At an Animal Control Hearing earlier this month Mrs Gibbs and Mary Phillips, president of the Wairarapa Kennel Association, appealed the classification.
Under the Dog Control Act 1996 a dog classified as menacing must be controlled by a muzzle and leash in public. Failure to comply with this can lead to the dog being seized, and in some cases put down.
The Hearing Committee informed Mrs Gibbs on July 24 that the decision had been made to uphold the classification.
Mrs Gibbs said Bailey would now wear a muzzle "for her own protection" and others but that she could still participate in dog shows without wearing the muzzle.
She did not want to comment further.
Masterton district councillor Jonathan Hooker said while there had been no question of Mrs Gibbs' ability to manage dogs, the decision was made purely because of concerns over the dog's behaviour.
Mr Hooker said although Bailey will not have to wear a muzzle in private, Mrs Gibbs will face the same responsibility and consequences if the dog bites anyone without its muzzle on, in private.