The Breeding Tie in Mating Dogs

Pet Care


June 5, 2020

A dog breeding tie or the copulatory tie occurs when dogs are mating. The bulbus glandis near the penis tip has tissues that fill with blood when the penis is inside the vagina, causing a lock between the two mating dogs. 

When it occurs, the dog lifts his hind leg such that it faces away from the female dog, and they are left there in a pitiful and painful-looking butt to butt position.

The occurrence may worry you as a first-time breeder, but it should not cause you any alarm because it will go away after 5 to 60 minutes. However, it is a bad idea to forcefully separate the couple because it could cause painful and permanent damage to their reproductive organs. You could also end up with a nasty bite for privacy interference! Here are a few things you need to learn about the breeding tie and what to do if your dogs lock during mating.  

How Does a Dog Breeding Tie Occur?

When dogs are ready to mate, their courtship has to happen before intercourse. The females enter the “pre-heat” period before her eggs are mature enough for fertilization. During this period, she turns down mating advances from male dogs who are in constant pursuit of her because of the pheromones she gives off. 

During this courtship period, the female dog chooses a suitable dog to father her puppies, and even if intercourse occurs, her eggs are not fertile. You can tell when she’s ready to mate by how she plays with the male dog turning her hind towards him. This is usually the best time for breeding. However, if you want to know the exact day when fertility is at its optimum, it’s advised to take the female dog to the veterinary for a hormonal blood test. These tests inform breeders when the chances of a female conceiving a litter with the selected male dog are at their highest. 

During mating, the male dog mounts the female at her hind before penetrating the vagina. Although most experienced dogs have no trouble at this stage, it might be necessary to reassure the female if she is small-sized by petting and holding her softly by the rib-cage. When she is ready, she relaxes her vulva walls to allow penetration. After mounting and a successful penetration, the dog holds its mate with its forelegs and thrusts its lower body in their infamous “doggy style” as they ejaculate. 

A dog’s penis, like that of any other mammal, has two types of erectile tissue. One allows blood to flow to the penis shaft, making it hard for penetration, while the second type fills the glans. A dog has two bulbus glandis, one at the base of the glans and the second at the base of its penis. A copulatory tie occurs when the dog is thrusting away, and the glans tissues engorge inside the vagina while the vulva walls squeeze it tightly such that it is too hard to withdraw.  

Why Does the Breeding Tie Occur?

Dogs form a breeding tie when the tissues of the bulbus glandis near the tip of the shaft fill with blood and swell. The bulbus glandis becomes stiff and expands more than three times its normal size while the vaginal walls tighten hard around it. The vulva walls clasp around the bulbus glandis in a lock called the copulatory lock or a breeding tie.

At this point, no external intervention from the breeder should remove this lock. A breeding tie is not necessary for pregnancy to occur because the first ejaculations inside the vagina are usually full of sperms. However, the copulatory lock increases the chances of fertilization because seminal fluids do not spill, unlike when the dog dismounts without a tie.

Conventionally, it is the female dogs that visit the stud dogs with the genes that the owners want for their litter. Most breeders ensure that a breeding tie occurs once or twice during the mating sessions. When the dogs are tied, it allows more time for the sperms to swim to the eggs for successful fertilization.

During the lock, the dog is still releasing prostatic fluid that pushes the sperm-filled ejaculation inside the uterus and towards the eggs. However, you should note that a breeding tie does not guarantee pregnancy, especially if the eggs are not mature. When the bulbus glandis knots inside, you should keep the dogs calm so that their genitalia is not harmed.

In most cases, the male dog crosses its hind leg such that the two face away from each other. Don’t laugh when you find them in this position, nor try to frighten them for sudden movements that could be painful and cause damage to their organs. A breeding tie also occurs for other mammals in the Canid family, such as wolves, jackals, and coyotes. 

If a copulatory tie does not form when dogs are mating, then it is called slip mating. Slip mating pregnancy rates are slimmer because there might be semen spillage when the female moves about. If you are trying to get puppies from a certain male breed, you should separate your female dog from the other dogs. 

In nature, during the estrus or heat period, she attracts and might mate with many suitors. Therefore, the eggs can be fertilized by semen from different dogs with a mixture of breeds in the litter. To avoid this mixture, breeders physically separate the mating couple from the rest of the pack.  

How Long Does a Breeding Tie Last?

A breeding tie can last anywhere between 5 minutes to an hour. You should not interrupt tied dogs, but let them rest until the penis grows flaccid. Ensure that the dogs in a breeding tie are not in a stressful environment that might increase anxiety. Once knotting is finished, your dogs will be back to business as usual.  

What Should You Do When Your Dogs Are in a Breeding Tie?

First, you should not panic as a dog owner when you find your dogs in a copulatory tie. Understand that it is normal when dogs are mating. Secondly, you should try to keep the dogs calm until the knotting subsides. If the female panics, she might try to move about while still tied, and it could cause damage to the penis as the dogs keep pulling. Try to reassure her if you find her whimpering in pain to lessen her anxiety. 

Dog mating requires little human intervention except during selective breeding. Also, do not try to pour ice on the genitalia. Knotting ends sooner when the dogs relax. Anxiety for either the male or female dog might cause a prolonged copulatory tie.

A breeding tie is bound to go away after the mating process is over and the bulbus glandis deflates. At such a time, you can assist the dog to retract the penis into the hood to avoid damage if it is still exposed.


If there is a misalliance such that you find the wrong stud dog tied to your female dog, you should not separate them forcefully. Allow them to untie first and then take your female dog to a veterinarian within 24 hours for an injection to abort the conceived litter.

Dog mating has allowed breeding different varieties of dogs with preferable characteristics over the centuries. A breeding tie occurs naturally during mating and always goes away when the bulbus glandis flattens.