"No matter which region you live in, the idea behind an annual larvicidal treatment is the same: to rid your horse of as many internal parasites as possible at least once a year, and then follow up with regular parasite control every 6-8 weeks. The benefits of a larvicidal treatment using the Panacur Powerpac will become apparent about four weeks after you complete the treatment. Your horse's coat will probably look shinier. It may ""fill out"" and act like it just feels better. And no matter what kind of rider you are, you'll notice a difference in your horse's performance and willingness to work."