Can a dog have two litters at the same time? What to Know

So, can puppies in the same litter have different fathers?

Yes! Female dogs can be mated by more than one dog during their fertile period meaning a mixture of sperm is present and waiting to fertilise her eggs when she ovulates. The technical term for this is superfecundation. This can also happen in other species, including humans where fraternal twins could each have a different father.

First, what is superfecundation in dogs?

Can a dog have two litters at the same time?

“Superfecundation occurs when a female mates with two or more males,” explains Donald Shellenberger, DVM, of VCA Smoketown Animal Hospital in Lancaster, Pennsylvania. “One litter can potentially have multiple fathers as long as they all mate with the female in the optimum time of conception.”

This means a litter might have two or even more fathers. This situation is often seen in stray animals, as well as in un-spayed females who live in close quarters with one or more intact male dogs. (In case you’re wondering, a single puppy cannot have multiple fathers; each individual puppy in a litter has only one father.)

“It’s probably more common in dogs than cats since cats ovulate with copulation,” Dr. Shellenberger says. “It can happen with other species, especially in animals with multiple eggs and large litter sizes.”

How can I tell if puppies in the same litter have a different father?

In some cases, it will be very obvious if puppies are from a different litter. For example, if you were intentionally mating your purebred Labrador with another Labrador, and some of her puppies look like labs but the others come out looking like poodles, then a mismating could have occurred! Your female dog may have been accidentally being mated by a poodle as well as the intended labrador during her fertile window.

However, if your dog was mated by two different sires of the same breed then you may not actually realise that the litter contains a mixture of DNA unless you saw both of the matings take place or they were planned.

So some litters you may not be able to tell without DNA testing whereas others are a bit more obvious!

Most of the time matings are very controlled affairs with breeders being aware of their bitches fertile period and only allowing them to mate with the male stud dog of their choice. However, accidents can happen! If your female dog escapes and gets out of your garden or runs off on a walk then a mismating could occur. Female dogs give off very strong scent signals, so an entire male dog could very quickly find and mate her.

Accidents happen very commonly within households too. If you have a mixture of entire male and female dogs then a mismating is much more likely to happen, despite your best efforts to keep them apart.

The Kennel Club now allows registrations of pedigree litters where planned dual matings have occurred. Since DNA testing has become more readily available these puppies can be easily checked with a cheek swab and the relevant sire recorded in the details for their registration. In the past, permission had to be sought in advance for this type of mating. But it has now been considered acceptable practice.

It is possible to have puppies within the same litter that are sired by two different fathers. Sperm can survive for several days in the bitches reproductive tract. So a couple of matings could lead to the fertilisation of different eggs by different fathers. In some cases, this is obvious (usually when there has been an accidental mismating!). But other times it can be hard to know for sure without DNA testing the puppies.

Should You Get Two Puppies From The Same Litter?