An improved nipple for feeding liquids to newborn and young bovine calves and other mammals. A horizontal flat portion of an upper end of the nipple has a downward curving periphery that merges into a vertical portion of a barrel at an exterior radius of 9 to 10 mm and an interior radius of 6.5 to 7.5 mm. The thickness of a wall of the upper end of the nipple is between 5 and 10% less than the thickness of the wall of the barrel. The flat portion of the upper end of the nipple 1 has a diameter in the range of 5 to 7 mm, which is about 20 to 25% of the inner diameter of the barrel. A bump-out may be formed on a base of the nipple to aid in removing and replacing the nipple on a bottle.
