Why Do We Breed Back to Back?
Image showing Canine Uterine Horns with 10 pups.
Breeding back to back heats with dams has been a topic of heavy discussion in the past; but with the help of research we are able to confidently say that skipping heats is no longer best practice for dams optimal health, for several reasons.
Firstly, when you look at the reproductive and nursing cycle of a dog and their healing needs, its fairly comparable to a human having a baby every 2 years or so. While we emphasize that dogs are not humans, I think that as an analogy, this can be quite helpful to some who find initial mental resistance with breeding a dam as frequently as twice a year.
Next is the effect of progesterone on the uterus. One of the most vocal proponents of breeding back-to-back is well-known reproductive specialist Dr. Robert Hutchinson.
In his seminars, Dr. Hutchinson explains that the progesterone level in the dam remains elevated for two months after ovulation weather or not she has a pregnancy. This is a critical fact, since progesterone can be inflammatory to the lining of the uterus.
When a dam cycles and there is no pregnancy, the uterine line thickens from the inflammatory effects of progesterone and that can increase the risk of infection (pyometra) and endometriosis. Pyometra is an inflammatory disease with a bacterial infection being a secondary factor.
An excerpt from the same seminar"
It's suggested not to skip a season because we have been preserving the uterus from the effects of progesterone; what would be the benefit of exposing her uterus to two months of progesterone? Progesterone's effect on the uterine lining is the reason why Dam's 6 and over have a 33.3 percent less chance of conceiving than Dams under 6 years of age.
Again, dogs are not humans, and while human females shed their uterine lining every cycle, dogs only shed their uterine lining when whelping. As linings stack up, they loose flexibility and elasticity, which can also contribute to fertility problems as the eggs have a harden time attaching.
When to not breed back to back:
It is of utmost importance to consult a qualified reproduction veterinarian, and the opinion of this vet should be your number one consideration for whether to breed back-to-back or skip a cycle. You should have your dam evaluated by a repo vet prior to every breeding.