Academic literature on the topic 'Thoroughbred horse'

Abstract The objective of this research was to identify the reproductive performance of Gayo horses and Thoroughbred horses. This research was conducted in Bener Meriah District, Aceh Province through a survey method. In this case, the research location was chosen intentionally (purposive sampling). The total population of Gayo horses in Bener Meriah is currently 227 horses. Among them, 78 horses were taken as the research samples with minimum requirement that the horses involved have at least given birth 2 times. Furthermore, the required data in this study were the reproductive performance characteristics of Gayo horses and Thoroughbred horses including: (1) estrous cycle; (2) estrous duration; (3) first mating age; (4) gestation period; (5) foaling interval; and (6) postpartum mating age. Based on the results, the data obtained are that the average length of estrous cycle of Gayo horses is 20.75±1.67 days, while Thoroughbred horses is 29±1.59 days. Furthermore, the length of time in estrous for Gayo horses is 5.80±1.20 days, while Thoroughbred Horses is 7.30±1.70 days. In addition, the average first mating for Gayo horse is 3.78±1.19 years, while for Thoroughbred horses is 3.10 ± 0.65 years. Furthermore, the gestational period of Gayo horse has an average of 335.40±5.00 days, while for Thoroughbred horses is 336.66±3.41 days. The foaling interval of Gayo horse is 458.43±37.14 days, while Thoroughbred horse is 477±16.65 days. Last, the average postpartum mating of Gayo horse is 123.03± 37.73 days, while the Thoroughbred horse is 141.26±15.88. Furthermore, the data obtained identified that the reproductive performance of Gayo and thoroughbred horse in Bener Meriah Regency is in normal condition.

This study aimed to determine the phylogenetic and bottleneck analyses of Turkish Thoroughbred and Arabian horse populations. In the study, genotyping was performed using a total of 17 microsatellite markers in the samples taken from 959 Thoroughbred and 813 Arabian horses. The average effective allele number in Arabian horses was 3.338 and the average number of alleles was 7.412 in Thorougbred horses. Genetic distance and genetic identity between Thoroughbred and Arabian breeds was 0.411 and 0.663, respectively. Also genetic identity in each Arabian and Thoroughbred horse populations was 1.000. The FCA table showed that the two breeds were completely separated from each other and were compatible. In conclusion; the bottlenecks of Thoroughbred and Arabian horse populations were in a normal L distribution and these horse breeds do not appear to have succumbed to introgression. Therefore, they are not yet at risk of extinction any time soon.

During the past eight years a comprehensive genetic linkage map for the horse has been generated in Newmarket, through a fruitful collaboration between the Genetics section at the AHT and Professor Twink Allen at the TBA Equine Fertility Unit (Swinburne et al., 2000). In order to assess whether the map was adequate to start mapping disease traits in which we are interested, it was decided to attempt to map a clear, easily scoreable trait such as grey coat colour in the Thoroughbred horse. Grey coat colour is inherited as an autosomal dominant trait. Thoroughbred horses are fairly inbred, and as such they represent one of the more difficult horse breeds for genetic mapping. The majority of grey Thoroughbreds trace their ancestry back to Allcock's Arabian who was born in 1700, and horsemen have long noted an association between grey coat colour and the incidence of melanomas. It is hoped that characterizing the mechanism of grey coat colour formation might also lead to an improved understanding of the molecular basis of melanoma formation.

The purpose of this study was to evaluate the frequency and time of specific behaviors in Thoroughbred and Haflinger horses reared in outdoor paddock environments. Therefore, 2 Thoroughbred and 2 Haflinger horses were used in the study, and the data were collected by video recording (112 hours in total) between 09:00 and 16:00 (7 h/day) for 16 days. Some behaviors examined during this period; eating from the hay rack, drinking water, grazing on the pasture, walking, running, standing, being next to the other horse and other activities (Rolling, lie down, etc.). Considering the total number of behaviors performed in both horse breeds, it was observed that Thoroughbred horses (154.82 times - 7 h/day) made more daily movements than Haflingers (134.63 times - 7 h/day). When the behavior of the horses in the paddock is assessed based on breed, Thoroughbreds were seen to repeat eating from the hay rack, drinking water activities significantly (P < 0.05) more frequently than the other breed, as were Haflingers when grazing on the pasture. There was no statistically significant difference in breeds among hours (P > 0.05), but when the repetition or intensity results of the movements were examined according to the study hours, it was discovered that the hours with the largest total number of movements were between 11:00 and 15:00. As a result, it has been determined that the behavior activities of Thoroughbred horses is more in an outdoor paddock area during the 09:00-16:00 hours of the day compared to Haflinger horses.

