Cryptosporidiosis as a Probable Factor in Neonatal Diarrhea of Calves

Abstract

SUMMARY Enteric Cryptosporidial infections were found in 8 of 23 neonatal calves with diarrhea. Infected calves were from 4 of 7 herds in which neonatal diarrhea had been a problem. Cryptosporidia were not found in 18 clinically normal calves from these same 7 herds. The infection persisted in 1 of the 4 affected herds for at least 10 months, and in at least 1 herd, was accompanied by rotavirus and Coronavirus infections. Cryptosporidiosis was transmitted (along with rotavirus and Coronavirus infections) to colostrum-deprived neonatal calves via gavage with scrapings of infected ileal mucosa. Cryptosporidia were demonstrated microscopically in Giemsa-stained smears of feces and ileal scrapings from infected calves. In autolyzed specimens, the parasites were demonstrable by such smears when they were no longer demonstrable by histologic sections of intestine. It was impossible to draw firm conclusions as to whether Cryptosporidia were responsible (solely or partially) for the diarrhea that occurred in infected calves. However, it was recommended that: (1) Cryptosporidia be regarded as common enteric pathogens of calves; (2) diagnosis be based on finding the organism on Giemsa-stained smears of feces or scrapings of ileal mucosa, supplemented when possible by histologic examination of ileum fixed in formalin immediately after death; and (3) treatment and control measures be those used for other coccidian parasites of calves.