Veterinary Medicine Commons^™

Glucocorticoid-Induced Chondrocyte Cytotoxicity At Doses Recommended For Intra-Articular Therapy In Horses, Wenying Zhu

Theses and Dissertations--Veterinary Science

Intra-articular glucocorticoid injections are commonly used to treat synovitis and osteoarthritis in horses. These agents are highly effective at relieving pain, swelling, and other symptoms of joint inflammation. The drugs also have therapeutic benefits by down regulating the expression of cytokines and protease enzymes that participate in the degradation of articular cartilage. However, detrimental effects on chondrocyte function and cell viability that is independent of osteoarthritis pathogenesis have been described and linked to glucocorticoid use. These side effects are both drug- and dose-dependent. This study tested the hypothesis that manufacture recommended dosage levels of methylprednisolone, betamethasone, and triamcinolone that are …

Uterine Artery Rupture, An Angiopathy Of The Reproductive System Of The Mare: Occurrence And Potential Effects, Ana G. Toro Mayorga

Theses and Dissertations--Veterinary Science

The intent of this research was to identify if the degenerative changes within arteries in the endometrium (endometrial angiopathies) correlate with degenerative changes in the uterine arteries and can be used as a predictor of increased risk for uterine artery rupture (UAR). With this objective specimens from 20 mares that died from uterine artery rupture and 21 control mares that died from unrelated causes were obtained from cases submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) over a two-year period. Postmortem specimens of each mare were collected from the left and right uterine arteries at the origin, bifurcation, …

The Roles Of Orthopaedic Pathology And Genetic Determinants In Equine Cervical Stenotic Myelopathy, Jennifer Gail Janes

Theses and Dissertations--Veterinary Science

Cervical stenotic myelopathy (CSM) is an important musculoskeletal and neurologic disease of the horse. Clinical disease occurs due to malformations of the vertebrae in the neck causing stenosis of the cervical vertebral canal and subsequent spinal cord compression. The disease is multifactorial in nature, therefore a clearer understanding of the etiology and pathogenesis of CSM will allow for improved management and therapeutic practices. This thesis examines issues of equine CSM diagnosis, skeletal tissue pathology, and inherited genetic determinants utilizing advances in biomedical imaging technologies and equine genomics. Magnetic resonance imaging (MRI) data provided a more complete assessment of the cervical …

Modulation Of Type-I Interferon Mediated Immune Response: A Novel Innate Immune Evasion Strategy Of Equine Herpesvirus 1, Sanjay Sarkar

Theses and Dissertations--Veterinary Science

Equine herpesvirus-1 (EHV-1) is one of the major viral pathogens causing respiratory disease, abortion, perinatal mortality and neurologic disease among horses resulting in significant economic losses to the equine industry. The virus can also remain latent in the horses and recrudesce at any time. Type-I interferons (IFNs) act as a first line of defense against many viral infections.

In this study we investigated the type-I IFN response against the neuropathogenic T953 strain of EHV-1 in equine endothelial cells (EECs). The results showed that after a transient induction of IFN-β mRNA as well as protein at an early time (3h) post …

Evaluation Of The Susceptibility And Humoral Immune Response Of Foals To Rhodococcus Equi Infection, Macarena G. Sanz

Theses and Dissertations--Veterinary Science

While Rhodococcus equi (R. equi) remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals, development of a relevant model to study this bacterium has proven difficult. As a result, the reasons for the underlying foal’s susceptibility to this disease are not well understood. Furthermore, data regarding the immune response of foals to R. equi infection remains controversial. We hypothesized that foals are susceptible to R. equi early in life and that this susceptibility decreases with age. Also, we hypothesized that specific subclasses of IgG antibodies to the virulence-associated protein of R. equi, VapA, …

Anti-Müllerian Hormone In Stallions And Mares: Physiological Variations, Clinical Applications, And Molecular Aspects, Anthony N.J. Claes

Theses and Dissertations--Veterinary Science

Anti-Müllerian hormone (AMH) is a homodimeric glycoprotein that is best known for its role in regression of the Müllerian duct in the male fetus. Accumulating evidence indicates that AMH also has an important role during different physiological processes after birth. In contrast to other species, relatively little is known about AMH in the horse. In chapter one, developmental and seasonal changes in serum AMH concentrations in male horses were determined, and the use of AMH for determination of retained cryptorchid testes was established. In chapter two, the interrelationship between plasma AMH concentrations, antral follicle counts (AFC), and age in mares …

