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Item A Beggar?s Ride: Tales From Within the Herd(2012-02-14) Jensen, Katie LaurieThis story suite is a work of autobiographical fiction, a coming of age tale which uses a young girl?s relationship to horses?along with various people and places connected to the horse world?as its narrative theme. The collection is comprised of twelve chapters, including an Introduction and Prologue and much later, an Interlude and Conclusion. While the first person narrative voice is maintained through most of the chapters herein, the Interlude uses second-person perspective. Additionally, NOW DEPARTING is written in the present narrative tense. Poems are interspersed throughout the work, between chapters, as transitional bridges for the reader.Item Calcium balance and bone density in immature horses fed a high protein diet(Texas A&M University, 2006-10-30) Spooner, Holly SueStudies in other species indicate high protein diets increase urinary calcium (Ca) excretion and may lead to negative calcium balance and reduced bone density. As overfeeding of protein is commonplace in the horse industry, this study was undertaken to determine the effects of excess dietary protein on growth, physiologic response, mineral balance, bone density, and bone geometry in immature horses. Sixteen 10-month-old American Quarter Horses were blocked by age and sex into two dietary treatments. The control diet was formulated to provide the NRC (1989) recommended concentration of crude protein, while the high protein diet provided 130% of NRC (1989) recommendations. All other nutrients were formulated at or slightly above NRC (1989) recommendations. Blood samples, feces, and urine were collected during the 116-day study to determine any diet effect on pH and mineral balance. Radiographs were made of the left third metacarpal (MCIII) to determine bone density via radiographic bone aluminum equivalence (RBAE), and bone geometry was determined metrically from the radiographs. Urine pH decreased over time (p < 0.001), but there were no diet effects on blood pH or urine pH. Conversely, when normalized to day 0 values, fecal pH was reduced by feeding the high protein treatment (p < 0.02). Density of dorsal and palmar cortices increased over time (p < 0.001), but no differences were observed between diets. But, normalized total medial-lateral (ML) width of the MCIII was higher in the control diet (p < 0.05). Fecal Ca loss was greater in horses fed the high protein diet (p < 0.005), while Ca absorption and retention were lower for horses on the high protein treatment (p < 0.02). Phosphorus (P) balance was not different between diets, although feeding the high protein diet resulted in higher P intake overall (p < 0.001). While excess dietary protein may decrease fecal pH, increase fecal Ca excretion, and decrease Ca absorption and retention, there was no consistent effect of the high protein diet on bone density over the course of this study. Further research is necessary to determine if feeding high-protein diets is detrimental to bone quality in the growing horse.Item Channels and sources used to gather equine-related information by college-age horse owners and enthusiasts(2009-05-15) Sullivan, Erin AleneThis thesis identifies the equine-related topics that are important to Texas college-age horse owners and enthusiasts and the channels/sources they use to get equine-related information. Little research has focused on this group to determine their information needs. Therefore, two focus groups were conducted in 2008 in Texas with college-age horse owners and enthusiasts to conduct a needs assessment. Participants were separated into competitive and recreational groups depending on their level of participation in the industry. They were asked what topics they consider important and what channels/sources they use to gain desired information. Training was the most mentioned topic overall, and the most mentioned by recreational participants. Alternative medical treatments was the most mentioned topic by competitive participants. Competitive participants reported a smaller number of topics as important, indicating that they have specialized information needs. Recreational participants emphasized broader, less specialized topics. Participants showed an interest in relevant and controversial topics affecting the equine industry. Participants also used a combination of channels/sources and competitive and recreational participants often placed importance on different channels/sources. Face-to-face communication was important to both groups. Magazines were important to competitive participants, while the Internet was important to recreational participants. Competitive participants doubted the trustworthiness of sources available through the Internet, but wanted more reliable sources to be made available in the future. Participants preferred to get information from industry specialist sources, such as trainers, veterinarians, other owners and enthusiasts, breed associations, and equine magazines. Participants? perceptions of trustworthiness were affected by the source?s ability to demonstrate equine-specific knowledge and the source?s reputation and success among equine industry members. The results suggests that the influence of the Internet has altered the traditional models of communication in which source selection determines channel use. In this study, the participants? Internet channel selection often determined their source use. The results also suggests that communicators wanting to reach this audience