Breeding to Predetermine Sex

In the future, might more dog breeders take advantage of technology to predetermine the sex of puppies in a litter?

In mammals, the male determines the sex of an offspring, while the female determines the size of a litter by the number of eggs she drops that become fertilized. We have all heard that there are sires who have a reputation for producing females. However, is it possible that breeders can control the sex of their puppies, rather than the stud dogs?

We breeders have tried many methods in hopes of predetermining the sexes of our litters. Many methods have been based on old wives’ tales, cultural traditions, proper timing, and even scientific data based on childbirths.

Many swear that if you breed early, you will get bitches. I know breeder friends who have been successful using this method. To prove this even further, when progesterone testing is done, the “optimal fertile” time for breeding conceives mostly males, which may be yet another argument to “breed early to get bitches.”

Breeders who have used the acid/alkaline method to predetermine the sexes believe it’s the pH level in the bitch’s vagina that makes the optimal environment for survival of either sex and acidic environment will produce bitches while an alkaline environment will produce males.

One external method involves swabbing the bitch’s vagina with a diluted mixture of white vinegar to increase the acidic pH that will favor bitch puppies, or by swabbing it with a baking soda solution to increase alkaline pH level that will produce male puppies. Although successful in predetermination, it may decrease the size of the litter. Was this because the male sperm did not survive in an acidic environment, and vice versa, thus decreasing the litter size? Or would the bitch have produced the chosen-sex pup without any intervention, being just the luck of the draw, since the chances are 50-50 of either sex?

Seemingly, a more successful method based on the bitch’s pH level is feeding her an acidic or alkaline diet, depending on the desired sex chosen. This diet should be administered about two weeks before breeding for optimal results with multiple births of the desired sex.

Now there is technology available that can predetermine the sexes. Since the 1990s, gender selection has become more prevalent in the livestock industry and is accomplished by sorting semen according to gender before insemination. By using a flow cytometer, X or Y chromosomes can be distinguished in sperm cells. Then the semen is sorted according to the gender it would produce. Breeders of cattle, horses, sheep, and pigs have been using this technology successfully for years. Cattle breeders want to breed heifers to produce milk and cheese, while sheep breeders want males for better wool quality.

Dog breeders have many reasons to benefit from sex-semen technology, but is there enough demand? This technology, licensed to Sexing Technologies, has already been used for predicting gender for dogs in service work where one sex is preferred over another: Trainers of dogs for the blind primarily want bitches, while male dogs are preferred for police work. However, right now the technology is cost prohibitive for the hobby breeder. Perhaps in the near future, however, sexed-semen technology will be a common tool easily available to dog breeders, and more affordable. —Roseann Fucillo, Papillon Club of America