Proestrus and Oestrus whats the difference? Number 1. Proestrus
Proestrus is the beginning of the oestrus cycle. This is the time when the bitch starts to attract male dogs although not yet receptive to breeding. As this phase continues, she may become more passive and playful. The vulva becomes moderately turgid and enlarged, and a blood-tinged discharge is present. Over a period of about 4-7 days, the vaginal cytology smears cells change from non-cornified to cornified cells. In other words, the cells change from small parabasal and intermediate cells to anuclear and superficial-intermediate cells. The changes indicate an increase of oestrogen from the follicles in the ovaries. This period lasts for about 9 days on average (a minimum of 3 days and a maximum of 3 weeks) and progresses to the oestrus phase.
Oestrus is what you may be waiting for. Number 2. Oestrus
During this phase, a normal bitch displays passive and receptive behaviour that enable breeding. Physical changes include a decrease in vaginal discharge, vulva becoming flaccid, and vulvar oedema becoming maximal. In this phase, vaginal cytology comprises of 80-100% cornified cells. The phase takes an average of 9 days, whereby receptive behaviour of the bitch increases following an increase of progesterone concentration and decline in oestrogen concentration. However, the duration in which the bitch will be receptive to mate dogs varies. Sometimes, this duration may not even coincide with her fertile period.
What triggers ovulation?
A surge in luteinizing hormone (LH) from the pituitary gland triggers ovulation.
What happens during canine ovulation?
Approximately 2 days after the surge of LH, ovulation of infertile and immature primary eggs (oocytes) begins. This is then followed by oocyte maturity after the next 1-3 days. The fertile (secondary) oocytes have a life span of 2-3 days, which means that the actual fertile period of the bitch is 3 to about 6 or 7 days after the LH surge. The most important breeding aspect from the reproductive cycles is that the flow of LH occurs when the progesterone concentration is initially released. This helps to time ovulation simply by measuring levels of either hormone in the blood.
How can we find out ovulation has occurred?
The timing for ovulation can be conducted using vaginal cytologic exams. Or it can be either conducted by assessing the concentration of progesterone in serum or testing for LH. To review the full cycle before breeding, tests are usually conducted on the first few days of proestrus phase and can be performed up to every 2-3 days to get the best time for breeding.
Progesterone concentrations are usually obtained every 48 hours when about 70% of the epithelial cells are cornified. The aim is to detect the first day when progesterone rose, which also correlates with the surge in LH. This day is known as day zero, and is used to determine the day that the bitch is most fertile. Usually, 2-7 days after day zero mark the days when the bitch is most fertile for breeding and to produce better rates of conception. However, the specific days and number of breeding depend on the type of semen being used. This could be fresh semen, chilled, or frozen.
When LH testing is used to determine the timing for ovulation, serum samples are tested daily. The samples are collected when the vaginal cytology contains a minimum of 70% superficial cells. An additional progesterone test is conducted 48 hours later to confirm LH surge or the initial increment in progesterone.
Progesterone concentrations are usually obtained every 48 hours when about 70% of the epithelial cells are cornified. The aim is to detect the first day when progesterone rose, which also correlates with the surge in LH. This day is known as day zero, and is used to determine the day that the bitch is most fertile. Usually, 2-7 days after day zero mark the days when the bitch is most fertile for breeding and to produce better rates of conception. However, the specific days and number of breeding depend on the type of semen being used. This could be fresh semen, chilled, or frozen.
When LH testing is used to determine the timing for ovulation, serum samples are tested daily. The samples are collected when the vaginal cytology contains a minimum of 70% superficial cells. An additional progesterone test is conducted 48 hours later to confirm LH surge or the initial increment in progesterone.
Progesterone Blood Testing / Ovulation Testing
When it comes to canine reproduction, the best and most successful time to breed a bitch is about 48 hours following ovulation. While several techniques can be used to determine this time, progesterone testing is effective and commonly used. Progesterone testing is not only easy, but also a reliable method of predicting a dog’s ovulation. The process involves taking a blood sample from the bitch for testing and get precise results.
Progesterone testing is important because judging the best time to breed the female dog can be difficult even for the experienced breeders. While some bitches can ovulate as early as the fifth day of their season, others can be as late as their twenty-fifth day. By starting progesterone testing early, it is possible to determine the best time for breeding.
The test is particularly important if the female has previously failed to produce a litter. It is also an important part of breeding when using chilled or frozen semen. Usually, chilled semen can only survive for 24 hours while frozen can survive for only about 12 hours, which makes correct timing vital.
Progesterone testing is important because judging the best time to breed the female dog can be difficult even for the experienced breeders. While some bitches can ovulate as early as the fifth day of their season, others can be as late as their twenty-fifth day. By starting progesterone testing early, it is possible to determine the best time for breeding.
The test is particularly important if the female has previously failed to produce a litter. It is also an important part of breeding when using chilled or frozen semen. Usually, chilled semen can only survive for 24 hours while frozen can survive for only about 12 hours, which makes correct timing vital.