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Abstract

Objective—To assess the likelihood of an introduction of foot-and-mouth disease (FMD) into the Malaysia-Thailand-Myanmar (MTM) peninsula through terrestrial movement of livestock.

Animals—89,294 cattle and buffalo legally moved into the MTM peninsula.

Procedures—A quantitative risk assessment was conducted by use of a stochastic simulation. Patterns of livestock movement were ascertained through review of relevant governmental records and regulations and by interviewing farmers, traders, and local officers when the records did not exist. Parameters identified in the process were the probabilities of livestock having FMD and of FMD infection going undetected during import processes. The probability of an animal accepted for import having FMD was also assessed. Sensitivity analysis was performed to determine the effects that each parameter had on the model.

Results—The simulation yielded an average consignment prevalence of 10.95%. Typically, each animal in a quarantine facility had a 2.7% chance of having an inapparent form of FMD infection; hence, it was likely an animal would not be identified as infected. Findings revealed that the mean probability of an animal accepted for import having FMD was 2.9%, and the risk was as high as 11%.

Conclusions and Clinical Relevance—Results of the model allowed for the evaluation of movement regulations currently imposed in the MTM peninsula. Evidence from the study suggested that current practices in animal movement were far from efficient in preventing introduction of FMD-infected animals into the MTM region, and additional measures will be necessary.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether viral involvement with platelets obtained from cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) is associated with altered platelet function or decreased platelet counts.

Sample Population—Platelets obtained from 8 cattle PI with BVDV and 6 age-, sex-, and breed-matched uninfected control cattle.

Procedure—Manual platelet counts were determined, and platelet function was assessed through optical aggregometry by use of the aggregation agonists ADP and platelet-activating factor. Identification of BVDV in serum and preparations of purified platelets was determined by use of virus isolation tests.

Results—No significant difference in platelet counts was detected between cattle PI with BVDV and control cattle. In response to the aggregation agonists, maximum aggregation percentage and slope of the aggregation curve were not significantly different between cattle PI with BVDV and control cattle. We isolated BVDV from serum of all PI cattle and from purified platelets of 6 of 8 PI cattle, but BVDV was not isolated from serum or platelets of control cattle.

Conclusions and Clinical Relevance—Isolation of BVDV from platelets in the peripheral circulation of cattle immunotolerant to BVDV does not result in altered platelet function or decreases in platelet counts. (Am J Vet Res 2005;66:1738–1742)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the disposition of gamithromycin in plasma, pulmonary epithelial lining fluid (PELF), bronchoalveolar lavage (BAL) cells, and lung tissue homogenate in cattle.

Animals—33 healthy Angus calves approximately 7 to 8 months of age.

Procedures—Calves were randomly assigned to 1 of 11 groups consisting of 3 calves each, which differed with respect to sample collection times. In 10 groups, 1 dose of gamithromycin (6 mg/kg) was administered SC in the neck of each calf (0 hours). The remaining 3 calves were not treated. Gamithromycin concentrations in plasma, PELF, lung tissue homogenate, and BAL cells (matrix) were measured at various points by means of high-performance liquid chromatography with tandem mass spectrometry.

Results—Time to maximum gamithromycin concentration was achieved at 1 hour for plasma, 12 hours for lung tissue, and 24 hours for PELF and BAL cells. Maximum gamithromycin concentration was 27.8 μg/g, 17.8 μg/mL, 4.61 μg/mL, and 0.433 μg/mL in lung tissue, BAL cells, PELF, and plasma, respectively. Terminal half-life was longer in BAL cells (125.0 hours) than in lung tissue (93.0 hours), plasma (62.0 hours), and PELF (50.6 hours). The ratio of matrix to plasma concentrations ranged between 4.7 and 127 for PELF, 16 and 650 for lung tissue, and 3.2 and 2,135 for BAL cells.

Conclusions and Clinical Relevance—Gamithromycin was rapidly absorbed after SC administration. Potentially therapeutic concentrations were achieved in PELF, BAL cells, and lung tissue within 30 minutes after administration and persisted for 7 (PELF) to > 15 (BAL cells and lung tissue) days after administration of a single dose.

