Recurrent Airway Obstruction (RAO)-affected horses experience bronchoconstriction and airway inflammation in response to inhalation of irritants including hay molds. Steaming hay reduces fungal content, but the effect on the antigenic potential has not been investigated. We tested the hypothesis that RAO-affected horses develop less severe clinical disease when fed steamed versus non-steamed hay and this reduction coincides with decreased hay fungal content. Six RAO-affected horses in clinical remission were divided in two groups and fed steamed or non-steamed hay for 10 days using a two-way cross-over design. Hay was steamed using a commercial hay-steamer. Clinical assessment was performed daily. Full assessment, including airway endoscopy, tracheal mucous scores and maximal change in pleural pressure, was performed on days 1, 5, and 10. Bronchial fluid sampling and cytology were performed on days 1 and 10. Hay core samples were collected pre- and post-steaming and cultured to determine fungal and bacterial concentrations. Statistical analysis was based on data distribution and quantity and performed using SAS®. P-value <0.05 was significant. Steaming significantly decreased the number of bacterial and fungal colony-forming-units in hay. Horses fed non-steamed hay experienced a significant increase in clinical score and a trend towards airway neutrophilia, while parameters were unchanged in horses fed steamed hay. Only horses fed non-steamed hay experienced a significant increase in tracheal mucous score. Horses fed steamed hay gained significantly more weight compared to horses fed non-steamed hay, even though the amount of hay consumed not greater on a dry matter basis. These results indicate that steaming reduces the RAO-affected horse's response to hay which coincides with a reduction in viable fungal content of hay. / Master of Science

The feeding activity of female black flies may cause considerable annoyance to saddle horses. Horses under attack become head-shy and difficult to manage, posing a potential hazard to riders. Stabling horses offers a means of protection against black fly feeding, but most horse owners cannot or will not stable their animals to prevent disturbance by noxious flies. Because stabling is an unsatisfactory control measure, I will evaluate various ear protectants to find easily applied materials of suitable effectiveness and duration on pastured animals to be of practical value to the owners. / Master of Science

Neutrophils, the chief phagocytic cells in most mammals, are critical in the inflammatory response. Regulation of neutrophil activity occurs through several mechanisms, including apoptosis. Dysfunction of neutrophil apoptosis has been implicated as a cause of organ damage in hyper-inflammatory conditions in human patients. This pilot study investigated apoptosis in circulating neutrophils from horses with surgical lesions in the large and small intestine. We hypothesized that delayed neutrophil apoptosis occurs in peripheral blood of horses undergoing surgery with acute abdominal disease, compared with elective orthopedic cases. Adult horses undergoing surgery for acute abdominal disease (N=10) and elective orthopedic surgery (control) (N=10) were studied. Peripheral blood was collected preoperatively and postoperatively. Neutrophils were isolated using Percoll gradient. Cells undergoing apoptosis were determined by flow cytometry using a commercially available staining kit (Annexin V-PE Apoptosis Detection Kit I, BD Pharmingen™). The Mann-Whitney U test was used to detect significant differences in neutrophil apoptosis between the two groups as well as between lesion types in the abdominal surgery group. Correlations between neutrophils in apoptosis and postoperative parameters were detected using Spearman's rank correlation coefficient. No significant differences in percentages of apoptotic neutrophils between groups were found; however, a significantly lower percentage of neutrophil apoptosis was present in horses with strangulating intestinal lesions versus nonstrangulating lesions. Current investigations about neutrophil apoptosis in human medicine may result in therapeutic intervention to prevent organ damage in hyper-inflammatory states. Understanding the role of neutrophil apoptosis in equine acute abdominal disease may guide the use of new treatments as they become available. / Master of Science

Master of Science

Because Virginia has been long regarded as a leading exponent of light horse production, it is particularly fitting that this subject should be included in the course of study for classes of vocational agriculture in the State. Virginia has provided the genesis of selective breeding to produce superior horses; through the efforts of Virginia horsemen has been evolved a type of animal adapted to pleasure, to work, and to general-purpose functions. Although mechanical power is utilized on some farms, the motor has not usurped, and cannot usurp, the place of the light horse for purposes which he is peculiarly adapted. In spite of the fact that the successful feeding, care, and management of light horses comprises an important aspect of farm business, modern data in teachable form on the subject is not readily available to the teacher of vocational agriculture. Thus the problem of acquiring up-to-date teaching data on light horses for students enrolled in classes of vocational agriculture in the high school is encountered. The selection of Orange County, Virginia, for the subject of intensive study was motivated by its topography, central location in the State, well-conducted horse breeding farms, experienced horsemen, and by the writer's experience as a teacher of vocational agriculture in the County, in which he noted the predominance of horse power over mechanical power on the home farms of the boys in his classes. It is hoped that the results of this study, in which practice is correlated with theory, may prove valuable to the teachers of agriculture and others interested in this subject. / Master of Science

