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Summary

In 1989, 4,808 cases of rabies in animals other than human beings were reported to the Centers for Disease Control, 1.8% more (4,724 to 4,808) than in 1988. Eighty-eight percent (4,224/4,808) of those affected were wild animals and 12% (584/4,808) were domestic animals. Cases were reported from 49 states, the District of Columbia, and Puerto Rico; Hawaii remained rabies-free. Skunks (1,657) continued to be the most commonly reported rabid wild animal. For the second consecutive year, more cats (212) were reported to be infected with rabies virus than any other domestic species. Compared with their 1988 reports, 5 states reported increases of greater than 100% (Alaska, 109%; New Jersey, 233%; Ohio, 133%; Oklahoma, 168%; and Washington, 125%), and 5 states reported decreases of greater than 50% (Connecticut, 63%; Mississippi, 56%; Montana, 67%; Nevada, 55%; and West Virginia, 53%) in 1989.

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To evaluate the biochemical and biomechanical properties of native and decellularized superficial digital flexor tendons (SDFTs) and deep digital flexor tendons (DDFTs) harvested from the pelvic limbs of orthopedically normal dogs.

SAMPLE 22 commercially supplied tendon specimens (10 SDFT and 12 DDFT) harvested from the pelvic limbs of 13 canine cadavers.

PROCEDURES DNA, glycosaminoglycan, collagen, and protein content were measured to biochemically compare native and decellularized SDFT and DDFT specimens. Mechanical testing was performed on 4 groups consisting of native tendons (5 SDFTs and 6 DDFTs) and decellularized tendons (5 SDFTs and 6 DDFTs). All tendons were preconditioned, and tension was applied to failure at 0.5 mm/s. Failure mode was video recorded for each tendon. Load-deformation and stress-strain curves were generated; calculations were performed to determine the Young modulus and stiffness. Biochemical and biomechanical data were statistically compared by use of the Wilcoxon rank sum test.

RESULTS Decellularized SDFT and DDFT specimens had significantly less DNA content than did native tendons. No significant differences were identified between native and decellularized specimens with respect to glycosaminoglycan, collagen, or protein content. Biomechanical comparison yielded no significant intra- or intergroup differences. All DDFT constructs failed at the tendon-clamp interface, whereas nearly half (4/10) of the SDFT constructs failed at midsubstance.

CONCLUSIONS AND CLINICAL RELEVANCE Decellularized commercial canine SDFT and DDFT specimens had similar biomechanical properties, compared with each other and with native tendons. The decellularization process significantly decreased DNA content while minimizing loss of extracellular matrix components. Decellularized canine flexor tendons may provide suitable, biocompatible graft scaffolds for bioengineering applications such as tendon or ligament repair.

Full access
in American Journal of Veterinary Research

Summary

To assess the suitability of sheep for exercise studies, the effect of incremental exercise and conditioning on oxygen consumption (Vo2 ) was studied. Six sheep were adapted to a treadmill and subsequently trained 8 weeks. The sheep were then studied, in random order, using 3 incremental exercise protocols (ex-1, ex-2, and ex-3). The protocols were chosen to approximate high (ex-1), moderate (ex-2), and low (ex-3) intensity exercise by varying treadmill speed and incline. The sheep were then conditioned for an additional 12 weeks and retested on the ex- 2 protocol. During exercise, Vo2 , gas exchange ratio (R), and rectal temperatures (Tb) were recorded. All 3 protocols resulted in significant increases in Vo2 , R, and Tb (P < 0.05). Maximum Vo2 for ex-1, 49.9 ± 5.0 ml/min/kg of body weight, was significantly greater than maximum Vo2 for ex-2 and ex-3, 37.8 ± 6.5 and 42.3 ± 6.0 ml/min/kg, respectively (P < 0.05), whereas maximum R and maximum Tb were similar. After the additional 12-week conditioning, time on the treadmill increased 40% from 9.58 ± 0.87 to 13.4 ± 0.44 minutes, and maximum V02 increased 27% to 48.1 ± 9.1 ml/min/kg. These data indicated that maximum Vo2 varied with intensity of the exercise, 12 weeks of maximal exercise conditioning was sufficient to produce a measurable training effect (ie, increase endurance and maximum oxygen consumption) and sheep are suitable for maximal exercise studies where Vo2 measurements are desired.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To identify and characterize motilin receptors in equine duodenum, jejunum, cecum, and large colon and to determine whether erythromycin lactobionate competes with porcine motilin for binding to these receptors.

