Force-feeding is also known as gavage, from a French word meaning "to gorge". This term specifically refers to force-feeding of geese and young cattle in order to fatten their livers in the production of foie gras and veal respectively. Gavage can also refer to the practice of administering liquids (such as medicines) to laboratory animals via a tube or syringe.
Force-feeding of birds is practiced mostly on geese or male Mulard ducks, a Muscovy/Pekin hybrid. Preparation for gavage usually begins 4-5 months before slaughter. For geese, after an initial free-range period and treatment to assist in esophagus dilation (eating grass, for example), the force-feeding commences. Gavage is performed 2—4 times a day for 2-5 weeks, depending on the size of the fowl, using a funnel attached to a slim metal or plastic feeding tube inserted into the bird'sthroat to deposit the food into the storage area in the esophagus. A grain mash, usually maize mixed with fats and vitamin supplements, is the feed of choice. Waterfowl are suited to the tube method due to a nonexistant gag-reflex and extremely flexible esophagi, so unlike other fowl such as chickens, gavage may be practiced with minimal discomfort for the bird. These migratory waterfowl are also ideal for gavage because of their natural ability to gain large amounts of weight in short periods of time before cold seasons. For this reason, gavage is usually a "finishing" stage before the bird is set for slaughter, for if left to its own devices after finishing, the bird will quickly return to its normal weight. The result of this practice is an severely enlarged, especially fatty liver, when if especially exaggerated is the liver disease hepatic lipidosis. The liver may swell up to 12 times its normal size (up to three pounds). While the livers are the coveted portions of these birds, the unctuous flesh of fattened geese and ducks as well as their feathers find a market. Due to protests from animal-rights groups against the method of obtaining these enlarged livers, gavage is outlawed in United Kingdom, Germany, the Czech Republic, Finland, Luxembourg, Norway, Poland, Sweden, Switzerland, Denmark and Israel, as well as in some, but not all, USA states. The USA's most recent ban on foie gras was in Chicago, Illinois.