In a farm at risk because prior seasons with crypto scours (confirmed): Check that all hygiene measures of cleaning are carried out daily.

Commence dosing all calves at the start of the season with EXAGEN for at least 3 days (twice daily) especially if this is done in a transition area before entering the main calf shed. younger than 10 days of age with EXAGEN.

At the start of a scours outbreak: Start dosing all calves just arriving into the calf unit using a twice daily regime. Dose twice daily for 10 days (or more). They are at high risk of developing infection irrespective of any precautions that may have been taken.

Oocysts are produced within 48 – 72 hours of the first infection.  High levels of oocysts can be produced before any scouring starts.  Remember that beta-cyclodextrin will substantially lower the numbers of oocysts and the number of calves excreting oocysts.

Generally the higher the intake of oocysts at the start of infection, the earlier the signs appear, and the more severe the signs of scouring and loss of appetite. This is also strain dependent, so farms may differ greatly in the severity of their problems.

Farmer report:

Recurring crypto scours on a farm between seasons is a common problem for many farmers. EXAGEN offers farmers another option to take control of this problem. By using EXAGEN twice daily, calves do not suffer the debilitating loss of appetite and require the farmer to intervene with intensive electrolyte management.

Calves can continue to be given their EXAGEN supplemented milk feeds.

Calves may still get scours at a lower intensity while at the same time retaining their appetite. The period over which scours occurs is markedly reduced. These calves still require isotonic electrolytes (either KRYPTADE or ENERVADE) while also making sure fresh water is available.

For the calf with scours just identified, to provide the best outcome to manage any occurring crypto scours, an additional KRYPTADE electrolyte dose should be given between the milk feeds. These feeds continue to contain EXAGEN.

Electrolytes given may also be offered as an ad lib source for their own rehydration e.g from two hours after evening feed overnight.

Faeces of treated non-scouring calves are described as ‘fluffy’.

Any mob receiving EXAGEN are reported to require an average of approximately 1 dose of electrolyte (KRYPTADE, or ENERVADE) per calf under this management system over the period of treatment.

Note: Different groups of calves with a different genetic type of crypto present, may result in a varying degree of intensity of challenge (Thompson 2016).  The colostrum management may also affect the degree of severity of signs experienced.  

What’s happening?

There are 2 types of oocysts produced and one of these immediately re-infects the intestine, the other 20% is excreted.  This one is particularly tough and  it remains resistant to any of the common disinfectants destroying other infectious agents. The recycling inside repeatedly creates inflammation and scouring results.  To knock out this recycling which keeps repeating until the calf’s natural immunity develops, EXAGEN is added to any feed for all young calves immediately they come into the shed i.e. from day 1 – 3 days of age.  This is repeated twice daily for 10-12 days.

EXAGEN however is no substitute for colostrum and colostrum management is very important for all calves.

Mixed Infections from multiple agents 


Mixed infections are very much more severe on young calves.

They often appear to be occurring sequentially, but this may be because the time to development of signs is much less for rotavirus (1 – 2 days) compared with Crypto which takes 4 -6 days to show signs of scouring.

Mixed infections will cause more serious dehydration, for even greater periods of time, with a longer period with loss of appetite.

KRYPTADE and EXAGEN will still provide substantial and significant benefits.


Damage to gut, and secondary infections can cause significant death rates up to 20 -30%.

The effects of septicaemia must be tackled immediately signs of disease show if calves are to be saved.  Secondary infections (bacterial in origin) occur as a result of damage to the lining of the gut, very early in the scouring period. These need to be caught as early as possible. If they are not, they too will add to abdominal discomfort and general poor thrift. Monitoring any sick calves (having elevated temperatures) with their temperature can be essential to pick these out early.

Prompt use of antibiotics is very important if these calves are to be saved.