The key to preventing outbreaks is minimizing heavy fecal contamination of the environment. Corrals, pens, small pastures used year after year with cattle confined for calving, breeding, weaning, etc., are high-risk environments for cattle disease. It helps to keep cattle spread out.

“Many producers confine cattle for calving to allow monitoring. Even if they move pairs out of the maternity trap into a larger pasture when calves are a few days old, the young calves have already picked up oocysts,” Faries says. If a calf nurses a dirty udder or lies in manure and licks himself, he ingests oocysts.

He says one ranch with a chronic problem addressed it by developing two maternity areas, which they alternate for use each year. The “off” year allows dry hot weather to sterilize the pen, leaving it fairly clean for use in alternate years.

“Another risk is congregating cattle in the same feeding area. If you use round bales and never move the feeders, or feed hay on the ground in the same high places in the field, manure builds up,” Faries says. 

Diagnosis of coccidiosis

If a calf has bloody diarrhea, the veterinarian may take a fecal sample and do a flotation test for coccidia. Whether you find them or not, however, doesn’t mean much.

“By the time a calf has diarrhea, it’s almost past the time when that calf is passing a lot of oocysts,” says Joe Dedrickson, Merial field director of veterinary services. A lack of oocysts doesn’t necessarily mean the calf doesn’t have coccidiosis; if he’s had bloody diarrhea for several days, most of the oocysts may already be passed.

“And if we find oocysts, they may not be the cause of the problem,” adds Faries. “Often, coccidiosis is suspected because the test was positive for oocysts. If there are large numbers of a pathogenic type, however, with a history of coccidiosis on the ranch, and an environment optimum for spread, we will probably call it coccidiosis.”