Thanks to all who replied!!
I ordered a month’s supply of the granules last night from Allivet. (Lowest price & free shipping) So we’ll see.
His recent history does NOT include: diarrhea, loss of appetite, colic*, drastic changes in diet, or changes in environment. Teeth are checked whenever the vet comes & floated when necessary. Wormed twice a year (now). This year, blood work revealed a very early case of Cushings and IR (IR has been on and off for the past 10 years, dependent on who-knows-what). Has recurring rain rot. Needs to have his horse buddies in the very next stall to prevent anxiety.
Not exactly low maintenance. :rolleyes:
*A couple of years ago, he had several severe colics. Increased salt saved his life. Seems to have a higher salt requirement than other horses.