Sample Population—Specimens of various segments of the intestinal tracts of 4 adult horses euthanatized for reasons unrelated to gastrointestinal tract disease.

Procedure—Cellular membranes were prepared from smooth muscle tissues of the duodenum, jejunum, pelvic flexure, and cecum. Affinity and distribution of motilin binding on membrane preparations were determined by use of 125I-labeled synthetic porcine motilin. Displacement studies were used to investigate competition between 125I-labeled synthetic porcine motilin and erythromycin lactobionate for binding to motilin receptors in various segments of bowel.

Results—Affinity of 125I-labeled synthetic porcine motilin for the equine motilin receptor was estimated to be 6.1nM. A significantly higher number of motilin receptors was found in the duodenum than in the pelvic flexure and cecum. The jejunum had a significantly higher number of motilin receptors than the cecum. Erythromycin lactobionate displacement of 125I-labeled porcine motilin from the equine motilin receptor did not differ significantly among various segments of bowel.

Conclusions and Clinical Relevance—Motilin receptors were found in the duodenum, jejunum, pelvic flexure, and cecum of horses. The highest number of motilin receptors was in the duodenum, and it decreased in more distal segments of bowel. Erythromycin lactobionate competed with motilin binding in the equine gastrointestinal tract. This suggests that 1 of the prokinetic actions of erythromycin in horses is likely to be secondary to binding on motilin receptors. (Am J Vet Res 2002;63:1545–1550)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether pigs can be infected with strains of vesicular stomatitis virus New Jersey (VSV-NJ) and vesicular stomatitis virus Indiana (VSV-I) isolated during recent vesicular stomatitis outbreaks that primarily involved horses in the western United States and determine the potential for these viruses to be transmitted by contact.

Animals—128 pigs.

Procedure—Pigs were challenged with VSV-NJ or VSV-I from the 1995 and 1997 outbreaks of vesicular stomatitis in the western United States, respectively, or with VSV-NJ (OS) associated with vesicular stomatitis in feral pigs on Ossabaw Island, Ga. Pigs (3/group) were inoculated with each virus via 3 routes and evaluated for viral shedding, seroconversion, and the development of vesicular lesions. In another experiment, the potential for contact transmission of each virus from experimentally infected to naïve pigs was evaluated.

Results—Infection of pigs was achieved for all 3 viruses as determined by virus isolation and detection of seroconversion. In inoculated pigs, all 3 viruses were isolated from multiple swab samples at concentrations sufficient to infect other pigs. However, compared with results obtained with the 2 VSV-NJ strains, viral titers associated with VSV-I were low and the duration of virus shedding was reduced. Results from the contact transmission trials were consistent with these results; virus transmission was detected most frequently with the VSV-NJ strains.

Conclusions and Clinical Relevance—Pigs can be infected with VSV-NJ and VSV-I. Differences in the extent of viral shedding and potential for contact transmission were apparent between serotypes but not between the VSV-NJ strains investigated. (Am J Vet Res 2004;65:1233–1239)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine incidence of and risk factors for major complications occurring in dogs within 30 days after cytoreductive surgery performed by a single pair of surgeons for treatment of suspected primary intracranial masses.

DESIGN Retrospective cohort study.

ANIMALS 160 client-owned dogs that underwent cytoreductive surgery for treatment of suspected primary intracranial masses between January 2009 and December 2015 at a veterinary teaching hospital.

PROCEDURES Medical records were retrospectively reviewed for complications occurring within 30 days after surgery. Data (eg, signalment, clinical signs, previous treatments, preoperative neurologic examination findings, neuroanatomical location, time from onset of clinical signs to surgery, surgical approach, and histopathologic diagnosis) were analyzed for associations with death and with development of major complications other than death.

RESULTS 21 (13.1%) dogs died (11 during hospitalization and 10 after discharge) and 30 (18.8%) developed major complications other than death during the first 30 days after surgery. Dogs with abnormal preoperative neurologic examination findings were more likely to develop complications or die. Dogs undergoing a suboccipital approach were more likely to die. The most common postoperative complications other than death were seizures (n = 18 [11.3%]), worsening of neurologic status (6 [3.8%]), and aspiration pneumonia (6 [3.8%]).

