Coccidiosis

Coccidiosis is a disease seen commonly in calves and yearlings.  In mild climates such as this, coccidia are present where-ever cattle are present.

Coccidia are microscopic organisms that invade and affect the gastrointestinal tract of young animals.  It is the damage to the lining of the large intestine which causes the clinical symptoms we observe:

  • Diarrhoea usually blood tinged
  • Straining
  • Tail switching
  • Occasional death
Coccidiosis is commonly associated with environments which allow a build up of coccidial oocysts or "eggs" to occur, eg overcrowding of calves, housing in dirty wet conditions with poor drainage and lack of paddock spelling.  These oocysts are ingested by the calves when they eat the pasture or lick infected calves.  Infected calves shed oocysts into the environment via their faeces.  Stresses such as heifers undergoing the stress of weaning, overcrowding and concurrent disease, can also predispose young animals to develop clinical disease.  It usually takes 3 to 4 weeks from the ingestion of the coccidial spores to the time that clinical signs are seen.

The diagnosis of coccidiosis can usually be made from clinical signs, this can be confirmed by microscopic examination of the faeces.

Hygiene of calf rearing facilities is the most important factor in limiting the problems caused by coccidia.  Preventing the calves from being showered with high levels of infective coccidial oocysts can be achieved by:

 

  • Hygienic calf sheds (slats, mesh or deep litter); well drained, clean, dry surfaces.
  • Low stocking rate in pens and in paddocks
  • Well drained calf paddocks
  • Rotating calf paddocks periodically
  • Ensuring that feed and water containers are off the ground
  • Regularly changing feeding areas in the paddocks
  • Isolation of affected calves
Affected calves should be treated immediately with sulfadimidine for three days, in severe cases broad-spectrum antibiotics such as Tribactril will be beneficial. Dehydration can be a problem in these calves, so adequate fluid therapy (either oral or intravenous) should be available if necessary.

On farms with persistent problems with coccidiosis, calves can be fed avoparcin and/or monensin (or other similar products) from birth to prevent infection.  Immunity to coccidiosis will still develop while on monensin but clinical disease is prevented.  This allows protection against coccidiosis when monensin is withdrawn.

Monensin is available in a number of commercial preparations which can be added to milk or be available in pellet form.



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