Yes, large dogs can get smaller dogs pregnant. Technically, any sized dog can get any other sized dog pregnant. Fertilization does not care about the size of the dogs involved.
However, it is a bit more difficult for highly different-sized dogs to mate. The size difference can make the act of mating a bit difficult, so there is less of a chance that it will happen naturally.
Dogs tend to be quite persistent, though. If a male and a female dog are left unsupervised when the female is in heat, there is a good chance that a litter will occur – even if there is a significant size difference between the two animals.
There are serious medical concerns when a small female becomes pregnant by a large male. Because the male is larger, the fetuses likely will be as well. This larger size can cause all sorts of health concerns for the female during pregnancy and birth.
For that reason, it is not recommended that females carry the puppies of larger dogs. If breeders are trying to combine two breeds of different sizes, they often artificially inseminate a larger female with the sperm of a smaller male. This process is much safer for the female and puppies.
If a female accidentally becomes pregnant by a much bigger male, there are many critical medical decisions that you may have to make.
How to Breed a Smaller Male Dog With a Larger Female
In general, if a smaller male dog is determined to mate with a larger female dog, his sexual desire will be strong enough that he will find a way. However, this doesn’t mean there aren’t risks involved and your male dog may need a helping hand. It is best to let him begin proceedings alone but be sure to step in if you see things going awry. It is also best practice to take both sexual partners for a full health check before encouraging them to mate, as any existing health conditions may be exacerbated by the process or may not make them a suitable genetic partner.
The first step your male dog may struggle with is mounting the female. He needs enough height to get up on top of her to penetrate her. If he cannot get high enough, you will need to find a suitable sturdy platform to give him the boost that he needs. Ensure you place it on a non-skid surface and that it has non-skid feet so that your dog will feel sure of his footing. It is also worth introducing the mating partners before the onset of the female’s fertile period (9-14 days after she goes into heat), so they can get to know one another’s smell. This should reduce anxiety levels next time around, meaning that all the dogs’ energy can be focused only on the task ahead.
Once the male has reached a height where he can penetrate the female, he may need some help to stay there. It can take a couple of minutes for the bulbous glands in his penis to begin to swell in preparation for the lock. Whilst this is happening, you can place your hand under his tail and push him firmly up so that his chest lifts onto the female’s back and his feet come off the floor. Hold him here until the male and female are both safely locked.
The next step is possibly the most important as it is where the most damage can occur. The mating lock can take place from anywhere between 15 and 40 minutes. A male dog who is of a similar size to the female will usually lift his leg over the female and turn his back to her. The two dogs will then stand back to back for the duration of the copulatory lock process. However, for a small male dog, lifting his leg over a huge female dog and turning around will not be an easy task. You may need to lift his leg over very gently and help turn him around. This process can seriously injure both dogs if not done correctly.
Once your dog has turned around he will still need some help to stay leveled with the female’s vagina until the lock is complete and he is released. You can place your dog back on his sturdy platform but ensure it is high enough to keep him reasonably leveled with the female as an extreme pulling on his penis may cause damage.
Throughout this process, you may also need to hold the female still so that she isn’t dragging the smaller male around by his penis. Depending on the height discrepancy, sometimes it is enough to just hold the female still throughout the whole process while the male gets to work. You may also be able to encourage the female to lie down on a cushion, so the male can get to her more easily. Never try to force the two dogs apart; always let lock finish naturally. In extreme circumstances, the process can take a full hour so be patient and never leave the dogs unsupervised.
During the Mating Process
Firstly, there are potential health problems with the act of breeding itself. If the size difference is significant, the male could potentially seriously injure the female when attempting to breed with her.
The breed of the female does matter – not necessarily just the size. Some petite females have sensitive spines and are prone to things like intervertebral disk disease (IVDD). While this isn’t an issue in regard to mating with a dog of a similar size (usually), it can be a problem with much bigger males. The male could potentially injure the female’s spinal column, causing pain and paralysis.
In most cases, the female won’t have to hold up the whole weight of the male. However, when the size is substantially different, this doesn’t always matter.
Some males are rougher during the mating process than others. There is often a lot of pawing and gentle biting going on. Usually, this doesn’t cause significant injuries to either dog. However, when the male is larger than the female, this pawing can cause injury.
It is also possible for the male’s penis to be much too large for the female. Attempts at mating could result in the female’s vagina being ripped or otherwise mutilated.
If the male successfully penetrates and forms a lock, the dogs must be kept very still. The weight of the female will not keep the larger male in place. He may very well decide to run around the yard, dragging the distressed female around with him. As you can imagine, this situation can be highly distressing for the female – and potentially even be fatal.
The male may also decide to lay down after the lock, potentially squishing the female if she is too small. It is unlikely he will turn around and navigate away from the female if she is exceedingly tiny.
Health Concerns When Breeding a Larger Male with a Smaller Female
Whether it was purposeful or not, several problems often arise when a small female is carrying the puppies of a substantially larger male.
FAQ
Does size matter in dog mating?
Why do dogs mate in public?