By day 6 my horse is now hating the idea of me giving her a syringe full gastrogard. I tried mixing it with a little grain, no luck. She absolutely needs it, but I can't seem to get her to take it without a fight. I'm afraid my easy to deworm horse is going to become a nightmare because of having to do gastrogard daily. Any tips? Thanks!

Before or after you give it to her, give her a syringe full of applesauce. That way they associate the syringe with a treat, instead of just something nasty getting shoved down their throat. I use this to teaach my colts to take wormer, and they're all rockstars at it. 

My horses love the taste of it. LOL Its like cinnamon I think. They do make injectable Omeprazole you can give IV as well but then you might be opening up a whole new can of worms. 

You can buy compounded omeprazole powder. It's WAY cheaper and mine eats it without a problem.

Are you escalating the situation? What I mean is: Are you standing there for 10-20 seconds, trying to get her to stand still, get yourself situated, getting the syringe in her mouth, fight, etc?

Or.... do you briskly walk up, confidently grab her halter at the same time you empty the syringe into her mouth, and then pat and walk away, all in about 2 seconds?

There is something to be said about presentation! While good ground manners are still good ground manners, be quick and don't give her any time to think about it or to fret.  Maybe you already are, but that is something to think about if you aren't.