Scours – Rehydration

Scouring calves lose body fluid, electrolytes (body salts) and energy. Weight loss is dramatic and the severe dehydration will often lead to death. It is imperative that rehydration therapy commences as soon as possible whether the scours are nutritional or infectious in origin, treatment (rehydration) remains the same. Lost body fluids and salts must be replaced and the calves fluid and electrolyte balance must be maintained whilst the calf is suffering from diarrhoea and during the recovery period.

Electrolytes have a much lower energy value than milk feeding and where possible milk feeding during scouring should be continued as much as possible. Never withhold milk from a young calf for more than 24 hours

A calves symptoms will determine the % dehydration when deciding how much to administer to your calf. See below for symtoms and percentages:

Diarrhoea only5%
Eyes slightly sunken, skin losing elasticity, calf staggering but still suckling7%
Eyes sunken, skin slow to flatten when pinched, sticky gums, calf depressed and reluctant to feed9%*
Eyes deeply sunken, skin won’t flatten out if pinched, calf cannot stand12%*

* These calves will need to have intravenous fluids administered by a veterinarian

Rehydration calculation formula

Guide to calculating the minimum electrolyte therapy for a scouring calf. In this example our calf is 45kg,


(Rehydration quota + Maintenance quota) = Total Electrolyte Volume

  1. The volume of fluid required for rehydration is obtained by multiplying the weight of the calf by the % of dehydration suffered.

    ∴ a 45 kg calf x 5% dehydration = 2.25L of electrolyte

  1. Next add the maintenance quota of electrolyte based on 10% of the calf weight.

    ∴ a 45 kg calf = 4.5L for maintenance

  1. So according to the formula:

    2.25L Dehydration + 4.5L Maintenance = 6.75L Rehydration

This calf needs 6.75L minimum rehydration per day.

Recommended electrolyte/milk feeding regime
Moderate ScoursMilk 1-2LElectrolytesMilkElectrolytes Ad-lib 2-4L
Total: 6-8L
Severe ScoursElectrolytes 2LMilk 1-2LElectrolytes 2LElectrolytes Ad-lib 4-6L
Total: 8-10L
  • Isolate the calf – keep records and feed accordingly
  • Offer electrolytes via a Bovivet tube drencher if the calf is not suckling. If the calf is suckling use a teat feeder, trough or bucket
  • No other calf should be allowed access to the sick calf’s electrolytes or milk in order to prevent cross infection. The sick calf must take all the fluids
  • Use a good quality electrolyte that has been recommended by your veterinarian
  • Ensure that the electrolytes and milk that are to be administered are warm

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John Hathaway
Businessman and Dairy Farmer (Reporoa)

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Calf Rearer and Beef Farmer (Maungatapere)

"I have used Ngahiwi Calf Milk Replacer for 20 seasons rearing thousands of calves in that time. Ngahiwi mixes easily and my young calves thrive. Ngahiwi contains, as standard, prebiotics, probiotics and a coccidiastat. Excellent product!"

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Bull Farmer (Waitakaruru)


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