Do female dogs have menstrual cycles?

the dogs reproductive cycle breaks down into four parts proestrus, estrus,diestrus, and anestrus. proestrus last about 9 days and is characterized by an attractiveness to male dogs but will not allow mating. the vulva may also appear red and swollen and may bleed. estrus is the period in which a femal dog will allow mating the vulvular swelling may decrease slightly and the bloody discharge may become yellow.this should also last about 9 days. this is the actual ovulation part of the cycle the dog will expirence a spike in certain hormone which will signal the release of eggs which will take 2-4 days to mature once relased. the period of fertility if 4 to 8 days after the lh hormone spike which can be determined by your veterinarian. the next phase is diestrus can last up to 57 days and is signified by an increase in progerstrone this will be the pregnancy if the dog is sucessfully bred. . after diestrus the dog will enter anestrous for a period of 90 to 150 days singnified by a reduction in hormones until the process starts again. the first to phases are the visible ones refered to as heat.