If feeding a senior feed, then check out those that supply extra calories in the form of fats, not NSC
Many senior feeds are high in fats, as those horses need more calories then the forage alone supplies, but because of metabolic issues, can;t have lots of hot calories, thus are fed cool calories (fats) the fiber in those senior feeds is beet pulp.
Senior feeds around here anyways, are not high in sugars ( grains and molasses ), but rather use cool calories (fats)
Ps, I use the term grain, as what a grain is, and not a slang applied to any hard feed)
Yes, beet pulp is an excellent source of added calories, Modern sugar beet plants are very good at extracting near 100% of the sugar from sugar beets, so that the pellets made form what remains, is a fiber that is very easy to digest, has an energy (calorie value between that of grain and forage, but because it is digested as a forage, has none of the associated risks of feeding NSC, directly in proportion of amount fed.
I use it year round for my IR horse, and any other horse that needed something to mix any additives in.
I do not feed any bagged pre mixed feeds. I feed horses as individuals and add what each horse needs. Thus, horses that are dry lotted, get vit E, flax,(source of Omega 3 ) as both are quickly lost in hay, plus my iR mare also has Magnesium added