​​​Preventing & Managing Coccidiosis in Cattle and Calves

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Bovine coccidiosis is one of the major diseases in young calves. It can quickly and easily spread through a herd and have devastating effects on calves — and productivity. Coccidiosis occurs wherever cattle are raised and makes its greatest impact on calves less than a year old, causing severe damage to the intestinal tract. It is associated with diarrh​o​ea of varying degrees of severity, secondary infections and even mortality. 

Coccidiosis has an impact on the profitability of each calf, with losses coming from several different factors. Long-term implications for the health and productivity of each animal can include:1   

  • Treatment cost 
  • Labo​u​r cost 
  • Reduced weight gain 
  • Reduced feed conversion ratio 
  • Increased susceptibility to diseases 

To ensure the health and profitability of your herd, discover how coccidiosis is diagnosed and how to prevent and manage illness within your operation. 

Young calfhood diarrh​o​ea is associated with lowered first-lactation milk production.2  

How to Diagnose Coccidiosis

The diagnosis of the disease in the herd can be made based on the symptoms and the history of disease within the operation. Without historical information, a diagnosis can be difficult to make, as clinical symptoms may precede the shedding of oocysts. Feacal testing of oocysts numbers can help with the confirmation of a coccidiosis diagnosis.1  

To protect the profitability of your herd, it is critical to treat calves before they display clinical symptoms. When clinical symptoms are displayed, serious damage to the intestinal lining has already occurred and the animal’s ability to effectively absorb feed and liquids is impaired. Use the chart below to recognize the subclinical and clinical symptoms of coccidiosis. 

Young calfhood diarrh​o​ea is associated with lowered first-lactation milk production. 
Subclinical SymptomsClinical Symptoms
Anorexia/decrease of appetiteDark green to blackish ​diarrhoea​
Loss of weightPresence of blood/threads of fiber/intestinal mucosa in the stools 
Dull and poor hair coatFever
General poor conditionLack of appetite
Loose ​faeces​Abdominal pains

Sampling and monitoring for the presence of Eimeria in fecal samples provides a good overview of the presence of coccidiosis in the herd. It is important to recognize when the herd could be most at risk in order to optimally test and treat.    

  • Outbreaks typically occur shortly after a herd has been regrouped. Knowing a farm’s history of coccidiosis can also help you predict when an outbreak is likely to occur — for example, the number of days after regrouping when previous outbreaks have occurred. 
  • Calves from 3 weeks to 6 months of age are at risk. 
  • Recognizing when clinical symptoms — such as ​diarrhoea​ — are likely to appear helps to identify the optimal time to treat the herd. 

Prevention and Management of Coccidiosis

As a multifactorial disease, the severity and manifestation of the disease varies from one farm to another. Oocysts capable of spreading the disease can survive pasture over winter, causing clinical disease in calves within a week after turnout to the infected pasture. As such, when developing a control program, it is important to consider several points for each case, including:  

  • Animals at risk: While cattle remain susceptible to coccidiosis until they acquire immunity, the typical age range for animals suffering from the disease is one month to a year of age. Stress, immune status and nutritional status can also affect susceptibility. 
  • Presence of pathogenic coccidia species: Infection with multiple Eimeria species is common. Eimeria bovis and Eimeria zuernii are the most common clinical manifestations of the disease, often presenting in diarrheic problems in animals released to pasture. 
  • Herd history: Understanding which animals are most at risk is vital in early prevention and management. Certain cattle management practices may be tied to disease manifestations, such as transportation and regrouping, or weather and feed variations. 
  • Spread of the disease: While the presence of many oocysts in the environment can explain disease manifestation, increased stress or other variables can place calves and other animals at risk despite relatively low numbers of coccidia. Quality of bedding, treatment of hay and colostrum uptake have all demonstrated high correlations with coccidiosis infections.3  

It is also important to take preventive measures that do not allow a buildup of infection of the environment. General health of animals must be ensured, with such measures as colostrum supplementation within the first 24 hours of birth. Proper environmental cleanliness and nutrition are also vital in preserving the ability to develop a natural immunity to the disease. 

Treatment with Baycox​TM​​ ​​Coccidiocide for Piglets and Cattle ​can help prevent clinical signs and production losses, while still allowing for the development of immunity. ​ One dose of Baycox is effective as it attacks all stages of the parasite in the animal. In the case of diarrhoea in calves, obtain a veterinary diagnosis of coccidiosis before using this product. Early treatment of calves as soon as the diagnosis is obtained will prevent further intestinal damage in affected animals and prevent infection of the herd. To obtain maximum benefit on farms with a history of coccidiosis, Baycox should be given approximately 1 week before the expected onset of clinical signs. Treatment of newly weaned calves at the time of milk withdrawal will control coccidiosis associated with weaning.​​ 

To learn more about how you can prevent and manage coccidiosis in your herd, contact your local Elanco representative today. 


1 The costs of coccidiosis; Veterinary Practice, August 2008 

2 Svensson C, Hultgren J. Associations between housing, management, and morbidity during rearing and subsequent first-lactation milk production of dairy cows in southwest Sweden. J Dairy Sci. 2008; 91(4):1510–1518. 

​​3 Ernst, J.V., H. Ciordia and J.A. Stuedeman (1984): Coccidia in cows and calves on pasture in north Georgia (USA). Vet. Parasitol. 15, 213-221. ​

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