Good afternoon Alan, a further thought on this place-name prompted by Borgue’s proximity to the Isle of Man. In Manx Gaelic there is (or was) apparently a word maase which means ‘cattle’ and which is incorporated in the place-name Ballavaase ‘Cattle Farm’ apparently where cattle for Peel Castle garrison were kept before slaughter. Moore mentions this on p192 of The Surnames and Place-Names of the Isle of Man. However Broderick does not seem to mention this farm but has Ballavaish which might be the same place (my Manx geography knowledge is shaky!) and he says this derives from Balley y vaaish ‘farm of/on the precipice, steep sided hill’ cf Ir baitheas/baithis ‘crown of the head, pate’. He also says màs, buttock is possible however. He does not mention the supposed Manx Gaelic word maase, cattle, anywhere in his volumes.