Mycoplasma bovis is known as a causative agent of many disorders in cattle. In Europe, there is still a lack of commercial vaccines against M. bovis infection. Acute phase response (APR) is a non-specific host reaction to infection, most seen in changes in production of acute phase proteins. The aim of this study was to analyse APR in calves administered with an experimental M. bovis vaccine. Twelve healthy female calves were divided into two equal groups: experimental and control. The experimental vaccine containing the field M. bovis strain and two adjuvants such as saponin and lysozyme dimer was subcutaneously administered to the experimental group. Phosphate buffered saline was taken as the placebo and given to the control group by the same route as the vaccine. Blood samples were collected prior to the study (day 0), then daily up to day 7, and then each seven days until day 84 post vaccination. The concentrations of serum amyloid A (SAA), haptoglobin (Hp), interferon-γ (IFN-γ), and inteleukin-4 (IL-4) were determined using commercial ELISA kits. Following the vaccination, a significant increase in SAA, Hp, and IFN-γ concentrations was observed when compared to the unvaccinated calves, whereas the IL-4 concentration was not detectable. The experimental saponin-based M. bovis vaccine containing lysozyme dimer adjuvant visibly stimulated the APR in the calves, and some specific cytokines (Th1-dependent) directly involved in this response.

Bovine Norovirus (BoNeV) which has been confirmed in Asia, America, and Europe, seems to be distributed worldwide, even though only reported from a number of countries. Bovine noroviruses are predominantly detected in diarrhoeic animals rather than neboviruses. The study reveals the importance of noro- and neboviruses in early age diarrhoea of calves. A total of 127 stool samples were collected from three provinces located in the central region of Turkey. Samples were subjected to nucleic acid isolation and reverse transcription and polymerase chain reaction (PCR). Positive samples were sequenced and analysed. According to PCR, five samples (3.93%) were found to be positive for bovine norovirus while 32 (25.19%) samples were found to be positive for bovine nebovirus. Phylogenetic analysis indicated that the novel Turkish norovirus strains were found to be of genotype III.2 and all novel neboviruses were substituted under Nebraska-like strains. Although predominantly bovine noroviruses are detected worldwide, the study indicated that bovine neboviruses were more prevalent in the studied area. We suggest that bovine neboviruses are more frequently responsible for calf diarrhoea than supposed by virologists. This is also the first report of neboviruses other than Kirklareli virus which is distantly related to neboviruses detected in Turkey.

Intestinal obstruction such as atresia coli causes pathophysiological changes in gastrointestinal tissue due to the rise of intra-abdominal pressure. The aim of this study is to determine the intestinal damage with intestinal biomarkers in calves with atresia coli. The study was conducted on 40 Holstein calves diagnosed with atresia coli with mild to moderate abdominal distention and 10 healthy Holstein calves which served as the control. Blood samples were collected from all calves, and then serum concentrations of intestinal biomarkers were estimated, namely intestinal fatty acid binding protein (IFABP), liver fatty acid binding protein (LFABP), trefoil factor 3 (TFF3), and intestinal alkaline phosphatase (IAP), using commercially available specific bovine ELISA kits. An automatic blood gas analyser was employed for determining the lactate concentration. The concentrations of serum LFABP (P < 0.01), IFABP, TFF3, IAP, and blood lactate (P < 0.001) were significantly higher in calves with atresia coli than in healthy calves. The calves affected with atresia coli exhibited severe intestinal damage, and IFABP, LFABP, and TFF3 have significant diagnostic importance and play a useful role in determining the intestinal damage due to intestinal obstruction. High levels of IAP and lactate may serve as a signal for the development of intestinal injury.

OBJECTIVE To evaluate cell-mediated and humoral immune responses of calves receiving 2 doses of a dual-adjuvanted vaccine containing inactivated bovine herpesvirus type 1 (BHV1) and bovine viral diarrhea virus types 1 (BVDV1) and 2 (BVDV2) before and after exposure to BHV1. ANIMALS 24 Holstein steers negative for anti-BHV1 antibodies and proliferative cell-mediated immune responses against BHV1 and BVDV. PROCEDURES Calves were randomly assigned to 3 groups. The vaccinated group (n = 10) received 2 doses of vaccine on days 0 and 21. Control (n = 10) and seeder (4) groups remained unvaccinated. Calves were commingled during the study except for the 3-day period (days 53 to 55) when seeders were inoculated with BHV1 (1.04 × 107 TCID50, IV) to serve as a source of virus for challenge (days 56 through 84). Rectal temperature and clinical illness scores were monitored, and blood and nasal specimens were obtained for determination of clinicopathologic and immunologic variables. RESULTS After BHV1 challenge, mean rectal temperature and clinical illness scores were lower for vaccinates than controls. In vaccinates, antibody titers against BHV1 and BVDV2, but not BVDV1, increased after challenge as did extracellular and intracellular interferon-γ expression, indicating a T helper 1 memory response. Additional results of cell marker expression were variable, with no significant increase or decrease associated with treatment. CONCLUSIONS AND CLINICAL RELEVANCE Calves administered 2 doses of a killed-virus vaccine developed cell-mediated and humoral immune responses to BHV1 and BVDV, which were protective against disease when those calves were subsequently exposed to BHV1.

