Cows are very smart because once they feed the calf they move away from the area so they don't bring attention to the calf. Feeding newborn calves can be one of the most fun jobs on the farm. At least that is what I think. I feed all of the calves born on the farm milk from a calf bottle as soon as they are able to drink. I always make sure the first milk a newborn calf drinks comes from it's mother for a very good reason.
Calves require milk from their mother because of the colostrum which their mother's milk contains.
Drinking their mother's colostrum ensures that a calf will have a greater resistance to disease it may come in contact with. I always keep some spare colostrum on hand in case something happens to a cow and need some for the orphan calf to drink. By doing this I make sure the calf at least has a chance at survival. When it comes to drinking from a calf bottle some calves are fast drinkers who seem to engulf the contents of the whole bottle with one swallow. While other calves seem to take their own sweet slow time drinking the contents of the bottle.