Newborn pigs in 86 litters were offered drinking water from four types of dispenser to determine how quickly each design would be discovered. On average piglets discovered water within about 24 h from an exposed water surface (bowl or cup), whereas discovery time was delayed to more than 72 h with nipple or push-lever dispensers. A prototype dispenser with a wide bowl and continuous bubbling action reduced (P < 0.05) average discovery time to about 14 h.
Phillips, P. A., & Fraser, D. (1991). Discovery of selected water dispensers by newborn pigs. Canadian Journal of Animal Science, 71(1), 233-236.