The Effect of the Husbandry System and Cortisol Status on the Response of Water Buffalo Calves to Vaccination with the Brucella abortus Vaccine RB51

Brucellosis negatively impacts animal and human health and causes major economic losses. The present study examined the relationship of husbandry system (insufficient, acceptable, optimal) and cortisol status on the response of buffalo calves to vaccination with the brucellosis vaccine RB51. Primary vaccination (1st) was at 6 months and secondary vaccination (2nd) at 12 months. Cortisol was ascertained in samples of hair and the antibody response to vaccination was measured in blood. Excretion of the bacterium Brucella abortus was determined in urine and feces. Buffalo calves in the insufficient system had greater (p < 0.05) cortisol (4.7 ± 0.5 pg/mg) at 1st vaccination than calves in the optimal system (2.8 ± 0.3 pg/mg). Cortisol was lower at the 2nd vaccination for all three systems which did not differ. Anti-RB51 antibodies were present in 28/30 buffalo after 2nd vaccination. The conditional R2 of 0.689 indicated that both husbandry system and cortisol status strongly influenced the response to vaccination with RB51. No shedding of Brucella spp. was observed. The study has shown that husbandry system and cortisol status influence the response of buffalo calves to vaccination with RB51.