For the 12 plus calf at side, what are you giving quantity wise every 3 days in summer for cubes? Weight that is?
For fiber ( of appropriate length) - if you have no pasture, what else do they get in spring/ summer/ fall besides protein cubes? Or is it just poor standing forage you are using as fiber fill and fixing protein with cubes?
I don't aim for fat cows unless mine are on good pasture or I'm finishing them. I want them great going into winter after breeding at 60 -90 days post calving, and then feed them well for sure last 2-3 months before calving, but I expect them to lose some condition at some point - if you have fat cows year round, they are getting way more than they need. I don't like ribs, but fat cows are costing me unless i have excess forage. I want good rumen fill though and some condition because mine deal with -30 and high winds with no shelter ( no trees here).
Mine get 3 cycles to breed back and are culled if they come into heat again. Id consider cutting back more on cubes after they are bred back and calves weaned.
I don't have feeders that make protein cubes doable. Cubes here are $15 bag right now, alfalfa hay is $100-150 for 1500 lbs. Even bad alfalfa here is 14-16% protein and when I only need 2-6 lbs per cow it's 1/3rd cost of any cubes. Anything they don't eat is fertilizer on the pasture and contributes to their fiber requirements. At that price, I can feed them six to 24 pounds a day and it becomes equal to the price of protein cubes, and I tell you a cow on Hay versus a cow on cubes and corn stalks there's a big difference.
There's also a lot more nuances to feeding stalls than hay which is more than protein, energy and fiber. I've seen more issues here with calving and deficiencies on stalks green feed ( oats, etc baled for feed) and cubes than on forages. Not that it can't be done, but there's extra in hay that we can't always make up in cubes
Maybe it's not financially doable, but. I'm doing one can't go wrong with 2-5 lbs hay