Prevention of Ovine Respiratory Complex in lambs based on vaccination

Abstract

Vaccination programs against Ovine Respiratory Complex (ORC) in lambs should be accompanied by non-specific preventive measure, e.g., establishment of proper management and husbandry conditions. Implementing a vaccination plan against ORC requires: involvement of all farm staff, recording data, a positive cost:benefit analysis and continuous monitoring over time. Licensed vaccines for sheep are only against Mannheimia haemolytica (MH), Bibersteinia trehalosi (BT) and Pasteurella multocida (PM). According to the antigens contained in the MH vaccines, these can be divided into outer membrane protein vaccines (OmpA), leucotoxoid vaccines (LKT) and iron regulated protein vaccines (IROMP). Each serotype of MH or BT presents differences in these three antigens, although in the case of IROMP, there is an effective cross protection among them. In addition, strains of bovine origin do not protect sheep and vice versa. For PM, vaccines containing bacteria grown in iron restricted conditions give better results. The lambs should be vaccinated during the first week of life followed by a booster dose three weeks apart. The best results are obtained with LKT vaccines, when the serotype that is present in the farm is included in the vaccine, or with IROMP, which can be applied in any situation. © 2019 Elsevier B.V.