Knowing LH0 — the day that the luteinizing hormone begins the pre-ovulatory surge — is an accurate way to predict the whelping date. It seems more precise than using date of ovulation, although knowing when a dog has ovulated is also useful data.
There is, however, slightly different info on what constitutes LH0.
Dr. Patrick Concannon, a well-regarded seminal-in-the-field researcher who studied canine reproduction for decades, identified LH0 as an “increase in progesterone from levels of 0.3 - 08 ng to levels of 0.9 to 3.0 ng/ml” (Concannon, 2000, Table 1). I have used his work for years and found it accurate.
Recent research by Hollinshead and Hanlon (2019) resulted in the authors’ estimating progesterone at LH0 to be 2.7 ± 0.6 ng/ml. I closely tracked Claire’s breeding four years ago using their data with excellent success (n=10 with fresh chilled semen).
Capella’s progesterone numbers are a bit of a conundrum in terms of establishing LH0.
Establishing LH0 matters for two reasons. First, it allows a highly accurate prediction of due date and that matters a lot; puppies cannot survive if they arrive early or late. Second, the window of fertilization is thought to be no more than about two days — we need to carefully time the breedings.
Optimal breeding days are LH 4 - 6.
Laying it all out like this makes me wish we could have gotten a breeding today. I feel confident that LH0 was Wednesday, 12/11. That said, tomorrow and Tuesday should also be optimal breeding days — especially tomorrow.
I love data.
Happy Sunday.
❤️
