Which Sefer or Sefarim is/are used in practical application of Shechita? General Halacha follows the שלחן ערוך, but does it in all areas?
In America, the custom is as the custom of Europe -- to use the sefer שמלה חדשה, written by Rabbi Alexander Sender Schor (1673-1737), even though on occasion he will disagree with the שלחן ערוך. Rabbi Schor also wrote תבואת שור (an explanation to Simlah Chadasha) and בכור שור, a commentary on Shas.
(see מטה אשר [commentary to שמלה חדשה] in 1:4, especially what he quotes from the דרכי תשובה)
I had heard that the custom in Israel is to use the בית דוד, though some commenters on this answer had heard otherwise.