Calf Scours (Neonatal Diarrhoea): Causes, Treatment & Rehydration Protocol

Calf Scours: The Disease That Kills More Calves Than Any Other

Neonatal calf diarrhoea — commonly called calf scours — is the leading cause of death in calves under one month of age worldwide. In the United States alone, USDA data shows that scours accounts for more than 56% of all pre-weaning calf deaths. In South Asia and Sub-Saharan Africa, the mortality rate in untreated outbreaks can exceed 70% when dehydration is severe.

The critical fact every cattle farmer must understand: calves almost never die from the diarrhoea itself. They die from dehydration, acidosis, and electrolyte loss. A calf that is losing fluid faster than it can absorb water will deteriorate within 24–48 hours. With correct, early rehydration treatment, the vast majority of scouring calves can be saved — even without antibiotics. This guide gives you the complete, evidence-based protocol.

Causes of Calf Scours — What You’re Dealing With

Calf scours has multiple causes. Identifying the likely cause guides treatment, because not all scours is the same — and unnecessary antibiotic use contributes to resistance. Age of onset is the most useful field diagnostic tool:

Severity Assessment — Use This Scale at First Examination

Assess every scouring calf using this four-point scoring system. Your score determines whether you manage in the field or call your vet immediately.

Oral Rehydration — The Life-Saving Treatment

Step-by-Step Oral Rehydration Protocol

1. Assess severity score. Only proceed with oral treatment for Score 1 and Score 2 calves.
2. Make up commercial electrolyte solution as per product instructions — ensure water is body-temperature warm (38–39°C). Cold electrolytes are less well absorbed.
3. Give 2 litres per feed by bottle or oesophageal tube feeder. Do NOT use a bucket for sick calves — they may inhale fluid.
4. Give 3–4 feeds in 24 hours for mild cases. Increase to every 4–6 hours for moderate cases.
5. Continue milk feeding alongside electrolytes — do NOT replace milk with electrolytes. Recent research confirms continued milk feeding improves recovery.
6. Add sodium bicarbonate (baking soda) solution separately if acidosis is suspected (weak, cold calf that still sucks). Do NOT mix with commercial electrolyte solution — this reduces efficacy.
7. Monitor for improvement after every feeding. If no improvement within 12 hours of correct oral treatment, escalate to IV fluids.

Homemade Oral Rehydration Solution (Emergency Use Only)

If commercial electrolytes are unavailable, the following emergency solution provides basic rehydration. Use commercial electrolytes as soon as possible — they contain amino acids and energy sources not present in this basic recipe.

• 1 litre of boiled and cooled clean water
• 1 teaspoon (5 g) of table salt (sodium chloride)
• 1 teaspoon (5 g) of baking soda (sodium bicarbonate)
• 6 teaspoons (30 g) of glucose or sugar

Give 1–2 litres per feed, 3–4 times daily. This is a short-term emergency measure only — seek veterinary advice and access to commercial electrolytes as quickly as possible.

Prevention: The 1-2-3 Colostrum Rule

The single most powerful intervention for preventing calf scours is correct colostrum management. Research consistently shows that calves receiving adequate quality colostrum in the first hours of life have dramatically lower rates of scours, respiratory disease, and mortality throughout the pre-weaning period.

• 1 — Give colostrum within the FIRST hour of birth (absorption begins declining immediately after birth)
• 2 — Give at LEAST 2 litres (beef calves) or 3 litres (dairy calves) in the first feed
• 3 — Give a THIRD feed within 12 hours to ensure continued antibody intake while gut absorption remains open
• Calf records: record each calf’s birth date, colostrum intake, and any health events. Allows you to identify risk patterns and respond faster in future outbreaks

Frequently Asked Questions

Should I stop milk feeding a scouring calf?

No — and this is one of the most common and damaging mistakes in calf management. Removing milk causes energy starvation and slows recovery. Multiple studies confirm that calves receiving both milk and electrolytes recover faster than those receiving electrolytes alone. Continue milk at normal volume. Simply add separate electrolyte feeds between milk feeds.

Do I need antibiotics for calf scours?

Most cases of calf scours are caused by viruses (rotavirus, coronavirus) or parasites (Cryptosporidium), which do not respond to antibiotics. Antibiotics are required when bacterial causes are confirmed or strongly suspected (E. coli K99 in Day 1–2 calves, or Salmonella at any age with fever and bloody scours). Unnecessary antibiotic use selects for resistant bacteria and does not improve recovery from viral or protozoal scours. Consult your vet for guidance.

How long do calf scours last?

With correct oral rehydration treatment, most viral and protozoal scours cases resolve within 3–5 days. E. coli scours treated with antibiotics within 12 hours of onset typically resolves in 2–3 days. Cryptosporidium cases are the most persistent — typically lasting 5–8 days even with good supportive care. If scours persists beyond 5 days without improvement despite treatment, consult your vet for further investigation.

Herd-Level Prevention Programme

• Vaccination of cows pre-calving: E. coli K99 and Rotavirus vaccines given 6 weeks pre-calving pass protective antibodies through colostrum to calves
• Clean calving environment: calving pens cleaned and disinfected between calvings. Deep straw bedding, dry and well-ventilated
• Isolation of scouring calves: immediately separate scouring calves from healthy calves — Cryptosporidium and Rotavirus are highly contagious
• Hydrogen peroxide or peroxymonosulphate disinfectants for Cryptosporidium decontamination (many standard disinfectants are ineffective against Cryptosporidium oocysts)
• Calf records: record each calf’s birth date, colostrum intake, and any health events. Allows you to identify risk patterns and respond faster in future outbreaks