Full access
in American Journal of Veterinary Research
in American Journal of Veterinary Research

Abstract

OBJECTIVE To assess the use of 3-D accelerometers to evaluate behavioral changes in cattle experimentally infected with a low-virulent strain of bovine viral diarrhea virus (BVDV).

ANIMALS 20 beef steers (mean weight, 238 kg).

PROCEDURES Calves were allocated to a BVDV (n = 10) or control (10) group. On day 0, calves in the BVDV group were inoculated with a low-virulent strain of BVDV (4 × 106 TCID50, intranasally), and calves in the control group were sham inoculated with BVDV-free medium (4 mL; intranasally). An accelerometer was affixed to the right hind limb of each calf on day −7 to record activity (lying, walking, and standing) continuously until 35 days after inoculation. Baseline was defined as days −7 to −1. Blood samples were collected at predetermined times for CBC, serum biochemical analysis, virus isolation, and determination of anti-BVDV antibody titers.

RESULTS All calves in the BVDV group developed viremia and anti-BVDV antibodies but developed only subclinical or mild disease. Calves in the control group did not develop viremia or anti-BVDV antibodies. Mean time allocated to each activity did not differ significantly between the BVDV and control groups on any day except day 8, when calves in the BVDV group spent less time standing than the calves in the control group. Following inoculation, calves in both groups tended to spend more time lying and less time walking and standing than they did during baseline.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that behavioral data obtained by accelerometers could not distinguish calves subclinically infected with BVDV from healthy control calves. However, subtle changes in the behavior of the BVDV-infected calves were detected and warrant further investigation.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To test the immunocompetence of isogenic families of rainbow trout by measuring their ability to accept or reject skin grafts.

Animals

3 families of isogenic rainbow trout (Oncorhynchus mykiss), produced by mating homozygous females and homozygous males, plus 4 Chinook salmon (O tshawytscha) were used in these experiments.

Procedure

Grafts (allografts, members of the same family; autografts, donor and recipient were the same fish; and xenografts, O tshawytscha as donor) were exchanged. Grafts were applied on day 0 and removed on day 21, placed in neutral-buffered formalin, and embedded in paraffin. Lymphocytes and nuclei were counted in representative stained sections in the epidermis, dermis, and hypodermis. Results were analyzed by univariate analysis, using the Shapiro-Wilk statistic.

Results

Autografts were retained and minimal histologic changes were apparent. Allografts were histologically similar to autografts. Xenografts were rejected.

Conclusions

Results indicate that the immune system of isogenic rainbow trout is unable to distinguish between family members within isogenic families, but that a vigorous response is mounted against Chinook salmon xenografts. The isogenic rainbow trout are immunocompetent with respect to the phenomenon of graft rejection. (Am J Vet Res 1996;57:1576–1579)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate platelet aggregation responses in calves experimentally infected with a thrombocytopenia-inducing type II bovine viral diarrhea virus (BVDV) isolate (BVDV 890).

Animals

9 neonatal male Holstein calves.

Procedure

5 calves were inoculated with BVDV 890, and 4 were used as controls. Platelet aggregation studies and attempts to isolate BVDV from platelets were performed 2 days before, the day of, and every 2 days for 12 days after inoculation. Platelet function was assessed by means of optical aggregometry, using adenosine diphosphate and platelet-activating factor as agonists. Bovine viral diarrhea virus was isolated from purified platelet preparations by use of an immunoperoxidase monolayer assay.

Results

Maximum percentage aggregation and slope of the aggregation curve decreased over time in calves infected with BVDV. Bovine viral diarrhea virus was not isolated from platelets from control calves, but it was isolated from infected calves from 4 through 12 days after inoculation.