should target specific topics to competitive and recreational audiences, use a multi-channel approach, establish trustworthiness, and explore the changing role of the Internet in agricultural communication.Item Copper and zinc balance in exercising horses fed two forms of mineral supplements(2009-05-15) Wagner, Elizabeth LynnThis study was undertaken to compare the absorption and retention of copper and zinc when supplemented to exercising horses in the form of sulfate or organic-chelate mineral supplements. Nine mature horses were used in a modified-switchback designed experiment consisting of seven 28-d periods. Horses were fed a diet consisting of 50% coastal Bermudagrass and 50% concentrate. All diets were balanced to meet the energy, protein, calcium and phosphorus requirements for horses performing moderate to intense exercise. Copper and zinc supplementation varied by period. During mineral depletion and repletion periods, horses respectively consumed diets with no supplemental mineral or Cu and Zn supplemented in the sulfate form to provide 100% of NRC (1989) values. In periods 4 and 7, horses were fed diets designed to provide 90% of NRC (1989) values for Cu and Zn supplied in the sulfate or organic-chelate forms. Horses were subjected to a standard exercise test on d 23 of periods 4 and 7 followed by a 4-d total fecal and urine collection. Blood samples were drawn every 28-d for determination of plasma Cu, Zn and ceruloplasmin concentration, and white blood cell counts and Cu,Zn-superoxide dismutase activity were evaluated in periods 4 and 7. Copper and zinc balance was determined from feed, fecal, urine and water samples obtained during the total collections in periods 4 and 7. Copper and Zn intake and fecal excretion were greater (P<0.05) for horses consuming the organic-chelate supplemented diet. Apparent Cu absorption as a percent of intake and retention as a percent of intake were also greater for this group. Plasma Cu, Zn and ceruloplasmin concentration was not different for horses consuming the two mineral supplement forms. White blood cell counts and superoxide dismutase activity were not affected by diet treatment. Formulation error and suspected sample contamination made it difficult to compare absorption and retention of Cu and Zn, but the use of a controlled repletion-depletion diet sequence appeared to be an effective experimental design component.Item Development of a Computer Program Demonstrating the Anatomy of the Equine Paranasal Sinuses(2012-07-16) Ruoff, Catherine MarieThe equine paranasal sinuses are a frequent site of disease. They are anatomically complex structures encased in bone that are difficult to visualize. Because of their complexity and location, accurate diagnosis and treatment of the affected sinus(es) is difficult without a good understanding of their anatomy. Use of 3-D computer models in anatomy education has increased in recent years and shows promise in teaching anatomy of complex structures. The goal of this thesis was to develop a computer program illustrating a 3-D model of the equine paranasal sinuses to aid teaching the anatomy of the paranasal sinuses. A CT scan of a horse?s head was performed and a 3-D reconstruction was generated. The paranasal sinuses were illustrated in the reconstructed images using Adobe Photoshop 6.0. Adobe Flash Professional CS5 was used to create an interactive computer program from the images. The resulting computer program depicts the sinuses and features of the skull at five key points plus or minus nine degrees of rotation.Item Discovery of Candidate Genes for Stallion Fertility from the Horse Y Chromosome(2012-02-14) Paria, NandinaThe genetic component of mammalian male fertility is complex and involves thousands of genes. The majority of these genes are distributed on autosomes and the X chromosome, while a small number are located on the Y chromosome. Human and mouse studies demonstrate that the most critical Y-linked male fertility genes are present in multiple copies, show testis-specific expression and are different between species. In the equine industry, where stallions are selected according to pedigrees and athletic abilities but not for reproductive performance, reduced fertility of many breeding stallions is a recognized problem. Therefore, the aim of the present research was to acquire comprehensive information about the organization of the horse Y chromosome (ECAY), identify Y-linked genes and investigate potential candidate genes regulating stallion fertility. To achieve theses goals, a direct cDNA (complementary DNA) selection procedure was used to isolate Y-linked genes from horse testes and 29 Y-specific genes were identified. All 29 genes were mapped to ECAY and their sequences were used to further expand the existing map. Copy number analysis identified 15 multicopy genes of which 9 were novel transcripts. Gene expression analysis on a panel of selected body tissues showed that some ECAY genes are expressed exclusively in testes while others show ubiquitous or intermediate expression. Quantitative Real-Time PCR using primers for 9 testis-specific multicopy genes revealed 5 genes with statistically significant differential expression in testis of normal fertile stallions and stallions with impaired fertility. Gene copy number analysis showed that the average copy number of 4 such genes was decreased in subfertile/infertile stallions compared to normal animals. Taken together, this research generated the first comprehensive physical gene map for the horse Y chromosome and identified a number of candidate