Browsing by Subject "Horse"
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Item Age-Related Effects on Markers of Inflammation and Cartilage Metabolism in Response to an Intra-Articular Lipopolysaccharide Challenge(2014-11-25) Kahn, Meredith KEighteen Quarter Horses were utilized in a randomized complete design for a 28 d experiment to evaluate age-related effects on inflammation and cartilage turnover after induction of a single inflammatory insult using lipopolysaccharide (LPS). Horses were grouped by age, with yearlings (yearling; n = 3 males, n = 3 females), 2 to 3 yr olds (2/3; n = 2 males, n = 4 females), and mature 5 to 8 yr olds (mature; n = 2 males, n = 4 females). On d 0, all horses were housed individually and fed diets that met or exceeded NRC (2007) requirements. On d 14, horses were challenged with an intra-articular injection of LPS. Carpal joints were randomly assigned to receive 0.5 ng LPS solution obtained from E. coli O55:B5, or 0.8mL sterile lactated Ringer?s solution as a contralateral control. Synovial fluid was collected prior to LPS injection at pre-injection h 0 (PIH 0) and 6, 12, 24, 168, and 336 h post-injection. Samples were later analyzed using commercial ELISA kits for prostaglandin E2 (PGE2), collagenase cleavage neoepitope (C2C), and carboxypropeptide of type II collagen (CPII). Heart rate (HR), respiratory rate (RR), and rectal temperature (RT) were monitored over the first 24 h and carpal circumference and surface temperature were recorded with additional measurements at 168 and 336 h. Data were analyzed using PROC MIXED procedure of SAS. Values for RT, HR, and RR were within normal range. HR and RT were influenced by age (P < 0.01), while RR was unaffected by age (P ? 0.21). Joint circumference was not influenced by age (P = 0.84), but circumference and surface temperature increased (P < 0.01) over time across all age groups. Synovial PGE2 concentrations tended (P = 0.09) to be influenced by age with yearlings having lower (P = 0.03) concentrations than mature horses. Synovial C2C concentrations were affected by age with yearlings and 2/3 yr olds having lower (P < 0.01) concentrations than mature horses. Concentrations of synovial CPII were influenced by age with yearlings and 2/3 yr old having lower (P ? 0.02) concentrations than mature horses. Ratios of CPII:C2C were influenced by age with mature and 2/3 yr old horses having increased (P < 0.01) values compared to yearlings. These results indicate that inflammation and corresponding cartilage turnover in response to LPS administration vary with age.Item Cytokine detection in eiav-infected equine monocyte-derived macrophages using quantitative real-time polymerase chain reaction(2009-05-15) Allen, Charlotte AnnetteThe replication of equine infectious anemia virus (EIAV) in macrophages not only leads to cell death, but also to the induction of a variety of cytokines that may affect immune function. Cytokine production may be responsible for the fever, anorexia, hemorrhages, lethargy or thrombocytopenia seen in the acute and chronic phases of equine infectious anemia (EIA). The study of the equine immune system and inflammatory responses, by measuring cytokine expression, can provide important insight into disease pathogenesis in the horse. We have extended studies of virulent and avirulent EIAV clones by examining the effects of Env proteins on cytokine expression in equine monocyte-derived macrophages (EMDM) using EIAV17, EIAV19, EIAV17SU, and EIAV17TM viruses. In the current studies a set of quantitative real-time polymerase chain reaction (QPCR) assays for the equine cytokines IL-1?, IL-1?, IL-6, IL-8 and TNF-? were validated using QPCR primers and probes which were generated for the aforementioned equine genes.Item Effects of Crude Protein Content on Intake and Digestion of Coastal Bermudagrass Hay by Horses(2011-08-08) Spurgin, Chelsey L.This study was conducted to determine the effect of forage CP level on intake and digestion of Coastal bermudagrass hay by horses. Four cecally fistulated geldings were used in a 4 x 4 Latin square design with four treatments and four periods. Horses were fed one of four Coastal bermudagrass hays consisting of 7, 10, 13, or 16% CP during each of the 4 15-d periods. Intake and apparent digestibility were determined for each horse at the end of each period by total fecal collection. In addition, cecal fluid and blood samples were collected from each horse on the last day of each period for determination of cecal ammonia, cecal pH, plasma urea nitrogen, and plasma glucose concentrations. Crude protein concentration of Coastal bermudagrass hay influenced equine intake and digestion. Increasing CP concentration linearly increased digestible OM intake (DOMI) from 3.79 to 5.98 kg/d for 7 and 16% CP hay, respectively (P = 0.04). Furthermore, as forage CP level increased, CP intake increased linearly (P < 0.01). Forage CP level had no effect on forage DM intake. Quadratic effects (P less than or equal to 0.05) were observed for forage OM, NDF, ADF, and digestible energy. Overall digestibility was lowest for the 7% CP hay and highest for the 10% CP hay. Cecal pH remained above 6.62 irrespective of treatment and time, indicating that cecal pH was suitable for microbial growth. As forage CP level increased, cecal ammonia concentration increased linearly from 0.03 mM for the 7% to 1.74 mM for the 15% CP hay (P < 0.01). Concentration of plasma glucose also linearly increased (P = 0.04) from 68.77 to 73.68 mg/dL as CP concentration increased from 7% to 16% CP. Plasma urea nitrogen exhibited a quadratic effect as concentration increased (P < 0.01) from 4.34 to 5.61 mM for the 7 and 16% CP hays, respectively.Item Evaluating the technique of using nitrogen retention as a response criterion for amino acid studies in the horse(Texas A&M University, 2007-09-17) Antilley, Teri JillSix Quarter Horse yearling fillies were used in a duplicated 3 x 3 Latin square designed experiment to evaluate the technique of nitrogen retention as a response criterion for amino acid studies in the horse. The yearlings were paired by age and randomly assigned to one of three concentrates fed with a medium quality Coastal Bermudagrass hay throughout the study. Diets were fed at approximately 1.9% of horse body weight per day, divided into twice daily feedings with a 60:40 concentrate: hay ratio. With the exception of lysine and threonine, proposed amino acid requirements for yearling horses were calculated using nutrient to calorie ratios of gilts weighing 80-120 kg and gaining 325 g/d. Diet A was amino acid sufficient, as provided by a soybean meal-based concentrate. Diet B was amino acid deficient, with a cottonseed hull-based concentrate. Diet A and Diet B were isonitrogenous, containing approximately 12% crude protein. Diet C used the identical concentrate as Diet B, with synthetic essential amino acids and cysteine orally dosed to match the amino acid levels in Diet A. Nitrogen retention was not different between Diet A and Diet B. Diet C resulted in differences from Diets A and B in nitrogen retention; however, differences were a consequence of nitrogen intake. Nitrogen retained as a percent of nitrogen absorbed was lower (P < 0.05) for Diet B than for Diet A, for data not accounting for endogenous fecal and urinary losses. There were no differences in nitrogen retained as a percent of nitrogen absorbed for horses fed Diet C, when compared to either Diet A or Diet B, for data not accounting for endogenous losses. It was concluded that differences in nitrogen retained as a percent of nitrogen absorbed were observed between amino acid sufficient diets and amino acid deficient diets. However, horses fed amino acid deficient diets and orally dosed with synthetic amino acids, likely require some modified dosage level to achieve the same or higher values in nitrogen retained as a percent of nitrogen absorbed as those values for amino acid sufficient diets.Item High resolution physical and comparative maps of horse chromosomes 14 (ECA14) and 21 (ECA21)(Texas A&M University, 2006-08-16) Goh, Glenda Lay BeeIn order to identify genes or markers responsible for economically important traits in the horse, the development of high resolution gene maps of individual equine chromosomes is essential. We herein report the construction of high resolution physically ordered radiation hybrid (RH) and comparative maps for horse chromosomes 14 and 21 (ECA14 and ECA21). These chromosomes predominantly share correspondence with human chromosome 5 (HSA5), though a small region on the proximal part of ECA21 corresponds to a ~5Mb region from the short arm of HSA19. The map for ECA14 consists of 128 markers (83 Type I and 45 Type II) and spans a total of 1828cR.Compared to this, the map of ECA21 is made up of 90 markers (64 Type I and 26 Type II), that segregate into two linkage groups spanning 278 and 760cR each. A total of 218 markers provide on average one marker every 0.9Mb along the length of the two equine chromosomes. This represents a 5-fold improvement over the previous maps. Of greater significance is the ~8-fold increase in the density of Type I loci that provide a comprehensive and finely aligned map for the two chromosomes in relation to homologues in a range of evolutionarily distantly related species, viz., human, chimpanzee, mouse, rat, dog, cattle, pig, cat and chicken. The orientation and alignment of the linkage groups was strengthened by 28 new FISH localizations, of which 27 are gene-specific (22 from HSA5 and 5 from HSA19). Comparative analysis between the horse and human reveals that the order of genes on HSA5 is remarkably well conserved in the horse, with an evolutionary break/fusion point that could be correlated to a ~2Mb region between 68.5 ?? 