Newer concepts in breeding:
What is the optimum progesterone level at the time of breeding?
LH surge is when the progesterone level is 2 nanograms. Ovulation occurs around 5-6 nanograms and you breed three days later, allowing the eggs to mature.
There is no statistical significance to a progesterone number once it goes up above the 5-6 range. At insemination, the range seen has been 11 ng/ml up to 50.4 ng/ml, which tells us that there is no magic number when inseminating. Although, the progesterone when using frozen semen, at the time of insemination should be above 15.
Other Vet clinics who do repro work like to see a significant rise of at least 3ng <following the 2 nanogram marker> in a 24 hour period and call this ovulation. For Frozen or fresh chilled semen, TCIs are done at 3 days and another one at 4 days after ovulation. If only one TCI or surgical can be done, then they go with 3 – 3 1/2 days post ovulation. Bitches are most fertile at days 3 and 4 post ovulation, especially if having semen directly deposited into the uterus via TCI or surgical. Typically at the time of procedure, we like to see bitches well over 20ng. 84 hours post ovulation - inseminate via TCI.
Progesterone machines are not all the same. A progesterone level was 5-6ng/mL on one machine might have been 4-5ng/mL or 8-10ng/mL on another one. The value needs to be properly interpreted: It’s important to rely on somebody, therefore, who is used to working with the laboratory or the machine that gives the results, so they are properly interpreted. Always run the progesterones with the same machine, at the same Vet clinic, or use the same laboratory.
Male dog sperm:
A male dog takes about 58 days to make a sperm cell and draws from it, each time he is collected. Approximately 700 million sperm are present per ejaculation, which means a male who is healthy and fertile, can be collected six or seven days in a row, without running out of sperm. Therefore, if a male dog who shows infertility, it will be a minimum of two to three months before improvement in semen will be seen.
Things you can do to help your male and female be fertile:
Not allowing the testes to become too hot or too cold, there is a reason that the testicles are hung outside the body - they need to be kept cool. Make sure your dog is not overweight, obese males and females have difficulty with reproduction. And, finally good dog food.
Brucellosis testing should be done on both males and females. On females, it should be done each time she’s going to be bred. On males, it should be run every six months. Brucellosis is passed in vaginal discharge, urine and milk.
Critical for getting pregnant:
Semen delivered at the right time
Semen traveling to the ovary
The fertilized egg implanting
Using frozen semen on maiden bitches:
Should you TCI maiden bitches with frozen semen, meaning bitches who have never had a litter?
Yes, with a caveat. Age. The younger the bitch, the better the chances of success. As mentioned above, the more heat cycles a bitch has gone through, the more the uterus wears out. At six years of age, a bitch’s conception rate diminishes, her conception rate drops a third and her litter sizes tend to drop. As long as the bitch has passed all her health testing and is over 2 years of age, this is when her chances of conception and litter size is the most successful. With TCI (trans cervical insemination), the semen is deposited in the same spot as surgical AI did. It is preferred over surgical AI because it doesn’t require an anesthetic or an incision. And, TCI allows for insemination of frozen semen two days in a row, as opposed to one with surgical AI. The benefit surgical AI provides is when a bitch is older and may have uterine damage. The Vet can look at the uterus and break down some of the cysts, with the uterus in hand.
Frozen semen lasts in the body six to twelve hours. Fresh semen from a dog for vaginal AI lasts 6, 7, 8 days. Chilled semen lasts about two to three days in a bitch.
Ovulation of the bitch:
When a bitch ovulates, the eggs are not ready to be fertilized, they have to go through a whole other myopic division and that takes place about 48 hours after ovulation. Fertilized eggs don’t implant in the uterus till day 17 or 18 after ovulation. The first third of the pregnancy, the eggs are not even attached to anything. Then, the eggs space themselves out evenly, the uterus swells and implantation takes place. Typically there are the same number of puppies, plus or minus one, in each horn. The next three weeks is development, this is when their palates close and their eyes come into position. It is only the last 12 days when the puppies double in size, which is why it is only the last 12 days that there becomes a lot of calorie demands. Calories become critically important the last two weeks of pregnancy and throughout nursing. A premium, performance food should be given during the last half of pregnancy and through nursing.
Reabsorption can take place until about day thirty-eight of pregnancy (from day of ovulation). Approximately 30 percent of all bitches resorb some of the puppies, which is why ultrasounding days 23-24 from ovulation gives you an idea of the number of puppies in the litter and whether resorption took place. Resorption takes place because of uterine lining damage and also because the bitch’s progesterone prematurely drops. Progesterone dropping tells the body it is time to get rid of the puppies, whether it is day 30, 40, 50 or day 63 (natural whelping time). Infections, chemicals can cause resorption.
63 days from ovulation is the bitch’s due date.
Back to back breeding:
Should you breed back to back, meaning two heat cycles in a row?
Yes. It is the way that a bitches heat cycle is made, as the bitches biology is such that her body is geared up to have two litters a year. After a bitch ovulates, she goes into diestrus and that diestrus means that when she ovulates the progesterone lasts as long as whether she is pregnant or is not pregnant. The inflammatory effects of progesterone on the uterus happen whether she is pregnant or not. The uterus, as a result of heat cycles, and progesterone from those heat cycles, causes extreme inflammation of the uterine lining. The bitch goes from a normal uterus when she is young, to eventually cystic endometrial hyperplasia, which is the forerunner to mucometra and eventually pyometritis. Pyometritis is not caused by bacteria, it is caused by progesterone. So, the uterus is being damaged by the bitch’s own heat cycle, not how many litters she has.
Puppy immunity from bitch:
Make sure your bitch is up to date on her vaccinations - pre-breeding. Not so much for the bitch, but for the puppies as they get minimal protection from the bitch through the placentas, but 95 percent of their protection comes from the colostrum. The colostrum is the first milk that the bitch puts out and puppies can absorb it for 16 hours. If the bitch hasn’t been protected (vaccinated) against parvo or distemper, then the puppies run out of that protection before vaccine time. Vaccinations should occur every three years.
References: Dr. Hutchison interview from June, 2021 and AKC.