genes for stallion fertility. The findings essentially expand our knowledge about Y chromosome genes in horses, open a new avenue for investigating the potential role of ECAY genes in stallion fertility which contribute to the development of molecular tools for the assessment of fertility in stallions.Item Effect of Omega 3 Polyunsaturated Fatty Acids (PUFAs) on Markers of Inflammation in Young Horses in Training(2011-02-22) Lucia, Jessica LaurenSixteen horses (2 to 4 yr; 357 to 439 kg BW) were utilized in a randomized complete block design for a 140 d trial to determine effect of omega 3 PUFAs (n-3) supplementation on markers of inflammation in young horses in training. Horses were fed treatments consisting of a control diet (n = 8) fed at 1% BW (as fed) or a treatment diet (n = 8) of concentrate fed at 0.75% BW (as fed) and 350 g of a marine n-3 supplement formulated to provide 15 g of eicosapentaenoic acid (EPA) and 20 g of docosahexaenoic acid (DHA). Body weight and body condition scores (BCS) were obtained biweekly and concentrate adjusted accordingly. Horses were exercised 5 d/wk by students in an equine training course. Type of activity and duration was monitored, along with heart rate to quantify workload. Exercise protocol was divided into 2 phases: phase I (d 0 to110) consisted of ground work and early training under saddle, and phase II (d 111 to 140) consisted of advance maneuvers and moderate workload. Synovial fluid was obtained from right radial carpal joint by arthrocentesis every 28 d and was analyzed for white blood cell count (WBC), total protein (TP), and specific gravity (SG). Serum concentrations of carboxypeptide type II collagen (CPII) and chondroitin sulfate 846 (CS-846) were analyzed by ELISA kits. Dietary treatment did not affect synovial WBC, TP, or SG. Also, concentrations of WBC and TP also did not differ over time. SG increased over time (P < 0.001) as horses moved from phase I to phase II of the trial. Dietary treatment did not influence concentrations of CPII or CS-846. CS-846 tended to increase over time (P = 0.09) and CPII concentrations also increased (P < 0.001) in response to changes in exercise. Furthermore, all horses gained BW and BCS throughout the trial (P < 0.001), but values were not influenced by treatment. This data indicates further studies are needed to determine the efficacy of n-3 supplementation as a preventative measure against development of osteoarthritis.Item Effect of Trace Mineral Supplementation on Gastric Ulcers in Exercising Yearling Horses(2010-10-12) Hayes, Alexa DawnEquine gastric ulcer syndrome (EGUS) has been reported to occur in 40% to over 90% of horses across multiple equestrian disciplines. The objective of this study was to evaluate the effect of trace mineral supplementation on gastric ulcers in exercising yearling horses. Twenty-one Quarter Horse yearlings, 15 to 18 mo of age, were randomly assigned to 1 of 3 treatment groups. The control group received no supplemental trace minerals, the inorganic group received supplemental sulfated trace minerals, and the organic treatment received supplemental amino acid complexed trace minerals. The trial consisted of 3 consecutive 28-d periods, separated by 5 d of diet acclimation. The basal ration included a 14% CP textured concentrate, with coastal Bermudagrass hay fed in Periods 1 and 3 and alfalfa consumed in Period 2. In Periods 1 and 2, horses were exercised on a mechanical horse-exerciser, but were lunged or underwent training in an undergraduate course in Period 3. At the end of each period, horses were transported for 6 h, 5 d before being endoscopically examined to assign ulcer scores. Data were analyzed as repeated measures using the mixed procedure of SAS, with the model including fixed effects of treatment, period, and their interaction (SAS 9.2). All P-values < 0.05 were considered significantly different. Baseline EGUS scores were not different among treatment groups, with a mean of 2.1. There was no effect of treatment in any period, or a period by treatment interaction. There was a significant period effect (P < 0.01). Mean ulcer scores in Periods 1, 2, and 3 were significantly lower than baseline, with mean scores of 1.5, 1.0, and 1.5, respectively. There was a tendency (P=0.06) for mean ulcer scores to be lower in Period 2 than in Periods 1 and 3, which were not different. Average daily intakes of Zn, Mn, Cu, and Co were significantly higher in the organic and inorganic than control horses (P < 0.0001). Under the conditions of this study, trace mineral supplementation did not affect gastric ulcer appearance and severity. However, it is possible that dietary and management alternatives, such as hay and concentrate types, could be anti-ulcerogenic.Item Effects of density and water availability on the behavior, physiology, and weight loss of slaughter horses during transport(Texas A&M University, 2007-04-25) Iacono, Christa MarieThe aim of this study was to determine the effects of density and provision of water on behavior, stress, and weight loss in slaughter horses during transport. A 16.2-m long, single deck, semi-trailer was divided into three compartments to create high, medium, and low density (5000, 4000, and 3000 kg per compartment, respectively) groups of slaughter horses. A total of six shipments containing 23 to 30 horses per shipment were transported in June and July of 2004 for 18 to 20 h. Horses were a variety of different breeds, ages, sexes, and body conditions, but were typical of slaughter horses. Jugular blood samples were taken from five horses in each of