Simply because they are thin does not mean they are lacking in vitamins or nutrition - it could simply be a sign of not getting enough feed. Conversely, it could also be a sign of a more serious underlying condition than simply lacking vitamins. I believe I would be very careful about how I went about giving vitamin A & D shots to cattle that are now grazing, or are on good quality hay. Both of these vitamins are oil soluble - as opposed to Vitamin C, which is water soluble, and any excess is eliminated from the body - which means that both A & D can build up to toxic levels under the right circumstances. You would probably be much farther ahead to slowly build them up on a high quality hay/forage, perhaps with a little grain mixed in, and good loose mineral until they are back at their proper weight. If that doesn't do it, call your vet and find out why.
