What is acidosis?

An increase in the hydrogen ion concentration within blood plasma results in what is commonly known as lactic acidosis. Lactic acid buildup can have serious ramifications on both the health and racing performance of a horse.

Mechanisms of action;

When a horse’s aerobic threshold (VO2 max) is exceeded during high intensity exercise (ie; galloping), large electrolyte losses occur (in particular sodium) and the anaerobic pathway of energy metabolism must be utilised.  Energy is derived from glycogen stores to fuel muscle contractions (anaerobic glycolysis) which results in the production of waste material in the form of lactic acid. A combination of excessive electrolyte losses and increased blood acidity (decrease in blood pH) contribute to muscle fatigue, soreness and stiffness during intense exercise

How can the incidence and severity of lactic acidosis be minimised?

• Increasing the mitochondrial volume and the muscle capacity for aerobic energy metabolism through the implementation of regular aerobic/sub-maximal intensity workouts.
• Increase blood volume and the oxidative capacity of haemoglobin through adequate provision of iron, butafosfan (bioavailable phosphorus) and Vitamin B12 which can be achieved by utilising Ranvet’s Foliphos®.
• Light exercise during recovery increases oxidative lactate utilisation to assist in reducing lactate accumulation and muscular acidity.
• Use of sodium based body acid neutralisers such as Ranvet’s Neutrolene® range combine with excess lactic acid to form a salt, buffering intra-muscular acidity and minimising sodium depletion.
• Provide fat based forms of energy such as Racing Oil® which are able to be rapidly broken down and utilised during sub-maximal  (aerobic) exercise, reducing the reliance on stored muscle glycogen and the subsequent production of lactic acid.

Conversely, what is alkalosis?   

A decrease in the hydrogen ion concentration within blood plasma results in what is commonly known as alkalosis. Similarly to acidosis, alkalosis can also have serious ramifications on the health and racing performance of a horse.

Mechanisms of action;

Horses which are involved in prolonged, sub-maximal exercise (ie; trotting/pacing) will experience large amounts of sweat loss and a subsequent increase in blood alkalinity (increase in blood pH). Sweat loss during sub-maximal exercise is associated with a significant reduction in chloride, potassium, calcium and magnesium ions. This results in an increase in plasma bicarbonate and blood alkalinity (alkalosis). Alkalosis may cause altered neuromuscular transmission, cardiac arrhythmias, gastro-intestinal disturbances, muscle cramps and diagrammatic flutters (‘thumps’).  Alkalosis may also impact on a horse’s VO2 max, therefore increasing the reliance on muscle glycogen to fuel muscle contractions.

Thumps is a result of excessive calcium losses via sweat and inadequate mobilisation of bone calcium stores.

How can the incidence and severity of alkalosis be minimised?

• Provide access to clean drinking water before/after exercise.
• Use of a portable electrolyte replacer such Electro Paste® pre and post hard work (NB; access to water is required to replenish body fluids following administration).
• Daily administration of Potassium Plus® will increase potassium and magnesium stores in addition to providing valuable anti-oxidants; Vitamin E and Selenium, to prevent free radical muscle damage during exercise.
• Provide fat based forms of energy such as Racing Oil® to reduce the reliance on muscle glycogen stores to fuel muscle contractions. By reducing muscle glycolysis, less lactic acid is produced which may assist in prolonging the onset of fatigue during exercise.

References:

–A.R PÖsÖ Monocarboxylate transporters and lactate metabolism in equine athletes: A review. ACTA Veterinaria Scandinavia 43 pp.63-74 (2002)

-Assenza, A., Caola, G., Fazio, F., Percipalle, M., Piccione, G. Assessment of anaerobic threshold in the galloper using a standardized exercise field test. Veterinari Medicina 49 pp. 291-297 (2004)

-Matsui, A . et al. Estimation of total sweating rate and mineral loss through sweat during exercise in 2-years old horses at cool ambient temperature, Journal of Equine Science  13 pp. 109-112 (2002).