One of the most effective methods of preventing ticks on dogs is to use a tick-repelling chemical, according to the Centers for Disease Control and Prevention. These often take the form of pyrethroids and are applied topically.
A popular form of tick-repelling chemical is a once-a-month topical repellent, explains Doctors Foster and Smith. These are usually applied in a thin long line along the dog's back and repel ticks for a full 30 days. They do not generally kill ticks, so they do not reduce the number of ticks in the environment. However, they are safe and effective at protecting the treated dog. Other forms of tick repellents include tick collars, sprays, powders and dips, but these need to be reapplied often or may be unsafe for other animals or children who come in contact with the dog.
Environmental control may also help reduce the number of ticks dogs are exposed to, notes WebMD. Dog owners should keep their homes dry and clean, and check their dogs regularly for ticks. If they find one, it should be removed immediately. Homeowners can trim tall grass and clean up leaf litter to help reduce ticks' habitat outside. Limiting the dog's exposure to tick-heavy environments can also help but is not foolproof. Natural methods of tick control generally have limited or short-term efficacy.