Fluid, electrolyte, and acid-base balances in three-day, combined-training horses.
Abstract: Horses competing in 3-day, combined-training events develop a metabolic acidosis that is partially compensated for by a respiratory alkalosis immediately after phases B and D. By the end of phase C and 30 minutes to 2 hours after phase D, the acidosis is resolved by the oxidation of lactate, and a metabolic alkalosis prevails. A reduction in TBW and cation content occurs, which often is not replenished 12 to 24 hours after the event, even though the serum or plasma concentration of various constituents may be within normal limits. Hypochloremia and hypocalcemia, however, may persist 12 or more hours after the speed and endurance test. All of the data cited in this article are from horses that successfully completed their respective tests. Nevertheless, some horses developed substantial fluid and cation losses. In horses that are not well conditioned or in competitions in which terrain, footing, or hot environments increase the thermal load or decrease heat loss, greater losses of fluids and electrolytes can be expected. Body weight losses exceeding 5% and cation losses exceeding 4000 mEq/L occur in endurance horses suffering from exhaustion and synchronous diaphragmatic flutter. In one study, two thirds of the Na+ lost during exercise-induced sweating in cool, dry conditions was replenished from salt supplements added to a balanced forage and concentrated diet. Consequently, horses in regular training and competition may benefit from salt supplementation. The composition of the salt supplement and the amount fed should be based on the composition of the horse's diet, degree of work, and environmental conditions. Horses competing in a 3-day, combined-training event may be expected to have persistent losses of weight and cations, particularly if conditions result in heavy sweating. Many horses in the field studies had minimal changes in weight and cation balance compared with pre-event values. The diet and electrolyte supplementation of the horses in the majority of these studies were unknown; consequently, no firm conclusions may be made regarding the degree of weight, water, and cationic losses. It is likely that the horse's large intestine serves as a reservoir for both fluid and electrolytes so that performance is not diminished, despite losses demonstrated consistently in treadmill studies. Horses that are inadequately trained or have other systemic or musculoskeletal problems or those that are competing in hot conditions may develop a variety of metabolic problems. It is hoped that knowledge of the fluid and electrolyte losses may help in treating horses with metabolic problems and, more importantly, in improving management of horses in training and competition to prevent any loss of performance.
Publication Date: 1998-04-30 PubMed ID: 9561692DOI: 10.1016/s0749-0739(17)30216-xGoogle Scholar: Lookup
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Summary
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The research explores the fluid, electrolyte, and acid-base balances in horses undergoing three-day combined training. The findings highlight that these horses develop a certain metabolic acidosis which is reasonably corrected by a respiratory alkalosis, and that horses often experience loss in body weight and cations which sometimes persist even a day later. It also suggests that supplementing the horse diet with salt can help to replace most of the sodium lost during exercise.
Metabolic Modifications
- The study initially discusses the metabolic shifts that racing horses go through during three-day training cycles. Immediate metabolic acidosis was observed after the B and D phases, which was partially corrected by a respiratory alkalosis.
- Lactate oxidation was responsible for resolving acidosis by the end of phase C and within 30 minutes to 2 hours after phase D, leading to a prevalent metabolic alkalosis.
Depletion of Body Fluids and Electrolytes
- The research identified a decrease in total body water (TBW) and cation content in the horses, which was often not replenished even 12 to 24 hours after the event, regardless of normal serum or plasma levels of various constituents.
- Conditions such as hypochloremia and hypocalcemia were found to remain for 12 or more hours after the speed and endurance tests.
Implications of Physical Conditioning and External Factors
- The research also looked at the variable impacts based on physical conditioning, terrain, footing, or environmental heat on the horse. Greater losses of fluids and electrolytes were noted in not well-conditioned horses or in competitions that increase the thermal load or decrease heat loss.
- Exhaustion and synchronous diaphragmatic flutter led to significant losses in body weight and cation content in endurance horses.
Effectiveness of Dietary Supplements
- Supplementing the horse diet with salt was found effective as it helped replace most of the sodium lost during exercise in cool, dry conditions. This suggests that regular salt supplementation may be beneficial for horses undergoing regular training and competitions.
Additional Considerations and Conclusions
- Conditions that increase sweating lead to continuous losses of weight and cations in horses undergoing three-day combined training.
- Despite weight and cationic losses, many horses had minimal changes in comparison with pre-event values. However, the horses’ diet and electrolyte supplementation in the studies were not completely known and thus no concrete conclusions could be made about the exact degree of loss.
- It is likely that the horse’s large intestine acts as a reservoir for fluid and electrolytes, hence insulating performance against losses.
- Inadequately trained horses or those under hot conditions, those with systemic or musculoskeletal problems may develop various metabolic problems.
- The study concluded with the hope that understanding fluid and electrolyte losses will improve the treatment of horses with metabolic issues and help develop preventive measures in training and competition management.
Cite This Article
APA
White SL.
(1998).
Fluid, electrolyte, and acid-base balances in three-day, combined-training horses.
Vet Clin North Am Equine Pract, 14(1), 137-145.
https://doi.org/10.1016/s0749-0739(17)30216-x Publication
Researcher Affiliations
- Department of Large Animal Medicine, University of Georgia, Athens, USA.
MeSH Terms
- Acid-Base Equilibrium / physiology
- Animals
- Horses / physiology
- Physical Conditioning, Animal / physiology
- Water-Electrolyte Balance / physiology
Citations
This article has been cited 3 times.- Mihelić K, Vrbanac Z, Bojanić K, Kostanjšak T, Ljubić BB, Gotić J, Vnuk D, Bottegaro NB. Changes in Acute Phase Response Biomarkers in Racing Endurance Horses. Animals (Basel) 2022 Oct 31;12(21).
- Jukes A, Gunew M, Marshall R. Severe muscle fasciculations and tremor in a cat with hypochloraemic metabolic alkalosis secondary to duodenal obstruction. JFMS Open Rep 2017 Jan-Jun;3(1):2055116916686427.
- Assenza A, Marafioti S, Congiu F, Giannetto C, Fazio F, Bruschetta D, Piccione G. Serum muscle-derived enzymes response during show jumping competition in horse. Vet World 2016 Mar;9(3):251-5.
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