Degree Type

Dissertation

Date of Award

2017

Degree Name

Doctor of Philosophy

Department

Veterinary Microbiology and Preventive Medicine

Major

Veterinary Microbiology

First Advisor

Alejandro Ramirez

Abstract

Infectious arthritis in growing pigs is considered the most common type of lameness encountered by veterinarians in the field. Efforts to mitigate, treat, and prevent infectious lameness by veterinarians have been problematic as the efficacy of antimicrobials for infectious arthritis is highly variable and diagnostic investigations often fail to yield actionable information about a field case. The goals of this dissertation were to address specific questions within this broad problem from an applied clinical research perspective.

The first research aim was to determine the most common primary diagnoses for lameness cases at a Midwest diagnostic laboratory and to collect descriptive data on infectious arthritis cases. From the retrospective review of lameness cases involving joints and legs at the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL), it was reinforced that infectious arthritis was indeed a common diagnosis (about 40% of all lameness diagnostic lab cases) and highlighted that about 20% of lameness cases yielded inconclusive findings. These results directed the research towards the development of a refined joint fluid collection technique and a new diagnostic test to improve the diagnostic process for practitioners. Specifically, various injectable anesthetic protocols were compared in terms of utility for joint fluid collection and samples collected from that study were used to create reference intervals for fluid analysis and cytologic evaluation for swine joint fluid. These reference intervals serve as a core diagnostic tests for arthropathies in other species but did not exist publically previously for swine. Telazol, ketamine, and xylazine (TKX) were the most effective anesthetic combination for joint fluid sample collection and this study yielded sufficient number of high quality samples to create the reference intervals (37 tarsus and 46 carpus samples). With these newly refined tools to diagnosis infectious arthritis, the final component of the dissertation was to address treatment considerations and determine if a water soluble macrolide (tylvalosin [TVN]) distributes and maintains concentrations in the joint fluid of healthy pigs. Tylvalosin was identified in joint fluid after oral gavage and during oral medication through ad libitum water access. Substantial variation in water disappearance between individual pigs highlighted large dose ranges between pigs. This was an unexpected finding and emphasized some of the challenges of treating groups of sick pigs with water soluble antimicrobials. Together, the studies in this dissertation contribute practical information for swine veterinarians related to the diagnosis and treatment of infectious arthritis in the field.

Copyright Owner

Paisley Canning

Language

en

File Format

application/pdf

File Size

115 pages

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