the three density treatments immediately before loading and after unloading at the completion of each shipment. All horses were weighed at the same time as the blood samples were collected. While the truck was stopped, horses in each of two compartments received water from three automatic water bowls in each side of a compartment. The water was provided for 1-h after 8 h of transport and then again just prior to unloading. The third, non-watered compartment served as a control for each of the 1-h watering sessions. Densities selected to receive water were alternated between shipments. The aggressive behavior of the horses for the six shipments was recorded using 12 video cameras installed in the trailer. All occurrences of aggressive behavior were counted from 15-min segments of video during 2-h intervals for each horse that was visible in each density group. Density did not significantly affect (P > 0.21) aggressive behavior, cortisol, serum chemistry profile, dehydration, and weight loss. Aggression level did not differ (P = 0.49) between the first and second halves of the shipments. Individual horses, rather than density, appeared to be the cause of aggressive behavior. The watered and non-watered groups did not differ (P > 0.54) in terms of aggression, cortisol, serum chemistry profile, dehydration, and weight loss. Density and provision of water did not significantly influence aggressive behavior, stress and weight loss in shipments of 18 to 20 h long during warm weather.Item Effects of Dietary Magnesium Status on Indices of Muscular Dysfunction in Exercising Horses(2011-02-22) Kurtz, Cassidy A.Throughout the performance horse industry, the occurance of various muscle disorders is common and can be detrimental to the performance and longevity of equine athletes. Research has revealed effects of diet manipulation, exercise, and electrolyte supplementation on the symptoms and occurrence of disorders like exertional rhabdomyolysis (ER). However, there has been no investigation on effects of Mg on muscle function in horses during exercise. Six Quarter Horse mares were used to study the effects of varying levels of Mg on indices of muscular dysfunction during a standardized exercise test (SET) on a highspeed treadmill. Three rations were used over three 28 d periods: control (Trt 1), low Mg (Trt 2), and high Mg (Trt 3). A baseline SET was conducted prior to day 0 (Trt 0). Blood samples were taken during the SET at rest, immediately post, 1 h, 6 h, and 24 h post exercise for analyses of serum muscle enzymes and Mg concentrations. Heart rates (HR), respiration rates (RR), and rectal temperatures (RT) also were documented. No effect of Trt was observed on HR or RR at any point throughout the SET. Resting RT?s were lowest in Trt 0 (P<0.05). There was no Trt effect on blood lactate (LA) during the SET; however, blood glucose (GLU) at rest in Trt 2 was lower than Trt 0 (P<0.05). Treatment had an effect on both resting serum creatine phosphokinase (CK), as Trt 3 was higher than Trt 0, and the change in CK from rest to 24 h post SET, where Trt 1 exhibited the greatest increase in CK concentration (P<0.05). Serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were not affected by Trt (P>0.05). Serum alkaline phosphatase (AP) at rest and 6 h post exercise was lower in Trt 2 than in Trt 3 (P<0.05). Additionally, serum P was lowest at rest in Trt 0 and highest 6 h post exercise in Trt 3, also varying within each Trt. Average daily intake (ADI) of Mg was higher in Trt 1 and 3 than in Trt 2 (P<0.05). Finally, at rest, immediately post and 24 h post exercise, serum Mg was highest in Trt 3 (P<0.05). Results suggest there is an effect of dietary Mg on serum muscle enzyme and Mg concentrations and potentially, overall performance in the equine athlete.Item Effects of exercise or oocyte heat shock on embryo development and gene expression in the horse(2009-05-15) Mortensen, Christopher JohnHorse owners commonly maintain their broodmares in training and competition during the breeding season. The effect this has on mare reproductive efficiency has received limited attention. Heat stress has shown to be detrimental to oocyte competence in other species and heat shock protein 70 has been shown to be an important gene in regulating cellular response to heat. Mares were exercised in a hot humid environment to determine the effects on reproductive efficiency. Embryos were collected at d 7 after ovulation from exercised and control mares. Oocyte developmental competence was measured after oocytes were subjected to a one time heat shock, 42 ?C for 2 or 4 h, at the onset or near completion of in vitro maturation. Embryos from both previous experiments were examined for HSP70 gene expression by real time RT-PCR. Exercised mares ovulated significantly smaller follicles, 39.8 vs. 41.5 mm diameter, and ovulated later after being given PGF2?, 8.5 vs. 9.2 d. Twenty-two embryos (22/35) were recovered from control mares, recovery rate of 63%. Significantly fewer embryos were recovered in exercised mares (11/32), recovery rate of 34%. A lower proportion of grade 1 embryos were recovered from exercised versus control mares (4/11 vs.16/22,respectively). No effect was observed on oocyte nuclear maturation or embryonic development after ICSI when oocytes were exposed to heat shock at the onset of IVM. A heat shock of 42 ?C for 2 or 4 h on oocytes during late IVM resulted, however, in a significantly lower rate of nuclear maturation, and a significant decrease in advanced embryo development (morulae plus blastocysts). Heat shock protein 70 