The estrus cycle or say the dog heat cycle can be divided into four stages so that the time to breed can be known easily for most effective breeding as well as prevention of unwanted pregnancy.
The first stage is the Proestrus Cycle during which the dog is infertile. But it should be kept in mind that the male sperm can live for several days, so it is necessary to have the dam wear a diaper or pants to avoid unwanted mating. This stage duration varies in different breeds from 4-20 days but the average is 7-10 days. There are three signs of dog coming into heat at this stage that are
Swollen Vulva This is one of the superlative ways to find out the beginning of heat cycle. The swelling has been defined earlier in detail. The dam’s nipples may swell slightly but this is not a best indicator of proestrus stage and might be tricky.
Discharge The dam starts having a bright red discharge and might suddenly start licking herself too often. Wipe her vulva with the help of a tissue. The bright red discharge on top of her swollen vulva is a pretty good indicator that that the dog is certainly coming into heat. It is rather important that one checks this, as timing is entirety when it comes to mating or rather preventing a mating of the dog. The first day that the dog starts having the bloody discharge is called “DAY 1”.
Suitors this part of the proestrus cycle will not be found on the owner’s dog, but in the presence of other dogs. There might be some neighbour dogs hanging out around the owner’s house. The reason is that they can smell the female’s heat cycle. The dam will be seen tucking her tail often, protecting herself, as she is not ready to accept a dam at this stage.
The second stage is the Estrus Stage that lasts from 5-14 days usually and shows the time when the dog is fertile. This is the stage when discharge changes colour from bright red to yellow or pink that occurs usually at day 8 or 9 since the dog has come into heat. Now the dog is ready to accept a sire by switching her tail to one side and wanting to be outside more than the normal days. Here, she is following the natural instinct to breed. Take care that the dam is kept mostly inside to prevent undesired mating and don’t take her to dog parks or dog markets in order to avoid causing trouble.
Next is the Diestrus stage of the heat cycle that mostly flinches at around day 24 and can last from 60-90 days depending on the dog specie. The dam is no longer fertile at this stage and the discharge changes from the straw or pinkish colour to the red colour again and then stops eventually. Yet, the smell is there and male dogs can be attracted to the dam so one should wait until the discharge has stopped completely before taking her to outside places.
Then there is the fourth and last stage called the Anestrus Stage that denotes the end of the dog heat cycle and marks the point when she is back to normal. This stage also lasts for 60-90 days, totalling to almost 6 months by combination of the days of Diestrus stage, after that the entire heat cycle starts again. The point to be noted at all stages is to have the pet under the supervision all the times so as to avoid any breeding problems or pregnancy issues.