Most horse owners administer oral deworming medication to their horses on a set schedule, often six times per year. The deworming process involves using a plastic syringe to inject a thick paste into the horse's mouth. Most horse owners do not specifically train their horses to accept this procedure. Consequently, many horses resist the procedure and some horses engage in behaviors, such as head shaking, pulling away, or even rearing, that may be dangerous to humans or to themselves. This study used a negative reinforcement shaping procedure to train six horses to accept dewormer medication. The procedure consisted of a food sampling phase followed by three shaping phases that simulated the deworming task, first using only the experimenter's hand, then a small syringe, and finally a large syringe. Once the horse was acclimated to the syringe, the horse's preferred liquid food was delivered through the syringe at the end of each trial. By the end of the study, all participants successfully completed the procedure and were able to stand still with no or minimal head movements while being dewormed.

Most horse training methods heavily rely on negative reinforcement and punishment. However, there is a movement in the horse community to utilize positive reinforcement to meet training goals. Although food has been used effective as a reinforcer with horses, social interaction has also been demonstrated to function as a positive reinforcer for animals. Utilizing social interaction as a reinforcer may lead to several benefits for both the trainer and animal. Some of the benefits can be improved relationships between animals and their caretakers and improved animal welfare. The purpose of this study was to apply Owens and Owens et al. previous research protocols to three equines to assess if social interaction, in the form of petting and gentle scratching, would function as a reinforcer. Using a changing criterion design, this study demonstrated that petting and gentle scratching could function as a reinforcer to teach three equines to stay and come in their natural environment.

A naturally occurring disease involving hyperplasia of the thyroid gland and a consistent pattern of musculoskeletal deformities of newborn foals in western Canada was first described in 1981. This disease was an important cause of foal mortality and, therefore, reproductive loss throughout western Canada during the 1990s and has since been recognized in western Ontario and the northwestern United States. A series of investigations were conducted to describe, characterize, and attempt to determine the pathogenesis and cause of this syndrome. Affected foals were typically born after a long gestation (x = 360 days, range = 340 to 400 days), were diagnosed as hypothyroid based on a poor response to the administration of thyroid-stimulating hormone, and had various musculoskeletal lesions of which mandibular prognathism, flexural deformities and rupture of tendons of the limbs, and incomplete ossification of the carpal and tarsal bones were present most commonly. In spite of the normal to long gestation, foals had signs of immaturity, were usually weak and unable to stand, became septic, and died or were euthanatised. Similar histories, clinical findings, and lesions were present in surgically created hypothyroid foals that were thyroidectomized in utero at about 210 days gestation. These findings supported the conclusion that foals which naturally developed these lesions were also hypothyroid in utero and that all the lesions present in affected foals were the result of the hypothyroidism and not of an underlying concurrent disease process. A case-control study was conducted to identify risk factors for naturally occurring congenital hypothyroidism. Information from congenitally hypothyroid foals concerning foal and dam signalment, farm environment, and dam management was compared with that from normal foals. Pregnant mares fed greenfeed, not supplemented with mineral, that left their "home farm" during gestation, or grazed irrigated pasture, had a 13.1 (<i>P</i>=0.0068), 5.6 (<i>P</i>=0.0472), 4.3 (<i>P</i>=0.0076) and approximately 15.3 (<i>P</i>=0.0245) times greater odds, respectively, of producing a congenitally hypothyroid foal than mares not exposed to these factors. Greenfeed often contains high levels of nitrate (NO₃^-) which is known to impair thyroid gland function. In light of this, forage samples from participating farms were analysed for nitrate levels. The odds of one or more congenitally hypothyroid foal being born on a farm feeding forage with at least a trace of nitrate was 8.0 times greater (<i>P</i>=0.0873) than the odds of the disease occurring a farm that fed forage free of nitrate. Further, the odds of a mare producing an affected foal when fed forage containing at least a trace of nitrate was 5.9 times greater (<i>P</i>=0.0007) than a mare fed nitrate-free forage.This study suggests that congenital hypothyroidism in foals may result from diets containing nitrate or low in iodine being fed to pregnant mares. These results need to be confirmed through further field investigations and controlled experiments. However, if they are accurate, there is cause for concern that other livestock raised in areas where congenitally hypothyroid foals occur may be exposed to the same dietary risk factors and may suffer similar disease.

