You would need about 8500 mg of flax oil per oz of ground flax seed.  If you can find it, might be easier to do liquid flax seed oil.  Another alternative which she would probably not object to is just using whole flax seed instead of ground.

Ground/milled flax is stable for around 6 months, although some claim up to almost 2 years.  Horses are probably much better at picking up off tastes from oxidized fats then we are and that will make them refuse the product. Of course, if it smells even remotely "off" to you, don't feed it.

Eleanor in PA
www.drkellon.com
EC Co-owner
Feb 2001