I agree with ffamom. if you're in doubt if it has nursed, I would try to get something down it ASAP. if she'll let you, it would be good to get the colostrum milked out of the cow and fed to the calf. If she won't let you milk her, I would go by a local dairy or TSC and get some colostrum and tube feed the calf. Especially with it being small, it can get weak really fast.