Milking a cow on Shabbos, Why not?

Milking a cow on Shabbos,

Why not?

6 different reasons, probably no other מלאכה,  has

a six way מחלוקה to which אב מלאכה it belongs to.

1.      מפרק(דש)        Rashi, Shabbos 95a

2.             קוצר         Yerushalmi, Shabbos 7 :Hl. 2

3.            ממחק       Tosfos, Shabbos 73b

4.             בורר         Rashbo, Shabbos 144b

5.             טוחן         Yeraim, # 274

6.              גוזז          Tosfos Rosh, Shabbos 95a