OBJECTIVE To measure cerebral blood flow (CBF) and cerebral blood volume (CBV) by means of perfusion CT in clinically normal Holstein calves. ANIMALS 9 Holstein calves. PROCEDURES Each of the 9 calves (mean age, 20.2 days) was anesthetized and received an injection of iodinated contrast medium into the right jugular vein at a rate of 4.0 mL/s. Dynamic CT scanning of the head at a level that included the mandibular condyle was initiated at the time of the contrast medium injection and continued for 100 seconds. A deconvolution method was used as an analytic algorithm. RESULTS Among the 9 calves, the mean ± SD CBF in the cerebral cortex, white matter, and thalamus was 44.3 ± 10.3 mL/100 g/min, 36.1 ± 7.5 mL/100 g/min, and 40.3 ± 7.5 mL/100 g/min, respectively. The CBF in white matter was significantly lower than that in the cerebral cortex or thalamus. The mean CBV in the cerebral cortex, white matter, and thalamus was 6.8 ± 1.0 mL/100 g, 5.2 ± 1.0 mL/100 g, and 5.7 ± 0.7 mL/100 g, respectively. The CBV in the cerebral cortex was significantly higher than that in the white matter or thalamus. CONCLUSIONS AND CLINICAL RELEVANCE Measurement of CBF and CBV in clinically normal calves by means of perfusion CT was feasible. The data obtained may be useful as baseline values for use in future research or for comparison with findings from calves with CNS diseases. Investigations to determine the lower limit of blood flow at which brain function can still be restored are warranted.

Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile are important human pathogens that are also carried by animals. The role of wild mammals on farms in their maintenance and transmission, however, is poorly understood. To determine if Norway rats (Rattus norvegicus) are potential carriers of these bacteria on Canadian farms, we tested 21 rats from swine farms in Ontario. The MRSA spa type t034 was isolated from 1 (4.8%) rat. This livestock-associated strain often colonizes pigs and pig farmers, suggesting that transmission among rats and pigs or environmental transmission is possible on pig farms. Clostridium difficile ribotype 078 was isolated from 1 rat from a different farm. This strain is associated with infection in piglets, calves, and humans. The identification of MRSA and C. difficile in Norway rats on farms in Canada adds to the growing knowledge about the role of rats in the ecology of these pathogens. Further studies are required to determine if rats play a part in the epidemiology of these pathogens on farms.

OBJECTIVE To compare the plasma pharmacokinetics of tulathromycin between 3-week-old (preweaned) and 6-month-old (weaned) calves and to characterize the distribution of tulathromcyin into pulmonary epithelial lining fluid (PELF) and interstitial fluid (ISF) of preweaned and weaned calves following SC administration of a single dose (2.5 mg/kg). ANIMALS 8 healthy 3-week-old and 8 healthy 6-month-old Holstein steers. PROCEDURES A jugular catheter and SC ultrafiltration probe were aseptically placed in the neck of each calf before tulathromycin administration. Blood, ISF, and bronchoalveolar lavage fluid samples were collected at predetermined times before and after tulathromycin administration for quantification of drug concentration. A urea dilution method was used to estimate tulathromycin concentration in PELF from that in bronchoalveolar lavage fluid. Tulathromycin–plasma protein binding was determined by in vitro methods. Plasma pharmacokinetics were determined by a 2-compartment model. Pharmacokinetic parameters and drug concentrations were compared between preweaned and weaned calves. RESULTS Clearance and volume of distribution per fraction of tulathromycin absorbed were significantly greater for weaned calves than preweaned calves. Tulathromycin–plasma protein binding was significantly greater for weaned calves than preweaned calves. Maximum PELF tulathromycin concentration was significantly greater than the maximum plasma and maximum ISF tulathromycin concentrations in both groups. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that age affected multiple pharmacokinetic parameters of tulathromycin, likely owing to physiologic changes as calves mature from preruminants to ruminants. Knowledge of those changes may be useful in the development of studies to evaluate potential dose adjustments during treatment of calves with respiratory tract disease.