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  • Author or Editor: L. J. Rivas x
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Abstract

Objective

To investigate the effect of IV administration of fluids on the furosemide-induced reduction in right atrial pressure (RAP) and relative change in blood volume (BV) of splenectomized mares.

Animals

5 splenectomized mares.

Procedure

RAP was measured by use of a micromanometer placed in the right atrium. Jugular venous blood was collected for measurement of hematocrit, plasma total protein concentration, and hemoglobin concentration. Right atrial pressure was recorded and blood samples were collected immediately before furosemide (1 mg/kg of body weight, IV) administration, then every 15 minutes for 240 minutes. Beginning 120 minutes after furosemide administration, polyionic fluids (lactated Ringer's solution) were administered (2 L q 15 min) for 120 minutes.

Results

Furosemide induced a significant (P < 0.05) decrease in mean RAP (7.6 ± 1.5 and 3.2 ± 1.2 mm of Hg before and 15 minutes after furosemide administration, respectively), and BV (8.4 ± 1.1 % by 15 minutes). Polyionic fluid administration restored RAP and BV The volume of polyionic fluids administered (32 ± 2 ml/kg) was not significantly different from the volume of urine produced (38 ± 7.8 ml/kg). Difference was not apparent in the relation between change in BV and RAP before or after fluid administration.

Conclusions

The effect of furosemide on RAP of horses is mediated in large part by furosemide-induced reduction in BV. However, an effect of furosemide on venous compliance cannot be excluded as contributing to the reduction in RAP. (Am J Vet Res 1997;58:632–635)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To explore whether early analysis of spatial data may result in identification of variables associated with epidemic spread of foot and mouth disease.

Sample Population—37 farms with infected cattle (ie, case farms) reported within the first 6 days of the 2001 Uruguayan foot-and-mouth disease epidemic.

Procedure—A georeferenced database was created and retrospective analysis was performed on case farm location in relation to farm density, cattle density, farm type (ie, beef vs dairy cattle production), road density, case farm distance to the nearest road, farm size, farm ownership, and day of infection. Mean or median results of 1 to 3 day versus 4 to 6 day spatial data were compared. Spatial-temporal associations were investigated by correlation analysis.

Results—Comparison of mean or median values between the first 3 days and days 4 to 6 of the epidemic and results of correlation analysis indicated a significant increase in road density, cattle density, and dairy cattle production and a significant decrease in farm size and case farm distance to the nearest road that developed over time. A route that linked most case farms by the shortest possible distance and also considered significantly associated variables was created. It included 86.1% of all case farms reported by 60 days into the epidemic.

Conclusions and Clinical Relevance—Epidemic direction can be assessed on the basis of road density and other spatial variables as early as 6 days into an epidemic. Epidemic control areas may be more effectively identified if local and regional georeferenced data are considered. (Am J Vet Res 2003;64:1519–1527)

Full access
in American Journal of Veterinary Research

Abstract

Objectives

To develop a reference database for characterization of bovine Staphylococcus aureus and Streptococcus agalactiae strains by automated ribotyping and to use it to assess the discriminatory power of this typing procedure and the geographic distribution of Sta aureus and Str agalactiae strains in New York state dairy herds.

Sample Population

22 commercial dairy herds.

Procedure

Isolates of Sta aureus and Str agalactiae from bovine milk were identified by standard bacteriologic procedures, then typed by automated ribotyping. Antimicrobial susceptibility of isolates was tested in vitro. Two indicators made from the data were percentage of farms with multiple ribotypes and percentage of single ribotypes found in several geographic regions. Standard bacteriologic diagnosis, automated ribotyping, and determination of antibiograms (Kirby-Bauer method) also were done.

Results

Of 50 Sta aureus and 44 Str agalactiae isolates from composite milk samples of 12 and 10 herds, respectively, 18 and 14 ribotypes, respectively, were identified. The discriminatory power of automated ribotyping was approximately 0.96 (Hunter-Gaston's formula). A higher percentage of herds with Sta aureus had multiple ribotypes. The most common Sta aureus ribotypes tended to have broader geographic distribution. Some Sta aureus ribotypes were significantly associated with antibiotic resistance profiles.

Conclusions

Automated ribotyping appears to characterize bovine strains of bacteria associated with intramammary infections with a high discriminatory index. Potential applications include identification of strains that appear to have broad geographic distribution suggesting interfarm transfer, discrimination between recurrent versus new intramammary infections (ie, for control of Str agalactiae and Sta aureus), and evaluation of antibiotic therapy. (Am J Vet Res 1997;58:482–487)

Free access
in American Journal of Veterinary Research