In adult horses and foals, renal dysfunction can occur as a secondary complication to gastrointestinal disorders, dehydration, septicemia, endotoxemia and nephrotoxic drug administration. Measurement of renal function is an important feature not only in the diagnosis, but also in the prognosis and management of renal disease. Commonly used drugs such as phenylbutazone and gentamicin can be highly nephrotoxic under certain conditions. Estimation of the glomerular filtration rate (GFR), accepted as one of the earliest and most sensitive assessments of renal function, can be determined in horses using standard techniques such as endogenous or exogenous renal creatinine clearance. These techniques can be time consuming, dangerous to perform on fractious patients, require trained personnel and are subject to errors most often associated with improper or incomplete urine collection. Recently, tests using iohexol, a radiographic contrast agent, have been developed to estimate the GFR in human beings, pigs, sheep, dogs, cats and horse foals with results that have been validated by traditional standards. Serum clearance of a substance that is freely filtered by the kidneys without tubular secretion or reabsorption, that is not protein bound, and that is not metabolized, is a measurement of glomerular filtration rate. Iohexol meets all of these requirements and thus its clearance from serum should accurately estimate GFR. Utilization of serum clearance studies for estimation of GFR provides a clinically feasible and reproducible method in order to measure GFR in horses. Other commonly used methods to assess renal function in horses are fraught with inherent and operator error. Serum clearance of iohexol does not necessitate collection of urine and has been shown to be a safe, reproducible method using collection of timed blood samples to assess renal function in humans and animals. The objectives of this project were 1) to determine a method of estimation of GFR based on serum clearance of a substance that meets the requirements of a marker for GFR, and 2) to make the method clinically applicable by developing a method using two blood samples to derive clearance and thus GFR in normal adult horses. Results of this study showed good agreement between GFR derived by exogenous creatinine clearance and serum clearance of iohexol. In addition, GFR values for all horses using either method were within published reference ranges for this species. The results of this study indicate that a single intravenous injection of iohexol at a dose of 150 mg/kg, followed by collection of 2 serum samples at 3 and 4 hours post injection can be used to estimate the GFR in healthy horses. / Master of Science

A study was performed to establish the appearance of normal equine laryngeal cartilages using magnetic resonance imaging. Specimens were acquired from clinically normal horses that were euthanized for reasons other than respiratory disease. Three in situ and 5 ex vivo larynges were imaged using a 0.3 Tesla system. Images were obtained in the transverse plane using T1-weighted 3D spin echo, T2-weighted 3D spin echo, T2-weighted gradient echo, short tau inversion recovery (STIR), and proton density spin echo sequences. Five ex vivo larynges were also imaged in the transverse plane using a 1.5 Tesla system, sequences included T1-weighted 3D spin echo, T2-weighted 3D turbo-spin echo, turbo inversion recovery (TIRM), and proton density spin echo sequences. A frozen gross laryngeal specimen was sliced in 5-mm transverse sections for comparison to the MR images. Excellent correlation was found between MR images and the gross transverse sections. Successful imaging was accomplished using both imaging systems; however, the 1.5 Tesla system yielded superior image resolution. The 0.3 Tesla imaging system would accommodate the intact equine head, which was not possible using the 1.5 Tesla MRI system. The internal morphology of the laryngeal cartilages was clearly identified in all imaging sequences obtained. Cartilages were found to differ in signal intensity based on the tissue composition and imaging sequences performed. MRI was determined to be a useful imaging modality for evaluating the cartilage morphology of the equine larynx. Further investigation is required to document pathologic morphology. / Master of Science

Hypotension is a common finding in hospitalized, critically ill neonatal foals. Hypotension may be a function of low cardiac output or increased cardiac output and decreased systemic vascular resistance. In the first instance, treatment would include fluids and/or inotropes and in the second, fluids and/or vasopressors. Therefore, cardiac output measurements are expected to help guide the treatment of hypotension associated with critical illness and/or anesthesia in neonatal foals. However, a practical and safe method of measuring cardiac output has not been described for the foal. Lithium dilution, a new method of cardiac output determination not requiring cardiac catheterization, has recently been reported in adult horses. We compared this method to thermodilution in isoflurane anesthetized, 30 to 42 hour old foals and found good agreement (mean bias 0.0474L/min; limits of agreement -3.03 to 3.12) between the two methods in a range of cardiac outputs from 5.4 to 20.4 liters/min. The lithium dilution technique is a practical and reliable method of measuring cardiac output in anesthetized neonatal foals, and warrants investigation in critically ill conscious foals. / Master of Science