70.9Mb positions on HSA5. Among the species analyzed to date, the HSA5 and 19p neighboring segment combination is unique to Perissodactyls and Cetartiodactyls, but, in the Perissodactyls, the portion of HSA5 that corresponds to this combination is HSA5p ?? q13, while in the Cetartiodactyls, it is HSA5q13 ?? qter. This leads us to postulate that this neighboring segment combination arose as separate events during the divergence of Perissodactyls and Cetartiodactyls from a common ancestor.Item Influence of Confinement Housing on the Cecal Environment of the Horse(2012-02-14) Wolford, AshleyEight cecally cannulated Quarter Horse geldings were utilized in a crossover design with two 28 d periods with a 21 d washout period between. Horses were adapted to dietary treatments from d 1 to 19, dry matter intake was determined from d 20 to 24, and cecal fluid was collected on d 28. Horses were paired by age and body weight (BW) and randomly assigned to treatment. Treatments consisted of housing horses individually in stalls or group housed in a dry lot pen. Regardless of treatment, all horses were individually fed a pelleted concentrate at 1% BW (as fed) offered twice daily 12 h apart. All horses had ad libitum access to coastal bermudagrass hay. Hay was offered to stalled horses initially at 2% BW (as fed) then adjusted based on 120% of a previous 3 d average of voluntary intake. A dual marker system was utilized for estimation of voluntary intake in all horses using titanium dioxide (TiO2) as the external marker and acid detergent insoluble ash (ADIA) as the internal marker. Cecal samples were collected 4-h after the morning meal and immediately analyzed for pH. Samples were transported to the USDA/ARS laboratory to enumerate total anaerobic bacteria and lactic acid bacteria, and to determine methane and ammonia activity. Cecal pH was influenced by housing (P = 0.02) with group housed horses having lower cecal pH values when compared to stalled horses (6.52 +/- 0.04 and 6.69 +/- 0.04, respectively). The cecal pH values of this study are similar to other reported values when feeding similar diets (5). Populations of cecal total anaerobic bacteria and lactobacillus were not influenced by housing (P >= 0.21). Treatments did not affect the production of acetate, propionate, or butyrate (P >= 0.15). Additionally, methane and ammonia production were not affected by treatments (P >= 0.17). Forage intake was greater for group housed horses (P = 0.04) than stalled (8.47 +/- 0.89 kg DM/d and 5.17 +/- 0.89 kg DM/d, respectively). In conclusion, confinement housing did not greatly influence the cecal environment of a horse when similar diets were offered.Item Mapping Athletic Performance Related Genes in the Equine Genome and a Genome Scan for Superior Athletic Performance in the Thoroughbred(2010-01-16) Durkin, Keith W.The primary goal of the Thoroughbred industry is to breed and train superior equine athletes capable of excelling on the racetrack. To date, research into the genetic underpinnings of athletic ability has been limited in the horse. Advances in equine genomics and the genetics of athletic performance in humans have opened up the possibility of investigating this important trait in the Thoroughbred. Initially, 46 candidate genes associated with human athletic performance were mapped in the equine genome by radiation hybrid (RH) and fluorescent in situ hybridization (FISH) mapping. RH data and later the draft equine genomic sequence allowed us to identify microsatellites adjacent to these and other candidate genes (95 in total). Additional microsatellites were added to increase genome coverage, producing a final panel of 186 markers. All the potential markers were initially screened on a pool of DNA for 16 Thoroughbreds to ensure they were polymorphic. The panel was genotyped on 162 Thoroughbreds in total; Centimorgans (cM) between microsatellites were determined with CRI-MAP. The animal?s athletic ability was estimated using career winnings loge transformed to create a linear trait; unraced animals were treated as missing data. Linkage analysis was carried out using the MERLIN program, and association analysis was carried out using the QTDT program. Appropriate thresholds for statistical significance were determined by carrying out 1000 simulated genome scans based on the structure of the original data. LOD scores above 1.54 met the criteria of statistical significance (with a 5% chance of type I error). In the actual genome scan, the marker L12.2 had the highest observed LOD score of 1.16 and p-value of 0.01 and consequently was not significant; the association analysis also did not detect significant association with performance on the track. Given the complexity of the phenotype under investigation and the modest sample size, the lack of linkage/association was not unexpected. Nevertheless, this study has contributed to the RH and FISH maps of the equine genome. Additionally, the development of the genome scanning panel for this study has provided useful information on the most informative microsatellites for linkage or association studies in the Thoroughbred.