I have a calf that is about 6 days old now, got caught in a cold rain a couple days ago and looked pretty weak. The next day I tubed it and put it in the barn. I saw when it was born it was up and trying to nurse, not sure if it actually got any colostrum. Anyways, got momma tied up and put the calf on a teat, it had no urge at all to suckle, took about 10 minutes to get it to, but it will not pick up the end of the teat on its own, just nuzzles around the bag and suckles on everything else. It is strong enough now while it is out on pasture to walk up and stick it's head into between the hind legs and suckle the vestigal teats, no way it grabs ahold of the big ones. So I am still tubing it twice a day because it sure don't act very strong so I don't think it is getting much milk. How long should I give this calf before I just need to pull it out of pasture and treat it as a bottle calf?