gene expression was shown to be related to quality score of in vivo-recovered embryos, with lower quality embryos recording a significantly higher relative expression. Heat shock of late stage IVM oocytes for 4 h resulted in significantly higher blastocyst HSP70 expression. Results of this study indicate that exercise in a hot humid environment is detrimental to mare reproductive efficiency, late-stage maturing oocytes are sensitive to heat, and HSP70 expression in equine embryos is related to embryo quality score and oocyte quality.Item Effects of Intra-Articular Lipopolysaccharide Injection on Systemic Cytokine Gene Expression and Leukocyte Population in Young Horses(2012-02-14) Mueller, CarrieNineteen yearling Quarter Horses were utilized in a randomized, complete block design to evaluate systemic cytokine gene expression and circulating leukocyte population in young horses following an intra-articular lipopolysaccharide (LPS) challenge. Horses were administered an injection of 0.25 ng (n = 7) or 0.50 ng (n = 6) of LPS or lactated Ringer?s solution (n = 6; control). Blood was collected via jugular catheter at pre-injection h 0 and at 2, 6, 12, and 24 h following aseptic injection of the left radiocarpal joint. Aseptic arthrocentesis was performed at the same times to sample synovial fluid for a companion study. Total RNA was isolated from leukocytes using a commercially available kit and real-time PCR was used to determine relative gene expression of the cytokines; interleukin (IL)-1beta (beta), IL-6, IL-8, IL-10, and tumor necrosis factor-alpha (TNF-alpha). Determination of total leukocyte subpopulations and differentials was performed by Texas Veterinary Medical Diagnostic Laboratory. Data were analyzed using the PROC MIX procedure of SAS. Gene expression of all cytokines analyzed was unaffected by treatment. However, changes over time were observed in some cytokines. Interleukin-1? was increased above baseline at 6, 12, and 24 h (P = 0.04), IL-6 was decreased slightly at 6 and 12 h and then increased at 24 h (P = 0.002), and TNF-alpha was increased at 6 and 12 h (P = 0.01). Only IL-8 exceeded a 2-fold change in expression (P = 0.01), peaking at 12 h and indicating greater responsiveness to arthrocentesis than was observed in the other cytokines. No treatment effects on the leukocyte population were observed; however, total circulating leukocytes increased over time (P = 0.04), peaking at 6 h post-injection. Similarly, an increase over time was observed in monocytes (P = 0.002) and in platelets (P = 0.01) at 24 h post-injection. The results indicate that regardless of treatment, a mild immune response was elicited, likely due to repeated arthrocentesis. Future experiments should consider the effects of arthrocentesis and potential systemic inflammatory response, even in control animals, when administering intra-articular LPS to young horses.Item Evaluation of bone biochemical markers and inflammatory markers in yearlings fed varying ratios of omega-6 and omega-3 polyunsaturated fatty acids(2009-05-15) Ross, Trinette NoelDiets formulated to contain varying ratios of omega 6 to omega 3 fatty acids were fed to exercising yearlings to evaluate bone activity and inflammatory response. Nine Quarter Horse yearlings were arranged within a triplicated 3 X 3 Latin Square experimental design and fed one of three diets. Exercise protocol was designed to stimulate sub-clinical inflammation and normal bone response. Body weight and physical growth measurements were not different between groups (P > 0.05), and feed intake was similar between groups (P > 0.05). Horses consuming soybean oil (SBO) diet had lower fatty acid profiles (% by weight) of C16:0 and C16:1 (P < 0.05) when compared to horses consuming either corn oil (CO) or menhaden/corn oil (MCO) diets. Though numerically different, percentage changes in C16:0 and C16:1 were not different between diets (P < 0.05). Horses consuming MCO had significantly higher measurements of C20:4, C20:5 and C22:6 over the 28 day period when compared to horses consuming SBO or CO. Percent change in mean concentrations of C20:5 were significantly different between the MCO group and the SBO group (P < 0.05) with no observed difference between MCO and CO treatment groups. Overall mean carboxyterminal telopeptide of type I collagen (ICTP) concentrations did not differ between diets (P > 0.05) nor was there a significant change from baseline values when compared to day 28 of the period. Mean Osteocalcin (OC) concentrations did not differ between treatments (P > 0.05). Numerically, OC levels were lower after 14 days, with subsequent increases occurring from day 14 to day 28; however, there was no significant day effect (P > 0.05). Mean measurements of PGE2 and fibrinogen, the two inflammation markers evaluated, did not differ among groups (P > 0.05). However, when fibrinogen data were normalized, horses consuming SBO had a significantly lower change in baseline values of fibrinogen compared to horses fed CO or MCO diets (P< 0.05). In general, horses fed SBO exhibited reduced levels of the inflammatory marker fibrinogen (P< 0.05). No other variable evaluated was influenced by the supplementation of varying ratios of polyunsaturated fatty acids into the equine diet.Item Genome-wide Transcriptome Analysis of Laminar Tissue During the Early Stages of Experimentally Induced Equine Laminitis(2012-02-14) Wang, JixinEquine laminitis is a debilitating disease that causes extreme sufferring in afflicted horses and often results in a lifetime of chronic pain. The exact sequence of pathophysiological