By Christine Grether
FBDCA Communications Committee Chair
Few events in a French Bulldog breeder’s life compare with the anxiety of properly timing a delivery, especially if it’s a c-section delivery. Pups taken too soon are jeopardized by underdeveloped lungs. Pups taken too late can be stressed by a uterine reduction of blood and oxygen and face serious illness or be stillborn. Especially, if the pups are stressed enough to pass meconium (the first black-tarry excretion) into the amniotic fluid surrounding them and it enters the lungs.
Most breeders go by the 63-Day Rule. From the day of ovulation they count forward 63 days, or exactly 9 weeks, to target the expected delivery date (Note: NOT from day of breeding, but from day of ovulation). However, the actual date can still vary a few days either way. What if the day of ovulation wasn’t calculated correctly, what if it’s a singleton litter, or what if the dam has ideas of her own? With even a day or two being critical to the survival of a puppy, how can this date be more accurate?
Animal reproduction veterinarians (theriogenologists) have come to the rescue of canine breeders by developing an improved method to determine the best delivery date. Calculating the day of ovulation and best breeding days has been performed for many years with progesterone testing, especially in the case of artificial insemination with chilled or frozen semen. Progesterone testing to calculate correct breeding days consists of taking a series of blood samples from the bitch. Each sample is sent to a lab, the level of progesterone in the blood is evaluated, and the rise is charted over the course of a few days. Now take that same testing procedure and reverse it to find the target date for delivery. Instead of charting a rise in progesterone, the fall of progesterone is followed. While reverse progesterone testing won’t completely eliminate the anxiety of timing a litter, it will reduce it, and more importantly, improve a litter’s viability by increasing the chance of being born on an optimal day.
One thing to note, many vets and breeders face an inconvenient delay of 18-24+ hours for test results because they must rely on offsite testing labs. We’d like to remind breeders, they should continue to monitor temperatures, pay close attention to physical and personality changes of the dam, and work with their personal vet to determine the best whelping time. Reverse progesterone testing is a valuable diagnostic tool, but it is not infallible.
Below is the procedure outlined by Dr. Robert V. Hutchinson, D.V.M, well-known animal reproduction specialist and director of the International Canine Semen Bank – Ohio. He graciously agreed to share his process and we thank him for sharing his information with the FBDCA membership.
Testing Progesterone Level to Determine Whelping Date
by Dr. Robert Hutchinson, DVM
“Just as progesterone rises to assist breeding timing, the decrease can also be of value for determining whelping time and c-section planning. The correlation of a pre-whelping progesterone level with the bitch’s body temperature will also help to determine how low a temperature drop can be anticipated pre-whelping.
When monitoring the serum progesterone level for breeding, one sees a very rapid rise in values. Pre-whelping progesterone levels, however, decrease in a much smoother, “gliding” pattern. The drop in progesterone pre-whelping is triggered by fetal cortisol causing the release of prostaglandin F2α. This potent hormone causes the progesterone to be suppressed, the cervix to open and subsequently the uterine muscles to contract. A larger litter (> 8 pups) may cause a quicker progesterone drop, while a smaller litter (< 3 pups) may cause a slower drop and can even cause the whelping time to go beyond the anticipated due date.
A progesterone level of < 2.5 ng/ml (ng/ml = nanograms of progesterone per milliliter of blood) will have the bitch in active labor. If the bitch is not in labor, but the progesterone level is 3.0 ng/ml or less, one can safely do a c-section if the date is near the anticipated due date.
A progesterone of > 5 ng/ml indicates at least 24 hours or more will pass before the onset of labor. Another progesterone test should be run in 24-48 hours depending on the body temperature and other signs of pending labor, (nesting, milk being present, lack of appetite, etc.)
A progesterone level between 3.0 and 5.0 ng/ml indicates that the time of whelping is close and another progesterone test should be run in 24 hours.”
Dr. Robert Hutchinson, DVM, practices animal medicine at Animal Clinic Northview and is the director of the International Canine Semen Bank – Ohio, both located in North Ridgeville, Ohio. He conducts breeder symposiums and has produced two DVDs on canine reproduction, “Maximizing Conception in the Bitch” and most recently, “Successful Whelping and Neonatal Survival.” If you are interested in the DVDs or learning more about his clinics, please visit: www.northviewvet.com