TB costs- depends on what frequency your area is on testing but your compulsory test is covered by the ministry but any pre movement tests covered by yourself (only needed if sending to market in store ring or selling live to another farm, not needed for fat ring or direct to slaughter). Vaccinations unless you have a problem you probably don't need to vaccinate- we vaccinated one year for rotavirus as had problems with it. Buying in calves though comes with risks associated with herd health- johnes, ibr, crypto, bvd, all big issues that can be brought in with calves. Probably go on 1 cow eating a small bale of hay per day if in but obviously this depends on the size of cow too. Worming also depends on fluke risk area, but be aware that wormers and pour ons come in large quantities so maybe best to find a neighbour that you can share with. Dairy bull calves are cheap for a reason and take a long time to finish, you would be better off buying a beef x breed in my opinion or even just sticking with 1 cow rearing 1 good calf.