events culminating in laminitis has not yet been characterized, and this is reflected in the lack of any consistently effective therapeutic strategy. For these reasons, we used a newly developed 21,000 element equine-specific whole-genome oligoarray to perform transcriptomic analysis on laminar tissue from horses with experimentally induced models of laminitis: carbohydrate overload (CHO), hyperinsulinaemia (HI), and oligofructose (OF). Samples were collected during the developmental (DEV) and Obel grade 1 (OG1) stages of laminitis for the CHO model. For the HI model, samples were collected at the Obel grade 2 (OG2) stage. For the OF model, samples were collected at the 12 h and 24 h time points. Appropriate control samples were obtained for all models. This is the first genome-wide transcriptome analysis of laminar tissue using an equine 21,000 70-mer long oligoarray approach in CHO, HI and OF induced laminitis. Overall, we identified the differential expression of genes encoding S100 calcium binding proteins, extracellular matrix proteins, glycoproteins, transporters, olfactory receptors, genes involved in signal transduction, body?s homeostasis, apoptosis, and immune response. Between CHO and OF models of laminitis, there were more shared genes. We discovered several common differentially expressed genes (i.e., ADAMTS1, CYCS and CXCL14) among all three models that are likely important to the pathogenesis of equine laminitis. We also discovered what appear to be central roles of apoptosis, inflammatory response, and intracellular ion homeostasis molecular processes in CHO and OF models of laminitis. Pathway analysis detected the NOD-like receptor signaling pathway, which is involved in recognition of intracellular bacteria in both the CHO and OF models of laminitis. Genetic network analysis indicated convergent pathway core molecules present in equine acute laminitis: p38 MAPK and NF-?B. Most importantly, our results of overexpression of anti-microbial genes (i.e., DEFB4, PI3, and CXCL14) suggest the central involvement of these genes in the progression of early equine laminitis and will allow refinement of current hypotheses of disease pathogenesis.Item Influence of an Intra-articular Lipopolysaccharide Challenge on Markers of Inflammation and Cartilage Metabolism and the Ability of Oral Glucosamine to Mitigate these Alterations in Young Horses(2013-02-04) Lucia, Jessica LaurenThis project established an in vivo method to identify and manipulate expression of markers of osteoarthritis (OA). Specifically, strategies that predictably induce joint inflammation to evaluate dietary methods of OA prevention in young horses have yet to be accomplished. Therefore, the 3 studies described herein were conducted to determine effectiveness of an intra-articular lipopolysaccharide (LPS) challenge on markers of inflammation and cartilage metabolism in young horses and potential of dietary glucosamine hydrochloride (HCl) to mitigate these alterations. In the first study, horses were challenged with 0.25 ng or 0.50 ng of intra-articular LPS solution or lactated ringer?s solution (control). Injection of LPS increased inflammation based on synovial prostaglandin E2 (PGE2) concentrations. Carboxypeptide of type II collagen (CPII), a maker of type II collagen synthesis, also increased in a dose-dependent manner. However, clinical parameters of health were not influenced and remained within normal ranges. Carpal circumference increased in response to repeated arthrocentesis. Lameness scores increased with LPS injection when compared to controls. This model of joint inflammation (0.5 ng LPS) was used in the second study to evaluate potential chondroprotective effects of oral glucosamine HCl supplementation in yearling horses. Specifically, the oral absorption of glucosamine HCl versus saline was determined by nasogastric dosing and incorporation of dietary glucosamine HCl into plasma and synovial fluid over time. Plasma and synovial fluid concentrations of glucosamine tended to increase over the 98-d period. In the third study, yearlings were challenged with intra-articular LPS to determine the potential of glucosamine HCl to mitigate inflammation when compared to contralateral joints. Injection of LPS increased synovial PGE2 and cartilage biomarkers CPII and collagenase cleavage neopeptide (C2C), a marker of type II collagen degradation. Oral glucosamine HCl decreased PGE2 and C2C concentrations, but increased levels of CPII. Results of these 3 studies provide a clearer understanding of joint inflammation and cartilage turnover in young horses and demonstrated a potential role of oral glucosamine to mitigate these effects and possibly prevent OA in horses.Item Influence of Dietary Starch Inclusion on Cecal Environment and Microbial Populations in Horses(2013-08-07) Warzecha, Christine MariePrevious research has documented shifts in microbial hindgut populations resulting from dietary starch inclusion, and recent evidence indicates only 30% of equine cecal contents has been cultured successfully. Next generation sequencing (NGS) techniques allows detection of new species previously undetected. Therefore, the objective of this study was to determine community profiles equine cecal microbiota in response to abrupt dietary starch inclusion. Seven cecally cannulated Quarter horse geldings (497 to 580 kg) were utilized in a crossover design with two 28 d periods and a 28 d washout between each. Horses were randomly assigned to dietary treatments consisting of commercial concentrate offered individually at either 0.6% (LS) or 