"Macushla" is an Irish song that was copyrighted in 1910, with music by Dermot MacMurrough and lyrics by Josephine V. Rowe.
The title is a transliteration of the Irish mo chuisle meaning "my pulse" as used in the phrase a chuisle mo chroí which means "pulse of my heart", and thus mo chuisle has come to mean "darling" or "sweetheart".
The phrase in its native form was used in the end credits of the 1996 film Michael Collins.
In the 2004 film Million Dollar Baby trainer Frankie has "Mo Chuisle" embroidered on the silks of boxer Maggie Fitzgerald (Hilary Swank) for her first overseas fight, and it is subsequently chanted by the various crowds in the film numerous times.
In the 1945 movie, Christmas in Connecticut, starring Barbara Stanwyck, the cow was called Macushla.