The effect of Escherichia coli J5 and modified live Salmonella dublin vaccines in artificially reared neonatal calves.
One thousand neonatal calves, allocated in a factorial design into four groups, were vaccinated subcutaneously with two doses each of either killed Escherichia coli (0111:B4) J5 bacterin or a UC Davis modified live, genetically altered (aro-) Salmonella dublin vaccine, or both, or with a placebo. In this prospective double-blind study to determine the immunogenicity and protective effects of both vaccines on bovine neonates in field conditions, calves were observed daily until 2 months of age, and serum samples from selected study calves were obtained at five different time points. No clinical adverse vaccine reactions were observed. Overall mortality was 7.5% (75 of 1000), E. coli and S. dublin infection being the most commonly associated aetiological agents of deaths. Both J5 (p < 0.01) and Salmonella (p = 0.05) vaccines were significantly effective in reducing the mortality rate but without an additive effect. The role of passive transfer was important in calf survival. The E. coli J5 and (aro-) S. dublin vaccination schedule employed significantly (p < 0.001) elevated J5 and Salmonella-specific serum ELISA antibody titres, respectively, by the sixth week of age.
Selim
S A
SA
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California (UCD), Davis, USA.
Cullor
J S
JS
Smith
B P
BP
Blanchard
P
P
Farver
T B
TB
Hoffman
R
R
Dilling
G
G
Roden
L D
LD
Wilgenburg
B
B
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000276:immunology*; D002417:Cattle; D002423:Cause of Death; D004311:Double-Blind Method; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology*; D011446:Prospective Studies; D012475:Salmonella / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary*
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines