Cats and Dogs
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What would happen if two male dogs mate?

Everything you wanted to know about the female season

Many clients have asked me about seasons (also known as heat) cycles so they can make sure their female (also known as “bitch” ) does not accidentally become pregnant, so I thought a short article would be helpful.

When do female dogs come into season?

This can vary by individual and breed. Typically, a female will come into season at around 6 months old, but it can occur from 4 months up until more than two years. Some breeds, such as the whippet, tend to come in to season around 13 months. It’s a good idea to ask your breeder what age the mother dog first came into season as this can be a useful guide as to when to expect your female to come into season. If you are aiming to breed (and don’t enter into this lightly, it’s an enormous responsibility as well as expensive if you do it properly), it’s very important NOT to let a female mate for the first two seasons due to lower egg quality and also because you will not know her temperament and her joints will not be developed enough for carrying a litter. A female will usually come into season twice a year, but once a year for giant breeds.

How long does a season (heat) last?

Typically, between 2-4 weeks, this is why we ask you to give your female dog four full weeks before coming back to training classes if she comes into season during one of our training courses. By the way, because a season is impossible to accurately predict, we will offset your missed sessions against the next course, so you will not be out of pocket.

When should I avoid letting my in-season female meet intact (uncastrated) male dogs to avoid a pregnancy?

To answer this I will need to explain a little about the dog’s reproductive cycle.

Proestrus stage:

The proestrus stage is the first stage of a heat cycle and it lasts approximately 9-10 days, during this time she will normally be bleeding. Sometimes you don’t see the blood if your female is very good at keeping herself clean. But you would notice her cleaning herself more. She will also very likely urinate more as she is marketing her fertility state to other males in the vicinity. You will also notice that her vulva (female genitals) will swell up significantly and will protrude outwards. Mostly, (but not always) the female will not be interested in mating a male at this time, even if he is interested in her. After about 9-10 days, the bleeding will become more watery, or stop. It is at this time your female will, most likely, be at her most fertile. This proestrus stage can last as long as 20 days in some dogs. So the end of bleeding can be a more useful indicator of peak fertility.

Estrus stage (FERTILE STAGE):

The estrus stage occurs after the proestrus stage, approximately from 9-10 days to 15-19 days. During this stage, your female will most likely be very receptive to being mated by any male and will even hunt them down and offer herself (fluzy!). Every male in the district will be tracking her by scent. There will be nothing you can do to stop her being mated if you take out your female, and you will likely end up with an unwanted litter. Many people think that once the bleeding stops, the season is over, when in fact, usually, when the bleeding stops and becomes more watery, she is at her most fertile and most likely to get pregnant. However, it is important to note that it can be possible for your female to become pregnant right up until the end of her season, up to four weeks. After estrus stage, the vulva should return to normal, at this stage, she is no longer fertile and she is safe to mix with intact male dogs.

Diestrus stage:

This is the stage that follows oestrus. The female will no longer be receptive to being mated. This stage lasts for about two months. Progestrone levels will peak three — four weeks after the start of diestrus and then revert to normal levels by the end of this stage. These hormone levels change regardless of whether or not the female is pregnant. As these hormone changes are occurring, it is important not to spay a female until after this stage. It is the ovaries that regulate the hormones, once removed, they will not be able to regulate hormone levels. This can leave your female in a state of unbalanced hormones, which can lead to ongoing behaviour problems if hormonally mediated behaviour problems occurred during the season.

Phantom Pregnancy

Some females will develop what is known as a «phantom pregnancy» during the diestrus stage. She will produce milk and you may see behaviour changes such as protection of resources and nesting. Some females manage this stage with no problems, but sometimes behaviour problems can occur. Also, it has been suggested that phantom pregnancy could pre-dispose the female to developing pyometra, a potentially fatal infection of the uterus. If your female’s behaviour changes during this stage, it is worth speaking to your vet. Monitor for elevated temperature (making sure that you use an ear thermometer, or lubricate the thermometer if inserting this anally to avoid inflicting pain and discomfort on her). The first signs of pyometra can often be changes in behaviour such as going off food, becoming lethargic. There will usually be a smelly discharge from the vulva. At this stage an emergency vet visit is necessary. Pyometra can kill very quickly.