Role Of Viral And Host Factors In Influenza Virus Mediated Inhibition Of Interleukin-23, Ashish Tiwari

Theses and Dissertations--Veterinary Science

Influenza virus is one of the major respiratory pathogens of humans as well as animals, including equines. There is an increasing evidence that bacterial infections are the most common cause of the death during influenza. In horses also, secondary bacterial pneumonia can lead to death, and surviving horses may take up to six months for the complete recovery resulting in heavy economic loss to the equine industry. Interleukin (IL)-23 mediated innate immune response has been shown to protect the host from various respiratory bacterial infections. However, studies to investigate the role of host and viral factors in the regulation of …

Examination Of The Snsag Surface Antigen Gene Family In Sarcocystis Neurona, Ablesh Gautam

Theses and Dissertations--Veterinary Science

Sarcocystis neurona is a protozoan parasite that causes the serious neurologic disease equine protozoal myeloencephalitis (EPM). The life cycle of S. neurona progresses through multiple developmental stages that differ morphologically and molecularly. The S. neurona merozoite surface is covered by multiple related proteins, which are orthologous to the surface antigen (SAG) gene family of Toxoplasma gondii. The SAG surface antigens in T. gondii and another related parasite Neospora caninum are life cycle stage-specific and seem necessary for parasite transmission and persistence of infection. The present research was conducted to explore the gene family of SnSAGs in S. …

Studies On Equine Placentitis, Igor Frederico Canisso

Theses and Dissertations--Veterinary Science

Two types of placentitis were studied: ascending and nocardioform placentitis. Although the first diagnosis of nocardioform placentitis was made three decades ago, little is known about the disease, due to the lack of an experimental model. In attempt to develop a research model, Crossiela equi was inoculated through intrauterine, intravenous, intrapharyngeal, and oral routes, but none of the routes resulted in nocardioform placentitis. This may indicate that unidentified factors may play a role in disease pathogenesis and that simple presence of bacteria is not sufficient to induce nocardioform placentitis. The second and major component of this dissertation involved the identification …

Equine Protozoal Myeloencephalitis: Investigation Of Genetic Susceptibility And Assessment Of An Equine Infection Method, Breanna M. Gaubatz

Theses and Dissertations--Veterinary Science

Equine protozoal myeloencephalitis (EPM) is a progressive neurological disease of horses caused by Sarcocystis neurona. Two projects were conducted to identify factors involved in the development of EPM. The first study explored a possible genetic susceptibility to EPM by attempting a genome-wide association study (GWAS) on formalin-fixed, paraffin-embedded (FFPE) tissue from 24 definitively-positive EPM horses. DNA extracted from tissues older than 14 months was inadequate for SNP analysis on the Illumina Equine SNP50 BeadChip probably due to degradation and formalin cross-linking. Results were inconclusive as analysis was not possible with the small sample set. The second study evaluated an …

Determination Of Farm-Specific Lawsonia Intracellularis Seroprevalence In Central Kentucky Thoroughbreds And The Identification Of Factors Contributing To Equine Proliferative Enteropathy, Allen E. Page

Theses and Dissertations--Veterinary Science

Lawsonia intracellularis and the disease it causes in horses, equine proliferative enteropathy (EPE), is an emerging pathogen of increasing importance to the horse industry from both an economic and welfare standpoint. Long recognized as an economically important disease of swine, the hallmark of EPE is a protein-losing enteropathy, where affected horses suffer weight loss and some ultimately succumb to the disease despite aggressive treatment. There are currently no known EPE preventative measures and the epidemiology of the disease remains poorly defined. While EPE is a sporadic disease affecting less than 25% of exposed horses, some farms experience clinical cases year …

Chondrodysplasia-Like Dwarfism In The Miniature Horse, John E. Eberth

Theses and Dissertations--Veterinary Science

Dwarfism is considered one of the most recognized congenital defects of animals and humans and can be hereditary or sporadic in cause and expression. There are two general morphologic categories within this vastly diverse disease. These categories are disproportionate and proportionate dwarfism and within each of these there are numerous phenotypes which have been extensively described in humans, and to a lesser extent in dogs, cattle, mice, chickens, and other domestic species. Ponies and Miniature horses largely differ from full size horses only by their stature. Ponies are often defined as those whose height is not greater than 14.2 hands; …

