Table of Contents and Abstracts

Bovine respiratory disease (BRD) often occurs during specific periods of increased susceptibility when stress, viral infection, or reduced air quality are thought to suppress respiratory defences. The innate immune system is rapidly responsive and broadly protective and could be a target for preventing BRD during these periods of increased susceptibility. This study tested the hypothesis that stimulation of pulmonary innate immune responses by aerosol delivery of a lysate of killed Escherichia coli and Staphylococcus aureus bacteria would protect calves against Mannheimia haemolytica pneumonia. Ten clean-catch colostrum-deprived Holstein calves were randomly assigned to receive either aerosolized bacterial lysate or saline 24 hours before M. haemolytica challenge. Effects of this treatment on clinical, hematologic, microbiologic, and pathologic outcomes were assessed. Compared to controls, lysate-treated calves had lower serum haptoglobin and blood leukocyte and neutrophil concentrations following M. haemolytica challenge. There were no differences in temperature, heart and respiratory rates, clinical scores, ultrasound lesions, or number of M. haemolytica in the nasal cavity or lung. Thus, treatment with bacterial lysate prior to M. haemolytica challenge appeared to ameliorate early measures of inflammation but did not provide sufficient protection to substantially alter the course of disease.

The objective of this field trial was to compare the effect of 3 different types of combination vaccines on growth performance in pigs under field conditions. The vaccines compared were: a trivalent vaccine containing porcine circovirus type 2a and 2b (PCV-2a/b); and Mycoplasma hyopneumoniae; a mixable bivalent vaccine containing PCV-2a and M. hyopneumoniae; and a ready-to-use bivalent vaccine containing PCV-2a and M. hyopneumoniae. Two farms were selected on the basis of their history of subclinical PCV-2d infection and enzootic pneumonia. A total of 120 pigs on each farm was randomly divided into 4 groups of 30 pigs each. The trivalent-vaccinated group from both farms outperformed each bivalent-vaccinated group in terms of growth performance. Growth performance was significantly improved during the fattening period (70 to 175 d of age) in the mixable bivalent-vaccinated group compared with the ready-to-use bivalent-vaccinated group on 1 farm. The trivalent-vaccinated group elicited higher levels of neutralizing antibodies and interferon-γ secreting cells (IFN-γ-SC) against PCV-2d, while simultaneously decreasing the levels of PCV-2d load in blood when compared with the mixable and ready-to-use bivalent-vaccinated groups. The trivalent-vaccinated group also elicited higher levels of IFN-γ-SC against M. hyopneumoniae and lower levels of M. hyopneumoniae load in the larynx when compared with the mixable and ready-to-use bivalent-vaccinated groups. The results of the present study demonstrated that a trivalent vaccine containing PCV-2a/b and M. hyopneumoniae resulted in a more productive parameter, higher immune responses, and less blood-viral and mycoplasmal larynx-loads when compared with the mixable and ready-to-use bivalent vaccines despite the presence of ongoing subclinical PCV-2d infection and enzootic pneumonia on the farms.

Vesicular disease caused by Seneca Valley virus (SVV) has recently emerged throughout China and caused certain industry losses. We used immunofluorescence and western blotting to confirm that 3 new SVV strains (CH-GDSG-2018-1, CH-GDSG-2018-2, and CH-GDSG-2018-3) were from 1 pig farm. Phylogenetic analysis revealed the following: i) all 3 strains belong to USA-GBI29-2015-like clades, ii) CH-GDSG-2018-3 might have diverged from CH-GDSG-2018-1 and CH-GDSG-2018-2, and iii) CH-GDSG-2018-3 is a recombinant of the CHhb17 and HeNKF-1 strains. Virus growth curves showed that CH-GDSG-2018-3 had stronger proliferation ability in vitro. Seneca Valley virus has evolved extensively within China and this study has furthered our understanding of SVV epidemiology.

The objective of this study was to evaluate the pharmacokinetics profile of ergot alkaloids when administered to sheep orally. Although ergot alkaloids frequently contaminate animal feed, current understanding of their pharmacokinetics in animals cannot adequately predict toxicity. Blood samples were collected from ewes at 0.5, 1, 3, 5, and 12 h after oral exposure to 4 ergot alkaloids: ergocornine, ergocristine, ergocryptine, and ergosine, followed by serum analysis of these alkaloids using high performance liquid chromatography and tandem mass spectrometry. The alkaloids showed extended absorption time, in addition to clear signs of enterohepatic circulation. This pharmacokinetic profile suggests potential enhanced toxicity in animals with disorders related to secretion of bile acid. It may also explain the high susceptibility of sheep to ergot poisoning compared to other species. An extended sampling protocol (> 12 h) is necessary, however, to identify the pharmacokinetic properties of ergot alkaloids in ewes. In conclusion, ewes exposed to ergot alkaloids showed a prolonged absorption phase and enterohepatic circulation, which is in contrast with human ergot pharmacokinetics.

The objective of this study was to compare maximal leakage pressures and locations of 2 functional end-to-end stapled anastomosis (FEESA) constructs. Grossly normal jejunum was harvested from 4 large breed dogs. Thirty-two 8-cm segments of bowel were used to construct 16 FEESA. Construct type was divided into 2 groups: traditional FEESA (tFEESA) and modified FEESA (mFEESA). Leakage pressures and locations were recorded and compared for the 2 groups. There was no difference in the leakage pressures of the tFEESA and the mFEESA. However, 1 tFEESA did leak at subphysiologic intestinal peristaltic pressures. Although no difference in maximal leakage pressure was detected between the 2 constructs, mFEESA is an attractive alternative to tFEESA, as it requires less equipment and none of the mFEESA constructs leaked at subphysiologic pressures.

There are limited options for treatment of the common disease, equine asthma. The aim of this study was to estimate the feasibility and potential efficacy of using nebulized lidocaine for treating equine asthma, while at the same time treating a separate cohort of asthmatic horses with inhaled budesonide. Nineteen horses with a history consistent with equine asthma were recruited from our referral population for a double-blind, randomized, controlled pilot clinical trial using Consolidated Standards of Reporting Trials (CONSORT) guidelines. After screening, 16 horses met the inclusion criteria for equine asthma and 13 horses actually completed the study. Horses were treated by their owners at home for 14 d before returning to our hospital for follow-up assessment. Interventions consisted of nebulization q12h for 14 d with 1.0 mg/kg body weight (BW) of lidocaine or corticosteroid treatment (nebulized budesonide 1 µg/kg, q12h). Clinical and tracheal mucus score, pulmonary function testing, and respiratory secretion cytology were assessed after 2 weeks of treatment to determine the outcome. Both lidocaine and budesonide cohorts had significant decreases (P < 0.05) in clinical score; the lidocaine cohort showed a significant decrease in bronchoalveolar lavage (BAL) neutrophil percentage and tracheal mucus score. Neither treatment resulted in significant changes in lung function parameters. No adverse events occurred. Lidocaine may be an effective and safe treatment for equine asthma in horses that cannot tolerate treatment with corticosteroids.

The pharmacokinetics and pharmacodynamics of midazolam were studied in eight 1-to-3-year-old healthy gelded donkeys. Blood samples were obtained. Heart rate, respiratory rate, rectal temperature, sedation/excitement, ataxia, and response to tactile and auditory stimuli were recorded at baseline until 48 hours after intravenous (IV) midazolam (0.1 mg/kg) administration. Plasma midazolam and 1-hydroxymidazolam were measured using reversed-phase high-performance liquid chromatography. Pharmacokinetic variables were calculated using non-compartmental analysis. Physiologic data were analyzed using a mixed-effects model followed by Dunnett’s test and behavioral data were analyzed using a Friedman test then a Dunn’s test; P < 0.05 was considered significant. Midazolam was detectable for up to 60 minutes post-treatment in 7 donkeys. The median total body clearance, volume of distribution at steady state, elimination half-life, and area under concentration-time profile were 1210 mL/kg/h, 359 mL/kg, 0.27 hours, and 82.7 h × ng/mL, respectively. 1-hydroxymidazolam was detected (29 to 105 ng/mL) between 5 to 15 minutes post-treatment in 4 donkeys. Compared to baseline, rectal temperature and ataxia increased from 90 to 720 minutes (P ≤ 0.038) and 3 to 15 minutes (P ≤ 0.024) post-treatment, respectively. No other parameters showed statistically significant differences. Healthy donkeys cleared midazolam rapidly from plasma after IV administration. Transient ataxia and recumbency without sedation were observed.

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is used for tumor evaluation. In veterinary medicine, anesthesia is an essential tool during the PET scanning process. However, the changes in FDG uptake in dogs that have undergone anesthesia for a longer duration have not been studied. This study aimed to analyze the influence of isoflurane anesthesia on FDG uptake in dogs undergoing PET. A crossover design was implemented by exposing 3 groups of 6 dogs to different durations of anesthesia (60, 90, and 150 minutes). Inhalation anesthesia was maintained throughout the scanning process (30 minutes) and FDG was injected 1 hour before the start of the PET scan. The standard uptake value of FDG was obtained for the 7 gross structures (whole brain, lung, salivary gland, liver, spleen, mediastinal blood pool, and kidney cortex) as well as for the 7 intracranial structures (frontal, parietal, temporal and occipital lobes, cerebellum, brain stem, and caudal colliculus). The whole brain and intracranial structures showed significantly lower FDG uptake in dogs with a longer duration of anesthesia, whereas other gross structures did not. Our results suggest that the duration of anesthesia should be considered when evaluating the uptake of FDG by the brain.

