A Review Of Calf Scours
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Newborn calves are extremely susceptible to calf scours especially during the first 28 days of life. Bacteria and viruses attack the lining of the calf's gut. The result is often watery diarrhea, with the calf losing nutrients and fluids and becoming dehydrated.
This page was last updated: February 1, 2010
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P. O. Box 1982
Clarkston, WA 99403
- There are two main forms of diarrhea.
-- Excess secretion into the intestine and normal reabsorption back out.
(Example -- E. coli K99)
-- Normal secretion into intestine with reduced back out (malabsorption). Example -- most other infectious diarrheal agents) -- Dehydration -- skin tents, mouth dry, legs and ears cold, eyes sink, urine
-- Body electrolyte (salts) loss and imbalance. Heart and muscle function impairment and the heart stops. -- The most common cause of calf death is due to E. coli infection.
- More about Rotaviral and Corona diarrhea.
-- The incubation period for calves is usually around three days.
-- Heifers' calves are more susceptible than cows' calves.
-- Virus kills the cells of the gut causing malabsorption scours.
-- Scouring calves shed millions of virus about three days after infection.
-- Carrier cows in the herd shed in low numbers.
-- Virus survives for weeks.
-- Vaccines are available. Vaccinate just before calving (heifers -- two shots, cows -- annual booster). Not always effective. Oral vaccine should be given in the back of the throat before the calf sucks colostrum. Antibiotics won't kill a virus.
- More about cryptosporidial scours.
-- Crypto bug is everywhere and survives for months on the ranch.
-- Vaccines not available and antibiotics aren't effective.
-- Not killed by most disinfectants. Cleaning pens and corrals is the only way to reduce the challenge.
-- Can be spread by dust in the air. Humans can get this infection.
E. coli K99
Salmonella spp (bacteria)
Type C (bacteria)
Age of Onset
Usually after 6 days -
can be 0-28
Most common at 1-5 days
Usually after 7-10 days -
can be 0-28
Usually at 7-21 days
Commonly at 1-7 days
Commonly at 7-28 days
Usually after 7 days
Mucus, watery brown or green diarrhea, blood
Effortless passing of yellow to white feces
Watery yellow feces
Watery brown or green feces with blood and mucus
Like E. coli, yellow to white feces (human infection also)
Sudden death (blood tinged feces)
Mucus and often bloody diarrhea
Table and information provided by: Bill Kvasnicka, University of Nevada-Reno Extension Veterinarian, 775-784-1377 or,