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Summary

To assess the effects on heart and lung function, a tiletamine-zolazepam (tz) anesthetic combination was evaluated in 10 Dorset-type ewes. Ewes were randomly allotted to 2 equal groups. Ewes of groups 1 and 2 were given a single bolus of tz (12 and 24 mg/kg of body weight, iv, respectively) at time zero. Hemodynamic, pulmonary, and ventilation variables were measured at 15-minute intervals to 120 minutes. Blood gas variables were evaluated at 5-minute intervals for the first 30 minutes, then at 15-minute intervals to 120 minutes. In all sheep, tz administration induced rapid, smooth induction, with gradual and unremarkable recovery. Anesthesia duration was not significantly different between groups (mean ± sd, 39 ± 5 and 40 ± 14 minutes for groups 1 and 2, respectively). Immediate drug effects included apnea, decreased mean arterial blood pressure, and arterial hypoxemia. Cardiac output was significantly decreased in both groups at all times after drug administration. Significant changes in group-1 ewes included increased pulmonary and systemic vascular resistances and decreased inspired minute ventilation, tidal volume, and respiratory airflow. Significant changes in group-2 ewes included increased systemic vascular resistance and decreased pulmonary arterial pressure, inspired minute ventilation, and respiratory airflow. Both drug dosages induced apneustic breathing patterns and caused significant changes in arterial and venous blood hemoglobin concentrations and pcv. Tiletamine-zolazepam is useful for intermediate-duration anesthesia in sheep. However, because of alterations in cardiopulmonary function, its use at the dosages evaluated by us is not recommended in studies, in which minimal effects on heart and lung function are required, or in sheep with compromised heart or lung function.

Free access
in American Journal of Veterinary Research

Objective

To describe clinical and clinicopathologic findings from dogs with histologic pulmonary lesions consistent with human adult respiratory distress syndrome and to identify potential risk factors.

Design

Retrospective study.

Animals

19 dogs with acute respiratory distress.

Procedure

Medical records of dogs were reviewed. Signalment, physical examination and clinicopathologic findings at admission, and thoracic radiographic and necropsy findings were recorded.

Results

The most common clinical sign was dyspnea. Respiratory rate ranged from 36 to 140 breaths/min, and abnormal breathing patterns were detected. Crackles were auscultated in 7 dogs. Severe diffuse interstitial and alveolar infiltrates were observed on thoracic radiography in 9 dogs shortly after arrival and developed later in 4 dogs. Four dogs were leukopenic and neutropenic. Disseminated intravascular coagulation was diagnosed in 2 dogs, and hypoalbuminemia was found in 8 dogs. Respiratory status deteriorated rapidly in all dogs, and 10 dogs were mechanically ventilated. Death was attributed solely to respiratory failure in 8 dogs. In the other 11 dogs, severe lesions in nonpulmonary organs, sepsis, or both may have contributed to death. The most common associated conditions that may have contributed to acute respiratory failure were microbial pneumonia, sepsis, aspiration pneumonia, and shock, with more than 1 factor found in 11 of 19 dogs.

Clinical Implications

The index of suspicion for acute respiratory distress syndrome should be high in dogs with bilateral pulmonary infiltrates and acute respiratory distress that rapidly progresses to failure. (J Am Vet Med Assoc 1996;208:1419-1427)

Free access
in Journal of the American Veterinary Medical Association

efficacy of TFPs in snakes. The primary objective of the study reported here was to quantify plasma fentanyl concentrations and evaluate antinociceptive and respiratory effects following application of TFPs in ball pythons. In a previous study, 16 TFP

