Thesis (Ph. D.)--Open University. BLDSC no. DXN059292.

Respiratory disease is an important cause of wastage in the Australian horse racing industry and viruses are frequently suspected as aetiological agents of respiratory disease or poor performance by clinicians and trainers but confirmation is seldom attempted. This thesis deals with the potential role of equine herpes virus types 1, 2, 4 and 5 in upper respiratory disease and poor performance in horses in Western Australia. The methodology selected for the identification of equine herpes viruses in tissues of horses was polymerase chain reaction (PCR) and therefore individual PCR assays were developed for the detection of each herpes virus, and then a nested multiplex PCR was developed to detect all four viruses. There was good correlation between the multiplex PCR for the detection of EHV and the detection of virus by isolation in cell culture, although a combination of the 2 techniques provided greater sensitivity than either technique alone. The multiplex PCR described appeared equally sensitive as specific PCR assays using a single set of primers for each individual virus but reduced labour and reagent costs. As latency is a well recognised phenomenon in the equine herpes viruses and the horse is subjected to a number of stresses which might induce reactivation of latent infections, it was hypothesised that there would be a background level of replication of the equine herpes viruses in clinically normal horses. Nasal swabs and peripheral blood leukocytes (PBL) were obtained from 282 clinical normal horses and examined for EHV. The results clearly demonstrated the widespread occurrence of EHV in the clinically healthy horses. The rate of detection of different types of EHV varied, as did the prevalence in young and adult horses. The most common EHV detected was EHV5: in 83.2% of 131 of horses <2 years of age; in 40% of horses >2 years of age. A prospective clinical study was conducted whereby respiratory tract samples and PBL from adult horses with respiratory disease and/or poor performance were examined for equine herpes viruses; the aim was to determine a possible association between equine herpes virus infection and respiratory disease and/or poor performance. The relative incidence of factors identified in the history, signalment, physical and laboratory evaluation of horses in the study population was compared between horses from which EHV was identified in respiratory samples and horses negative for equine herpes virus. The results indicated that equine herpes viruses were important causes of respiratory disease in the study population, and that haematological and cytological data were a poor indicator of such equine herpes virus infection. The occurrence of equine herpes virus in nasal swabs and PBL of weaned or unweaned foals from Thoroughbred breeding establishments was determined and provided data on the occurrence of EHV in association with respiratory disease. EHV5 was detected in nasal swabs and/or PBL at a high prevalence rate in healthy foals and yearling horses but its occurrence was not associated with clinical signs of respiratory disease. In contrast, EHV2 was detected more commonly in nasal swabs and/or PBL from foals with respiratory disease than in similar samples from healthy horses. Experimental infection of 8 horses with EHV2 was attempted and induced clinical signs of respiratory disease, but less severe than observed in the epidemiological studies. The results suggested that EHV2 is associated with mild upper respiratory tract infection in young horses.

Repeatabilities (t) and heritabilities (h²) for racing time were estimated from data on 7206 2- and 3-year-old standardbred racehorses competing in charted races at six tracks between 1975 and 1976. There were a total of 38,487 records from 2367 sire progeny groups. The data were divided according to gait into two subsets. Trotters only were used to test alternative models proposed to characterize horse’s racing time. Initially, class of race was recognized as a subjective categorization reflective of non-random assignment of horses to races. After extensive investigation, it was concluded that adjustment of horse’s time should include regression on pace (time of the winner). Data were analyzed within track-age-gait subclasses. Intra-horse regression coefficients of time on pace (sec/sec) ranged from .61 ± .08 to .79 ± .05. When records were adjusted for pace, repeatability and heritability estimates ranged from .32 ± .08 to .55 ± .04 and from -.25 ± .22 to .66 ± .15, respectively. Pooled estimates of t and h² were .44 ± .01 and .29 ± .03, respectively. When records were not adjusted for pace, sire, horse and error variance components were inflated by environmental bias (t_pooled = .62: h² pooled = .36). When records were pre-adjusted for pace, the permanent environmental variance appeared smaller compared with the total phenotypic variance than if there was no preadjustrnent for pace. Since genetic progress is based on selection of genetically superior sires and dams, time adjusted for pace should be used for estimation of breeding values and for objective evaluation of an individual horse's real ability to compete against horses having similar abilities. Thus, resulting breeding values should be more accurate dnd biased to a lesser degree than if unadjusted racing times were utilized. / Ph. D.

