Dehydration Evaluation and Treatment in Dairy Calves

By Rodney Dennis, Dairy Nutritionist/Calf Specialist

Evaluating and monitoring dehydration in dairy calves is an important task for good calf performance and survivability.  This requires good management – careful observation, attention to individual calves and the ability to monitor dehydration.  Sick calves may lose up to 10% of their bodyweight in a single day when they are scouring.  When a calf losses 14% of its bodyweight, death occurs and it is the dehydration, not microorganisms, that typically kills these scouring calves (Table 1).  Early identification and treatment of dehydrated calves will help increase calf survival rates.

Steps to Evaluate Dehydration

  1. The first step is to evaluate the fecal scores of your calves.  Calves with very loose or runny feces are at a high risk of being dehydrated.
  2. Inspect those calves that are at risk for the classic signs of dehydration:
    1. Sunken eyes
    2. Dry mouth and nose
    3. Weight loss
    4. Fast or very slow pulse
    5. Cold ears and/or cold legs

Tenting Test for Dehydration

A good test for dehydration is the skin tenting check.  To conduct a tenting test:

  1. Firmly pinch the loose folds of skin on the neck of the calf and check to see how long the skin remains tented.
  2. If the skin remains tented for 2 to 6 seconds, the calf is moderately dehydrated.  Start oral feeding of a good electrolyte like Kentrol to assist rehydration.
  3. If the skin remains tented longer than 6 seconds, it is an indication that the calf is severely dehydrated (10% dehydrated).  Calves observed in this state of dehydration need professional veterinary interventions with intravenous fluid administration. Following the intravenous therapy, oral electrolyte therapy should be continued to maintain proper hydration.

Treating Dehydrated or Scouring Calves

At the first signs of dehydration (section 2 above and tenting of 2-3 seconds), the easiest way to treat is oral feeding calves an electrolyte solution like Kentrol.  If the calf is exhibiting moderate to severe dehydration or not consuming liquids orally, the Kentrol should be given via an esophageal feeder.

Kent Kentrol contains dextrose and other energy sources; alkalinizing agents to treat acidosis; and sodium, potassium, and chloride to replenish lost electrolytes.  Kentrol also contains a gelling agent to aid absorption and reduce scouring.  Feed moderately dehydrated calves 2 quarts of Kentrol electrolyte solution, mixed according to the label recommendations twice daily until calves recover.  During this period, continue feeding dehydrated calves milk or Milk Replacer to ensure nutrient intake.  Kentrol (100 grams per 2 qt. water) and Milk Replacer (10 oz. per 2 qt. water) should be mixed separately per directions and fed to achieve recommended intakes.  The Kentrol mixture should be fed before or after Milk Replacer for 2 to 4 days or until the calf is no longer scouring and does not appear to be dehydrated based on skin tenting and observation.  When properly mixed separately, the Kentrol and Milk Replacer can be fed at the same time as long as recommended daily intakes are achieved.  However, never mix the recommended amount of Kent Kentrol and Milk Replacer in only two quarts of water as the resulting mixture is too high in osmolarity and may cause additional scouring.  When feeding waste milk, wait at least 30 minutes after milk feeding before feeding electrolytes, since most electrolytes contain bicarbonate or citrate, which can prevent milk clotting in the abomasum.

Table 1: Clinical Symptoms That Help Evaluate Amount of Dehydration in Calves




Diarrhea, no clinical signs, strong suckling reflex


Mild depression, skin tenting 2-6 seconds, calf still suckling, sunken eyes, weak


Calf depressed, laying down, eyes very sunken, dry gums, skin tenting >6 seconds


Calf will not stand, cool extremities, skin won’t flatten when tented, comatose

Over 14%

Adapted from J. M. Naylor, Can. Vet. J. (1989).