Ubisi into esamanzi akhiqizwa ngama-mammary glands atholakala ezilwaneni ezingama-mammals. Lokhu kuwukudla kokuqala kwezilwanyana nezingane ngaphambi kokwazi ukudla okunye ukudla. Ubusi lokuqala olubizwa ngokuthi yi-lactation luqukethe i-colustrum, elihambisa ama-antibodies kamama aye enganeni futhi lokhu kungehlisa ubungozi bezifo eziningi enganeni. Le-athikhili iyisigcino (isiNgisi: "a stub"). Ungakwazi ukusiza uWikipedia: ngokuyikhulisa.