At weaning give a combination worm drench orally or Eclipse E injectable or Eclipse pour-on. Whilst calves are on their mothers' milk based diet internal parasites do not cause many issues but once weaned it is a major handbrake on pasture bases growth rates.
Minerals for weaners: it is hard to go past long acting selenium (Selovin LA) as a way to reliably sustain levels for the next 12 months. Copper is also important. Copacap copper bullets are longer acting, but Coppermax injection is a good alternative going into the winter, especially if wintering on brassicas. Covexin 10 in 1 (or at a minimum Multine 5 in 1) vaccine is well justified at weaning and again 1 month later. These vaccinations are critical if going onto fodderbeet.
Summary Recommendation at weaning: 1 x drench, 1 x mineral (selenium), 1 x vaccine (1st covexin). 5 weeks later: 1 x mineral (copper) 2nd covexin and drench if required.