What Happens If a Purebred Dog Gets Pregnant By a Mutt?

a purebred dog and a mixed breed dog on the beach together

I have heard many times throughout my life; people claim that if a purebred bitch mates with a mutt, it would ruin them. I wanted to see if there was any truism to this older, yet widely held belief. After spending several days reading every research paper that I could find on the subject, here is an all-in-one compilation of what I learned.

The most common suggestion I read was that if your purebred bitch mated with a mutt, it would “ruin” being able to breed her for the rest of her life and cause future breedings to inherit genetic code from the mutt. That is an older and somewhat archaic belief that is false. While there are some circumstances that could “ruin” your bitch by breeding, the futurity of the bitches offspring at the genetic level is not among them.

While that belief has all but disappeared today, there are a few people that still hold fast to this view. So, where did this belief originate, and why did it disappear for the most part? What should you do if your purebred got pregnant by a mutt? Let me try to answer all the questions that I found about this subject during my search.

Telegony: What is it to Dogs and Their Breeders?

Maybe you have heard someone state this belief before. The idea that a female of a species would be “ruined” is not a new belief and might be a much older notion than you thought. The theory is known today as telegony. This hereditary theory states that while an individual inherits traits from the mother and the father, that individual also may inherit traits from the males that have previously known (had coitus with) the mother.

This theory applied to any creature, be it human or animal. This speculation is dated back to Aristotle and was written in Aristotle’s Biology – this was a compilation of scientific views and observations made by Aristotle to explain his theory of biology. It was a widely accepted theory throughout antiquity, revived during the middle ages, and was repopularized during the victorian era by August Weismann. The name Weismann coined for the belief, “Telegony,” was derived from the Greek epic poem about Telegonus, written by Plato.

This theory was later challenged when Gregor Mendel proposed his theory of biological inheritance, known as Mendelian inheritance, during his studies of pea plants. While Mendel’s ideas were controversial at first, they were later rediscovered by William Bateson in 1900. Many scientists have since tested and combined other hypotheses in with Mendelian’s theory, and today is the fundamental basis of our current understanding of genetics. While the telegony theory has died within humans, there seem to be a few that still believe it relevant to dogs today.

The only scientific study I could find supporting any aspect of telegony is a study that A. J. Crean and his colleagues did in 2014, which you can read about here.

While testing a type of fly, they found that environmental factors could potentially play a role in subsequent breedings; however, genetics did not at all. These tests were concluded in high and low conditions and gave no evidence to the theory that your dog can carry over any traits from prior breedings to the current breeding.

Can a Mutt Breeding to Your Dog Ruin It?

The answer here is, unfortunately, yes and no. It can, but it won’t always. From above, hopefully, you have a clear understanding of what telegony is and why it is an old wives’ tale. Knowing that your dog can’t carry on the genetic information from prior breeding to future breedings, you can dismiss any notion of your bitch being ruined for life as far as that goes.

However, there are other ways that your bitch actually could be ‘ruined,’ depending upon your definition of ruined. If your bitch is a show dog, I have heard of several cases where accidental breeding caused the bitch to have structural problems that kept it from being able to be a show dog again. Birthing and nursing litters back to back may also be mentally and physically taxing for the dam. Another way is if it were a problematic pregnancy and, in doing so, made it medically unsafe for that bitch to have another pregnancy. If the pregnancy causes medical issues, the bitch might have to be spayed. Doing so would disqualify her from being shown in conformation again at a dog show.

Also, whether the bitch was too old or not old enough, at the time of mating, can potentially cause an increased risk or other health problems for the bitch. If you are unsure if she is at risk, you should consult with your veterinarian before breeding her the next time.

Are There a “Morning After” Pills For Dogs?

While spaying the bitch would terminate an unwanted pregnancy, it would eliminate the chance of her being able to have puppies in the future. However, there are ways to terminate the pregnancy without having her spayed. There is only one option that I will cover, as the other methods I found I think are absolutely barbaric, and I wouldn’t recommend them to anyone.

While referred to as either a “mismate injection,” a “mismate jab,” or a “misalliance treatment,” yes, there is a “morning-after pill” of sorts for dogs. It is actually a shot, not a pill.

Made by Virbac, the drug is called Alizin. It is required to have two shots, 24 hours apart, to be effective. It should be given subcutaneously (under the skin) into the scruff of the neck. Alizin is found to be most effective 21 days or less after the pregnancy but may be administered with a diminishing effect up to 45 days afterward (although I wouldn’t recommend it). Up to 21 days, the treatment is 97.4%-100% (99% avg) effective according to their studies. Between 21 to 45 days after mating, the treatment drops to 88.7%-97.7% (95% avg) effective. They recommend never doing it after the 45-day mark.

