Field study on an intranasal vaccination protocol in veal calves farms

The field trial involved 2,136 animals reared in a veal calves operation located in the Po Valley. Calves were randomly allocated in two groups (A and B). Group A (1,087 calves) was immunized with a live-combo vaccine to BRS and PI-3 viruses (Rispoval RS+PI3 IntraNasal - Zoetis) administered intranasally 10 days post-arrival, in single dose. Group B (1,049 calves) was kept as control, unvaccinated. The animals were followed during the whole fattening period to detect morbidity and mortality rates, the main performances and the quantity of antibiotics for the treatment of infectious diseases, mainly respiratory ones. At the end of the fattening period among the groups A and B, two subgroups (A1 and B1), each of 50 calves were constituted. These animals were followed at the slaughterhouse at detecting and scoring lung lesions (mean lung lesions score). The statistical analysis showed a significant reduction of the mean lung lesion score in vaccinated animals (subgroup A1) in comparison to the controls, kept unvaccinated (subgroup B1). The mean mortality rates were 5.89% in group A vs 6.50% in group B and the morbidity rates were 4,62 in group A vs 6.16 in group B. The mean values regarding the performances detected in group A vs group B were not statistically significant. Regarding the antibiotic use, the vaccinated group showed a reduction of 9% of daily antibiotic treatments in comparison to the control one. This field trial showed that the efficacy of vaccination to control respiratory diseases and to reduce antibiotic use during the growing period in veal calves operation. By and large the adoption of a vaccination protocol to control respiratory diseases by using an early mucosal immunization should be considered a pivotal tool to improve animal health and reduction of antibiotic use in white veal calves operations. However, further studies are necessary to improve vaccination protocols specifically devoted to control respiratory diseases in this kind of bovine meat industry