During the days your dog is fertile and ready to mate she is likely to tolerate and welcome male approaches more than usual. She may also hold her tail up during encounters or lift her tail to one side to make it easier for males to sniff her back. This is called “flagging.” However, this is not a cast-iron sign. Some females reject being mounted by males, no matter if they are fertile or not. A female which is in estrus or close to being in estrus will often flag even when they are pet or scratched on the backside by their owner. This is often a quick test some breeders may conduct to determine where a female is within her heat cycle. However, it has no true accuracy and some females in full ovulation may not even react to it.
More potty business
Many dogs in heat need to “go” more often than usual. During the fertile days her urine contains pheromones and hormones to attract males. Females will wish to mark their territory in several areas within her boundaries and instinctively feel the need to do so more often than their normal bathroom breaks.
During the different stages of the heat cycle the dog may or may not loose bloody discharge, alternating in color and amount. If you notice blood discharge from the vulva and do not suspect any other health problem, this indeed is a tell-tale sign that your dog is in a heat cycle.
Please note: Because of the very large differences between individuals, the bloody discharge is not necessarily a reliable clue to tell, which stage of her cycle your dog is currently in. It could indicate everything from Proestrus, through Estrus (fertile!) to Diestrus.
*The time spans given in the infographics at the beginning of this essay are only average values, which can vary largely among individuals!
Managing the “mess in the house”
If your dog usually bleeds a lot during her heat, keeping the discharge from spreading may be desired. Besides doggie diapers, in this post you find a great alternative that may be tolerated easier by your dog and also less leaky than many diapers – the dog heat suit.