1.2% BW (HS; as fed) daily divided into 2 meals at 12 h intervals. Prior to start of each period horses were allowed ad libitum access to coastal bermudagrass (Cynodon dactylon) hay and concentrate was fed on d 1 with no adaptation. Samples of cecal fluid were collected on d 1 prior to 0 h and 3, 6, 9, and 12 h post morning meal and on d 1, 2, 3, and 7 at 6 h post morning meal. Cecal pH was determined immediately and a samples of cecal fluid were stored. Genomic DNA was extracted and the V4-V6 segment of 16s rRNA gene was PCR amplified using universal Eubacterial primers 530Fand 1100R and sequenced on the Roche 454 FLX platform. The reads were denoised, chimera checked, and Operational Taxonomic Units (OTUs) were identified using the reference Ribosomal Database Project 16S rRNA dataset. Data were analyzed using PROC MIXED procedure of SAS. Bacterial phyla were largely unaffected by dietary treatment for the first 12 h after the initial concentrate meal except for Verrucomicrobia which was greater in LS horses (P ? 0.04). Regardless of treatment, Bacteriodetes increased (P ? 0.02) over the first 12 h following initial addition of dietary starch. Adaptation to dietary treatments over 7 d resulted in decreased numbers of Tenericutes (P ? 0.07) in HS horses compared to LS. Cecal environment and microbial populations were altered after abrupt and long term exposure to dietary starch.Item Influence of Maternal Plane of Nutrition and Arginine Supplementation on Mares and Their Foals: Glucose and Insulin Dynamics(2012-10-19) Hanson, AndreaThirty-two Quarter horse mares (468 to 668 kg BW; 3 to 19 yr) were utilized in a randomized complete block design. Animals were blocked by expected foaling date and randomly assigned to treatments within block. Treatments began 110 d prior to expected foaling date and were arranged as a 2 x 2 factorial consisting of two planes of nutrition, moderate (Mod; 0.5% BW as fed grain/d) or high (High; 1% BW as fed grain/d) and two levels of L-arginine supplementation, 0.21 g/kg BW/d (Arg) or no supplemental Arg (Con; L-alanine to maintain isonitrogenous diets). Mares were housed by block, allowed ad libitum access to water and coastal bermudagrass (Cynodon dactylon) hay, and fed commercial grain twice daily in individual stalls. A modified frequent sampling i.v. glucose tolerance test (FSIGT) was performed on mares during the 11th month gestation and on foals at 5 and 30 d of age. Jugular catheters were placed 1 h before FSIGT, and horses were allowed ad libitum access to bermudagrass hay and water throughout. After a baseline plasma sample was collected, a glucose bolus of 0.3 g/kg BW was administered. Blood samples were collected at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, and 19 min. At minute 20, an insulin bolus of 30 mU/kg BW was administered. Blood samples continued to be collected at 22, 23, 24, 25, 27, 30, 35, 40, 50, 60, 70, 80, 90, 100, 120, 150, and 180 min. Samples were placed into tubes containing sodium heparin, immediately placed on ice, and centrifuged within 20 min. Plasma was then collected, placed in microtubes and frozen at -20 degrees C for later analysis. Glucose concentrations were analyzed using a colorimetric assay and insulin concentrations determined using a commercial RIA kit. There was no influence of dietary treatment on mare glucose area under the curve (AUCg) or peak glucose (PG) and insulin (PI) concentrations (P >= 0.55). Mare insulin area under the curve (AUCi) tended to be influenced by the interaction between nutritional plane and ARG supplementation (P <= 0.06) with HighCon mares having greater AUCi than ModCon (P <= 0.05), and HighCon mares having greater AUCi than mares fed HighArg (P <= 0.05). Foal AUCg, AUCi, and PI were not influenced by maternal diet. However, PG concentration in foals tended to be influenced by mare AA supplementation with foals from Con mares having higher concentrations compared to Arg (P <= 0.09) An influence of age was observed on foal AUCg and AUCi. Foal AUCg was greater at 5 d compared to 30 d (P <= 0.003). Foal AUCi tended to be greater at 30 d compared to 5 d (P <= 0.08). Data suggest maternal plane of nutrition and arginine supplementation can alter mare and foal glucose and insulin dynamics.Item Integrated high-resolution physical and comparative gene maps in horses(Texas A&M University, 2007-04-25) Brinkmeyer Langford, Candice LeaHigh-resolution physically ordered gene maps for the horse (Equus caballus, ECA) are essential to the identification of genes associated with hereditary diseases and traits of interest like fertility, coat color, and disease resistance or susceptibility. Such maps also serve as foundations for genome comparisons across species and form the basis to study chromosome evolution. In this study seven equine chromosomes (ECA6, 7, 10, 15, 18, 21 and X) corresponding to human chromosomes (HSA) 2, 19 and X were selected for high-resolution mapping on the basis of their potential involvement in diseases and conditions of importance to horses. To accomplish this, gene- and sequence-specific markers were generated and genotyped on the TAMU 5000rad horse x hamster RH panel. Additionally, screening of a BAC library by overgoes and subsequent STS content mapping and fingerprinting approaches were used to assemble and verify a BAC contig along a ~5 Mb span on ECA21. Dense gene maps were generated for each of the seven equine chromosomes by adding 408 new markers (285 type I and 123 type II) to the current maps of these chromosomes, thereby greatly improving overall map resolution to one mapped marker every 960kb on average (range: 700 kb ?????? 