Humans and horses weaved together wonderful stories of adventure and generosity. As a part of human history and civilization, Arabian horses ignite imagination throughout the world. Populations of this breed exist in many countries. Here I explored different populations of Arabians representing Middle Eastern and Western populations. The main two aims of this study were to provide the genetic diversity description of Arabians from different origins and to examine the traditional classification system of the breed. A third aim was to tackle the distribution pattern of the genetic variability within the genome to show whether there are differences in relative variability of different types of markers. First, I analyzed the genetic structure of 537Arabian horses from seven populations by using microsatellites. The results consistently showed higher levels of diversity within the Middle Eastern populations compared to the Western populations. All American-Arabians showed differentiation from Middle Eastern populations. Second, I sequenced the whole mtDNA D-loop of 251 Arabian horses. The whole D-loop sequence was more informative than using just the HVR1. Native populations from the Middle East, such as Syrian, represented a hot spot of genetic diversity. Most importantly, there was no evidence that the Arabian horse breed has clear subdivisions depending on the traditional maternal based strain classification system. Third, I tested the heterozygosity distribution pattern along the genome of 22 Peruvian Paso horses using 232 microsatellites and Single Nucleotide Polymorphisms (SNPs). The pattern of genetic diversity was completely different between these two markers where no correlation was found. Runs of homozygosity test of SNPs and associated microsatellites noticeably showed that all of associated microsatellites loci were homozygous in the matched case. The findings of this study will help in understanding the evolutionary history and developing breeding and conservation programs of horses. This study provided databases including parentage testing system and maternal lineages that will help to recover the Syrian Arabian population after the armed conflict started in Syria in 2011. The results here can be applied not only to horses, but also to other animal species with similar criteria.

Observed and expected heterozygosity (H) levels for ten electrophoretic blood marker loci and expected H for seven red blood cell (RBC) anitgen/antibody loci were examined for 20 years in American Standardbred and 30 years in American Saddlebred horses. Standardbreds were classed by gait, Trotter and Pacer, and evaluated separately in most analyses. 4,404 Trotters and 12,271 Pacers were found to have statistically highly significant losses of mean total observed H through time for the ten electrophoretic loci (P<0.005), although in Trotters the loss was more extreme (P<<0.001). Loss of H in 5984 Saddlebreds was not significant (P=0.259). Correlations of RBC expected H through time showed decreases in all three groups.

African horse sickness (AHS) is a non-contagious viral disease transmitted by an arthropod vector and is endemic to sub-Saharan Africa. The disease affects all equine species, but is more severe in horses and other equid species not native to Africa. Vaccination is the only demonstrated means of its prevention. The horse-owning public provides much anecdotal evidence of prophylactic strategies, such as repellents, stabling, alternate hosts, traps, paraffin, blankets, smoke or fans. The present study investigated the relationship of these strategies to the incidence of AHS, and evaluated alternate hosts, wind speed and repellents on the activity of males and females of the different Culicoides species.. Cypermethrin and citronella-containing repellents repelled the most female midges. Sheep and cattle offer an alternate blood meal to gravid and nulliparous female midges. Fans are very effective in keeping midges away from horses. Methods are summarised for the horse owner to implement in addition to vaccination to prevent AHS. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

African horse sickness virus causes a non-contagious, infectious disease of equids. It is epizootic to sub-Saharan Africa and parts of the Middle East. The epizootics caused by the virus have caused widespread devastation amongst equids worldwide. Fortunately no epizootic has lasted more than 5 years outside of sub- Saharan Africa. It is vectored by species of Culicoides midges (Diptera: Ceratopogonidae) and most importantly by the two Avarita species of C. imicola Keiffer and C. bolitinos Meiswinkel. The literature pertaining to the study and research of the virus, the disease and the vectors is reviewed. Models allowing prediction of future possible outbreaks as well as details of control strategies and findings of researchers are presented and discussed. The virus needs a long term reservoir host in which to overwinter and various theories are discussed. Control measures in South Africa are suggested so that outbreaks of the disease can be reduced. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermarizburg, 2008.

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.

This thesis comprises an introductory review of the literature, followed by reports of two experiments which are presented in the form of scientific papers. For this reason, there may be some repetition between chapters, particularly in terms of experimental procedure. To avoid unnecessary repetition, a single list of references is given at the end of the thesis. For the sake of completeness , several appendices are attached to Chapters Two and Three which would not ordinarily be included in a scientific paper. The literature review looks at the passive transfer of immunity from the mare to the foal, the consequences of failure of passive transfer of immunity and different methods of testing whether the transfer of passive immunity has occurred. The review concludes with a discussion of vaccination programmes against African horse sickness. Trial One evaluated different tests for determining whether the transfer of passive immunity from mare to foal has occurred in order to determine which of these tests should be used preferentially. A single radial immunodiffusion test was used as the reference standard. A series of samples .was taken from a group of foals and tested using four methods: single radial immunodiffusion , glutaraldehyde coagulation, zinc sulphate turbidity and protein refractometer tests. Trial Two explored African horse sickness vaccination programmes, focusing on when to vaccinate foals for the first time. A series of samples was taken from a group of foals from birth until two months after their second set of African horse sickness vaccinations (one year old). The samples were tested for the presence of African horse sickness antibodies for each of the nine serotypes to determine when maternal immunity fades and to evaluate the effect of each vaccination on the level of immunity. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

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