (étendue : 10-100 % ) et 35 % (étendue : 0-100 % ) pour les sérovars 2, 3 et 9. Il existe une association positive ($P < 0.001$) entre les trois sérovars. Le pourcentage de porcs séropositifs vis-à-vis du sérovar 2 était plus élevé dans les porcheries où les éleveurs avaient introduit de nouvelles cochettes provenant de plus de 2 élevages (OR = 2.33; $P < 0.05$) et dans les porcheries avec des mesures de biosécurité insuffisantes (OR = 4.62; $P < 0.05$). La prévalence du sérovar 3 était plus élevée lorsque les porcs étaient abattus entre mai et août d'une part et de novembre à décembre d'autre part (OR = 5.96; $P < 0.001$), dans les élevages sans unité de pré-engraissement (OR = 2.63; $P < 0.01$) ainsi que dans les élevages avec une entrée d'air directe (OR = 1.92; $P < 0.05$). La détection d'animaux séropositifs pour le sérovar 9 augmentait dans les élevages avec des mesures de biosécurité insuffisantes (OR = 1.76; $P < 0.05$). Cette étude a démontré que les infections à A. pleuropneumoniae étaient fréquentes dans les élevages sélectionnés et que les facteurs de risque étaient différents selon le sérovar impliqué. L'introduction de cochettes dans le troupeau et les mesures de biosécurité sont des facteurs de risque qui peuvent être facilement améliorés dans des élevages porcins.

An experimental infection with classical swine fever (CSF) virus in E2 sub-unit marker vaccine vaccinated gilts was conducted in order to evaluate the effect of vaccination on virus transmission and course of the disease. Therefore, clinical signs as well as horizontal and vertical virus transmission were monitored in two inoculated, non-vaccinated and 10 vaccinated conventional gilts, housed in individual sow boxes. Within 10 days post-inoculation, all vaccinated gilts became infected. Depending on the definition of the infectious period, two different estimates of R0 were calculated (R0=14.8 and 3.3), both significantly larger than 1 (P

Aesculin-hydrolyzing, catalase-negative, gram-positive cocci isolated from subclinical intramammary infections in dairy cows were identified to species level using growth characteristics and biochemical activity. The results indicated that the aesculin-hydrolyzing cocci associated with this type of infection are a very heterogenic group. S. uberis strains, including inulin- or beta-glucuronidase-negative isolates, accounted for only about one-third of the collection, and Enterococcus faecalis strains for one-fifth. Other species of some importance included (in descending order of isolation frequency) Aerococcus viridans, Streptococcus pluranimalium, Lactococcus garvieae, Streptococcus bovis and Streptococcus gallolyticus.

The spread of classical swine fever virus was investigated in an isolation unit containing four pens, each containing six slaughter pigs. One pig in the middle pen of three adjacent pens was inoculated intramuscularly and intranasally with the virus. The fourth pen was located in a separate compartment. containing six slaughter pigs. One pig in the middle pen of three adjacent pens was inoculated intramuscularly and intranasally with the virus. The fourth pen was located in a separate compartment. The pens were visited in a strict order to study, first, the effect of indirect contact via contaminated clothing and footwear on the spread of the virus to adjacent pens and, secondly, the airborne transmission of the virus between compartments. The pigs were examined and blood samples were taken every other day for 62 days for virological and serological analyses. The virus was highly contagious for the five pigs that were in direct contad with the inoculated pig, but spread to the other pens only after all the pigs in the originally infeded pen had become viraemic. The spread of the virus was promoted by contaminated clothing and footwear, but airbome transmission contributed considerably to the spread of the virus within the pighouse. The first clinical signs observed after the virus was introduced into a pen were decreased feed intake, increased mean rectal temperature and apathy. Neither the clinical course of the infection, nor the pattem of seroconversion observed over time, was affected by the differences in the intensity of contact with the virus between the pigs in the different pens.

A preliminary investigation was performed to examine whether insulin resistance is a factor in the pathogenesis of cystic ovarian disease (COD) in high-yielding dairy cows. In total 30 cows, of which 15 were diagnosed as suffering from COD based on the anamnesis and clinical examination, and the other 15 served as matched controls, were subjected to an intravenous glucose tolerance test (IVGTT). The aim of the study was to investigate whether insulin activity was altered in COD cows. Differences in glucose clearance between the COD cows and their controls were analyzed comparing the fractional turnover rate (k), the glucose half-time (T1/2), and the area under the curve (AUC) 60 and 120 min after infusion. Differences in insulin response were analyzed comparing the insulin increment, the insulin peak concentration, and the AUC 60 and 120 min after glucose infusion. Although insulin resistance, attended by a secondary hyperinsulinemia, is stated to directly contribute to the ovarian abnormalities that characterize the polycystic ovary syndrome (PCOS) in human medicine, this was not observed in COD cows. On the contrary, COD cows appeared to have a low insulin response following an intravenous glucose load as compared with their matched controls. This was illustrated by significantly lower insulin increments (P = 0.04) and lower insulin peak concentrations (P = 0.04). As COD cows had a significantly lower insulin response to a standard glucose load, it was concluded that insulin could be a factor in the pathogenesis of COD in dairy cows.

An atypical Staphylococcus aureus (S. aureus) strain, isolated in a dairy herd over an 8 month period, was examined. The S. aureus strain was clumping factor negative, weakly heat-resistant deoxyribonuclease positive and produced narrow zones of double haemolysis. In total, 57 quarter infections were observed. Prevalence data per month, calculated as the percentage of quarters infected with this atypical S. aureus strain varied from 7.5% to 17.7% and the new infection rate varied from 0.14 to 0.55. In routine bacteriology, the large number of quarters infected with the atypical S. aureus could easily be misclassified as quarters infected with non-aureus staphylococci.