No description available.

Thesis (M. Sc. Vet. Sc.)--University of Sydney, 2008. / Includes graphs and tables. Title from title screen (viewed June 11, 2009) Submitted in fulfilment of the requirements for the degree of Master of Science in Veterinary Science to the Faculty of Veterinary Science. Degree awarded 2008; thesis submitted 2007. Includes bibliography. Also available in print form.

Thesis (M.S.)--California Polytechnic State University, 2010. / Title from PDF title page; viewed on March 18, 2010. Major professor: Hazelwood, Scott, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Biomedical Engineering." "February 2010." Includes bibliographical references (p. 87-89).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 36-40). Also available via the Internet.

Osteoarthritis of the metacarpo/metatarsophalangeal joint is a major cause of lameness in the horse. Magnetic resonance imaging and particularly delayed gadolinium enhanced imaging of cartilage (dGEMRIC) and T2 cartilage mapping in humans has been shown to visualize cartilage matrix changes in osteoarthritis early in the disease process. T2 mapping is a non-invasive technique characterizing hyaline articular cartilage and repair tissue. In dGEMRIC, the negatively charged administered Gd-DTPA2−, penetrates hyaline cartilage in an inverse relationship to the proteoglycan concentration thereof. In osteoarthritis, proteoglycan concentration is decreased with increased penetration of Gd-DTPA2− due to a relative decrease in negative charge of the proteoglycan-depleted cartilage. This study was performed on normal cadaver limbs of twelve euthanized racing Thoroughbreds. Six horses’ midcondylar distal third metacarpals/metatarsals (Mc3s/Mt3s) underwent six precontrast inversion recovery (IR) sequences for dGEMRIC T1 relaxation time calculation, as well as T2 mapping sequences using a 1.5T machine. Gd-DTPA2- was injected intra-articularly and the same six IR sequences repeated at 30, 60, 120, and 180 minutes post-injection at the same midcondylar sites. The distal Mc3/Mt3 cartilage thickness was measured histologically and compared to selected images of the T1 and T2 weighted sequences. T1 and T2 maps were created by fitting the respective data into mono-exponential relaxation equations for each pixel, and mean values of certain regions of interest were calculated. A second group of six horses’ fore and hind limbs were randomly assigned to two groups and the limbs either chilled or frozen, allowed to return to room temperature and scanned similarly to the first control group. Chilling and freezing effects on dGEMRIC and T2 mapping results were evaluated. The main conclusions from this study are that IR and proton density weighted (T2 mapping) sequences can measure distal Mc3/Mt3 cartilage thickness where the cartilage doesn’t overlap with that of the proximal phalanx. However, accurate measurement was hampered by the thin cartilage in this region. dGEMRIC mapping, using intra-articular Gd-DTPA2- is a feasible technique and T1 relaxation times decrease in a similar fashion to that of the human, with the optimal time of scanning after intra-articular Gd-DTPA2- injection being 60-120 minutes. There is little effect on T1 or T2 relaxation time and mapping images after chilling and freezing of the limbs except where the magic angle effect predominates in the T2 mapping sequences. Limitations of this study include relatively coarse spatial resolution of the thin cartilage, the overlap of the distal Mc3/Mt3 cartilage with the adjacent phalanx and the relatively low number of limbs used, resulting in low statistical power, particularly in the frozen limbs’ study. In spite of these limitations, this study provides technical information and reference values of dGEMRIC and T2 mapping in the cadaver distal Mc3/Mt3 of the normal Thoroughbred horse of value for forthcoming studies. Future studies need to evaluate intravenous administration of Gd-DTPA2- and cartilage mapping in live exercised vs. non-exercised horses. Ultimately, dGEMRIC and T2 mapping of horse metacarpo/metatarso-phalangeal joints with differing degrees of osteoarthritis should be used to attempt to diagnose early cartilage degeneration to endeavour to halt or delay its progression. / Thesis (PhD)--University of Pretoria, 2013. / gm2013 / Companion Animal Clinical Studies / unrestricted

Thesis (MSc (Production Animal Studies, Veterinary Science))--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Many factors influence the reproductive efficiency of thoroughbred mares. This thesisestimated two separate models for 13 farms in the 2004 breeding season. One model isestimated for pregnancy outcomes, the other is estimated for breeding intervals.Statistically significant variables include age of the mare, number of breedings, certainmedications, farm size, last date of breeding for the first model. Statistically significantvariables for the second model include age, status of mare, number of breedings, certainmedication, and farm size. The model has implication to achieve an optimal breedingschedule and associated management decisions

Thesis (M.S.)--University of Kentucky, 2008. / Title from document title page (viewed on March 18, 2008). Document formatted into pages; contains: viii, 73 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 67-72).

