Corvac-3 is an inactivated oil adjuvant bacterin from Merck Animal Health that protects chickens against infectious coryza caused by Avibacterium paragallinarum serotypes A, B, and C. It is a go to vaccine for flocks facing coryza pressure since cross protection between serotypes is limited.Key Uses Vaccination of healthy chickens 5 weeks of age or older against infectious coryza Broad spectrum coverage of coryza serotypes A, B, and C Given as a 0.5 mL subcutaneous injection in the back of the neck A second dose about 4 weeks after the first, and 3 to 4 weeks before onset of lay, is recommended for lasting protection Administration and Safety NotesDo not vaccinate during the critical egg laying period from onset until peak production, since it may cause a drop in egg output. Merck's label lists a 42 day pre-slaughter interval; always confirm current withdrawal guidance with your veterinarian.
