This document defines and describes dehydration in animals. It discusses the causes of dehydration as either inadequate water intake or excessive fluid loss. There are three types of dehydration - hypotonic, isotonic, and hypertonic - depending on sodium levels. Clinical signs include dry skin, eye recession, hypothermia, weight loss, and weakness. Field tests like skin pinch tests and capillary refill time can diagnose dehydration. Treatment involves fluid therapy with isotonic saline or other fluids to restore fluid levels based on the animal's weight and degree of dehydration. Additional fluids may be given orally or intravenously depending on the severity of dehydration.

1. By
Prof Mohamed Ghanem

2. Definition
 A disturbance in water balance in which
more fluid is lost from the body than is
absorbed resulting in reduction in the
circulating blood volume.
 In contrast, the rapid ingestion of large
quantity of water can lead to overhydration
(water intoxication)

3. Etiology and pathogenesis
 There are 2 main causes for dehydration
 1- inadequate water intake
 2- excessive fluid loss
inadequate
water intake
Excessive
fluid loss

5. Types of dehydration
 1- hypotonic (hyponatremic) dehydration
 Occurs in acute diarrhea in calves due to excessive
loss of sodium in feces from extracellular tissues…..
Severe dehydration
 2- isotonic (isonatremic) dehydration
 Occurs when there is a parallel loss of sodium and
water in case of simple enteritis, copious sweating
and nephrosis….. Mild dehydration
 3-hypertonic (hypernatremic) dehydration
 Loss or deprivation of water with minor loss of sodium
 Occurs in animals unable to drink due to esophageal
obstruction ….. Mild dehydration

6. Clinical findings
 Dryness and shrinkage or wrinkling of skin
 Recession of the eye into the orbit is one of the
best indicator of dehydration in calves.
 Hypothermia
 Loss of body weight
 Muscular weakness
 Anorexia or inappetance
 Excessive animal thirst
 Reduction of milk yield in lactating animals
 oliguria

7. Field tests to diagnose dehydration
 1- pinching test or skin fold test
 Pinching the skin of neck and lateral thorax
between fingers rotating 90 degree and note
the time required for the fold to disappear
 Normal time: less than 2 seconds, if increases
indicated dehydration.
 2- capillary refill time (2 seconds)
 3- degree of eye recession in the orbit

8. Sunken eye in a calf with
dehydration

9. Delayed skin fold test in a calf
with dehydration

10. Lab exam
 1- increased PCV %
 2- increased total proteins
 3- metabolic acidosis
 4- Elevated level of blood urea nitrogen

11. Treatment
 Fluid and electrolyte thrapy
 Isotonic saline (0.9% NaCl) to expand blood
volume
 5% sodium bicarb in severe acidosis
 Lactated ringers in metabolic acidosis
 Hypertonic Nacl 7.2% in endotoxic shock

12. Amount of fluids

13.  a simple calculation can be done to
identify how much fluid is required.
 Take the % dehydrated and multiply by the
calf’s body weight in kg.
 For example, (36 kg) calf is determined to
be 9% dehydrated.
.09 X 36 kg = 3.24 – This means that 3.24
liters of fluid (oral electrolytes, or IV fluid)
are required to replace what has been lost.

14.  After the initial calculated fluid dose is
administered, additional fluids can be
given at a rate of 5 mL for every 1 kg,
every hour

15.  Oral Fluid Administration: Oral fluids
should only be used in calves that are 1-
5% dehydrated

16. Questions
dr.mohamedghanem@yahoo.com
Reference
Veterinary medicine 11th ed
Constable et al