If you are planning to breed your dog, we recommend having your female’s blood levels of progesterone tested and monitored during her heat cycle. Progesterone is a hormone released during the estrus cycle. A progesterone test is a simple blood serum test to determine the optimal time to breed your female.
When checking a progesterone level during your female’s heat cycle, your veterinarian is looking for a rise in progesterone to determine the time of ovulation. From this value your veterinarian can determine the best time and method for breeding your female.
Usually we will ask that you bring your female in for her first progesterone test seven days after first sign of heat. At this first appointment we will discuss pertinent information such as type of breeding (natural, vaginal insemination, transcervical insemination, or surgical insemination) and evaluate her health for pregnancy. We also perform a vaginal cytology to determine the stage of heat cycle and look any signs of infection.
We then run subsequent progesterone tests every other day until the value reaches 5.0 ng/ml, which is the level at which ovulation occurs.
If you are planning on breeding your female, progesterone testing can optimize breeding timing and improve her pregnancy results
LH Testing (Luteinizing Hormone)
LH refers to Luteinizing Hormone. This hormone is released during the estrous cycle. Testing LH levels during a female’s estrous cycle is key when considering a frozen semen surgical insemination. To better understand the role of the luteinizing hormone in reproduction, it is beneficial to understand the canine estrous cycle.
A bitch typically goes through an estrous cycle twice a year, averaging seven months apart. The estrous cycle is divided into four stages, anestrus, proestrus, estrus and diestrus.
The beginning stage of the estrous cycle is anestrus. At this time the female is not receptive to the male, there is no ovarian activity, and in fact her reproductive tract is in repair at this time. This stage can last from 1 – 6 months followed by proestrus.
During proestrus the female becomes attractive to the male, but is not receptive at this point. The owner usually begins to see vaginal bleeding and vulvular swelling and progesterone levels begin to rise. The proestrus phase lasts an average of nine days, followed by the estrus cycle.
We recommend having females examined seven days after the first sign of blood. During this visit the doctor performs a vaginal cytology to confirm the female is in heat, and to identify any abnormalities such as an over growth of bacteria. We also start progesterone testing at this time. If you are considering a surgical insemination we begin saving samples of serum to identify the LH spike.
Estrus is the phase in which females become receptive to the males, she may start “flagging” when males are around. There is also more vulvular swelling noticed and vaginal discharge starts to diminish. The progesterone levels continue to rise while the estrogen level decreases. During this time the LH levels spike, triggering ovulation as well as a spike in progesterone levels. Usually eggs are released two days after the LH spike. This is the true fertile period and can last 24 hrs.
Determining the LH spike is important when considering a surgical insemination–especially when using frozen semen. There is short window of opportunity for conception during the heat cycle so we need to be sure of the exact time of ovulation in order determine the correct time to perform the surgical insemination.
The final stage of the estrous cycle is diestrus. During this stage there is a decrease in the female’s attraction to the male, vaginal discharge and vulvular swelling. The progesterone levels continue to increase and then decline during the end of diestrus. This stage lasts for about 2 – 3 months.
In short, Luteinizing Hormone is a hormone that triggers ovulation during the estrus cycle. If you are considering a surgical insemination for your female, LH testing is a valuable tool for determining the time of ovulation.
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