Thoroughbreds are some of the most famous racehorses worldwide and are currently animals of high economic value. To understand genomic variability in Thoroughbreds, we identified genome-wide insertions and deletions (INDELs) and obtained their allele frequencies in this study. INDELs were obtained from whole-genome sequencing data of 101 Thoroughbred racehorses by mapping sequence reads to the horse reference genome. By integrating individual data, 1,453,349 and 113,047 INDELs were identified in the autosomal (1–31) and X chromosomes, respectively, while 18 INDELs were identified on the mitochondrial genome, totaling 1,566,414 INDELs. Of those, 779,457 loci (49.8%) were novel INDELs, while 786,957 loci (50.2%) were already registered in Ensembl. The sizes of diallelic INDELs ranged from −286 to +476, and the majority, 717,736 (52.14%) and 220,672 (16.03%), were 1-bp and 2-bp variants, respectively. Numerous INDELs were found to have lower frequencies of alternative (Alt) alleles. Many rare variants with low Alt allele frequencies (<0.5%) were also detected. In addition, 5955 loci were genotyped as having a minor allele frequency of 0.5 and being heterogeneous genotypes in all the horses. While short-read sequencing and its mapping to reference genome is a simple way of detecting variants, fake variants may be detected. Therefore, our data help to identify true variants in Thoroughbred horses. The INDEL database we constructed will provide useful information for genetic studies and industrial applications in Thoroughbred horses, including a gene-editing test for gene-doping control and a parentage test using INDELs for horse registration and identification.

The Waler horse breed is an integral part of Australian history. The purposes of this study were to analyse the genetic variability in Waler horses from Australia and to investigate genetic relationships with other horse breeds. We examined the genetic diversity of 70 Waler horses sampled from seven breeding stations in Australia. Also we analysed the relationships of these horses with 11 other horse breeds. Analysis of the genetic structure was carried out using 15 microsatellite loci, genetic distances, AMOVA, factorial correspondence analysis and a Bayesian method. We found that the genetic diversity in the Waler was greater than the domestic horse mean and exceeded that of all endangered horse breeds. Our findings also revealed moderate population subdivision rather than inbreeding. All genetic similarity measures indicated that the Thoroughbred might be a key ancestor to the Waler. This study indicates that there is no immediate concern for loss of variation in Waler horses. Also, there clearly has been a strong input from the Thoroughbred into the Waler horse breed. However, the genetic evidence suggests that this input was not just direct but also came through other types of horses with a Thoroughbred cross background.

The unwanted horse problem is the most serious issue confronting the equestrian industry. Thus, it is recommended that retired racehorses switch to become saddle horses for ‘the second life of a racing veteran’ because training and using retired Thoroughbred racehorses as saddle horses is the most cost-effective option. The current study aimed to analyze the effects of saddle horse conversion training on gaits of retired Thoroughbred racehorses. Our study included 12 retired Thoroughbred racehorses. These Thoroughbred racehorses performed the retraining 20–50 min a day, five times per week for three months. There are some critical findings in this study. The results show that the decreased stride length of each foot decreased the displacements of the center of mass and the center of the head. In addition, after retraining, there was a significant decrease in the head–neck angle and displacement between the center of the head and the center of the neck. These changes in the horse’s movements mean that the habitual movements for racing are gradually changed to optimal movements for a saddle horse.

The present research aimed to characterize the Persian Kurdish horse population relative to the Persian Arabian and American Thoroughbred populations using genome-wide SNP data. Fifty-eight Kurdish, 38 Persian Arabian and 83 Thoroughbred horses were genotyped across 670,796 markers. After quality control and pruning to eliminate linkage disequilibrium between loci which resulted in 13,554 SNPs in 52 Kurdish, 24 Persian Arabian and 58 Thoroughbred horses, the Kurdish horses were generally distinguished from the Persian Arabian samples by Principal Component Analyses, cluster analyses and calculation of pairwise FST. Both Persian breeds were discriminated from the Thoroughbred. Pairwise FST between the two Persian samples (0.013) was significantly greater than zero and several fold less than those found between the Thoroughbred and Kurdish (0.052) or Thoroughbred and Persian Arabian (0.057). Cluster analysis assuming three genetic clusters assigned the Kurdish horse and Thoroughbred to distinct clusters (0.942 in cluster 2 and 0.953 in cluster 3 respectively); the Persian Arabian was not in a distinct cluster (0.519 in cluster 1), demonstrating shared ancestry or recent admixture with the Kurdish breed. Diversity as quantified by expected heterozygosity was the highest in the Kurdish horse (0.342), followed by the Persian Arabian (0.328) and the Thoroughbred (0.326). Analysis of Molecular Variance showed that 4.47% of the genetic variation was present among populations (P<0.001). Population-specific inbreeding indices (FIS) were not significantly different from zero in any of the populations. Analysis of individual inbreeding based on runs of homozygosity using a larger SNP set suggested greater diversity in both the Kurdish and Persian Arabian than in the Thoroughbred. These results have implications for developing conservation strategies to achieve sound breeding goals while maintaining genetic diversity.

