Electrolytes and Fluids

Question 1

Fluids

Answer 1

50% of BW

10% of all fluid is blood

Question 2

Intracellular Fluids

Answer 2

Liquid contained within the cell, such as cytoplasm

- Muscle cells contain high amount of liquid

Question 3

Extracellular Fluids (Interstitial Fluids)

Answer 3

Liquid outside of the cells, including all blood/plasma, synovial fluids, and the “basal laminae”
- Most fluid contained in vasculature - veins, arteries, capillaries

Question 4

Measuring Extracellular Fluids

Answer 4

BV = PCV + PV
BV - blood volume
PCV - packed cell volume - RBC
PV - plasma volume - water, dissolved, glucose/proteins, etc.

Question 5

Variations in Blood Volume

Answer 5

Varies based on age, breed, exercise, and hydration status of animal
- if both PCV and PV increase, sign of overtraining

Question 6

Variation in Plasma Volume

Answer 6

Varies based on hydration, or exercise

• Low PV - dehydrated
• High PV - anemic
• if horse has just finished exercising, PV will be low due to released RBC

Question 7

Normal Ions in Blood

Answer 7

Ions - Na+, K+, Cl-
Buffers - Ca+, Mg2+, carbonate
Normal osmolarity = 290 mOsm/L

Question 8

Loss of Electrolytes

Answer 8

Ions are lost through sweat (hypertonic)
Sweat glands act like a “funnel” and can loose up to 12 L/hour
Loss of ions (NaCl, KCl, etc.) can cause fatigue, hyperkalemia, etc.
- Latherine protein - also draws out water, “foamy”

Question 9

Maintaining Plasma Levels

Answer 9

Training - improves sweating ability
- Also cools horses down
- Do hose off sweaty horses, but remove water afterwards or it will trap heat
Regulation by osmoreceptors

Question 10

Osmoreceptors

Answer 10

Arginine vasopressin (ADH) - antidiruetic that targets kidneys
Aldosterone - sodium retention that targets kidneys

Question 11

Anhydrosis

Answer 11

Inability to sweat, or not sweating at sufficient levels to cool off

Question 12

Increase Core Temperature

Answer 12

An increase in the core temperature over 101 (normal 99-101.5) can cause proteins to denature
Denatured proteins, especially intestine, can leak bacteria into the body - endotoxins

Question 13

Dehydration

Answer 13

Exhaustion due to heat, fluid, and/or electrolyte loss and substrate (glucose) depletion
- Stop work immediately and cool horse off
- Mild = loss of 5-6% BW in water (20-30 L)
- Moderate = loss of 7-9% BW in water (30-40 L)
- Severe = loss of >10% BW in water (>40 L)
Can lead to heart arrhythmia, laminitis, colic

Question 14

Laminitis

Answer 14

Can be caused by release of endotoxins, increased temperature of hoof, decreased circulation to legs

Question 15

Post-Exercise Recovery

Answer 15

Water ad-libitium, UNLESS severely dehydrated where too much water could offset ion balance
Electrolyte pastes - few days before, day of, day after
Increase glucose - hay/carbs