ENTERIC PATHOGENS IN INTENSIVELY REARED VEAL CALVES

Observations were made on development of diarrhea in special-fed calve s (n = 460) on 8 commercial facilities during 2 successive 16-week pro duction cycles at weeks 0, 2, 4, 8, 12 and 16. A total of 23% were aff ected, with peak number of calves with diarrhea observed at week 0. Su spected enteropathogens were identified in 86% of these calves, most c ommonly cryptosporidia, coronavirus, and rotavirus. Identified potenti al zoonotic pathogens included Giardia and Salmonella spp and verotoxi genic Escherichia coli. Noncytopathic bovine viral diarrhea virus was isolated from 6 calves that had repeated bouts of illness. Only 22% of calves entering the veal facilities had adequate transfer of passive immunity. At week 0, serum IgG concentration in calves that subsequent ly died or had diarrhea was lower (P < 0.001) than that in healthy cal ves. All calves that died (n = 6) during the first 4 weeks of producti on had complete failure of transfer of passive immunity.