Veterinary Technician Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Both puppies and kittens can start heartworm-preventative therapy at 8 weeks of age. This timing is significant because by this age, young animals are generally large enough to safely tolerate preventative medications, and it is important to begin heartworm prevention early to effectively protect them from the disease.

Starting heartworm preventative therapy at 8 weeks helps ensure that pets are shielded from the risk of heartworm disease as they grow. Heartworm disease is serious and can lead to severe health issues, so initiating prevention at this age is a proactive measure to safeguard their health as they become more active and spend time outdoors, which increases their exposure to mosquitoes that transmit heartworm larvae.

As for the other options, starting heartworm prevention earlier than 8 weeks may not be safe or effective, as younger animals may not have the size or digestive maturity to properly handle the medication. Waiting until 12 weeks or 6 months, while potentially safe, delays necessary prevention, thereby increasing the risk of heartworm exposure during a pet's developmental period.