is it ok to give cows colostrum 
Ok - yes. Useful - not very. Powdered reconstituted colostrum formulated for lambs does a waaaayyy much better job for lambs than colostrum from a cow.
Best = own mum's colostrum
2nd best = another ewe's colostrum from the same farm/flock
3rd best = another ewe's colostrum from a different farm/flock
4th best = Powdered reconstituted colostrum formulated for lambs
5th best (so I hear) = goat's colostrum from the same farm
6th best (ditto) = goat's colostrum from a different farm
8th best = cow's colostrum from the same farm
9th best = cow's colostrum from a different farm
If I don't have ewe's colostrum then I give the powdered reconstituted colostrum formulated for lambs.
Plus, if I think it could use more local antibodies, cow's colostrum from our farm. But I would never give a lamb
just the cow's colostrum.