I have a set of twins that must have some genetic defect that makes them look at their dams udder, think about nursing, then say "ehh, what's the point?" The dam is wonderful mother, has done well in the past here. She has a beautiful udder, lots of milk, contiunually talking to her lambs, stands still so they can nurse. I have been tubing them for 3+ days with her colostrum / milk / and some sav-a-lamb. They even have a heat lamp at night

. Yesterday I tried putting a little oral vit B in too, not much difference today.
Any other tricks to get lambs to nurse, or are these destined for the compost pile? We had a cold rainy snap last week and I've saved 12+ other lambs that were practically dead from the cold. These 2 have me perplexed, as they were born on pasture on a beautiful day.