Siu, Man Tat. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 51-54). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii-iii / Table of Contents --- p.iv / Chapter Chapter 1 --- Introduction --- p.1-10 / Chapter Chapter 2 --- Literature Review --- p.11-13 / Chapter Chapter 3 --- Data --- p.14-20 / Chapter Chapter 4 --- Model --- p.21-30 / Chapter Chapter 5 --- Empirical Result --- p.31-43 / Chapter Chapter 6 --- Discussion and Conclusion --- p.44-50 / References --- p.51-54 / Figures and Appendix --- p.55-66

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1978. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / B.S.

No description available.

Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Health Sciences. Bibliography: leaves 164-198.

Radiographic examination of Thoroughbred racehorses at the time of the yearling sales is common practice in South Africa. Although it is generally accepted that yearlings will have some radiographic changes, there is only one study that estimated the prevalence of these changes in Thoroughbred racehorse yearlings in South Africa. Furniss et al reported on the occurrence of radiographic abnormalities over a one-year period (Furniss 2011). Furniss et al. study differs from other studies in that there was a higher prevalence of palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments and a lower prevalence of pedal osteitis, dorsal osteochondral fragmentation of the metatarsophalangeal joint, distal metacarpal saggital ridge changes, ulnar carpal bone lucencies, carpal osteophytes, distal intertarsal and tarsometatarsal joint changes, tarsal osteochondrosis lesions and stifle osteochondrosis lesions was found. This study will further assist practitioners to identify joints where the most prevalent changes are likely to occur. Our objective was to describe the prevalence and distribution of radiographic changes in the metacarpophalangeal joint, metatarsophalangeal joint, carpi, tarsi, stifle and fore digits of racing Thoroughbred yearlings in South Africa when examined as part of a pre-purchase examination during the Annual National Yearling Sales extending from 2008 through 2010. Thoroughbred racehorse yearlings were subjected to radiographic evaluation including the digit (n= 566 ), metacarpophalangeal joint (n=566 ), metatarsophalangeal joint (n= 566), carpi (n= 566), tarsi (n= 566) and stifle (n=566 ). The radiographic changes were categorised by location and type of change present for each series. The digit Where informal comparisons with previously published data can be made, similar changes of pedal osteitis were recorded in this study, with a total percentage of 6.7%. There was an 8.7% prevalence of inversion of the third pedal bone. Other studies describing radiographic changes in Thoroughbred racehorse yearlings did not investigate inversion of the third pedal bone, therefore results cannot be compared. The metacarpophalangeal and metatarsophalangeal joints with proximal The metacarpophalangeal and metatarsophalangeal joints with proximal sesamoid bones The prevalence of dorsoproximal phalanx one fragmentation (1.2%) of metacarpophalangeal joints were similar compared to other studies. Osteochondral fragmentation of proximal plantar phalanx one (6%) was 8.5 times more prevalent when compared to proximal palmar phalanx one (0.7%). The latter prevalence is in agreement with similar studies. There were low incidences of subchondral cyst-like lesions seen in distal third metacarpus (0.4%), distal third metatarsus (0.2%) and proximal first phalanx, similar to other studies. The most common change recorded on the dorsal aspect of distal third metacarpus and metatarsus was a well-defined semi-circular notch (dorsal aspect of distal third metacarpus 20.3%; dorsal aspect of distal third metatarsus 27%) similar to other studies. Our study showed a higher prevalence of lucencies present at dorsal aspect of distal third metacarpus (8.5%) and metatarsus (4.2%) compared to other studies. There was a marked lower prevalence in the current study of flat distal palmar third metacarpal condyles (6%). Prevalence of palmar and plantar third metacarpal and metatarsal supracondylar lysis were markedly higher in the present study. Slight palmar and plantar third metacarpus and metatarsus supracondylar lysis was seen in 19.3% of the horses. Moderate to extreme palmar and plantar third metacarpus and metatarsus supracondylar lysis were present in 10.2% of the horses. The carpi There was a higher prevalence of dorsomedial carpal disease in our study population (11.3%) and prevalence of carpal osseous cyst-like lesions such as a circular lucency in ulnar carpal bone was lower (14%). A markedly higher prevalence of 4.2% in carpal osteochondral fragmentation was found. The tarsi Osteochondrosis of the tarsocrural joint showed a similar prevalence (13.4 %). Degenerative joint disease of tarsometatarsal joint had a higher prevalence (36%) than the centrodistal (distal intertarsal) joint (20.3%). There was also a higher incidence of degenerative joint disease in tarsometatarsal joint (36%). The stifle In the current study, osteochondrosis of the stifle had a similar prevalence (3.6%) when compared to other studies. 6 Conclusion In South Africa Thoroughbred racehorse yearlings, radiographic changes most commonly involved the metacarpo- and metatarsophalangeal joints, carpi and tarsi. This study revealed markedly higher prevalence of palmar and plantar third metacarpal and metatarsal supracondylar lysis (slight 19.3% and moderate to extreme 10.2%), carpal osteochondral fragmentation (4.2%) and degenerative joint disease in tarsometatarsal joint (36%). Establishment of normal prevalence and distribution of radiographic changes in South Africa Thoroughbred yearlings will allow for comparison with populations of young horses worldwide. Knowledge of the normal prevalence will assist veterinarians to identify joints in which radiographic changes are most likely to occur. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Companion Animal Clinical Studies / unrestricted

