The effects of furosemide on cortisol concentrations when paired with exercise in Standardbred horses
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Davey, Maddison K..
The effects of furosemide on cortisol concentrations when paired with exercise in Standardbred horses. Retrieved from
https://doi.org/doi:10.7282/t3-31qs-gs44Export
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TitleThe effects of furosemide on cortisol concentrations when paired with exercise in Standardbred horses
Date Created2021
Other Date2021-05 (degree)
Extent1 online resource (vi, 61 pages) : illustrations
DescriptionExercise Induced Pulmonary Hemorrhage (EIPH) is a common occurrence in racehorses undergoing race conditions. The exact mechanisms behind this condition, which leads to blood in the airways, and in extreme cases, epistaxis, are not entirely known, making finding an efficacious treatment difficult. Currently the main course of action is administration of furosemide (LASIX), a loop diuretic, to horses as a preventative measure. Furosemide is able to change the hemodynamics of the horses in such a way that is believed to lessen the stimulus for bleeding. These hemodynamic changes will lead to downstream effects, as the horse tries to maintain homeostasis, affecting atrial natriuretic peptide (ANP), plasma renin activity (PRA), arginine vasopressin (AVP), and aldosterone. The changes to these hormones in turn will affect the hypothalamic pituitary adrenal (HPA) axis, leading to potential changes in cortisol concentrations seen in the exercising horse. PURPOSE: This study tested the hypothesis that administration of furosemide to a racehorse before a simulated race test would affect cortisol concentrations. METHODS: Eight healthy Standardbred horses (4 mares, 4 geldings, 492 ± 36 kg, 13± 2 years) were tested in this experiment using a 4-week repeated measures cross-over design. Horses were assigned to one of four treatments each week, being either treatment 1: furosemide and exercise, treatment 2: furosemide and no exercise, treatment 3: no furosemide and exercise, or treatment 4: no furosemide and no exercise. The exercise protocol used was a stimulated race test (SRT) with the initial speed being at 4.0 m/s for 2 minutes, followed by maximal speed of 9-10 m/s for 2 minutes, and a cool down at 3.5 m/s for 2 minutes. The treadmill was set to 6% incline. Furosemide was administered intravenously at a dosage of 1 mg/kg body weight. Blood was taken intravenously at five time points, 4 hours pre SRT, 5 min pre SRT, 5 mins post SRT, 4 hours post SRT, and 20 hours post SRT. Packed cell volume was measured from whole blood collected in EDTA tubes using the microhematocrit method and total plasma protein was measured using refractometry. Plasma cortisol concentrations were measured using an ELISA kit validated for use in horses. A two-way repeated-measures ANOVA was used to analyze results. The null hypothesis was rejected when p<0.05. RESULTS: It was found that there was greater packed cell volume as well as higher total plasma protein concentrations following SRT (p<0.05). There was a significant difference in body weights at time point +4hrs compared to -4hrs in all groups (p<0.05). Cortisol concentrations were significantly different at different time points within four treatments (p<0.05), however, there was no significant difference between cortisol concentrations due to the treatment group (p=0.743). CONCLUSIONS: It was concluded that exercise and time had a greater effect on cortisol concentrations than furosemide.
NoteM.S.
NoteIncludes bibliographical references
Genretheses, ETD graduate
LanguageEnglish
CollectionSchool of Graduate Studies Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.
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