The Vet-Kem Ovicollar for Dogs is designed to prevent flea population build up in your home by killing flea eggs before they hatch. The ovicidal activity of Precor Insect Growth Regulator, the active ingredient used in the Vet-Kem Ovicollar for Dogs, effectively breaks the flea life cycle by killing flea eggs laid on your dog for up to 8 months. With Precor® Insect Growth Regulator (IGR) and Integral Buckle.