Ingestion Of Endophyte-Infected Tall Fescue Seed Induces Peripheral Vasoconstriction But Does Not Affect Cyclicity In Non-Pregnant Mares, And A Population Of Biogenic Amine Receptors Relative To Vasoconstriction Is Identified, Daniel Andrew Hestad

Theses and Dissertations--Veterinary Science

Three experiments were conducted to explore the effect of fescue toxicosis on vasoconstriction and various parameters of the estrous cycle. In the experiment of Chapter 3, a 2x2 crossover experimental design with repeated measures was implemented to test whether the ingestion of endophyte-infected tall fescue seed would alter blood hormone concentrations of prolactin, progesterone, and estradiol, interovulatory intervals, and corpus luteum blood flow. Also, Doppler ultrasonography was used to assess whether palmar artery and palmar vein lumen diameter, area, circumference, and resistivity index could be altered by the ingestion of endophyte-infected tall fescue seed. Ingestion of endophyte-infected tall fescue seed …

The Transmission Dynamics Of Equine Herpesvirus Type 1 (Ehv-1) Infection In Outbreaks Characterized Predominately By Neurologic Or Respiratory Illness, Barry Jay Meade

Theses and Dissertations--Veterinary Science

Formalized epidemiological field investigations were conducted to compare and contrast the transmission dynamics of EHV-1 neurological disease among horses stabled at Churchill Downs Racetrack, Louisville, Kentucky and of EHV-1 respiratory illness among horses stabled in the student barn at Murray State University. Differences were assessed by means of statistical and mathematical modeling techniques applied to survey and biological data collected over the course of the respective disease events.

Regression methods applied to survey data enabled the construction of a statistical model to predict a date of onset of illness for horses within each equine cohort. Comparisons of the epidemic curves …

Breeding Induced Endometritis In The Mare: The Local Innate Immune Response, Elizabeth Moran Woodward

Theses and Dissertations--Veterinary Science

Uterine inflammation after breeding is considered necessary for the clearance of excess semen and debris from the uterus. A subpopulation of mares fails to clear the inflammation in a timely fashion, and develops a persistent breeding induced endometritis (PBIE). Experiments were preformed to evaluate correlations of PBIE to endometrial quality and age. Mares of advanced age and poor endometrial quality had a higher incidence of PBIE. In addition, mares fluctuated in susceptibility to PBIE from one season to the next. The uterine inflammatory gene expression in susceptible and resistant mares within the first 24 hours after breeding was investigated. The …

Development Of Molecular Diagnostic Assays For Equine Respiratory Viruses And Analysis Of The Role Of Equine Arteritis Virus Envelope Proteins In The Early Events Of Virus Entry, Zhengchun Lu

Theses and Dissertations--Veterinary Science

There is an urgent need for detection of viral respiratory pathogens to identify the causal agent(s) involved and to prevent the spread of related diseases. The first part of this dissertation focuses on development, optimization and validation of Real-time reverse transcription polymerase chain reaction (rRT-PCR) assays for the detection of several common equine viral pathogens: equine arteritis virus (EAV), equine influenza virus and equine rhinitis viruses A and B. Emphasis of the second part of this dissertation is on studying the role of EAV envelope proteins in virus attachment and entry. Using an infectious cDNA clone of EAV and reverse …

Genetic Immunization In The Horse: The Potential For Enhanced Immune Responses With Deacylated Polyethyleneimine (Pei) And Immunostimulatory Cytokines As Vaccine Adjuvants, Deborah Lee Even

Theses and Dissertations--Veterinary Science

DNA vaccines in larger animals, such as horses, are generally less effective and elicit significantly weaker immune responses, than in small animal model systems. To provide optimal protection against pathogenic microorganisms, the induction of both humoral and cellular immune responses from DNA vaccination may be necessary. One limitation to DNA immunization in the horse is the difficulty in generating high levels of antigen-specific antibody and CTL responses. Previous work in the laboratory has demonstrated that expression constructs containing native sequences encoding the surface unit (SU) envelope glycoprotein (pCiSU) of the Equine Infectious Anemia Virus (EIAV) are ineffective at stimulating immune …