Abstract. Interest in horse breeding in the Stavropol Territory is not accidental: it is a traditional and historically developed branch of animal husbandry. The priority link of the branch, of course, is pedigree horse breeding. Goal is the analysis of the of thoroughbred horse breed population in the Stavropol Territory on the example of the leading breeding farms. The object of the study were stallions (n = 16) and breeding mares (n = 86) thoroughbred horse breed, bred in breeding farms of the Stavropol Territory (Agricultural Production Enterprise “Svobodnyy trud” LLC, Agricultural Production Enterprise “Novomaryevskoye” LLC, Federal State Unitary Enterprise “Rassvet-Stavropol”). Information sources of research: pedigree horses, scoring, statements of results, catalogs of stallions State stud books of horses of thoroughbred riding breed, data from KONI-3 information retrieval system. Results and scope. Used in breeding farms of Stavropol territory stallions of thoroughbred horse breed are represented by 5 genealogical lines: Northern Dancer, Native Dancer, Nasrullah, Blandford and Man O’War. The number of stallions belonging to the old Phalaris line is 14 heads (87,5 %). One head each (6,25 %) falls on the representative of the Blandford line in Agricultural Production Enterprise “Novomaryevskoye” LLC and the Man O'War line at the Federal State Unitary Enterprise “Rassvet-Stavropol”. Evaluation of the mares in the nuclear stock thoroughbred riding breed showed that their genealogical structure is represented by 12 lines. It should be noted that 5 lines of Northern Dancer, Native Dancer, Nasrullah, Fairway and Turn-to go back to one ancestor, the line of Phalaris, which accounts for 82,6 % of the total number of breeding mares. The obtained results can be used in further research, the practical work of livestock breeding farmers and individuals engaged in breeding horses of thoroughbred riding breed. The results of the research can be recommended as educational material for students and undergraduates of universities studying in the areas of training zootechnical profile. The scientific novelty of the research lies in the fact that, for the first time, a comparative genealogical and zootechnical characteristization of stallions and mares of the nuclear of thoroughbred horse breed bred in the Stavropol Territory was carried out.

Measurements of 7 body measures and 6 indices of body conformation on 34 breeding individuals of Moravian warm-blooded horse and 19 of Sarvar horse (Leutstettener) were used to analyse the effect of country of origin (Czech Republik, Germany), sire lines or breed (Furioso, Przedswit, English thoroughbred, Sarvar, Others) and age (4 classes). All horses were measured by one person. Measures and indexes were analysed by GLM procedure. Significant differences were found between both Czech and German population only in index of body frame. Sarvar horses are longer to their height than Moravian warm-blooded horses. The shorter body frame have the horses by English thoroughbred, the longer by Furioso. The younger horses are higher than the older. According to results of Linear Description of Body Conformation we found out, that population of Sarvar horse is more balanced than population of Moravian warm-blooded horse.

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.

