Even though there is alfalfa, and alfalfa isn't generally recommended for adult pet rabbits due to the higher protein and calcium content, the amount used as an ingredient in those pellets doesn't raise the protein too high (12.5%). The calcium max is on the higher end though (1.2%), compared to some other brands, so I'd feed a reduced amount of the Select, than if feeding a lower calcium pellet (0.75% max), along with feeding a good quality free fed grass hay. And if feeding a bladder sludge prone bun, probably a different lower calcium pellet would be better, if pellets can be fed at all.
Science select is a good brand, and the adult food is adequate when too much isn't fed. It's not necessarily that alfalfa as an ingredient is bad for adult pet rabbits, it's the amount that's fed that can create issues with the kidneys, bladder, and with weight gain. So if a reduced amount is fed, it will reduce the potential issues higher protein and calcium can create. Science Selects House Rabbit and Grain Free pellets have slightly lower calcium levels, which is better in my opinion.
