Coccidiosis in Calves
Minimize stress and prevent nutritional and health problems to keep coccidiosis from becoming a problem.
Coccidiosis is an intestinal disease caused by protozoa that calves pick up from the environment. Most cattle encounter these protozoa and develop an immunity, but continue to shed a few oocytes in their feces, which can then contaminate feed or water and be picked up by other cattle. Calves are most vulnerable to developing coccidiosis because they don’t yet have much immunity. If they ingest a high number of protozoa in a dirty environment, they may break with coccidiosis.
James Hawkins, a consultant for Merial located in Jackson, Miss., says cattle eventually develop a good immune response, but it takes time.
“Situations in which we see serious disease with coccidiosis are where young calves are kept in a drylot or small pen rather than on pasture. If there are high numbers of calves in a small area, this makes it worse because contamination is greater,” Hawkins says. “People who run into problems are usually backgrounders who buy small calves from many sources and put them together — keeping them for 90 days or less and reselling them. Then they buy another group, putting new ones in the same facility.”
The number of coccidia organisms in these facilities builds up to high levels, he explains.
“This parasite is a normal inhabitant of the intestines in healthy animals. We run into problems when calves haven’t had time to develop an immune response and are exposed to high levels of infection,” Hawkins says. “They are most vulnerable when stressed, because stress tends to suppress normal immune response. If calves have already been exposed for a couple months, you would consider them to be immune. Yet, if those animals get highly stressed, they might show signs of coccidiosis.”
Cold weather, wet weather or hot weather can be a stress that hinders their immune system. Nutritional stress can also be a factor, as many cattle experienced during the last several years of drought in many parts of the country.
“We’ve seen more problems in young cattle coming from drought areas,” he observes, adding that during the past 12 years or so, there have been more problems with coccidiosis in pastured cattle, which normally wouldn’t be expected.
“If you see coccidiosis in a group of calves, there is usually something else causing them to be more vulnerable, either severe stress, parasites or some other disease,” Hawkins says. “Taking a group of calves off the cows, shipping them somewhere else and introducing them to a bunch of other calves from different places is enough stress to throw them into a problem.”
Hawkins emphasizes that is why producers need to take care of “everything else” healthwise.
“We need good parasite control, a good vaccination program, and make sure calves have good nutrition,” he advises. “When shipping calves or putting a bunch together, you don’t want them to get dehydrated or to go without food too long. All these little things can add up to trouble.”
Editor’s Note: Heather Smith Thomas is a freelancer and cattlewoman from Salmon, Idaho.