Thirteen Thoroughbred farms in Virginia provided 260 horses for the study of growth patterns of horses from birth to July of the yearling year. Measurements included heart girth, wither and hip height, body length, chest width, knee to ground length, cannon bone circumference and body weight, as estimated by heart girth. Quadratic regression equations, adjusted for the effects of farm, sex and month were developed to describe the growth of foals. Foals born in January-February were smallest overall at birth, 30 and 90 d-of-age (P< .01) May-June foals were largest at birth. Differences in wither height, body length and body weight of foals born in May-June vs in January-February at 30 d-of-age, were 1.7, 3.8 cm and 21.6 kg, respectively; At 90 d-of-age, differences were 1.6, 4.9 cm and 13.3 kg, respectively. Differences in size due to birth month were apparent up to 270 d-of-age. May-June foals exhibited the fastest initial growth rate. Colts were intermittently larger than fillies subsequent to 150 d-of-age. In January of the yearling year, birth mouch influenced all measurements (P< .01). Foals born in January to March were larger than foals born in April to June. In July of the yearling year, differences were identified less often and actual differences in size were smaller than in January. Average differences in heart girth and wither height of foals born in January to March compared to foals born in April to June were 8.4 and 5.1 cm in January and 5.2 and 3.6 cm in July of the yearling year. Foals born in April to June displayed larger gains during the first 7 mo of their yearling year than did early-born foals. Correlation coefficients between measures of foals up to 400 d-of-age decreased or remained the same. Thus, growth in various proportions was asynchronous. Regression coefficients that described the resemblance between wither heights of parents and offspring increased with age and were highest in July of the yearling year. Offspring-midparent regression coefficients of 1982 foals increased from .50 ±.18 at 30 d-of-age to .78 ±.14 at 400 d-of-age. The regression coefficient in July was .84 ±.15. / Ph. D.