A radiographic examination forms part of the pre-purchase examination of Thoroughbred yearlings at national sales in many countries. This data enables the recording of the prevalence of radiographic changes in selected Thoroughbred populations around the world and assists veterinarians in advising clients on the purchase of yearlings. This has financial implications for the client as well as the racing industry as a whole. Radiographic examinations of the 269 Thoroughbred yearlings lodged at the 2008 National Yearling Sale in Germiston, South Africa were collected and individually evaluated. The prevalence of radiographic changes was recorded and percentages calculated. These changes were compared to studies of other yearling populations. Radiographic changes present in the studied Thoroughbred population are: pedal osteitis 1.26%, metatarsophalangeal joint dorsal osteochondral fragmentation 1.60%, sagittal ridge changes 5.7%, ulnar carpal bone lucencies 8.33%, carpal osteophytes 1.19%, distal intertarsal and tarsometatarsal joint radiographic changes 9.92%, tarsal osteochondrosis lesions 4.4% and stifle joint osteochondrosis lesions 0.4%. These changes were found to be of lower prevalence when compared to similar studies. The prevalence of dorsal osteochondral fragments in the metacarpophalangeal joint was 1.60% which was similar to other studies. A higher prevalence of vascular channels was visible in the proximal sesamoid bones as well as irregular borders and lucencies. Palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments had a recorded prevalence of 2% and 7.10%, respectively, this prevalence being generally higher when compared to similar studies. There was an absence of palmar metacarpal disease, supracondylar lysis, proximal sesamoid bone fractures and carpal osteochondral fragmentation in the current study. Additional findings recorded in the current study were: proximal interphalangeal joint hyperextension (left front 15.13%, right front 18.91%), the solar angle (right front 2.38°, left front 2.79°), the prevalence of carpal bone one (30.95%) and carpal bone five (1.59%). The study population was limited to the radiographs lodged at the sale repository. As radiographic changes may influence sale price of the yearling, radiographs of yearlings with severe radiographic changes may not have been lodged at the repository. For these reasons the prevalence of radiographic changes recorded in the current study may not be a true reflection of the entire 2006 Thoroughbred foal crop. Further work to correlate radiographic changes to differences in management, pre-sale exercise programmes and genetics needs to be done. The effect of radiographic changes on the future performance of the Thoroughbred yearling also warrants further investigation. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Companion Animal Clinical Studies / unrestricted

This group of experiments focused on relationships between diet, somatotropic axis, and growth. Growth hormone (GH) and insulin-like growth factor I (IGF-I) are factors in the somatotropic axis, and important to development of growth cartilage in the young animal. The entire study was divided into four main experiments. Characteristics of growth in 113 Thoroughbred foals born over a five year period were described with a series of empirical and physiological equations. Glycemic and insulinemic responses to different feed compositions were evaluated with glycemic response tests. The 24 hr pattern of plasma glucose, insulin, GH, and IGF-I was described in yearlings fed two meals a day. Finally, an association between ADG and IGF-I was described in Thoroughbreds from birth to 16 mo of age. Feeding diets to the foal that influence the somatotropic axis during growth may affect development of growth cartilage in unexpected or detrimental ways. The pattern of weight in Thoroughbred foals from birth to 16 mo of age was most closely described by multiple regression with a combination of age, girth, body length, and physeal circumference (R2 = 0.99). Glycemic and insulinemic responses were significantly higher in yearlings fed a sugar and starch supplement when compared to those fed a fat and fiber supplement (P = 0.043 and 0.031; respectively). Glucose and insulin secretion was significantly affected by the feeding of two meals in a 24 hr period (P < 0.0001). Plasma IGF-I was positively correlated with ADG from birth to 16 mo of age in foals fed either a fat and fiber or sugar and starch supplement (r = 0.34, P < 0.0001). The results from the series of experiments described here suggest a possible role of dietary mangement in reducing the risk of skeletal disorders that involve the influence of IGF-I on chondrocyte maturation. / Ph. D.