Etiquettes for walking an in-season female.

Please don’t walk your in-season female dog in public. Her scent will attract every intact male in your neighbourhood. Even castrated dogs will hunt down the scent of an in-season female and even a castrated male dog can “mate” with her. The mating (tying) process can take many minutes (typically half an hour) during which time, your female and the male will be locked together. Better to avoid this embarrassment. You will not want just ANY dog to mate your bitch. Dogs can carry sexually transmitted diseases just as humans can, one of which is a sexually transmitted form of cancer! Also, you should be carefully choosing a mate based on being free from genetic disorders and having an exemplary (perfect) temperament.

Please be responsible. there are so very many dogs in rescue centres, the last thing anyone needs is more unplanned litters. Only breed from your dog if you are prepared to breed from dogs that have no behaviour problems (especially aggression), undertake DNA testing and are knowledgeable about how to choose the right sire for your female. Breeding a litter is not an easy thing that you must leave to the mother dog. You will need to be at home with her for several months to supervise and provide appropriate support. Preparing to breed an ideal litter will cost you in excess of £1,000.00 before you even have the litter. C-Section is common and can cost several thousands of pounds. Having a properly planned litter is not a profitable activity.


How do I know if a male dog is castrated?

If you look at the male dog from behind, if a dog is not castrated, you will be able to see his testicles. If there are no testicles, perhaps just a flap of skin hanging down, the dog has been castrated, or chemically castrated.

Can my uncastrated dog still mate with an in — season female?

Your dog can still tie. This means he will penetrate the female but, if he has been castrated, he will not be able to impregnate her. However, the tie can last for many minutes (typically around half an hour), during which time you will not be able to separate them. You should never try to separate them when tied as you could cause injury.

How do I prevent my intact male dog from mating my in-season bitch when they live together?

Please do not keep them together during this time. The male will likely become very frustrated at not being able to reach his fertile friend, and this can — and does — lead to aggressive outbursts. Male dogs can be very creative at finding ways to get to an in-season female, it would be almost impossible to prevent them from mating. Be fair on him and board him with a friend or family member until her season is finished.

Can my female dog get pregnant from more than one male dog?

Yes, you can have puppies from different fathers if your dog has mated more than once. This is called “mixed paternity litter”.

Denise Nuttall B.Sc (Hons), M.Res

Full Member APBC (Association of Pet Behaviour Counsellors), Full Member TCBTS (The Canine Training & Behaviour Society)

Animal Behaviour & Training Council (ABTC) Registered Animal Training Instructor
Animal Behaviour & Training Council (ABTC) Registered Clinical Animal Behaviourist

Reproduction in Dogs

Reproductive Season, Heat, Oestrus, And Pregnancy Tests

Puberty or sexual maturity in the female dog usually occurs around six months of age. The smaller breeds tend to go into oestrus or «heat» earlier and some females can have their first «heat» cycle as early as four months of age. On the other hand, the large and giant breeds can be up to two years old before they come into heat for the first time.

How Often Do Female Dogs Come Into Heat?

On average this occurs about twice a year or every six months, although it varies from dog to dog. When cycling first begins, there may be a great deal of variability in the time between cycles. This is normal. Some females take eighteen months to two years to develop a regular cycle.

There is no evidence that irregular heat cycles predispose the dog to false pregnancies or pyometra (uterine infection). Small breeds tend to cycle more regularly than the larger breeds. Three and occasionally four heat cycles per year can be normal in some females.

Very large breeds may only have a «heat» cycle once every 12-18 months. In most giant breeds (Great Danes, Irish Wolfhounds, St Bernard’s, etc.) an oestrus cycle every twelve months is common.

How Long Does A «Heat» Cycle Or Oestrus Last?

«Heat» cycles vary, but average two to three weeks for most dogs. «Heat» should be considered to begin with the first signs of vulvar discharge, or when the female begins licking or paying attention to her vulva. The vulva will begin to appear swollen. It ends when all discharge ceases and the vulva has returned to its normal size.

What Are The Signs Of A Dog In «Heat»?