Developmental Orthopaedic Disease (DOD) describes problems affecting the limbs of young horses, including abnormal bone, joint and tendon development. DOD is responsible for major economic losses in the Thoroughbred industry. Investigation into the epidemiology of DOD in Australia and Ireland as described in this thesis has allowed valuable comparisons and recommendations to be made between the studs in these countries. The project described in this thesis commenced in 1999, with the aim to: a) Establish the incidence of DOD on a stud in Australia and to compare this with similar data for a stud in Ireland b) To determine relationships between factors affecting severity and incidence of DOD in foals with respect to the country in which they are bred and raised c) To further identify risk factor areas associated with the development of DOD Records of 1717 mares from a major stud in Ireland and another in Australia were made available. Foal weight, age of mare, condition of mare, foal sire and date of birth were monitored over two years. The occurrence of DOD was recorded against these data. The incidence of DOD was found to be higher on the stud in Australia (average 49.85%) than on the stud in Ireland (average 14%). Foal weight was found to be a significant factor affecting DOD, with heavier foals showing a proportionally higher severity of the problem. The Australian stud had a higher incidence of DOD in 2000 compared to 1999 (65.2% affected vs 32.1% in 1999), whereas the Irish stud had a lower incidence in 1999 compared to 2000 (11.8% affected vs 16.2% in 2000). The dramatic increase in the incidence of DOD in Australian foals over the 1999-2000 period is representative of the increase in a major problem in the industry, as well as greater awareness of the problem over recent years. It highlights the urgent need for further research into understanding the cause(s) of DOD. Overall recommendations arising from the study include that a large scale, long term study be undertaken in Australia. Further investigation into the nutrition of horses in Ireland and Australia would be of great usefulness in understanding DOD, as would possible genetic links. An issue requiring attention is that of developing a standard definition of the disorder. Considering the wide range of disorders which may fit under the umbrella term DOD, a clear definition is of great importance. The incidence of DOD on one large farm in Ireland was found to be currently low and stable relative to its another large stud farm in Australia. This is a significant finding as the genetic pool of the horses share similarities on both farms, particularly as stallions shuttling between hemispheres sire many foals on both farms. Thus, the data provided herein provide an excellent basis for further valuable comparative studies investigating DOD in foals with a similar genetic background but subjected to differing environmental conditions.

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
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The thoroughbred horse has been selectively bred for speed and has a high capacity for carbohydrate metabolism. The following series of studies investigated the relative contribution of fat and carbohydrate to energy production during exercise of varying intensity. Furthermore the work assessed the capacity of the horse to increase the contribution of fat to energy production as the result of either an acute increase in the availability of plasma free fatty acids (FFA) or as the result of chronic fat supplementation. Finally an adaptational response to feeding a fat supplemented diet was described. The variation in plasma long chain FFA over a 24 hour period was described. The early hours of the morning represented the period of greatest variability in plasma FFA concentration. This period was characterised by a significant increase in total and individual FFA concentration, which was unrelated to feed intake. As a result of the reported circadian rhythm in plasma FFA all subsequent exercise studies were performed during the period of least variability in plasma FFA concentration. A model for the pre-exercise elevation of plasma FFA, using a combination of a triglyceride emulsion and the heparinoid type substance pentosan polysulphate, was used to investigate the effect of increased FFA availability on fat utilisation during prolonged low intensity exercise. Pentosan polysulphate was used in preference to heparin following an investigation of their relative lipolytic and anticoagulative properties. Pentosan polysulphate when administered at 3 times the dose of heparin resulted in a comparable increase in plasma total lipase activity. When co-administered with a triglyceride emulsion, pentosan polysulphate resulted in a similar increase in plasma FFA concentration relative to that produced with the same triglyceride emulsion and heparin. The anticoagulative effect of pentosan polysulphate, however, was approximately 9 times less than that of heparin, as measured by activated partial thromboplastin time. The contribution of fat and carbohydrate to energy production during exercise was influenced by both the intensity and duration of exercise, as indicated by measurements of respiratory exchange ratio (RER). The inter-horse variability in RER was greatest during low intensity exercise. An increase in the contribution of carbohydrate to energy production occurred at the onset and during the early stages of prolonged exercise and as the result of an increase in exercise intensity. A proportion of horses exhibited an increase in the utilisation of fat during low intensity prolonged exercise as a result of a pre-exercise elevation in plasma FFA concentration. RER was consistently lower during exercise in 5 out of the 7 horses studied following a pre-exercise elevation of plasma FFA. Furthermore, plasma glucose concentration was elevated above that observed during the control session in 4 of these 5 horses for at least the first 15 minutes of exercise. A prolonged period of fat supplementation resulted in an improved management of the fat load. Following 10 weeks of dietary treatment a significant increase in plasma cholesterol concentration and a significant decrease in plasma triglyceride concentration was reported. The decrease in plasma triglyceride concentration was associated with a mean 50% increase in post pentosan polysulphate plasma total lipase activity. It is suggested that the increase in the post pentosan polysulphate plasma total lipase activity may have reflected an increase in muscle lipoprotein lipase activity. A significant increase in the activity of muscle citrate synthase was observed during the period of fat supplementation. No significant change occurred in muscle ß-hydroxyacyl CoA dehydrogenase activity or in the concentration of resting muscle glycogen and triglyceride as a result of fat supplementation. RER was significantly lower in the latter stages of prolonged low intensity exercise, during the period of fat supplementation, relative to the same exercise performed before the introduction and following 5 weeks of withdrawal of the fat supplemented diet. The reduction in RER during the period of fat supplementation was associated with a greater exercise induced increase in plasma FFA concentration. The above differences were also apparent during moderate intensity exercise, although, examination of the individual horse data revealed that the effect was not as clear as that observed during low intensity exercise. No significant differences were reported in either RER or plasma FFA concentration in response to moderate/high intensity exercise during the period of fat supplementation. Neither were any significant differences observed in either RER or plasma FFA concentration in the control group at any exercise intensity. An increased availability of plasma FFA and an increase in the oxidative capacity of muscle, as well as an enhanced ability to utilise plasma triglycerides may have contributed to the increase in fat utilisation, observed during low and moderate intensity exercise, in response to fat supplementation. The effect of differences in the hormonal response to a fat supplemented diet as a precipitant of the observed adaptational responses in these studies requires further investigation.

