Having just read Myra Savant Harris' Advanced Canine Reproduction and Puppy Care, I feel the need to share some dramatic and important information with those breeders using my stud dogs. Many of us have been frustrated with the lack of fertility in our bitches. Myra's book has some profound explanations.
First, if you have bitches who don't cycle regularly, she suggests changing how you keep your dogs. Simply: Put them outside in the sunshine. If you can't do that, install full spectrum lighting in your kennel or dog room and keep it bright at least 12 hours a day. Horse people know the importance of light for reproduction, so do those who keep chickens for egg production. What can it hurt? It is an inexpensive fix and you should see results in five or six weeks.
Now lets assume your bitch is already in season. Myra agrees with all the professionals who say fresh semen can live 5-7 days and chilled, extended semen 3-5 days, possibly more, as long as it is kept chilled and in ideal conditions. However, she thinks they are all dead wrong on how long chilled semen lives inside the bitch. She believes our window once we do our insemination is 12 hours before the sperm dies. Wow.
Therefore two things are critical: Determining the day of ovulation and the method of insemination. She believes that actual numbers we get when progesterone testing are not so critical or telling, what is important is the day those numbers begin to spike quickly. It is her opinion that somewhere between 4.0-6.0 ng/ml or so is when most bitches ovulate, but to know for sure you need to test every day once your girl hits 4.0, and if there is a significant jump, say two or more points in 24 hours, that is the day of ovulation. Many people like to keep testing until they see very high numbers, but her experience is that once ovulation occurs and the numbers rise at a significant pace, all bitches are different. So again, determining the day of ovulation is key.
At that point she believes that eggs are only ripe and able to be fertilized 2 1/2-4 days after ovulation. Specifically, 60-96 hours after ovulation. So you can see that if the sperm only live for 12 hours in the bitch, our window for the sperm to fertilize all the available eggs and produce a large litter is indeed very small.
The other thing she thinks works against chilled semen AIs is the sheer size of a bitch's reproductive tract. The vaginal tract itself is significantly longer than a human's, and the uterus has two horns reaching well into the bitches body, with the fallopian tubes at the far ends. This is why surgical inseminations have so much greater success rate. If sperm only have a 12 hour lifespan and have such a great distance to travel before they are even able to begin attempting to fertilize the eggs, it is no wonder few seem to make it. Putting the sperm directly where they need to be via surgical insemination dramatically increases fertility rates with chilled semen. I now tell people--if this breeding is important, do a surgical. We, personally, have had 100% success with surgicals. We also now put our bitches on antibiotics for 14 days when they come in season. Between these two changes we now are having big litters again.
However, if a surgical implant is not an option, you must do your very best to stimulate a tie when you do an artificial insemination. While tied the dog will pull against the bitch, causing her to contract and draw the semen into her uterus. Tests have shown elevating a bitch's hind end does nothing to increase conception. Guide Dogs for the Blind follow every AI with a natural tie performed by a vasectomized dog. Their conception rate since doing so has increased dramatically. Minitube sells an AI catheter with a balloon to stimulate a tie for $30, I strongly suggest if not doing a surgical, use one of these. I hope to keep them in stock and to provide them for those doing AIs, just ask me before we need do breed your girl. If neither of those are options, simply have your girl stand while you feather her vulva or vaginal wall with a sterile gloved hand. Not constantly, that will lose its effectiveness, but every two or three minutes. And do that for at least 15-25 minutes.
Whoa! You are saying. That is way different from what I have always done, or what my vet is telling me to do. I agree, it is. But I also think most vets do not give seminars to breeders, or take calls from breeders day and night, so are able to get input in such large numbers. I think what she is saying sounds right, and I personally, will be using this information with my bitches. I sincerely hope all of you who are breeding your girls to my boys will do the same. It is always difficult to go against what your veterinarian suggests, but it is not their bitch and their money and their hopes and dreams wrapped up in this litter. It is yours. If you want to get your girl pregnant, please use the latest and best information you can find, and here it is. Insist.
If you would like to learn more, I encourage you to order Myra's books. She is an neonatal ICU RN, and is simply a wealth of knowledge. Go to myrasavantharris and order a copy of Advanced Canine Reproduction and Puppy Care, The Seminar. You will be glad you did. Plus she has a ton of other great supplies for whelping and newborns.
Good luck with your breedings!
For a more specific interpretation of progesterone results,
this chart from Michigan State University may be useful
0.9-1.88ng/ml: Minimun of two days before ovulation is expected.
Results of 0.9-1.2 may persist for a week or longer before increasing
2.2-3.77: Minimum of one day before ovulation is expected.
Estimated window for breeding is from 3-5 days, but could be longer
4.0-5.66: Ovulation is impending or has just occured.
Estimated window for breeding is 2-4 days
5.9-9.75: Ovulation recently occurred.
Estimated window for breeding is 1-3 days.
10.0-20.1: Ova have matured, optimal potential for fertility.
Estimated window for breeding is 0-2 days.
20.4-28.3: Ova have matured but aging, decreased potential for fertility.
Breed at once.
28.3: Too late or very reduced potential for fertility.