Breeding dates are determined with various factors in mind. Type of semen, number of inseminations, type of insemination, and bitches history can all influence breeding dates.
Determining Breeding Dates and Ovulation
Determining Breeding Dates
We recommend that progesterone testing be started between 5-7 days into the heat cycle.
The progesterone tests that we run will help us to determine ovulation. We also obtain a vaginal cytology sample or “smear” with a sterile swab from the vaginal lining when we draw the blood for the progesterone test. The progesterone level from the blood gives us an indication of when the bitch ovulates. There is no single number for determining the time of ovulation; we are looking for a number between 4ng/ml to 8ng/ml as the start of ovulation. Most typical bitches ovulate around 5ng/ml. The results are evaluated by the doctor keeping in mind the speed of rise, the type of breeding and type of semen. Many times the doctors will recommend rechecking the progesterone level after the level has reached a level of 5-8 in order to confirm rise and the rate of the progesterone rise especially with frozen semen breedings.
For frozen semen breedings, we also use LH (lutenizing hormone) testing. The LH peak occurs 48 hours prior to ovulation and the hormone is only detectable for 24 hours. In order to perform the test, we draw blood every day at the same time. We separate the serum and freeze it daily. We continue to test the progesterone levels every 2-3 days and when the doctors feel that the bitch has ovulated, we will test the LH on the frozen serum that was draw 2 days prior to the suspected ovulation. If the LH test is (+) then we have confirmed that the ovulation occurred the day they suspected. If the LH test is (-) then they will determine whether the test should be repeated on the day before or after the suspected LH peak. There are rare occasions when the LH peak is not detected.
After ovulation, the eggs need time to mature or “ripen” so that they can be fertilized. The eggs are typically ready 48 hours after ovulation and can be fertilized for several days. This is where the type of sperm can change the breeding dates. We can expect fresh collected semen to last for 24-48 hours or longer, fresh chilled around 24 hours after insemination and frozen around 12 hours. Of course, the quality of the semen is a big determining factor in this equation. Typically, we start breeding a day later for frozen semen and prefer two, sometimes three breeding for maximum conception rates.
After discussing your breeding plan with a veterinarian during your pets Pre-Breeding office visit we will start the ovulation timing process.
If the ovulation timing requires daily blood draws we also offer boarding services at an additional charge.
Speak to one of our veterinary care staff members to schedule your pet’s appointment.
Ovulation timing is a valuable tool in any breeding plan. It allows us to determine when to breed a bitch to optimize the chance for pregnancy, as well as achieve pregnancy in many bitches thought to be infertile. Timing is essential for specialty breeding when using fresh-chilled and frozen semen, and can also help us accurately predict due dates.
It will help you to understand the bitch’s heat cycle (estrus). As you probably know, female dogs come in heat about twice a year. The heat will last about 3-4 weeks, and in the normal course of breeding, the bitch will stand to be bred somewhere between 8 and 15 days along. This varies a lot, and some bitches need to be bred as early as 4-6 days, others as late as 20-30.
The three most important hormones in the bitch’s estrous cycle are progesterone, L.H., and estrogen.
Progesterone testing also helps our veterinarians determine ovulation. Progesterone is also normally at very low levels, then as the heat cycle progresses, progesterone will show a rise. Unfortunately, there is not a single number for determining the exact ovulation date. Our veterinarians look for a result between 4ng/ml-8ng/ml to determine baseline for beginning of ovulation cycle. As progesterone timing continues we look for a distinctive rise from the initial baseline results.
Progesterone remains elevated for 8-9 weeks (gestational period) whether or not the bitch is pregnant or was bred. At the end of the pregnancy (or non-pregnancy), the progesterone will begin to drop. The drop in progesterone causes labor to start and is also responsible for the symptoms of false pregnancy.
Luteinizing Hormone (LH) actually causes ovulation. LH remains at very low levels in the blood, then suddenly surges two days prior to ovulation. The eggs must mature before they become capable of being fertilized. The eggs are mature for only a few days, after which they deteriorate if they have not been fertilized.
It is possible to test for the LH level, and this is actually the most accurate way to do it. However, since LH is only elevated for a short time (as little as 18-24 hours), blood must be drawn at the same time daily until ovulation is confirmed. Rose City Veterinarians strongly recommend LH testing for frozen semen breeding or bitches thought to be infertile.
Estrogen causes the vulvar swelling, bleeding, and the changes in the vagina that Rose City veterinarians use to do “vaginal smears.” Estrogen is the hormone that causes the bitch to act receptive. In most bitches, estrogen rises anywhere from 5 to 20 days before ovulation. Because of this very wide range, vaginal smear cytology’s are only a rough estimate of cornification of cells in the vaginal canal. Vaginal smears play no active role in confirming ovulation.