Had a couple of dairy cross cows end up looking like that usually found they were feeding more than one calf I usually move them up into another paddock near the house drench and feed them up for a few weeks if they dont start to improve its time for the vet or the knackers
Good looking calf. I try to keep the cows condition up, but my purpose for the cows is for them to produce calves. So if they produce a good calf year after year then I keep them, no matter what they look like. If they look great and don't produce an annual calf then they are useless.
I have Murray Greys, too. When mine start dropping weight I make sure they have 2+ good flakes of grass hay morning and night; mine usually get grain as well, which helps a ton. Make sure she gets minerals (loose if possible) and that the other cows are letting her eat.