Re: Success syringing metformin
My horse did the same thing with his flax that your horse did. He suddenly refused anything with flax it in it. He started eating it again when I bought bulk flax seeds from the feed store that I grind fresh myself. I can only think that the "fresh" ground packaged flax (it was human grade) that I had previously fed must have been off. They are far more sensitive to smell and taste than we are. Now my horse happily eats his bucket of supplements with a cup of ground flax 2x per day.
It's worth a shot to try and it is much, much cheaper. Good luck, I hope it works! (fingers crossed on the blood work for your mare - and curb chain jingles for luck!)
Joy and Willie (PPID/IR)
Nevada County, CA - 2019
Case history: https://ecir.groups.io/g/CaseHistory/files/Joy%20and%20Willie
Willie's photo album: https://ecir.groups.io/g/CaseHistory/album?id=242526