Dehydration in Calves

Assessing Hydration Status:

* It is essential that any animal, particularly calves with diarrhea, have oral, subcutaneous (SQ), or intravenous (IV) fluid supplementation.

Use the following guidelines to determine the hydration status of an animal:

% Dehydrated

Eyeball Position

*Skin Remains 
Tented (sec)

Mucous Membranes










Slightly sunken




Gap between eyeball and surrounding tissue


Tacky to dry


Large gap and very sunken



*See page B115 for additional information on skin tent.

Fluid Replacement:

Once the level of dehydration in the calf has been determined, a simple calculation can be done to identify how much fluid is required.

  1. Take the % dehydrated and multiply by the calf’s body weight in kg.
  2. For example, an 80 lb. (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, SQ, or IV fluid) are required to replace what has been lost.
  3. After the initial calculated fluid dose is administered, additional fluids can be given at a rate of 5 mL for every 2.2 lbs., every hour. In addition to the 5 mL/2.2 lbs/hour, an additional 1-4 liters each day may be required to keep up with continued fluid losses because of diarrhea, etc.

1 gallon = 3.7 liters and 1 kg = 2.2 lbs.
In this example the calf weighs 36 kg (80 lbs. divided by 2.2 = 36 kg)

This fluid can be given orally (PO), SQ, or IV (V is much better in an animal that is down and lethargic). Only sterile fluid (0.9% saline solution or sodium chloride) should be administered SQ or IV. See page F755 for additional suggestions.

Oral Fluid Administration: Oral fluids should only be used in calves that are 1-5% dehydrated. If the calf is more dehydrated than this, oral fluids alone do not meet the calf’s needs. The most common problems with oral fluid administration is that the method and frequency of administration is not ideal and the quantity administered is often insufficient. To overcome these problems, the following suggestions are a must:

  1. Reconstitute the oral electrolyte exactly according to the manufacturer’s
  2. Calculate the calf’s fluid requirements using the previous example.
    Administer no more than 2 liters at one time.
  3. The best way for a calf to obtain oral fluids is by suckling a nipple bottle. This allows the fluid to enter the abomasum through the esophageal groove. If the calf is too weak to suckle, fluids can be administered with an esophageal feeder. See page B850 for instructions on using an esophageal feeder. This method, however, causes the fluid to enter the rumen directly and not the abomasum. Frequent feedings with an esophageal feeder can cause decreased gastrointestinal (rumen/intestines) function and other complications.
  4. Do not be reluctant to administer milk replacers in addition to electrolytes. Electrolytes do not contain adequate nutrition for the calf and therefore milk replacers are necessary. It is true that some milk replacers can increase the amount of diarrhea that is seen. This is a necessary trade off for the extra nutrition the calf requires.
  5. All electrolytes and milk replacers should be fed at least 30 minutes apart and never mix the two fluids. Milk digestion is slowed when combined with oral electrolytes.
  6. The frequency of feedings can be variable and depend on the severity of the fluid loss and management issues. In general, calves that are only slightly dehydrated may require only two oral feedings, while calves that are around 5% dehydrated may require feeding every 2 hours.


Subcutaneous (SQ) Fluid Administration: This method of fluid administration should be used in those calves that are 6-8% dehydrated. If SQ fluids are given, remember the following:

  1. If the calf is greater than 8% dehydrated, IV fluids should be given.
  2. Warm the fluids to body temperature before administration.
  3. Use only sterile isotonic fluids (0.9% saline solution).
  4. Because of potential infections, do not add glucose to any fluid given SQ.
  5. The loose skin areas of the neck, shoulder, and behind the elbow are great areas to administer SQ fluid. The injection area should be cleaned and sterilized before inserting the needle.
  6. The fluid can be given as one large bolus or can be given over a period of time. Do not give over 500 mL in one location and over 2 liters total to one calf at one time. It usually takes about 4-6 hours for the fluid to completely absorb.

* Oral and SQ fluids can be given at the same time and are often a great method of restoring proper hydration.


Intravenous (IV) Fluid Administration: IV fluid administration requires that a sterile catheter be placed in the animal. This requires professional help and additional training. Once the catheter is in place, the following should be considered:

  1. Only administer sterile fluids (0.9% saline solution).
  2. Calculate the animal’s fluid needs by utilizing the table and example at the front of this discussion.
  3. Most calves are acidotic (meaning that they have a low blood pH). Because of this, bicarbonate should be added to each liter of fluid. If 0.9% sterile saline solution or sodium chloride is used, approximately 150 mL of 8.4% sodium bicarbonate should be added to the first 2-3 liters of IV fluids.
  4. Supplemental glucose may also be necessary, particularly if the animal is not eating. Placing about 60 mL of a 50% dextrose solution in each
    1 liter of IV fluid is sufficient.
  5. In general, once the amount of fluid the calf requires is calculated, two-thirds of that amount can be given in the first hour. For example, if the calf requires 6 liters of fluid, 4 liters can be given in the first hour. After the first hour, the rest of fluids (2 liters) can be given evenly over a 2-3 hour period.
  6. After the initial calculated fluid dose is administered, additional fluids can be given at a rate of 5 mL for every 2.2 lbs. every hour. This means that an 80 lb. (36 kg) calf that is 9% dehydrated should initially receive 3.24 liters of fluid total. Approximately 2 liters should be given in the first hour, and the final liter given over a 2-3 hour period. Once the 3.24 liters are given, a dose of 180 mL of fluid should be given every hour until the animal is fully rehydrated and back to normal.
  7. In addition to the 5 mL/2.2 lbs/hour, an additional 1-4 liters each day
    may be required to keep up with continued fluid losses because of diarrhea, etc.