Browsing by Author "Sigler, Dennis H."
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Item Care and Management of Horses on the Ranch(AgriLife Extension, Texas A&M University System) Sigler, Dennis H.Item Conditioning and Retraining the Equine Athlete(AgriLife Extension, Texas A&M University System) Sigler, Dennis H.Item Effect of Concentrate Form on Gastric Ulcer Syndrome in Horses(2012-02-14) Huth, Lindsey; Sigler, Dennis H.; Cavinder, Clay A.; Cohen, Noah D.Equine gastric ulcer syndrome (EGUS) is common amongst equine athletes of various disciplines and linked to decreased performance. Prevalence among racehorses has been reported to be over 90%, performance horses at 60%, and endurances horses at about 70%. In swine, concentrate form and smaller particle size increase gastric ulceration; thus, the objective of this study was to investigate the effect of concentrate type on EGUS. Quarter Horse yearlings (n=19; 12-18 mo) were blocked by initial EGUS score on a scale of 0 to 4 (0= no ulceration or hyperkeratosis, 4= extensive, deep ulceration) and sex, and utilized in a 77-d cross-over design with two 28-d periods separated by a 21-d washout period. During the first 28-d period, horses were separated into 1 of 2 treatment groups that were all fed Bermuda grass hay and either a commercially available pelleted or textured concentrate. After the initial 28-d period, horses were all fed pelleted feed and Bermuda grass hay for a 21-d washout period then treatment groups were switched for the final 28-d period. Baseline EGUS scores were not different between horses assigned to either treatment (mean 1.1); however, upon treatment, horses fed textured feed acquired a reduced incidence of ulceration as compared to those fed pelleted (mean score of 1.6 vs 1.1, respectively; P =0.02). Degree and incidence of ulceration was influenced by concentrate form; yearlings fed pelleted feed had higher ulcer scores then those fed textured feed. Therefore, the findings of this study suggests that textured feed may be a effective management tool to aid in the reduction of severity in horses afflicted with EGUS.Item Effect of Trace Mineral Supplementation on Gastric Ulcers in Exercising Yearling Horses(2010-10-12) Hayes, Alexa Dawn; Sigler, Dennis H.; Cohen, Noah D.; Cavinder, Clay A.Equine 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 Dietary Magnesium Status on Indices of Muscular Dysfunction in Exercising Horses(2011-02-22) Kurtz, Cassidy A.; Sigler, Dennis H.; Cavinder, Clay A.; Fluckey, JamesThroughout 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 Evaluation of Stress Before, During, and After Transport in Naive Yearling Horses(2010-07-14) Garey, Shannon M.; Friend, Ted H.; Berghman, Luc R.; Sigler, Dennis H.Recently, the European Union published regulations regarding the welfare of horses during transport requiring that horses be transported in individual stalls separated by partitions. The objective of this study was to determine if concentrations of cortisol, corticosterone, or dehydroepiandrosterone (DHEA) differed among horses with no prior transport experience when transported in individual stalls versus loose groups. Twenty na�ve yearlings were assigned to either individual stalls or a loose group, then transported for 6 hours. Ten horses were transported per day (5 in stalls and 5 in a loose group) over a two day trial. The experiment was replicated with a second trial 35 days later, and utilized a switchback design where the horses exchanged treatments between trials. Blood samples were collected and analyzed for cortisol, corticosterone, and DHEA concentrations at pre-transport, 2, 4, and 6 h of transport, and at 2 and 4 h after unloading. After Trial 2, the horses? changed housing from group paddocks to stalls and a follow-up experiment was conducted. The data were analyzed using a mixed model repeated measures ANOVA with the animal as the subject, with trial, treatment, sample time, and treatment-sample time interaction in the model with unstructured covariance (SAS 9.1). Differences between sample times within each trial, and pre-transport concentrations between trials, were analyzed using paired t-tests (SPSS 12.0.1). No significant differences were found in hormone concentrations for horses transported in individual stalls versus in loose groups. Horses exhibited a significant elevation in cortisol and corticosterone during transport which returned to pre-transport concentrations by 2 hr after transport (P < 0.01). Mean pre-transport cortisol concentrations rose significantly in Trial 3 (7.87 ng/ml) from Trials 1 (2.71 ng/ml) and 2 (2.84 ng/ml) (P < 0.001). Pre-transport concentrations of DHEA in Trials 1 (482 pg/ml) and 2 (392 pg/ml) also rose significantly in Trial 3 (1607 pg/ml) (P < 0.01). Changes in cortisol and DHEA indicated that transportation was a significant stressor for horses, however, being transported in a loose group versus individual stalls was not different. Also, housing changes from paddocks to stalls resulted in significant increases in pre-transport concentrations of stress-related compounds.Item What Texas Horse Owners Need to Know About Equine Piroplasmosis(AgriLife Extension, Texas A&M University System) Sigler, Dennis H.; Hairgrove, Tom B.; Norman, Tracy E.