John G. Kirkpatrick Director Veterinary Extension 
Glenn Selk Extension Beef Cattle Specialist 
 

The disease: Coccidiosis in cattle usually presents as acute diarrhea (with or without blood), straining, severe weight loss, and not uncommonly as a neurologic form which usually results in death of the animal.  The more chronic form of the disease causes growth retardation and / or a stressor causing an increased susceptibility to other infections such as salmonellosis (intestinal disease) or Bovine Respiratory Disease.  Coccidiosis is primarily a disease of young animals but can effect older animals that are in poor condition.  It occurs commonly in over-crowed conditions but can occur in free -ranging conditions that have congregating areas such as feed grounds and watering areas. 

The disease agent: Coccidia are protozoan parasites that are host specific, e.g. cattle have their specific coccidia (Eimeria sp.) (Fig. 1), poultry have their coccidia, etc.  The oocyst (infective form of the parasite) is usually shed in the feces affected animals and that of inapparent carrier animals.  The oocyst is highly resistant and can survive in moist shaded areas for several years. 

 
Figure 1 Oocysts of Eimeria sp. coccidium of cattle. 
     Oocysts are shown X 400. 

Transmission: Coccidiosis is transmitted from animal to animal by the fecal – oral route.  Infected fecal material contaminating feed, water, or soil serves as carriers of the oocyst for the susceptible animal to contract the disease by eating, drinking, or licking itself.  It is well to remember that the severity of clinical disease depends on the number of oocysts ingested.  The more oocysts ingested the more severe the disease. 

Diagnosis: Coccidiosis is diagnosed by clinical signs, fecal examination by flotation or smear, and by postmortem examination. 

Treatment: Isolate the sick animal to prevent increased contamination of the premises. Clinical signs usually occur about 17 days after ingestion of oocysts.  By the time clinical signs occur the disease damage is far advanced and the life cycle in the animal is completed.  Amprolium at 10 mg / kg / day for 5 days and sulfonamides are commonly used as treatments for clinical disease.  Supportive treatments and drugs to prevent secondary infections are in order due to the animals debilitated state.  Remember if there is one clinical case in a group of cattle it is highly probable that others are exposed that harbor coccidia in the intermediate stages of development.  Due to the drug susceptibility of the parasite in the intermediate stages of development preventive measures should be instituted. 

Control:  Anticoccidial drugs commonly used in cattle should be used at label recommendations paying careful attention to maintaining preventive levels for periods long enough to effect the life cycle of coccidia. 

Anticoccidial drugs for use in cattle. 

Amprolium  Corid®   Therapeutic 10mg/kg/day for 5 days 
     Preventive 5mg/kg/day for 28 days 
 Sulfonamides*   Therapeutic label recommendations 

 Monensin Rumensin® Preventive 1 mg/kg/day, 10 – 30 g/ton 
 Lasalocid Bovatec® Preventive 1 mg/kg/day, 10 – 30 g/ton 
 
 Decoquinate Deccox® Preventive 0.5 mg/kg/day for 28 days or longer 

* Several trade names 
Warning 
Check with your veterinarian to establish a diagnosis and course of treatment and prevention. 
 Always read and follow label instructions 
 
Conclusions: 
1. Coccidiosis is a costly parasitic disease primarily of young cattle whether in intensive animal husbandry conditions or free ranging on pastures. 
2. It causes both severe illness with possible death or subtle illness causing stress and debilitation of the animal resulting in secondary disease thus further jeopardizing the health of the animal. 
3. Treatment and control must be two fold.  Good animal husbandry measures to prevent the ingestion of infective oocyst by other cattle and the use of anticoccidial drugs to prevent further disease and premise contamination. 
4. Remember animals not showing clinical signs may still break with coccidiosis following the institution of anticoccidial drugs.  The coccidia may be advanced beyond a point of drug susceptibility in their cycle.  This does not mean to stop preventive measures.  You are using drugs to prevent disease in the animal and also to decrease the concentration of the parasite on your premises.