So what numbers are important?

Those that dramatically improve the success of your breedings, both in numbers of pregnancies and puppies. If you are a seasoned breeder doing a natural breeding at home with your own experienced dogs, you may not need them but they sure are worth it if you are:

• a novice breeder
• experiencing missed breedings
• breeding older brood bitches and/or stud dogs
• investing in fresh-chilled or frozen semen
• traveling to do a breeding

Here are the two numbers I depend on in my breeding program:

1. Reading Vaginal CytologyPercent Cornification:

I don’t know why vaginal cytology has lost favor among breeders in recent years. Although it won’t tell you when to breed, it can allow you to optimize your progesterone testing and, even more importantly, help you pinpoint when your litter is due better than any other method. Best of all, it is a skill you can learn to do yourself, saving you vet visits and bills.

I do my own smears starting the day my bitch comes in season, so I can be sure I caught her first day and that I don’t miss her progression. I continue smears every day or two until she is 80% cornified. At that point, she is in estrus so additional smears won’t help me figure out when to breed so I then turn to progesterone testing. However, using vaginal smears in this way has dramatically cut down on the number of early progesterone tests I run—you know, the $120 ones where she is at 0.2 nanograms per milliliter (ng/ml) for days!

I do a few more smears after I’ve bred my bitch so I can determine the first day of diestrus. In these smears, I am looking for the dramatic drop in cornified cells, from full to less than 20% cornification. The day I see this drop, we know my girl is in diestrus and her pups will be born in 57 days, plus or minus one day.

Tube for Progesterone Testing

2. Progesterone level:

The number one reason that I have missed breedings over the years is poor timing. Believe it or not, it’s not so easy to figure out when to breed, sometimes even with experienced stud dogs and brood bitches. Researchers are still fine-tuning how we should interpret and use progesterone levels to breed most successfully but my experience and reading have taught me to look for two things before breeding:

1. progesterone level between 4 and 10 ng/ml (6 and 31.4 nmol/l) to indicate likely ovulation
2. a minimum of a 3-4 ng/ml jump in progesterone over a 24-hour period to confirm ovulation

Although the typical bitch will ovulate when her progesterone is at or above 5.0 ng/ml, there is a lot of variation so we look for that jump in progesterone that confirms ovulation did occur. Can you tell that variability is a theme in breeding dogs? If your bitches are all typical, you can breed the old way on Days 9, 11 and 13. But if they are not, it’s best to be prepared with another plan that includes vaginal smears and progesterone.

So as dog breeders, we don’t have to know a lot about numbers but focusing on the right ones rather than less important ones will help you have more success with your breedings!

If you would a copy of our Breeding By the Numbers case study, showing how we use these numbers, as well as our BONUS Vaginal Cytology Resource Guide, click here to download your FREE copy.

Click Here to Download

Thanks!

My thanks to Dr. Mary Stankovics and Deb Leach from Straws to Paws, who taught me to do and read vaginal cytology, and my vet, Dr Jim Zgoda, Otterkill Animal Hospital, who always lets me look over his shoulder at the lovely slides he prepares.