According to Virbac’s website Alizin contains aglepristone, which is a synthetic progesterone antagonist. Meaning it is, in essence, a hormone therapy that binds itself to the progesterone receptors on the uterus without activating those receptors. Without the fertilized ova being able to implant themselves on the wall of the uterus, pregnancy cannot be maintained. It will also cease existing pregnancies by restricting the maintenance of the fertilized ova from the uterus, which will cause the pregnancy to be lost. From looking through the studies, it is the most effective (and safest) option for ceasing unwanted pregnancies in dogs, but there are potential side-effects that you should know about beforehand.

If the injections did not work, you should monitor the bitch closely, as the puppies may be compromised, and other problems may occur. Depending on how far along the bitch was in the pregnancy when you used it, it could cause possible side effects.

Possible side effects according to Virbac:

Stage administeredPossible Side Effects
Early Pregnancy TerminationAcute discharge
Mid-Pregnancy TerminationFetal expulsion within 7 days of the first injection
Brownish vulval discharge for several days
Reduced appetite
Slight depression
Transitory anorexia
Mammary gland congestion
Late Pregnancy TerminationSigns of parturition
Expulsion of fetuses
More information on Alizin can be found on their website

Other possible side effects reported from field trials:

  • Anorexia
  • Excitation
  • Depression
  • Vomiting
  • Diarrhea

They recommend rechecking the bitch 7-10 days after the second injection (or 21 days post-mating, whichever is later) to ensure the abortion has occurred. If, in the rare case of failure, they say it is possible to repeat the treatment as long as you are still under the 45-day mark. If that happened, I would make sure to consult with your veterinarian first.

Can mutts reproduce?

This is another question that I ran into a few times.
Mutts are capable of reproducing in the same manner as any other dog or bitch. The caveat would be if they can do so by themselves or with assistance. Looking at purebred dogs, for example, most breeds are capable of breeding by themselves and without assistance. The English Bulldog, on the other hand, is generally ineffective in trying to do so and may need help to breed successfully.

Can a Purebred Dog Have Puppies With a Mutt?

Since a purebred and mutt are of the same species, they are able to mate and produce offspring. This can happen whether the male is purebred, and the female is a mutt, or the female is purebred, and the male is a mutt.

What If a Mutt Tied With My Bitch And I Already Bred Her?

When bitches go in estrus, their cycle generally will last for two weeks, but in some cases up to 3 weeks. She is more susceptible to getting pregnant while she is “prime,” or at the most fertile part of the cycle. Generally, you can tell when that is by her discharge becoming more watery. But, contrary to popular belief, a bitch can get pregnant at any time during estrus, as the sperm may survive for up to a week in the reproductive tract, and still be capable of fertilizing her eggs.

During normal breedings, you may let the dog and bitch ‘tie’ together every other day, for a total of 2 or 3 matings. If she has already mated once or twice and then ties with a mutt, she can become pregnant with some of the mutts puppies. The only way to really know for sure when the litter is produced is to do a DNA test on them, and figure out which ones are from the purposeful breeding.

How many breeds make up a mutt?

A mutt simply means the dog is of mixed breeding. This can be either from 2 purebred dogs, all the way up to a long line of mixed breeding. The term mutt was neologized in the late 1800s, and was a derogatory term referring to “stupid dogs” as well as “stupid people.”

Today, mutts are generally referred to as ‘mixed breeds’ or ‘All-American dogs.’

How do you unstick (untie) a dog after mating?

When a dog and a bitch “tie” together, it is best at this point to let nature take its course. You can separate them before they tie, but afterward could prove harmful for both.

When they get stuck together, it is because the dog’s organ will swell up inside the bitch, and her organ will “latch on.” If you forcibly try to untie them, it could cause rips and tears in one or both of their sexual organs. After the dog finishes with the final ejaculation, the swelling in his organ will start to subside, and they will be able to separate naturally. This will typically last for 15-20 minutes, but in some cases, they may stay tied for up to 30 minutes. If, for any reason, they are staying tied much longer than this, you should call your vet and see what they want you to do.

In conclusion, a purebred dog is just as capable of getting pregnant by a mixed breed as it is from another purebred dog. The best course for this is to maintain a watchful eye on your bitch when she is in heat and keep her separated from other dogs when you are unable to do so during her estrus phase.

If, however, unplanned breeding was to happen, you still have choices as to what would be the best course of action for you and your dog. The most important thing I can say is that if you keep the litter, make sure you find or provide excellent homes for them.

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I think animals are amazing, I couldn't imagine life without them.