what kind of dog? how old? heat gap is from 6 to 8 months however sometimes abot og 9 and mao sad na common reason na dapat alternate jud ang pagpamabdos da dog. and myt be wlang lang ka kabantay ky naa cal tawag na silent heat nga dli kaau swollen and this should be keep together with the male... and if the damn is older na normal na like humans menopause..heheheh. Im not a vet just have an experience so u may not have to take my word.....