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
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Respiratory conditions causing poor performance in horses are usually as result of upper respiratory tract diseases or are of pulmonary origin. The tracheal is rarely a cause of primary respiratory problems in the horse, but tracheal dimensions, particularly height, may be useful in evaluating upper repiratory tract conditions cranial to the trachea and lung pathology, due to resultant change in differential pressures between these areas. The normal radiological equine tracheal height along its length has as yet not been reported. Standing lateral radiographs of the cervical and thoracic trachea of 15 clinically normal sedated Thoroughbred horses, 3-6 years old, were made at peak inspiration and end expiration. Maximum height of the larynx, and trachea at the level of the third and fifth cervical vertebra, at the level of the first thoracic vertebra, carina and the left and right primary bronchi were measured. Ratios of laryngeal height relative to the third cervical vertebral body length and tracheal heights relative to the vertebral body lengths of adjacent third and fifth cervical vertebrae and first thoracic vertebra, and carina heights relative to a mid-thoracic vertebra, respectively were made, as well as tracheal height at the fist thoracic vertebra ratio with the thoracic inlet height. Known size metallic markers were used to determine magnification corrected tracheal heights in the sagittal plane and effect of body mass and height at the withers on tracheal height was determined. The magnification corrected radiological airway heights at end expiration and peak inspiration were measured and respectively the mean values were found to be: laryngeal height: 5.89 cm and 5.86 cm, tracheal height at the third cervical vertebra: 4.17 cm and 4.04 cm, tracheal height at the fifth cervical vertebra: 3.62 cm and 3.59 cm, tracheal height at the first thoracic vertebra: 3.4 cm and 3.23 cm and carina height: 3.85 cm and 4.12 cm. The ratios of these measurements to nearby vertebral body lengths were respectively: laryngeal height at the third cervical vertebra: 0.56 and 0.56, tracheal height at the third cervical vertebra: 0.4 and 0.39, tracheal height at the fifth cervical vertebra: 0.37 and 0.37, tracheal height at the first thoracic vertebra: 0.59 and 0.59, and carina height: 0.91 and 0.94. The ratio tracheal height at the first thoracic vertebra to the thoracic inlet respectively 0.15 and 0.15. Although there was no statistical difference in the data, there was a trend towards a higher tracheal height at expiration. No correlation was found between tracheal height and body mass or tracheal height and height at the withers, and measured tracheal height was generally lower than predicted tracheal height, possibly as result of sedation used. The small range of body mass and height in this study as well as the relatively small number of horses evaluated may account for the lack of correlation to predicted tracheal height. This study in normal horses may serve as a reference when radiologically evaluating cases of upper respiratory tract and lung pathology, where the tracheal dimensions may differ significantly due to differences in airway resistance and biomechanics. Radiographs to evaluate tracheal height can be made independent of respiratory phase in sedated horses, and it is recommended that ratios of tracheal height to an adjacent vertebral body length are more reliable values to compare within and between horses. It is recommended to take tracheal height measured at the fifth cervical vertebra since this measurement showed a slightly smaller standard deviation than at other sites measured as well as a medium amount of clinical effect. If only thoracic radiographs are made, measurements of tracheal height at the thoracic inlet is the alternative (the standard cranioventral view), but it is recommended to include the distal aspect of the first rib if the thoracic inlet is to be measured.
Dissertation (MMedVet)--University of Pretoria, 2008.
Companion Animal Clinical Studies
unrestricted

