Mucosal immune responses in peri-parturient dairy cattle.

The objectives of this study were to evaluate mucosal immune responses in peripartum Holstein cows, to assess the impact of intranasal modified live viral (MLV) vaccination on mucosal immunity, and to explore the relationship between genotype and peripartum immune responses. Eighty multiparous Holstein cows were randomized to receive either: 1) intranasal MLV tri-valent viral vaccine 18-24 days prior to expected calving (DC); 2) the same vaccine within twelve hours after parturition (F); 3) vaccine at both time points (DCF), or 4) no vaccine (CON). Nasal secretions and sera were collected from all cattle pre-vaccination and on multiple days before and after calving to determine concentrations of interferon beta (IFN-beta) and IFN-gamma and bovine herpesvirus-1 (BHV-1-) and bovine respiratory syncytial virus (BRSV-) specific IgA in nasal secretions, and BHV-1 and BRSV serum neutralizing (SN) titers. Cows were genotyped by bead-based microarray, genotypes were used to categorize previously established health traits, and relationships between immune responses and genotype were evaluated. There was no significant effect of vaccination on immune responses, although all vaccinated groups demonstrated numerically increased IFN-gamma within four days post vaccination. There was a significant (P <0.0001) time effect on nasal IgA in CON, F, and DCF groups, with the highest nasal IgA titers measured post calving. There was a significant (P <0.0001) time effect on nasal IFN-beta in all groups. Significant relationships between genotype and immune response were not detected. Contrary to previous reports of systemic immunosuppression, bovine mucosal responses appear to be intact in the peripartum period.