The genetic identity of Russian indigenous populations of the dark forest honeybee (Apis mellifera mellifera) is gradually being lost due to spontaneous hybridization and gene introgression from other subspecies, which are transferred into the forest and forest-steppe zones for commercial beekeeping. The objective of this study was to evaluate the effectiveness of various conservation and beekeeping practices in the complex biosphere reserve “Bashkir Urals” (the Southern Urals) in conserving the gene pool of the indigenous Burzyan bee population. We discovered that the variant Q of the COI-COII locus of mitochondrial DNA, which dominates in other bee subspecies, is absent in colonies in the remote landscape zones of this reserve. This haplotype occurs with a relatively low frequency in borts (natural tree hollows) and colods (manmade hollow pieces of logs hung on trees), which are used in wild-hive beekeeping. The proportion of the genetic marker is significantly higher in apiaries, as well as in borts and colods in parts of the reserve without strict conservation regimes. When using 9 microsatellite loci, a tendency was found to increase allelic diversity in subpopulations with a higher occurrence of the haplotype Q. Based on the patterns revealed, ways are discussed for improving measures to conserve the gene pool of the bee population.

Established test methods for detecting foot-and-mouth disease virus (FMDV) rely on sample collection from live animals. However, circumstances exist in which it is not possible to collect the desired samples. Meat juice has been explored as an alternative for the detection of FMDV and has previously proven successful by real-time reverse transcription polymerase chain reaction and lateral flow strip test. Meat juice has not yet been assessed for the detection of antibodies to FMDV. This study, therefore, evaluated meat juice for the detection of antibodies to structural proteins by existing serotype-specific solid phase competitive enzyme-linked immunosorbent assays. Antibodies to FMDV structural proteins were detected in meat juice from experimentally infected pigs beginning 6- or 7-days post-infection (DPI) and continued until 21 to 28 DPI. Sera were tested in tandem and followed similar antibody detection patterns. The results show that meat juice can be used for detection of anti-FMDV structural protein antibodies.

The objective of this study was to develop multiplex polymerase chain reaction (PCR) for the simultaneous detection of porcine circovirus 2 (PCV-2) and differentiation among 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) in collected clinical lymph node samples. The multiplex PCR detected each of 4 PCV-2 genotypes (2a, 2b, 2d, and 2e) to a dilution of 2 × 10¹ copies/µL. PCV-2a, PCV-2b, PCV-2d, and PCV-2e were propagated in tissues prior to DNA extraction for use in multiplex PCR for the simultaneous detection and differentiation of 4 PCV-2 genotypes. The designed multiplex PCR effectively detected and differentiated various combinations of multiple infection, such as PCV-2a+2b, PCV-2a+2d, PCV-2b+2d, PCV-2a+2e, and PCV-2a+2b+2d, in clinical lymph node samples. The results of this study demonstrated that multiplex PCR testing of clinical samples developed herein was able to simultaneously detect and differentiate among the 4 PCV-2 genotypes (PCV-2a, 2b, 2d, and 2e).

Swine vesicular disease (SVD) is an infectious viral disease of pigs. The clinical symptoms of SVD are indistinguishable from other vesicular diseases. In countries free of vesicular diseases, rapid SVD diagnosis and differentiation from other vesicular diseases are essential. In this report, a competitive enzyme-linked immunosorbent assay (cELISA) was developed and validated to improve the current SVD serological diagnosis. In this cELISA, an anti-SVD monoclonal antibody (mAb) captures the recombinant SVD virus-like particle (SVD-VLP) antigen, and 5B7 mAb is used as a competitor to compete with polyclonal antibodies in SVD-positive sera. The cut-off value of the SVD-VLP based cELISA (SVD-VLP cELISA) is ≥ 65% inhibition (%). The determined diagnostic specificity was 99.2%. SVD-VLP cELISA successfully detected SVD antibodies in the sera of SVD-infected animals and produced a diagnostic sensitivity of 100%. A panel of SVD positive sere including outbreak samples (n = 11) and samples (n = 5) from experimentally inoculated pigs, were correctly identified as positive by the SVD-VLP cELISA. In terms of reducing false positives detected by the currently used cELISA (5B7 cELISA), the performance of SVD-VLP cELISA is comparable to the gold standard virus neutralization test.