Based on the question and answer brought in the Chaim Ad Olam (by Yaakov Chaim Sofer), we can say two things:
“vehilchoso” is brought to exclude ("לאפוקי") other opinions.
it tells us that this one opinion is an obligation, you don't have two equally valid options.
Rashi (Chulin 49A) says that the Gemara decided what the Halacha was. Meaning, there was an argument, and the last Yeshivot of the Talmudic era decided what the Halacha would be. (It would appear that Rashi holds that this was the Yeshiva of Rav Ashi - see Rashi on the bottom of Sukkot 3B)
See also the Yad Malachai (Rule 252), who brings what the Rosh, Ran, and Ramban say it means. But I didn't look up the sources to get context.
Based on here and here, it appears that there are some who hold that it was the Savuraim who added these Halachic Rulings. This would probably depend on who is credited with finalizing the text of the Talmud (see here and here).