Flexor tendonitis is a common cause of lameness and wastage in the equine athlete. Current techniques for tendonitis therapy provide limited success, and horses that do recover tend to return at a decreased level of performance. Current treatment techniques have begun to focus on regenerative medicine to improve tissue healing. Investigations of new treatments are made difficult by the lack of reliable in vitro models that allow for accurate comparison of treatment protocols. New techniques are often implemented into the clinical setting prior to thorough investigation for safety and efficacy. In vitro testing is an important step in the development of new therapeutic agents. However, results of in vitro tests should only be deemed as useful if the model used is one that is reliable and mimics the clinical situation that the reseachers are attempting to investigate. Equine flexor tendonitis is believed to be the result of microdamage caused by cyclic loading of tendons. Cyclic loading of fibroblasts results in increased production of the inflammatory cytokine prostaglandin E2 (PGE2). Thus the exposure of tendon fibroblasts to exogenous PGE2 may induce metabolic changes in the cells similar to what is seen in clinically affected animals making this a useful model for the investigation of therapeutic techniques. Currently a variety of techniques exist for treatment of flexor tendonitis; however, no single treatment has separated itself as superior. A new technique using autogenous conditioned serum (ACS) in humans for treatment of muscle injury has been shown to speed tissue regeneration. ACS produced from human blood has been shown to contain significantly increased levels of III growth factors that may improve tendon fibril formation and strength. We propose to investigate the effect of ACS on cellular metabolism in equine tendon fibroblast monolayers. This will involve cell culture, PGE2-induced cellular injury, and analysis of the cellular response to injury when treated with ACS. Controls will include fetal bovine serum, normal equine serum, and ACS without PGE2-induced cellular injury. The cellular response will be investigated biochemically by quantification of DNA, glycosaminoglycan, and soluble collagen levels and by real time PCR to assess gene expression for matrix metalloproteinases (MMP)-1, MMP-3, and MMP-13, collagen types I and III, and the non-collagenous proteins cartilage oligomeric matrix protein (COMP) and decorin. Data will be analyzed by analysis of variance and post-hoc comparisons. Significance will be set at p<0.05. We hypothesize that the addition of exogenous PGE2 to culture media for monolayers of equine tendon fibroblasts will insight alterations in cellular metabolism that will generate a suitable model for the in vitro study of fibroblast response to novel therapies. We then hypothesize that the addition of ACS to PGE2-treated fibroblasts will result in increased gene expression for collagen types I and III, cartilage oligomeric matrix protein, and decorin. ACS will also stimulate increased protein production of collagen and glycosaminoglycans, and stimulate increased cell proliferation. The use of ACS will decrease gene expression of inflammatory molecules important in tendon degradation, namely matrix metalloproteinases -1, -3, and -13. / Master of Science

Thesis (MPhil)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The focus of this study is to investigate the role that horses played in the Ancient Near East, specifically during the reign of the Neo-Assyrian king Ashurnasirpal II (883-859BC). By studying nine of the reliefs from the North-West Palace at Nimrud, the function of horses with regard to warfare during that time was explored. The analysis included an examination of all horses and equine tack, which consists of chariots, bridles, bits, breastplates and decorations. The reliefs are studied by using Erwin Panofsky’s Theoretical Scheme, which allows for three stages of analysis. Each of the reliefs is examined as a whole, in order to place the relief in context, followed by a detailed breakdown of the horses, specifically their body language, as well as their tack and the function thereof. It was found that the Assyrians used the horses’ body language to help set the tone of the relief, as the horses would display aggressive body language when under attack and relaxed body language when not under attack, for example reliefs showing parades or military camps. It was also noted that the horses of the enemies were illustrated in such a way as to show the prowess of the victorious Neo-Assyrian army. It was found that horses were instrumental in warfare as well as depicting status and rank within the military structures. / AFRIKAANSE OPSOMMING: Die fokus van hierdie studie is om die rol wat perde in die Ou Nabye Ooste gespeel het, te ondersoek, spesifiek tydens die bewind van die Neo-Assiriese koning Ashurnasirpal II (883-859 v.C.). Deur nege van die reliëfs van die Noordwes-Paleis by Nimrud te bestudeer, is die funksie van perde met betrekking tot oorlogvoering gedurende daardie tyd ondersoek. Die analise sluit ’n ondersoek van alle perde en perdetuig in, wat uit waens, tome, stange, borsplate en versierings bestaan. Die reliëfs word bestudeer deur Erwin Panofsky se Teoretiese Skema, wat vir drie fases van ontleding voorsiening maak, te gebruik. Elkeen van die reliëfs word as ’n geheel ondersoek, ten einde die reliëf in konteks te plaas, gevolg deur ’n volledige uiteensetting van die perde, spesifiek hul lyftaal, asook hul tuie en die funksie daarvan. Daar is gevind dat die Assiriërs die perde se lyftaal gebruik het om die toon van die reliëf te help stel. Die perde sou aggressiewe lyftaal vertoon wanneer hulle aangeval word en ontspanne lyftaal wanneer hulle nie aangeval word nie, byvoorbeeld reliëfs wat parades of militêre kampe wys. Daar is ook opgemerk dat die perde van die vyande op so ’n wyse geïllustreer is om die dapperheid/vaardigheid van die oorwinnende Neo-Assiriese leër te toon. Daar is gevind dat perde instrumenteel in oorlogvoering was asook dat hulle status en rang binne die militêre strukture uitgebeeld het.