It's not just what we know... it's how much we care!

Predicting the time of ovulation is the main tool we have available to us, to ensure optimal timing of breeding or artificial insemination.

We have been using our Progesterone assay machine for 12 months now and have been very happy with its speed and accuracy. Within about 15 minutes of collecting blood from a bitch, we have a result. This is a vast improvement from earlier times, when we would send a blood away to a laboratory, and hope to have a result within 24 hours.

There are other indicators of impending ovulation: the behaviour or receptivity of the bitch, vaginal cytology, and the appearance of the vagina on scoping. The other, very accurate method we have at our disposal is ultrasound. Ultrasound detects ovulation by visualising the disappearance of follicles within the ovaries. If done every day, ovulation can be accurately predicted within 24 hours.

Since the arrival of “new” Progesterone machines, there has been discussion amongst breeders and vets as to their accuracy. Since we use ultrasound extensively, we thought we would do some “quality assurance” to compare our progesterone results to the ultrasound.

We are happy to say that our progesterone machine has consistently predicted ovulation, with a high degree of accuracy, as the following images indicate:

FIGURE 1: PRE-OVULATION

Note the appearance of the follicles and ovary on the scan and the concurrent progesterone reading. We have done this multiple times and the results have always been the same.

FIGURE 2: POST OVULATION (24 HOURS LATER)

If ultrasound is so accurate, why not just use this all the time??

This is a good question. It would avoid the dog having the discomfort of blood tests and is quick and painless.

However, there are some limitations, namely:

• The availability of a suitable ultrasound machine and ultrasonographer: particularly as they need to be done daily towards the time of ovulation.
• Some dogs are difficult to ultrasound. A calm, smaller dog of normal or lean body weight is an ultrasonographer’s dream. Dogs with thick coats often require a small shave site each side of the abdomen.

In summary, ultrasound has given us added confidence in the accuracy of our progesterone machine for predicting ovulation.

For those bitches who are difficult breeders, or have had difficulty falling pregnant, or have lost pregnancies in the past, a reproductive tract ultrasound is a useful diagnostic tool. It can diagnose ovarian and uterine disease or structural abnormalities. When exact timing is paramount (e.g. using frozen semen), the use of ultrasound in combination with progesterone and vaginoscopy, is the gold standard. We are happy to offer this service to our valued breeding clients at Wingham and Valley Vets.