Neonatal Calf Diarrhea - Part 1

Adapted by Dr. Patricia C. Blanchard, California Animal Health and Food Safety Laboratory

Calf diarrhea is a multifactorial disease caused by interaction of calf (immunity status, age), environment and organism factors. The most common organisms found in ­<35 day old calves with diarrhea are cryptosporidia, rotavirus, coronavirus, Salmonella, attaching and effacing E. coli and K99 E. coli. At CAHFS, some organisms, such as attaching and effacing E. coli are only detectable by examination of the intestine of calves so fecal only testing of live calves does not detect them.  Increased illness and deaths in calves is often due to the presence of more than one organism.

The age of onset and type of diarrhea can provide clues to the likely causes. K99 E. coli causes watery diarrhea, severe dehydration and electrolyte loss but can only attach and cause diarrhea in calves <6 days of age, and most cases occur in 1-3 day old calves. The best prevention is the use of dry cow K99 vaccines so the colostrum contains antibodies that protect the newborn calf. In the face of an outbreak, use of commercial K99 antibody fed to calves at birth is also effective. Parasitic diseases like cryptosporidia take several days to cause diarrhea and are not found in the feces until after 3 days of age. When blood is seen in the feces this usually indicates the presence of one of three organisms, Salmonella, coronavirus or attaching and effacing E. coli. Rarely blood can be seen with severe cryptosporidia infections and is also seen with Clostridium perfringens type C infection but the latter is a rare cause of diarrhea in calves.  In the fall of 2012 and winter of 2013, CAHFS saw a marked increase in the occurrence of attaching and effacing E. coli, a disease CAHFS can only diagnose by examination of the intestine (ileum and colon) of dead calves. Owners often reported seeing bloody diarrhea or flecks of blood in the feces. Review of cases from 14 premises revealed age at the time of death ranged from 4-21 days with an average of 11 days. Calves were reportedly sick for 1-3 days before death.

The source of milk may be a factor if unpasteurized hospital milk with antibiotics or bacteria like Salmonella is fed to calves.  Extensive use of oral antibiotics can suppress the normal healthy bacterial flora in the intestine which makes calves more susceptible to infection with Salmonella, yeast and other fungi. If the pasteurizer is not working properly it might overheat milk degrading its quality or not have sufficient time and temperature levels to kill organisms. Salmonella Newport (group C2) and S. Typhimurium (group B) will also cause diarrhea in postpartum cows and can be found in hospital milk from diarrheic cows. Salmonella Dublin is the most common Salmonella seen in 1-3 month old calves but is also seen in younger calves and can be shed in the milk of carrier cows even without diarrhea. S. Dublin often causes septicemia with fever and respiratory signs in calves while the other types of Salmonella are usually limited to intestinal infections causing diarrhea.

Determining the causes of calf diarrhea can assist in identifying weaknesses in calf management programs and implementing changes to prevent future problems.

Link to PDF Version: Neonatal Calf Diarrhea