Dissertation (PhD(Agric))--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: This study was carried out to investigate whether environmental and/or genetic factors had an effect on the incidence of epistaxis related to exercise-induced pulmonary haemorrhage among racehorses in Southern Africa. A further aim was to estimate the heritability of liability to epistaxis in the Southern African Thoroughbred population. For the purpose of the environmental study, the data covering the period 1986-2001 and involving a total of778 532-race runs, were analysed. This included the following race start information: date of race (day/month/year), age, sex, breeder, trainer, distance, jockey, state of going, weight carried, centre of racing and altitude. The genetic part of the data was two-fold in nature and included firstly the analysis of all horses that suffered epistaxis whilst racing in Southern Africa from 1986 to 2001 and involving 1118 individual bleeders. The second genetic analysis included the same Southern African population plus those Southern African horses exported to Mauritius and then being recorded as bleeders in that country (1252 bleeders in total). Pedigree data covering the period 1960-1986 was used as required to calculate the incidence of bleeding amongst ancestors of the post 1986 era. Only pedigrees of horses that raced were included in this study as it was not possible to predict whether non-runners would have bled had they raced. Consequently all non-runners and also those that raced overseas in countries where bleeding occurrence was not recorded were excluded. Veterinarians employed by the Jockey Club suspended officially recorded horses that showed epistaxis as demonstrated by frank bleeding from the nostrils after racing. Oncourse endoscopy is not employed as a routine on any of the Southern African racetracks. In the environmental study epistaxis was identified in 1 287 race starts (0.165%). Epistaxis related to exercise-induced pulmonary haemorrhage was significantly (p<0.001) associated with altitude, age, race year, month and the day of racing. More horses demonstrated epistaxis at sea level than at altitude, between the months of May - October than the rest of the year, in older horses than in horses less than three-years old, after 1995 than between the years 1986 and 1995, and on Fridays and Sundays than on any other week day. No association could be established between epistaxis and breeder, trainer, distance, jockey, state of going, sex and weight carried. The heritability of liability method as described by Falconer (1989) was used to estimate the relative importance of heredity and environment. For the period investigated, the population incidence for epistaxis in Southern African horses was 2.1%. The estimation of heritability ofliability showed that first-degree relatives had a figure of 55.4%. The heritability of second- and third degree relatives were 41.3% and 30.4% respectively. The data investigated depicts horses that bled almost exclusively on race days as only a small percentage (- 5%) was reported as having bled during exercise. Accordingly, the full extent of epistaxis amongst racing Thoroughbreds in Southern Africa is difficult to gauge. Pedigree and race run data from Thoroughbreds racing in Southern Africa, covering the period 1986-2002 (63 146) horses in pedigree data-set and 778 532 race runs, were further analysed in order to study genetic and environmental factors affecting the incidence of epistaxis as associated with EIPH (exercise-induced pulmonary haemorrhage). As fixed effects for the model, variables that were tested significantly in a preliminary data analyses, were included. Various combinations of such variables namely age, weight, altitude, sex, month and going were tested. Fixed effects that were included in the fmal model were gender, going and altitude. The heritability estimates from a logit transformed analysis for epistaxis fitting both the animal and sire generalized mixed models were 0.23 and 0.40 respectively, which indicated that epistaxis as associated with EIPH in the Southern African Thoroughbred sires has a strong genetic basis. Genetic trends indicating an increase in epistaxis were also found. It is concluded that the frequency of epistaxis related to pulmonary haemorrhage is associated with altitude, winter and spring months and the horse's age. It is suggested that racing at a lower altitude may increase the probability of exercise-induced pulmonary haemorrhage. It is clear that epistaxis in the racing Thoroughbred has a strong genetic basis. It is further suggested that horses showing frank bleeding from the nostrils after racing or exercise, be suspended and not used for breeding purposes. This would result in relatively fast progress being made towards eradicating this costly scourge of the modem Thoroughbred racehorse. Affected stallions and those racing whilst being treated with furosemide, should be barred from breeding and not be considered as future sires. Estimated breeding values for epistaxis should be used as a tool for selecting against it and be considered in breeding programmes to decrease the incidence thereof. / AFRIKAANSE OPSOMMING: 'n GENETIESE ANALISE VAN DIE VOORKOMS VAN LONGBLOEDING IN DIE SUID-AFRIKAANSE RENPERD: Die doel met hierdie studie was om vas te stelof omgewings- of genetiese faktore enige invloed op die voorkoms van longbloeding in die Suid-Afrikaanse renperd het. 