The objective of this study is to determine if fat as an energy source, and fiber in a pasture supplement will be beneficial when compared to a concentrate high in sugar and starch. In the first experiment, 12 pregnant and lactating mares were used in three different glycemic response tests to determine the effect of feeds on pregnant mares. The mares were fed a pelleted concentrate (PC) three months before foaling; after foaling they were divided into two groups and fed a feed high in sugar and starch (SS), or a feed high in fat and fiber (FF). The second experiment, used the same 12 mares (R mares) and 10 barren mares (B mares) in three different tests to determine the effects of the feeds, season and reproductive stage. A series of blood samples was collected via a jugular catheter from 0 to 390 min after consuming a meal. Glucose and insulin baseline and peak values, increments and areas under curves (AUC) were compared by ANOVA. For the first experiment, responses to PC did not differ between the two groups. Peak plasma glucose and insulin concentrations were higher in SS group than in FF during both early and late lactation. Glucose and insulin AUCs were higher in SS than in FF during both early and late lactation. In the second experiment, peak glucose increments had differences for the main effects feed, pregnancy and season, and interactions feed by pregnancy and feed by season. The glucose AUC values showed similar differences for the main effects and the interaction feed by pregnancy. Peak insulin increments had a difference for feed and pregnancy, but not the interactions. Insulin AUCs also revealed a difference between feed and pregnancy, and also for season, and the interaction feed by pregnancy. These results indicate that metabolic fluctuations are moderated by the replacement of sugar and starch with fat and fiber. This replacement may reduce the risk of certain digestive and metabolic disorders.
Master of Science

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.

Рассматриваются результаты прилития посторонней кро- ви к орловской рысистой породе от момента создания до сегодняшних дней. The results of use of other breeds blood to Orlov Trotter breed are reported from the moment of its creation till nowadays.

В 2001 г. в долине р. Чаган на Алтае найдена и опубликована Д.В.Черемисиным удивительная миниатюра, гравированная на скале в древнетюркское время. В центре изображен породистый конь с тамгой на крупе, с двух сторон удерживаемый на веревках воинами третий воин готовится выстрелить в животное из лука. Первоначально воспринятая как сцена укрощения или жертвоприношения коня, эта картина теперь рассматривается авторами как необычный для традиционного наскального искусства и для эпоса кочевников Центральной Азии сюжет, повествующий о намеренном убийстве коня, отмеченного тамгой его владельца. Точный возраст миниатюры пока не установлен. Своеобразная форма тамги имеет сходство с тамгами басмылов, представленными на памятниках Монголии, но более напоминает тамгу тюргешей, известную по нумизматическим материалам и петроглифам Семиречья. In 2001 an amazing miniature engraved during the Old-Turkic period on a rock in the Chagan Valley in the Altai, was found and published by D.V. Cheremisin. In the center of the composition a thoroughbred horse with a tamga on its croup is engraved, it is held with ropes by two warriors the third warrior is preparing to shoot the animal with a bow. Originally perceived as a scene of taming or sacrificing a horse, this depiction is now considered by the authors as a subject, unusual for the traditional rock art and for the epic of Central Asian nomads: the purposive killing of a horse marked by its owners tamga. The exact dating of the engravings has not yet been established. The peculiar form of the tamga resembles the Basmyls tamga represented in rock art and at the memorial stele from Bombogor (Mongolia), but is more reminiscent of the tamga of the Turgeshes, known from early medieval coins and petroglyphs of the Semirechye in Kazakhstan.

Изучена связь вариантов аллелей гена миостатина (MSTN) с работоспособностью лошадей чистокровной верховой породы, проявленной ими в гладких скачках на разные дистанции. Вы- явлено, генотип С/Т характерен для лошадей, побеждавших на дистанциях 2000-2400 м, и в то же время не исключает их побед на более длинных или более коротких дистанциях. Генотип С/С свойственен лошадям, побеждавшим на дистанциях до 1800 м, а генотип Т/Т в основном характерен для лошадей, побеждавших на дистанциях более 2800м. It is studied the relation of alleles variants of myostatin gene (MSTN) with the performance of Thoroughbred horses in flat races on the different distances. It was found that C/T genotype is characterized for horses won on the distance 2000-4000 m. At the same time it does not exclude their wins on the longer or shorter distances. C/C genotype is peculiar to horses won on the distance to 1800 m, and T/T genotype is peculiar to horses won on the distance more than 2800 m.