My gelding Odin with EMS is a notoriously picky eater with a history of ulcers and colitis.
When I started him on Metformin he was feeling poorly (reaction to Exceed antiobiotic and his insulin wasn’t very well controlled yet). I tried syringing with milk of magnesia as recommended and he hated it.
We started him on doxycycline, started his ulcer meds, increased his Prascend, waited about 6 days, and then I tried again, grinding the Metformin very fine and mixing it in with the Stabul 1 banana flavor pellets, some salt, and plenty of water.
Now he’s happily slurping that mix down and the med is getting in.
I think he wasn’t doing well with the attempt to administer Metformin at first because he was feeling poorly overall; I’ve heard Dr. Kellond mention that that can often put them off feed/meds.
Not sure if that helps for you or not but maybe check the other levels for your horse, tweak anything if needed then try the Metformin in feed/water?
Good luck! It can be such a challenge to figure out what works for them!
+ Odin (2010 BLM Mustang Gelding - IR, dx 2022), Bella (2008 BLM Mustang Mare - PPID/Cushings dx 2000) + Fiki (2015 Arabian, ok so far!)
Odin and Bella Case Histories