'n Verdere doelstelling was om die oorerflikheid op die onderliggende verspreiding van longbloeding in die Suid-Afrikaanse Volbloedpopulasie te bepaal. Vir die omgewingstudie is data wat oor die periode 1986-2001 strek en wat 'n totaal van 778 532 wedren-deelnames ingesluit het, statisties ondersoek. Die data het die volgende inligting ingesluit: datum van deelname, ouderdom, geslag, teler, afrigter, afstand van wedren, jokkie, toestand van baanoppervlakte, gewig gedra, sentrum waar deelname plaasgevind het en die hoogte bo seespieël van die sentrum. Die studie van die genetiese aspekte het eerstens 'n analise van al die perde wat longbloeding tydens 'n wedren in Suider-Afrika gedurende die jare 1986-2002 ondervind het (I118 perde), en tweedens dieselfde populasie perde, plus die Suiderlike-Afrikaanse perde wat uitgevoer is na Mauritius en bloeding daar ondervind het, (1252 perde), ingesluit. Ter aanvulling is uitgebreide stamboomdata van voorouers gedurende 1960-1986 gebruik om die voorkoms van longbloeding tydens die post 1986 tydvak te bepaal. Slegs stambome van renperde wat aktief aan renne deelgeneem het, is in die data ingesluit aangesien dit nie moontlik was om te voorspel of 'n perd wat nooit aan wedrenne deelgeneem het nie, longbloeding sou ondervind indien dit wel deelgeneem het. Dus is alle renperde wat nooit aan wedrenne deelgeneem het, asook daardie perde wat in die buiteland deelgeneem en waar longbloeding nie aangeteken word nie, uitgesluit. Alle perde wat bloeding van die neus na wedrenne getoon het, is deur veeartse in diens van die Jokkie Klub van Suid-Afrika ondersoek, as 'n bloeier aangeteken en van verdere deelname aan wedrenne geskors. Endoskopie word op geen van die Suid- Afrikaanse renbane as 'n standaard praktyk na wedrenne uitgevoer nie. Longbloeding het in 1 287 perde of gedurende 0.165% van alle wedrenne plaasgevind. Longbloeding soos geassossieer met EIPH, (exercise-induced pulmonary haemorrhage), is betekenisvol (p<0.001) met hoogte bo seespieël, ouderdom, dag van deelname, maand, en jaar verbind. Meer perde het longbloeding by seevlak in vergelyking met hoër vlakke bo seespieël ondervind, tussen die maande Mei-Oktober as die res van die jaar, in perde ouer as drie-jaar, na 1995 as tussen die jare 1986-1995, op Vrydae en Sondae as enige ander dag van die week. en meer by reuns as by merries of hingste. Geen verwantskap kon tussen bloeding en teler, afrigter, afstand, jokkie, toestand van baan, geslag en gewig gedra, gevind word nie. Die oorerflikheid op die onderliggende verspreiding vir longbloeding soos omskryf deur Falconer (1989), is gebruik om die relatiewe belangrikheid van oorerflikheid en omgewing te bepaal. Vir die periode bestudeer, was die voorkoms van longbloeding in die Suid-Afrikaanse renperd 2.1%. Die oorerflikheid van longbloeding was 55.4% vir eerste-graadse verwantes. By tweede-graadse verwantes was die ooretlikheid 41.3% en by derde-graadse verwantes 30.4%. Die data wat ondersoek is, was bykans uitsluitlik die van perde wat tydens wedrenne gebloei het en slegs 'n baie klein persentasie (~ 5%) was aangeteken as perde wat tydens oefening gebloei het. Dus is die volle omvang van longbloeding in Suider-Afrikaanse Volbloedperde moeilik om akkuraat te bepaal. Die stamboom- en wedrendata van Suid-Afrikaanse Volbloedperde is verder ontleed in 'n poging om die genetiese en omgewingsfaktore se invloed op die voorkoms van longbloeding, soos geassosieer met EIPH te bepaal. As vaste effekte vir die model is veranderlikes wat betekenisvol gevind was, ingesluit. Verskeie kombinasies van hierdie veranderlikes soos ouderdom, gewig, hoogte bo seespieël, geslag, maand en toestand van die baan is ingesluit. Die vaste effekte wat in die finale model ingesluit is, was geslag, toestand van die baan en hoogte bo seespieël. Die beraamde oorerflikheid verkry vanaf 'n "logit" getransformeerde analise vir longbloeding wat beide die diere- en vader- gemengde model gepas het, was onderskeidelik 0.23 en 0.40, wat 'n aanduidending is dat longbloeding, soos geassosieer met ElPH, 'n sterk genetiese grondslag het. Genetiese tendense het ook gedui op 'n toename in die voorkoms van longbloeding, veraloor die laaste vyf jaar van die studie. Samevattend is die bevinding dat die frekwensie van longbloeding 'n betekenisvolle verwantskap toon met hoogte bo seespieël, winter en lente maande en die perd se ouderdom. Dit word voorgestel dat renperde wat deelneem aan wedrenne by laer vlakke van hoogte bo seespieël, meer onderhewig aan longbloeding sal wees. Uit die resultate verkry is dit duidelik dat longbloeding 'n genetiese grondslag het. Dit word voorgestel dat perde wat fisiese simptome van neusbloeding na of gedurende wedrenne toon, geskors word van verdere deelname en ook nie toegelaat word om mee te teel nie. Hierdie maatreëls behoort aanleiding te gee dat relatief vinnige vordering gemaak sal word in die strewe om hierdie ongewenste sindroom in die moderne Volbloed te verminder. Aangetaste hingste, asook die wat aan wedrenne deelgeneem het terwyl hul behandeling ontvang met furosemide, moet nie toegelaat word om te teel en nie as toekomstige teelhingste oorweeg word nie. Die waarde van voorspelde teelwaardes vir longbloeding moet nie onderskat word in seleksie daarteen nie en moet in teelprogamme om die voorkoms daarvan te verminder, oorweeg word.