Understanding the canine estrous cycle

Understanding the canine estrous cycle

Learning about all three stages of the canine estrous cycle is an important prerequisite to becoming a successful dog breeder.

As a dog breeder, understanding the canine estrous cycle isn’t just important – it’s essential! The cycle consists of three stages: proestrus, estrus, and diestrus, each lasting about two to three weeks. Let’s take a closer look at each stage and break down what to expect in each.

When does the cycle begin?

When young female dogs first begin to cycle, it’s normal for them to be irregular at first. In fact, it can take up to two years for a female dog to develop a regular cycle. Depending on the size of the dog, her first heat will occur between six and 15 months of age, with larger dogs experiencing their first heat later than smaller dogs. Most dogs come into heat twice per year, although the interval also varies depending on the dog’s size. Smaller dogs may cycle three times per year while giant breed dogs may only cycle once every 12 months.

The proestrus stage

The proestrus stage lasts approximately nine days with a range of three to 17 days. It is first indicated by a bloody discharge from the vulva. During this stage the female may become aggressive toward male dogs.

The estrus stage

The estrus stage comes next and lasts approximately nine days with a range of three to 18 days. In order to be considered “normal”, the total time of proestrus and estrus should not exceed 21 days.

The first sign of estrus is the female’s willingness to accept a male through “flagging” – standing with the rear legs firmly placed and the tail lifted over her back.

The diestrus stage

Diestrus is the final stage of the canine estrous cycle and lasts approximately 60 days. The difference between estrus and diestrus is indistinguishable.

The benefits measuring progesterone

If you are a breeder, it’s important to know when ovulation occurs in your breeding dog. One of the most accurate ways to determine the onset of ovulation is by measuring progesterone levels. Ovulation occurs when progesterone blood levels reach 5-6ng/ml.

In order to determine this, tests need to be done regularly before and during the estrous cycle. At-home test kits allow breeders to immediately track what stage their dogs are at, which saves multiple costly vet visits and expedites the progesterone testing process.