Coccidia are so common in the United States that they can be found in beef and dairy calves from operations of all sizes and in all seasons, including cold winter weather. This means almost all calves are vulnerable to the damaging effects of coccidiosis, especially when the stress of changing weather creates a higher risk for disease. Joe Dedrickson, DVM, Merial, offers these key concepts to battling coccidiosis this winter:

  • Calves from all environments and operations are at risk of developing coccidiosis.
  • The prevalence of coccidiosis infection is usually high, with reports of 100% in calves.
  • Coccidiosis is a stress-induced disease. Stressors included weaning, shipping, putting animals into large groups, changing rations and  —  the most common  —  changing weather.
  • In addition to causing stress, cold weather causes animals to group together, multiplying the risk of infection.
  • Diagnosis of coccidiosis is difficult, and visible signs don’t occur until three to eight weeks after the initial infection. By then, much of the economic damage is already done.
  • Diagnosis by fecal exam may not always be effective because the passage of oocysts, the infective form of coccidia, lags even behind the onset of clinical signs.
  • Prevention must be twofold: Use good animal husbandry measures to prevent ingestion of oocysts by cattle and use a coccidiostat with a prevention and treatment label to combat the disease before it starts.
  • Pay careful attention to maintaining preventive levels for periods long enough to affect the life cycle of coccidia. 
  • If treatment is needed, use a coccidiostat solution product, at the first signs of the disease  —  such as diarrhea and dehydration. Producers should consider treating on a herd basis. Once a calf shows signs of the disease, it is likely the rest of the group has been exposed.
  • Because of the difficulty of identifying the disease before the damage is done, prevention methods are best to help avoid subclinical and clinical incidences of coccidiosis.