Electrolytes are important for replenishing losses of sodium, chloride, potassium, calcium and magnesium which are all depleted during sweating, stress, disease, shipment, conditioning and performance. When these nutrients are not replenished, dehydration occurs. In practical settings, dehydration is measured by percentage of body weight loss. When small percentages are lost, such as less than 5%, increased water consumption and skin tenting may be noted. When larger percentages are lost and fluid balance is disrupted, it makes the body work harder to establish osmotic balance and metabolic complications may occur. The heart rate increases to pump blood, which is diluted, to the brain, muscle and extremities. If severe dehydration occurs, exhaustion may also become an issue and animals will become uncoordinated, weak, colicky and can collapse.
Electrolytes in elementary terms are salts that disassociate in solution. Of most importance are sodium, chloride, potassium, magnesium and calcium. These minerals are important for brain and heart function, metabolism, nerve synapses and muscle contraction. Bodily fluids such as intracellular and extracellular fluid contain electrolytes. Milk, urine and sweat all contain portions of electrolytes. Depending on where this fluid is located (intracellular or extracellular) dictates what mineral is of higher concentration. Blood, stomach and intestinal fluid, for example, are an example of extracellular fluid and contains higher levels of sodium. Intracellular tissue is that found within cells and is higher in potassium.
Animals and humans are not all the same in how they lose electrolytes. For example, deer and elk sweat more than humans and their concentration of sodium is not conserved as well. Rapid and profuse sweating rids the body of salt rapidly. If the sodium concentration in extracellular fluid increases or blood volume drops and becomes concentrated, a signal goes out indicating to the animal that it should drink and is dehydrated.
Supplementing electrolytes in excess is not recommended. In the same manner, providing too much salt is also not recommended. A balance between intracellular and extracellular fluids, energy and water availability needs to be addressed for optimum performance, health and recovery. Excess electrolyte consumption causes increased water consumption and excess urinary excretion due to an imbalance in osmotic pressure and increased filtration by the kidneys. Too much salt also causes increased water consumption to a certain threshold but may not lead to increased urinary excretion causing edema and increased blood pressure.
An electrolyte which contains both electrolyte salts: sodium, chloride, potassium, calcium, magnesium and certain sugars will help the animal replenish lost salts and provide energy to effectively metabolize these nutrients and recover. This is very important for young stock or animals recovering from surgery. Performance animals, long hauled animals, severely stressed or conditioned animals will all need a blend of salts and sugars to effectively recover and maintain energy due to less fatigue, more energy and proper hydration.
More important than whether to use a salt-based or sugar-based electrolyte is to find a superior electrolyte which contains both in moderation and offers these electrolytes in a palatable form which may either be fed when animals do not have the signal to drink, or soluble in water for those animals that will readily consume the electrolyte mixture.