Buy Heartgard Plus Brown for Large Dogs 51-100 lbs Online Heartgard Plus Brown for Large Dogs is multi-worming protection for 6 weeks and older puppies and dogs that weigh between 51-100 lbs. save up to 50% + Extra 5% off by choosing the auto-order feature. Additionally, BudgetPetWorld offers FREE SHIPPING on all orders, regardless of size or number. Wow, that's a deal!