A quick change adapter and method for use in intravenous treatment of large animals such as cattle, horses, pigs, goats and the like. A method for changing bottles of fluids used in intravenous (IV) fluid therapy, includes the steps of (a) providing an IV set including a funnel having a connection aperture, the funnel being constructed of elastic material； (b) providing an adapter apparatus comprising a cannular portion adapted for sealing mating with the fluid egress aperture of a fluid bottle and a lip portion adapted for sealing mating with the funnel aperture； (c) coupling the interface apparatus in a semi-permanent fashion to the funnel by inserting the lip portion into the funnel connection aperture； (d) inserting the cannular portion into the fluid egress aperture of the fluid bottle； and (e) inverting the fluid bottle to facilitate the flow of fluid. The adapter for connecting an IV Set to a bottle containing fluid, the IV Set of the type having a flexible funnel with a female-type connection aperture, includes a generally cylindrical body with a fluid flow lumen, the body having a lip disposed at one end adapted for male-type connection to the IV Set connection aperture, the opposing end of the body being adapted for male-type insertion into the fluid egress aperture of the bottle.
