Ditto what everyone else said but here's my question:
Has this horse always been fed bagged feed, when she starts holding water or will she swell up on plain corn (don't feed her oats as somebody else mentioned).
If she's being fed bagged feed, 99.9% of all horse feed uses soy for a protein source. It is not uncommon to have a horse with soy intolerance
. I have one and his reaction is that he gets mean & ugly if he eats soy. He also has intolerance to oats & corn.
My point is trying feeding this horse something that is soy-free AND grain-free, yet will still give her the needed vitamins/minerals.
1. EquiPride Horse equine ? EquiPride and EquiLix
2. McCauley's 10% Balancer McCauley'sŪ M10 Balancer
3. A liquid vitamin and use either pelleted beet pulp or equine rice bran as a carrier; rice bran is 22% fat but my grain-intolerant horse handles it just fine. Tuttle's Horse Care Products - Y-Tex Corporation
4. I would get rid of the alfalfa and stick to a good quality mixed grass hay.
Along with having a oat/corn/soy intolerant horse, I also have two horses with metabolic issues. One is a hard keeper the other an air fern. These options are how I feed my three
Hope this helps:)