Combating Dehydration

As a dairy or veal producer we all have experienced dehydration in calves. Regardless the cause, or the time of year it’s a challenge on farm.

Young calves have about five to 10 % more body fluid that adult animals. Calves are 75% water by body weight and can lose close to 20% body weight per day with diarrhea. To maintain normal cellular functions, the average water intake rate is 40-60 milliliters of fluid per kilogram of body weight daily. The average 100lb. calf would require approximately 4.5 litres of water daily for maintenance.

Combating DehydrationWeaned calves without free-choice water accessibility should be fed a minimum of 10% of their body weight in water. Calves subjected to heat stress or scours will require an additional 20—30% daily of water intake for maintenance of body functions.

How do your calves measure up? Are you recognizing the signs of dehydration early enough?

Signs of dehydration:

  • Sunken eyes
  • Dry mouth and nose
  • Gum condition, sticky/tacky, light pink-pale
  • Attitude-does the calf need encouragement to get up or drink?
  • Ability to stand or suckle
  • Weight loss
  • Fast or very slow pulse
  • Cold ears and/or cold legs

If you are not sure if the calf is dehydrated try the tenting test:

  • Firmly pinch the loose folds of skin on the neck of the calf and count the number of seconds it takes to flatten.
  • If the skin flattens in less than two seconds, this indicates normal hydration.
  • If the skin remains tented for two to six seconds, the calf is moderately or about eight percent dehydrated.
  • If the skin remains tented longer than six seconds, the calf is severely or about ten percent dehydrated.

If the calf is dehydrated it will need to have a good oral electrolyte solution. A quality product should include:

  • Sodium (Na)=90-130 mmol/L
  • Potassium (K)=10-30 mmol/L
  • Chlorine (CL)=40-80 mEq/L
  • Osmolality=500-600 mOsm/L
  • Contain acetate as a buffer-this is a precursor for energy
  • Avoid fiber – this will not help the calf firm up manure

Always mix electrolytes according to label directions to keep the correct ratio. Taking calves off milk is not recommended as they need the energy and protein that milk provides.

To determine the amount of electrolytes to feed, multiply the weight of the calf by the percent dehydration, and then divide by two to get the litres of liquid needed. For example, if a 100lb. calf is eight percent dehydrated (100 x0.08) you would divide eight by two that would equal four. That would be the amount of litres needed per day in addition to normal milk feeding to correct the dehydration. (100x.08)=8/2=4. During hot temperatures these amounts would be increased significantly. Healthy calves under heat stress will drink between six and 12 litres of water daily just to maintain hydration.

Calf Dehydration Assessment

Mild dehydration Moderate dehydration Severe dehydration
Hydration <5% loss 5-8% loss 9+%loss
Stance standing weak flat out
Skin tent <3 seconds 3-5 seconds 6+ seconds
Membranes/gum condition pink, moist sticky/tacky, light pink dry and pale, cold
Eyes bright slightly recessed significant recession
Suckle reflex strong weak none
Attitude mild depression dopey maybe non responsive
Action oral fluids oral & intravenous fluids or sub Q saline intravenous fluids (no oral fluids until able to suckle)

(Source Matthew J. Boyle, DVM Freeport Veterinary Service) modified

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