If ewes have not had a bionic capsule or boost of B12 pre-lambing there is a possibility that lambs could end up with depleted B12 levels by weaning time. We don’t routinely test for B12 levels in pre-weaned lambs, but I have found some ewes with marginal to deficient levels of B12 at pre-lamb. It therefore may be of benefit to top-up B12 levels at tailing in lambs before they become deficient.
A 0.5ml dose of smart shot can elevate B12 levels for ~3 months. Smart shot users seem to keep coming back to it and it is the only serious way to correct low B12/cobalt issues. Short acting B12 can be useful for maximizing weaning drafts if B12 levels are low.