CONCLUSIONS AND CLINICAL RELEVANCE Results of the present study provided valuable information on predisposing factors, odds of major complications or death, and incidences of major complications or death in dogs during the first 30 days after undergoing cytoreductive surgery for treatment of suspected primary intracranial masses. Careful case selection may help improve outcomes and minimize complications.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the prevalence and temporal onset of lung lesions in lambs and the impact of lung lesions on growth of affected lambs.

Animals—259 crossbred wether lambs from a single flock in the upper Midwestern United States.

Procedure—An observational study was conducted. Lambs born in the spring and fall were slaughtered at finished weight or at a predetermined time point. Lungs of each lamb were examined and classified as normal, moderate lesions (consolidation > 5% but ≤ 50% of any lobe), or severe lesions (consolidation > 50% of any lobe). Data were examined to detect effects of prevalence or severity of lung lesions on growth and carcass traits.

Results—57 of 89 (64%) spring-born lambs had lung lesions characterized by consolidation of lung tissue. A small number of lambs had pulmonary adhesions or active abscesses. In contrast, only 31 of 108 (29%) fall-born lambs had lung lesions. Severe lung lesions were associated with a significant reduction in average daily gain. Severe lung lesions were not detected until the middle of the finishing period and were associated with culture of Mannheimia haemolytica or Pasteurella multocida.

Conclusions and Clinical Relevance—Analysis of results indicates that the prevalence of severe lung lesions can be quite high in lambs. Severe lung lesions can lead to greatly decreased growth performance of lambs.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To assess the cardiovascular effects of the α2-adrenergic receptor agonist medetomidine in healthy cats anesthetized with 2% isoflurane.

Animals

11 clinically normal cats.

Procedure

Cats were anesthetized with isoflurane, and catheters were inserted for measurement of aortic, left ventricular, and right atrial pressures. For data collection, end-tidal isoflurane concentration was reduced to 2%, and end-tidal CO2 was maintained at 35 to 40 mm of Hg by use of positive-pressure ventilation. After measurement of baseline data, medetomidine (0.01 mg/kg of body weight, IM) was administered and data were collected continuously for 75 minutes. At the end of data collection, incisions were closed and cats were allowed to recover from anesthesia.

Results

Medetomidine significantly increased mean arterial pressure and systemic vascular resistance. The increase in mean arterial pressure was maximal at 17.8 ± 7 minutes after medetomidine administration. Medetomidine also increased left ventricular peak systolic pressure, left ventricular end diastolic pressure, and right atrial pressure. Medetomidine significantly decreased heart rate and mean aortic flow.

Conclusions

The low dosage of medetomidine (0.01 mg/kg, IM) promoted severe vasoconstriction in isoflurane-anesthetized cats, and resulted in sustained increases in left ventricular preload and afterload. (Am J Vet Res 1998;59:509–513)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate viral and bacterial respiratory pathogens and Mycoplasma spp isolated from lung tissues of cattle with acute interstitial pneumonia (AIP) and cattle that had died as a result of other causes.

Sample Population—186 samples of lung tissues collected from cattle housed in 14 feedlots in the western United States.

Procedure—Lung tissues were collected during routine postmortem examination and submitted for histologic, microbiologic, and toxicologic examinations. Histologic diagnoses were categorized for AIP, bronchopneumonia (BP), control samples (no evidence of disease), and other disorders.

Results—Cattle affected with AIP had been in feedlots for a mean of 127.2 days before death, which was longer than cattle with BP and control cattle. Detection of a viral respiratory pathogen (eg, bovine respiratory syncytial virus [BRSV], bovine viral diarrhea virus, bovine herpesvirus 1, or parainfluenza virus 3) was not associated with histologic category of lung tissues. Bovine respiratory syncytial virus was detected in 8.3% of AIP samples and 24.0% of control samples. Histologic category was associated with isolation of an aerobic bacterial agent and Mycoplasma spp. Cattle with BP were at greatest risk for isolation of an aerobic bacterial agent and Mycoplasma spp.

Conclusion and Clinical Relevance—Analysis of these results suggests that AIP in feedlot cattle is not a consequence of infection with BRSV. The increased risk of isolation of an aerobic bacterial agent from cattle with AIP, compared with control cattle, may indicate a causal role or an opportunistic infection that follows development of AIP. (Am J Vet Res 2001; 62:1519–1524)

Full access
in American Journal of Veterinary Research