The Specific Immune Response after Vaccination against Neonatal Calf Diarrhoea Differs between Apparent Similar Vaccines in a Case Study

SIMPLE SUMMARY: Neonatal calf diarrhoea (NCD) is a complex, multifactorial disease involving pathogens but also environmental, nutritional and management factors. Enterotoxigenic Escherichia coli (ETEC), rotavirus (BoRV) and coronavirus (BoCV) are the main enteric pathogens involved. NCD is a major health challenge that impacts on farm profitability, calf welfare and antimicrobial usage. Thus, a key part of prevention is optimisation of preventive programs for NCD such as vaccinating cows to increase passive immunity transfer for their offspring during the neonatal period. In this study, it was demonstrated that dam vaccination against NCD is an excellent tool to increase specific immunity; how different vaccines differ in their specific immune response and, consequently, in the amount of specific passive transfer of antibodies to their calves. One of the most relevant findings is the importance of inducing a specific immune response for the three NCD pathogens. ABSTRACT: Neonatal calf diarrhoea (NCD) is a major health challenge with a negative impact on farm profitability, calf welfare and antimicrobial use. Neonatal calves are particularly sensitive to enteric infections. Thus, a key point for prevention is minimising infectious pressure and maximising specific immune responses. An amount of 120 dams not previously vaccinated against NCD were randomly allocated to one of three study groups: negative control versus two vaccinated groups (A and B). In the control group, the average level of antibodies was significantly low for both BoCV and ETEC (15.6 and 13.9% in the colostrum samples, respectively), demonstrating the importance of dam vaccination. Indeed, the level of specific immunity was significantly increased for BoCV and ETEC with dam vaccination using both one-shot vaccines versus the control group. Moreover, the statistical analysis revealed a significantly higher level of antibodies for BoCV and ETEC in colostrum samples in vaccine A versus vaccine B and the control group. In accordance, the calf serum demonstrated a significantly higher level and greater homogeneity of antibodies against BoCV and ETEC in the Vaccine A group versus other experimental groups (p < 0.05). In conclusion, this study demonstrated a different specific immune response for the pathogens depending on the vaccine used to control NCD in cows.