When meal feeding of dairy calves is discontinued and calves are grazing areas previously contaminated with coccidia oocysts, then this is the time we will see the effects of coccidia in younger stock.
The disease will show in a couple of ways. The first is a low grade (sub clinical) infection with lower growth rates and a failure to thrive and the second presentation is where we will be called to calves with diarrhoea, straining often with blood in their faeces/dung.
From our work more and more farms have coccidia present and there is an increased need for treatments around the time medicated meal is withdrawn.
The coccidia life-cycle starts with coccidia oocysts on pasture being eaten by the calf and infection starting in the small intestine. The damage to the lining of the small intestine results in calves not thriving.
Within a couple of weeks, if the disease progresses, coccidia infection will then affect the large intestine and hence the diarrhoea and blood.
Progression of the disease will be affected by the level of contamination calves are exposed to i.e. the number of oocysts being consumed as well as the calf’s’ health and resilience and the weather conditions (wet weather favours the survivability of oocysts on pasture).
The incubation time within the calf for coccidiosis is 2 to 4 weeks from the cessation of meal feeding and we recommend the drenching of calves with Catolyst when meal is removed.
Catalyst is coccidiocidal, that is it kills all stages of the coccidia lifecycle which assists in lowering pasture contamination of oocysts and prevents both sub-clinical and clinical disease.
Even when faecal oocysts indicate a low level of infection, NZ based studies have shown a consistent weight gain advantage of 3 to 5 kg during the 5 weeks after weaning in calves orally treated with Catolyst (3 mls per 10 kg pf body weight).
If you have had coccidia in your calves previously, then do not hesitate to treat around the medicated meal is taken away or if you are uncertain, we can test fresh faeces (we will look for the presence of oocysts).
We also recommend the injection of all calves with Multmin around the time of weaning to assist in building maximum immunity.
If you would like further information please talk to one of our large animal vets.