We use the Ivomec injectable  (for cattle), draw it into a syringe, and inject the contents of this syringe into a big one with no needle on it that has 10 or 15 cc's of pancake sypup already in it. Some of the horses (once they're used to it) will actually suck it out of the syringe.

Every three or four months.... more often if they are on short grass, less if grass is tall or ground is white. Or I forget    or procrastinate....   :wink: