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Video 5 Oral rehydration principles


Oral rehydration is an essential tool in managing calves with diarrhoea and even for older animals like cows that may be sick.

The common things we treat with oral rehydration are

  • Calf scour or diarrhoea
  • Shock or septicaemias. A good example of this is E-coli mastitis in dairy cows
  • Supportive treatments when animals are sick. This could be a freshly calved cow with scour or for any severe infectious disease and decreased appetite.

Why do we use rehydration therapy?

Dehydration causes many symptoms and side effects. It lowers immunity and can drop the core temperature of young animals.

We use oral fluids to reverse dehydration. It is very important we replace lost electrolytes and often to give other substances that will reverse some of the symptoms we see.

In calf diarrhoea this will be things like acidosis and also energy (in the form of glucose).

How do we assess dehydration in a calf?

One way to do this is by using “skin tent”, which means pulling a fold of skin out and watching how fast or slow it recoils. Any slowness in skin recoil can indicate that hydration status is poor.

The eye is also very useful for assessing dehydration in calves. If the eye begins to sink away into the skull from the lid you can be sure of pretty severe dehydration.

I’ll keep saying that the trick with dehydration is to act fast with fluids.


How do we administer fluids

A stomach tube in calves is a really effective way of administering oral fluids. Watch my top tips on stomach tubing calves here https://youtu.be/s1aFlt3__iw

With cows, a stomach pump works well. This can administer large volumes quite safely and effectively. For most severe infections cows respond well to oral fluids.

Fluids can be administered by your vet intravenously. This works rapidly to bring the blood volume up and help reverse dehydration.

Picking the right electrolyte

We could assume if an animal is lacking fluids you would just give it water? This is sort of true in some ways, but there is actually real science to rehydration therapy particularly in sick animals.

If an animal is water-deprived then most likely water will be the solution. However where we have scour and other metabolic issues it becomes more complicated.

We get fluid loss and electrolyte imbalances. These important metabolites like Na K Cl (electrolytes)  play a key role in the functioning of healthy cells and many other things.

When we give electrolytes we also speed up the rate of absorption of fluids from the gut into the bloodstream and body.

We measure electrolytes based on their SID value playing particular attention to sodium (Na target 90-130 mmol/l).

With calf scour we must also reverse blood acidosis with alkalising agents. Acidosis can be very detrimental to the young calf. Electrolyte solutions can also contain short term energy hits like glucose to help energy, appetite and keep animals going.

Watch the VIDEO above as I dig into the science of oral rehydration.

Remember though

  1. Act fast if suspicious of dehydration and administer fluids
  2. Mix fluids correctly as instructed
  3. Give them regularly and often

Calves with scouring should get (2 extra) feeds of 2 litre electrolyte solution between milk feeding. Keep your scouring calf on milk also.









Hydra-Power Advanced is ideal for calves at risk of, during periods of and recovering from digestive disturbance (diarrhoea).

Thought for the day

Farm safety is always something we need to put front and centre on every farm. A lot of accidents can happen when people are rushing or maybe occasionally taking chances.

With our health system potentially being very busy over the coming weeks. Nobody wants to be in a situation where they end up in an accident and or in hospital. Take your time and don’t take risks.

Most importantly take care!


If people feel I can help them in any way my email is info@tommythevet.ie

Big thanks to Nettex for their support in helping me make #50in50 happen


Happy safe farming


































Hydra-Power Advanced is ideal for calves at risk of, during periods of and recovering from digestive disturbance (diarrheoa).



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