Full access
in American Journal of Veterinary Research

Summary

Adherence of Mycoplasma hyopneumoniae to the mucosa of the distal portion of the respiratory tract of swine is an important initial event in development of mycoplasmal pneumonia. A suitable in vitro model of adherence would be useful for investigation of mycoplasmal and host cell factors involved in this process. We have developed an adherence assay, using suspensions of porcine respiratory tract ciliated epithelial cells and M hyopneumoniae. Tracheal epithelial cells, collected by use of cytologic brushes, were mixed with broth cultures of M hyopneumoniae and the mixtures were incubated, diluted, vortexed, and sedimented. Pellets were spread on glass slides, stained with a fluorescent antibody against M hyopneumoniae, and evaluated by fluorescent microscopy. Fluorescence was observed principally among cilia on the ciliated tufts of epithelial cells. Only a few organisms were observed adhering on the nonciliated parts of ciliated cells or on other cell types. When mycoplasmas were preincubated with low dilutions of serum from swine convalescing from M hyopneumoniae disease, attachment was partially inhibited (P < 0.05). Significant inhibition of attachment was not observed when organisms were preincubated with higher dilutions of convalescent serum, with purified IgG from hyperimmune serum against M hyopneumoniae, or with low dilutions of lung lavage fluids (from convalescent swine) that contained specific IgA antibodies against M hyopneumoniae. Preincubation of the organisms with periodate and trypsin abolished attachment and formaldehyde decreased it (P < 0.05), whereas a variety of carbohydrates had no effect on attachment. Preincubation with dextran sulfate, ammonium sulfate, magnesium sulfate, and methionine reduced attachment (P < 0.05). Treatment of cell-Mycoplasma mixtures with the hydrophobic bond-breaking agent tetramethylurea, or incubation in absence of salt, or at low temperature also reduced attachment (P < 0.05). Attachment was not observed when ovine, rabbit, or guinea pig ciliated respiratory tract cells were mixed with M hyopneumoniae. Attachment of M dispar to porcine ciliated cells could not be detected, whereas M hyorhinis attached nonspecifically to all cell types in suspensions of porcine tracheal mucosa. These results indicate that adherence of M hyopneumoniae may be a host-specific event that is mediated by proteins and carbohydrates on the surface of the organism and by sulfur-containing molecules in the host cell membrane. The highly polarized location of the mycoplasmas on the cilia of epithelial cells indicates possible existence of stereospecific interactions between mycoplasmal adhesin(s) and receptor(s) on host cells. However, decreased adherence obtained by incubating Mycoplasma-ciliated cell mixtures with tetramethyl-urea, by incubating mixtures in absence of salt or at low temperature, indicates that nonspecific hydrophobic interactions might have a role in the attachment process.

Free access
in American Journal of Veterinary Research

characterize risk factors for BRD in nursing beef calves. Bovine respiratory disease in nursing calves has been reported in approximately 20% of US beef cow-calf herds, 4,5 and a 2014 analysis estimates that BRD in nursing calves costs US cow-calf producers

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in Journal of the American Veterinary Medical Association

Bovine respiratory disease complex is the most economically consequential disease affecting the beef feedlot industry. 1 Identification of calves with BRDC is routinely performed on the basis of visual observation of signs of depression, nasal

Full access
in Journal of the American Veterinary Medical Association

Bovine respiratory disease is the most economically important disease in the beef cattle industry, developing primarily in high-risk, recently weaned commingled cattle arriving at the feedlot. 1 Despite the use of so-called new

Full access
in American Journal of Veterinary Research

Mycoplasma spp were first documented in 1934, 1 but their role in respiratory disease in dogs remains unclear. Mycoplasma spp are readily isolated from the oropharynges of healthy dogs and are generally accepted as commensal organisms in the

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether an inactivated bovine respiratory syncytial virus (BRSV) vaccine would protect calves from infection with virulent BRSV.

Design—Randomized controlled trial.

Animals—27 nine-week-old calves seronegative for BRSV exposure.

Procedure—Group-1 calves (n = 9) were not vaccinated. Group-2 calves (n = 9) were vaccinated on days 0 and 21 with an inactivated BRSV vaccine containing a minimum immunizing dose of antigen. Group-3 calves (n = 9) were vaccinated on days 0 and 21 with an inactivated BRSV vaccine containing an amount of antigen similar to that in a commercial vaccine. All calves were challenged with virulent BRSV on day 42. Clinical signs and immune responses were monitored for 8 days after challenge. Calves were euthanatized on day 50, and lungs were examined for lesions.

Results—Vaccination elicited increases in BRSV-specific IgG and virus neutralizing antibody titers and in production of interferon-γ. Virus neutralizing antibody titers were consistently less than IgG titers. Challenge with BRSV resulted in severe respiratory tract disease and extensive pulmonary lesions in control calves, whereas vaccinated calves had less severe signs of clinical disease and less extensive pulmonary lesions. The percentage of vaccinated calves that shed virus in nasal secretions was significantly lower than the percentage of control calves that did, and peak viral titer was lower for vaccinated than for control calves.

Conclusions and Clinical Relevance—Results suggest that the inactivated BRSV vaccine provided clinical protection from experimental infection with virulent virus and decreased the severity of pulmonary lesions. Efficacy was similar to that reported for modified-live BRSV vaccines. (J Am Vet Med Assoc 2001;218:1973–1980)

Full access
in Journal of the American Veterinary Medical Association

Bovine respiratory disease complex is a multifaceted disease caused by a combination of viral and bacterial pathogens that affect immunosuppressed calves. In dairy cattle, Pasteurella multocida is the most common bacterial pathogen; however

Full access
in Journal of the American Veterinary Medical Association