Enlighten me, please..

Could some one please, please tell me what a milk sausage is? My understanding of sausage is that it is a meat preparation. H had a breakfast somewhere where this lady brought in this heavenly breakfast casserole. H *asked* her for the recipe! I could not believe myself that he actually did! It is so unlike him to care for trivial(according to him, not me) things like food. The recipe calls for “1 cup sausage (milk)”. Could someone tell me what that is?