For the final edition of our calf scour series we will look at Cryptosporidiosis.  Cryptosporidiosis is a common scour, which generally affects calves at two weeks old, but can occur in calves from five to 35 days old. The parasite is transmitted via the ingestion of the pathogen through infected faecal matter. Calves commonly pick it up from calf pens, water, unclean feeding equipment or dirty bedding or anything that has been contaminated with dung containing the parasite.

Cryptosporidiosis can also be contracted by humans so great care and hygiene measures should be applied when dealing with sick calves.


It can be difficult to distinguish cryptosporidiosis from other types of scour as the symptoms can be very similar.  The best way to confirm whether it is cryptosporidiosis effecting a calf is to send faecal samples from scouring calves to a lab for testing or to send any calves that has died from scour to a  veterinary laboratory for a post-mortem.


  • Persistent diarrhoea
  • Lethargic calves
  • Calves that stop drinking, then becoming dehydrated
  • High mortality rate, especially where other types of scour such as rotavirus are also present
  • Rapid spread of the scour between calves once one becomes infected


  • The best way to avoid spread of cryptosporidiosis is to pen calves individually for the first 2 weeks of life
  • Feed electrolytes to keep the calve nourished and to avoid dehydration
  • Halocur (halofuginone lactate) can be given to calves as a preventative to cryptosporidiosis and can also be used to treat infected calves
  • On farms where there is a known problem with cryptosporidiosis, calves should be given Halocur in the first 24 hours after birth
  • If an outbreak occurs, unaffected healthy calves should be separated out and moved immediately from the contaminated environment.

For further advice on any of the above, please contact a member of the Moocall team to speak to some of our breeding specialists on +353 1 96 96 038 or email