After calling Gaga's song Born This Way "reductive", accusing Gaga of ripping off her hit song Express Yourself, and performing a mashup of the two songs at her MDNA Tour followed up by the chorus of her song She's Not Me, it seems as though Madonna still has a big grudge against Lady Gaga.
In an interview on a Brazilian TV show Madonna said, when asked about Born This Way, “I’m a really big fan of [‘Born This Way’]. I’m glad that I helped Gaga write it.”
Gaga has yet to directly reply to Madonna, but she did however seem to acknowledge Madonna at one of her Born This Way Ball shows when she said, "It sometimes makes people feel better about themselves to put other people down or make fun of them or maybe make a mockery of their work, and that doesn’t make me feel good at all. That just makes me feel like I’m not being a good human being."
Source: http://newsroom.mtv.com/2012/07/24/madonna-lady-gaga-born-this-way-express-yourself-im-glad-that-i-helped-gaga-write-it/