1.3 Mb). Moreover, the contig on ECA21 contained 47 markers (42 genes and 5 microsatellites) as well as 106 STS markers distributed along 207 BAC clones. Comparisons of these maps with other species revealed a remarkably high level of horse-human X chromosome conservation, as well as two evolutionary breakpoints unique to Perissodactyls or Equids for the equine homologues of HSA19 and HSA2, one of which has been more precisely localized by the ECA21 contig. Thus, high resolution maps developed for these chromosomes i) provide a basis to map traits of interest rapidly to specific chromosomal regions, ii) facilitate searches for candidate genes for these traits by fine comparisons of the equine regions with corresponding segments in other species, and iii) enable understanding the evolution of the chromosomes. Expansion of this work to the entire equine genome will be important for developing novel strategies for diagnosis, prevention, and treatment of equine diseases.Item Physical mapping and characterization of the equine lymphocyte antigen (ELA) complex(Texas A&M University, 2005-08-29) Seabury, Ashley GustafsonThe major histocompatibility complex (MHC) is a genomic region comprised of a linked cluster of genes and gene families that play an important role in both the adaptive and innate immune responses. Genes within the MHC have also been associated with susceptibility and/or resistance to certain diseases, such as haemochromatosis, insulindependent diabetes, and psoriasis. As a result of these associations the MHC is one the most extensively studied regions of the mammalian genome. The MHCs of a wide variety of species, such as human (HLA), mouse (H-2), pig (SLA), and cow (BoLA), have been characterized with respect to gene content, genomic organization of class I, class II, and class III regions, and comparative organization. Comparative analyses have been useful in delineating the evolutionary development of the MHC. While the MHC of many mammalian species has been investigated, little research has been performed on the equine (Equus caballus) MHC. The equine MHC is referred to as the equine lymphocyte antigen (ELA) complex and is located on chromosome ECA20q. The research that has been done on ELA focused on identifying gene copy number and genetic polymorphisms in the classical class I and class II genes. To better characterize the gene content and organization of ELA, we isolated 103 bacterial artificial chromosome (BAC) clones from a horse BAC library containing well conserved genes found within mammalian MHCs. These BAC clones were assembled into two sequence-ready ordered contigs that span the ELA complex. The first contig which has a minimum tiling path of nine BAC clones contains the ELA class II region and spans 800 kb. The class I and III regions are contained within the second contig which has a 14 BAC clone minimum tiling path and spans 1.6 Mb. This study will report on the construction of the two BAC contigs which span the ELA complex, and characterization of the gene content and organization of the ELA complex.Item The Effect of Dietary Starch Concentration on Glycogen Replenishment in Performance Horses(2013-12-12) Vonderohe, CaitlinFour Quarter Horses (2 to 3 yr; 401 to 432 kg BW) were used in a simple crossover design for a 49-d study to determine the effect of dietary starch levels on post-exercise glycogen replenishment. Horses were fed either high starch (HS) or low starch (LS) concentrates at 0.75% BW/d plus l.0% BW/d Coastal Bermudagrass hay for 14 d, and then worked to fatigue in a standardized exercise test (SET). After a 14-d washout period, horses were switched to the opposite diet for 14 d and then again performed the SET. The LS and HS concentrates were commercially available feeds. Total diets provided an average of 997.6 g of starch and 553.7 g of starch/d in the HS and LS diets, respectively. Throughout the trial, horses were lightly exercised for 30 min, 3 d/wk. The SET consisted of a 30-min warm-up period at a brisk trot in a panel exerciser, followed by 27 min of gradually ascending high-intensity work on a treadmill. Skeletal muscle biopsies were taken from the biceps femoris at rest, immediately after the SET, and again at 6-, 24- and 48-h post-exercise. Samples were flash frozen in liquid nitrogen and stored at -80?C until analysis for later muscle glycogen concentration using a commercial kit. Venous blood samples were taken at rest, immediately post exercise and every 15 min for 3 h post-exercise. Blood samples were analyzed for lactate, glucose, total protein and Ca concentration. Data were analyzed using Proc Mixed (SAS) procedure with main effects of sample time, horse, period, trt and time x trt interaction. Horses on the HS diet had a higher muscle glycogen concentration (P <0.05) at 48 h post exercise than the LS horses (18.1 vs. 10.6 ?g/mg wet wt). At 6 h, HS horses had a more rapid rate of repletion, as observed by the higher glycogen concentration (P<0.05) compared to the immediate post-exercise samples (15.4 vs. 7.9 ?g/mg wet wt); whereas, the LS horses did not return to normal levels until 24 h post SET. Results indicated that horses on the LS diet, which is representative of low-starch feeding programs commonly observed in the industry, replenish their skeletal muscle glycogen slower than horses on the HS diet. Based on this study, performance horses undergoing multiple bouts of intense exercise may benefit physiologically from receiving diets that contain more than 553.7 g of starch/day.