Calf Scours Fluid Therapy Calculator
how much electrolyte, and when to call the vet.
Estimate how dehydrated a scouring calf is, work out its oral electrolyte needs for the next 24 hours, and spot the signs that mean it needs IV fluids now.
24-Hour Fluid Plan
Deficit + maintenance + ongoing losses, given as oral electrolytes.
Oral electrolytes for the next 24 hours
Treating a Scouring Calf with Fluids
Diarrhoea kills calves mainly through dehydration and loss of salts.
The fluid a calf needs in a day has three parts: the deficit it has already lost (body weight × dehydration %), maintenance for normal body needs, and the ongoing losses in the diarrhoea that will continue while it is sick.
Estimate dehydration by how far the eye has sunk into its socket and how long a pinched fold of neck skin takes to flatten. A calf that is 8% dehydrated or more, cannot stand, has no suckle reflex, or has a cold mouth or legs usually needs intravenous fluids, which only a vet can give.
How to use this calculator
- Choose kg · L or lb · gal, then enter the calf's body weight. Weigh it or use a weight tape if you can.
- Check dehydration. Look at how far the eyeball has sunk into its socket, then pinch a fold of skin on the side of the neck and count the seconds it takes to flatten. Pick the matching options; the tool uses the worse of the two. If your vet has given you a dehydration %, choose "Enter % directly" instead.
- Choose how bad the diarrhoea is. This sets the ongoing losses: about 1 L a day for mild, 2 L for moderate and 3–4 L for severe.
- Leave maintenance at 50 mL/kg/day and electrolyte feeds at 3 a day unless your vet suggests different figures.
- Tick any warning signs that apply: the calf cannot stand, has no suckle reflex, or has a cold mouth, ears or legs.
Reading the result
The total for 24 h is the oral electrolyte volume the calf needs over the next day, split into the number of feeds you chose. The three smaller boxes show where it comes from: the deficit catches up on fluid already lost, maintenance covers normal needs, and ongoing losses replace what the diarrhoea will keep taking. Keep feeding milk as usual and give the electrolyte feeds between milk feeds. If the red box appears, oral fluids are not enough: call your vet for IV fluids. Recheck the calf every few hours and run the numbers again if it gets better or worse.
Common questions
Should I stop milk while the calf has scours?
No. Calves with diarrhoea keep their weight and heal faster when milk is continued. Give oral electrolytes as extra feeds between milk feeds.
Which electrolyte should I use?
Use a commercial oral rehydration product made for calves and mix it exactly as the label says. Ask your vet which product suits your calves.
How do I judge eye recession?
Look at the gap between the eyeball and the lower eyelid; the eye sinks back into its socket as the calf dries out. A gap of 0–2 mm fits under 5% dehydration, while 6–8 mm fits 10–12%, which is an emergency. Use the skin tent as a second check.
Can I mix the electrolytes into the milk?
Only if the product label says it can be mixed with milk. Otherwise give it as a separate feed between milk feeds, made up exactly as the label says.
When can I stop giving electrolytes?
When the diarrhoea has cleared and the calf is bright, standing and drinking its milk well. If it is not improving, or is getting weaker, call your vet rather than just giving more fluid.
Decision support only. Not a substitute for your veterinarian.