Vented liner (10) for milking plants comprising a head (14) incorporating an orifice (19) constituting the mouthpiece for the teat (18) of the animal being milked, a body (15) comprising the central portion of the vented liner (10) in which the teat (18) is housed during milking, a milk tube (16) comprising the portion of vented liner (10) located opposite the head (14), an insert (20) which can be inserted within the head (14) of the vented liner (10), the said insert (20) comprising a shaft (23), a head of the insert (22) connected to the shaft (23) and a through-hole (26) made longitudinally in the shaft (23) and passing through the head of the insert (22) and the shaft (23) to allow a controlled constant inflow of air into the head (14) of the vented liner (10), a thread (24) capable of being screwed onto the head (14) of the vented liner (10) penetrating the rubber of which the liner is made being provided in the shaft (23), and/or the through-hole (26) comprising an upper portion (28) of constant diameter provided alongside the head of insert (22) and a lower divergent portion (29) provided in the shaft (23) in order to make the through-hole (26) self-cleaning.L'invention concerne un manchon trayeur aéré (10) pour installations de traite, comprenant une tête (14) incorporant un orifice (19) constituant l'embout pour la mamelle (18) de l'animal en cours de traite, un corps (15) comprenant la partie centrale du manchon trayeur aéré (10) dans laquelle la mamelle (18) est logée pendant la traite, un tube à lait (16) comprenant la partie de manchon trayeur aéré (10) située à l'opposé de la tête (14), un insert (20) qui peut être inséré dans la tête (14) du manchon trayeur aéré (10), ledit insert (20) comprenant une tige (23), une tête de l'insert (22) reliée à la tige (23) et un trou traversant (26) réalisé longitudinalement dans la tige (23) et passant à travers la tête de l'insert (22) et la tige (23) pour permettre un flux d'entrée constant contrôlé d'air dans l