Conclusions and Clinical Relevance

Results suggest that platelet function may be depressed in calves infected with type II BVDV. Although the mechanism for altered platelet function was not determined, it likely involved an increase in the percentage of aged platelets in the circulation, a direct virus-platelet interaction, or an indirect virus-platelet interaction. Platelet dysfunction, in addition to thrombocytopenia, may contribute to the hemorrhagic syndrome associated with acute type II BVDV infection in calves. (Am J Vet Res 1999;60:1396–1401)

Free access
in American Journal of Veterinary Research

SUMMARY

A 55-kd protein with mRNA transport activity found in fetal rat liver cells and plasma from mice, rats, and human beings with malignant neoplasms has been designated oncofetal protein 55 (ofp 55). Monoclonal antibody produced to rat ofp 55 cross-reacts with human ofp 55. Using this monoclonal antibody in a bioassay measuring mRNA transport stimulated by ofp 55, we tested the plasma from 19 dogs with a variety of malignant neoplasms, including carcinomas, sarcomas, lymphomas, and melanomas, and compared the results with plasma from 20 clinically normal dogs without evidence of neoplasia. The mean mRNA transport activity from the group of dogs with malignant neoplasms was 0.43 ± 0.28%/mg of protein. Mean transport activity from the group of control dogs was 0.04 ± 0.02%/mg of protein. These means were significantly different (P < 0.0001). The degree of overlap between these 2 groups in their ofp 55-related mRNA transport activity was minimal, and measurement of this protein appears to have potential for the early detection of malignant neoplasms in dogs.

Free access
in American Journal of Veterinary Research

Objective

To determine the effect of furosemide on performance of Thoroughbreds racing on dirt surfaces at tracks in the United States and Canada.

Design

Cross-sectional study.

Animals

All Thoroughbreds (n = 22,589) that finished a race on dirt surfaces at tracks in the United States and Canada between June 28 and July 13, 1997 in jurisdictions that allowed the use of furosemide.

Procedure

Race records were analyzed by use of multivariable ANOVA procedures and logistic regression analyses to determine the effect of furosemide on estimated 6-furlong race time, estimated racing speed, race earnings, and finish position. Principal component analysis was used to create orthogonal scores from multiple collinear variables for inclusion in the models.

Results

Furosemide was administered to 16,761 (74.2%) horses. Horses that received furosemide raced faster, earned more money, and were more likely to win or finish in the top 3 positions than horses that did not. The magnitude of the effect of furosemide on estimated 6-furlong race time varied with sex, with the greatest effect in males. When comparing horses of the same sex, horses receiving furosemide had an estimated 6-furlong race time that ranged from 0.56 ± 0.04 seconds (least-squares mean ± SE) to 1.09 ± 0.07 seconds less than that for horses not receiving furosemide, a difference equivalent to 3 to 5.5 lengths.

Conclusions and Clinical Relevance

Because of the pervasive use of furosemide and its apparent association with superior performance in Thoroughbred racehorses, further consideration of the use of furosemide and investigation of its effects in horses is warranted. (J Am Vet Med Assoc 1999;215:670–675)

Free access
in Journal of the American Veterinary Medical Association

Objective

To evaluate the risk and efficacy of pulmonary lobectomy in dogs with pneumonia.

Design

Retrospective study.

Animals

59 dogs with pneumonia.

Procedure

Review of medical records and telephone conversations.

Results

54.2% of dogs had resolution of pneumonia after lobectomy, 20.3% died in the perioperative period, and 25.4% survived the perioperative period but pneumonia did not resolve. Pneumonia was caused by bacteria (25 dogs), fungi (12), foreign bodies (8), parasites (1), viruses (1), and allergies (1). In 11 dogs, the etiologic agent was not isolated. Bacterial or fungal pneumonias were significantly less likely to resolve compared with foreign body pneumonia or when an etiologic agent was not isolated. Perioperative mortality rate increased significantly with an increase in number of pulmonary lobes removed. Complications during surgery significantly increased perioperative mortality rate. Surgical era (1972 to 1983 vs 1984 to 1994) was a significant predictor of mortality, with the odds of dying in the perioperative period being 11 times greater between 1972 to 1983. The odds of failure to resolve pneumonia was 3 times greater during 1972 to 1983.

Clinical Implications

Number of pulmonary lobes removed and complications during surgery significantly affect perioperative mortality rate. Identification of etiologic agents may help in predicting dogs likely to resolve pneumonia after surgery.

Free access
in Journal of the American Veterinary Medical Association