Improving control of IB 
variants in layers and breeders

The ever-changing nature of IB variants continuously challenges the ability to control them. Careful use of two already available genetically different live-attenuated vaccines and an inactivated vaccine containing two different antigens might improve protection against most, if not all, the IB variants emerging worldwide. By Jane K. A. Cook, Consultant Microbiologist, MSD Animal Health Infectious bronchitis (IB) continues to be one of the most important diseases of chickens of all ages worldwid