432 — Infertility in Dogs: Regular, Random and Rare Causes - a podcast by Laura Reeves

Infertility Issues: Regular, Random and Rare CausesDr. Marty Greer, DVM joins host Laura Reeves for a wide-ranging conversation on the causes of infertility in our breeding bitches. From split seasons, ovarian and uterine cysts, to semen allergy and genetic incompatibility, we cover a lot of ground.
Marty was kind enough to provide the following"check list"of fertility issues to share with our listeners.
Why isn't my female pregnant? What can I do about it?You did your homework – and have the perfect bitch, in her best condition and found the ideal male to mate her to. Both of them have passed all of the health clearances recommended for your breed. They have the temperaments you are looking for and their traits are complimentary to one another.
You know the most common causes of apparent or actual pregnancy failure are:Poorly timed breedings
Poor semen quality and/or quantity.Failure to maintain a pregnancy

Timing the breeding:The timing of the breeding, based on progesterone levels (bred 2 to 3 days post-ovulation depending on semen type used), was just right. Most veterinarians recommend breeding 2 days after ovulation with fresh and fresh chilled shipped semen and 3 days with frozen semen. Ovulation is assumed to occur when the progesterone reaches 5 ng/dl (different units are used in other countries) with a range of 4 to 10 ng/dl. LH testing is also done in some clinics. LH, Luteinizing hormone, directly indicates ovulation, while progesterone is an estimation of ovulation. Progesterone is easier to measure and test as it can be done every few days, using human technology. LH requires daily testing and is canine specific.Semen quality and quantity:You know the stud dog had good quality and quantity semen – there was a semen analysis completed prior to shipping the semen. Your vet looked at it prior to inseminating your bitch and said the semen looked great, based on the sperm count (for a Bernese Mountain dog, the count should be 1 billion total), the morphology (shape and appearance of each sperm cell) and motility (how active and progressively motile it was on a microscopic evaluation).
Yet, she is not pregnant. Why? And if you try to breed her again, what can you do differently to improve the chances she will carry a litter to term?First, we need to determine if she failed to conceive, failed to achieve fetal/placental implantation, or conceived and lost the litter. If you don't have her ultrasounded, you won't know if she failed to conceive or failed to maintain the pregnancy. A relaxin test or palpation is not adequate – these do not assess for fetal viability. This information is big piece of the puzzle. When you are trying to justify the decision to do an ultrasound, this is the best reason to do so – this is not the place to scrimp.
If the ultrasound shows no pregnancy, and the semen and timing were good, then causes for failure to conceive or failure for fetuses to implant should be explored. These include:Was there a Semen quality assessment?Was the sperm count low?
Was there abnormal semen morphology? Was the semen stained and assessed by a veterinarian?Was there poor semen motility? The semen needs to be progressively normal.
Was there poor semen longevity? Holding a small sample of semen in extended in the refrigerator and reassessing it 24 and 48 hours later can be useful.Was there timing failure? This is a good time to review the timing of the breeding.
Did she complete her ovulation?Failure to complete the ovulation. Did the progesterone testing continue past 5 ng/dl? If not, she may have not had a complete ovulatory cycle.
Cystic ovaries? An ovarian cyst can interfere with a complete ovulatory cycle.Split cycle? If she failed to complete her ovulation, she may have split her cycle and will come back into heat in the next 4 to 6 weeks.

Failure of adequate semen deposition: Fertile sperm must reach a fertile egg.If this was a natural breeding, was there a...

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