What the Heck Is low starch forage replacer?

https://storyvergey.com/s/vK99pSofpILGebpk5jJ4-

Gentle horse feed for sensitive stomachs, designed to support comfortable digestion, hindgut health and better nutrient absorption. A low-starch fibre-rich formula with naturally sourced ingredients to help maintain calm digestion and general wellbeing.