After hunting down something solid to reference for half an hour, I thought I'd just ask! Anyone know of any research I can point to?
I don't have anything with an exact time quote, but the American Academy of Pediatrics' Policy Statement on Breastfeeding states that "The alert, healthy newborn infant is capable of latching on to a breast without specific assistance within the first hour after birth. Dry the infant, assign Apgar scores, and perform the initial physical assessment while the infant is with the mother. The mother is an optimal heat source for the infant. Delay weighing, measuring, bathing, needle-sticks, and eye prophylaxis until after the first feeding is completed."
The whole Policy Statement is here: http://aappolicy.aappublications.org/cgi/content/full/pediatrics;115/2/496
Hope that helps!