The most notable sign is vaginal bleeding. This may not become apparent until a few days after the female has actually come into oestrus. Vulvar swelling should be taken as the first sign in addition to the female paying increased attention (such as licking the area) to her rear end.

From the beginning of the heat period she will be attractive to male dogs, but will usually not be receptive, or allow mating, until about 7-10 days later. The discharge will usually become less bloodstained at this time.

Some females experience heavy vaginal bleeding during oestrus. If you are concerned, please consult your veterinarian.

You may also find that she is passing small quantities of urine more frequently. The urine contains both pheromones and hormones which signal any interested males that she will be receptive soon.

How Soon After An Oestrous Cycle Can A Bitch Be Desexed?

When an animal is in season, there is an increased blood supply to both the uterus and the ovaries. Dogs can be desexed whilst they are in season, but generally we try to do the surgery 8 weeks after the start of their last oestrous cycle.

When Is The Best Time To Mate Your Dog?

This can be difficult. Most ovulate and are receptive around the eleventh day of oestrus. The discharge will then be less bloody and the female will be actively looking for a male. However, ovulation may occur either early or late during the «heat» cycle.

Mating Age For Male Dogs:

A male dog is mature for mating possibly from 4 months onwards but generally, it is considered at about 6 months.

Are There Any Tests To Determine When To Mate Your Dog?

Yes. There are two simple tests that your veterinarian can perform.

  1. Vaginal smear test — A simple microscopic examination of vaginal cells will detect changes in cell appearance and numbers. This test has been used for many years and is reasonably reliable. It is non-invasive and does not cause discomfort for the female. Most vaginal smears are performed serially, over several days, to look for changes in the cells that predict ovulation and the best time for breeding.
  2. Serum progesterone test — This measures the progesterone level in the blood. This test is very sensitive and has become popular due to its accuracy. Some pets will require several tests to predict ovulation.

Both tests can be performed at the veterinary practice. The serum progesterone test gives a very good indication of when mating is most likely to be successful and is useful for females that have a history of unsuccessful mating or for breeding dogs that have to travel a considerable distance to the male dog.

What Can You Do To Ensure Mating Is Successful?

Surprisingly, male dogs appear to be more stress sensitive than females during mating. Successful matings are more common when the male dog is in its own environment. For this reason, females are usually taken to the male dog’s home for breeding.

The time of mating is extremely critical and it is highly recommended that you have tested your female to determine the optimal days for breeding. For most females, the best time for breeding is between the tenth and fourteenth day of oestrus. However, some females ovulate as early as the third or fourth day or as late as the eighteenth day. Blood tests will assist in determining the best period for your dog.

It is normal to arrange for two matings for your dog, often twenty-four or forty-eight hours apart. Check these details with the owner of the stud when making initial enquiries. Also, inquire as to the procedure if your female dog does not become pregnant as a result of the stud service. It is common for owners of the male dog to offer a free service next time.

You were told that your female had «tied» well with a dog and that only one service was necessary. What does this mean?

The genital anatomy of the male and female is such that during coitus part of the dog’s penis (the bulbis glandis) enlarges and is held firmly by the contracted muscles of the vagina, thus preventing the penis from being withdrawn. This is the «tie» that is considered a desirable feature of a successful mating. It is important to note that pregnancy can occur without a «tie». Once «tied» the male dog will often step over the female or be turned by handlers into a position so that the animals are back to back.

You found your dog «tied» to a female dog during a mismating. Was there anything you could do to separate them?

There is little point in trying to separate animals that are locked in this way. Buckets of cold water, water pistols, cap guns, and so forth do little to speed up the process of separation and merely upset the dogs. In fact, forced separation can result in serious injury to the female and should be avoided.

If a mismating has occurred, discuss it with your veterinarian as soon as possible.

Why you should spay/neuter your pet

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The choice to spay or neuter your pet may be one of the most important decisions you make impacting their long-term health—and your wallet!

Your pet’s health and longevity

The average lifespan of spayed and neutered cats and dogs is demonstrably longer than the lifespan of those not. A University of Georgia study, based on the medical records of more than 70,000 animal patients, found that the life expectancy of neutered male dogs was 13.8% longer and that of spayed female dogs was 26.3% longer. The average age of death of intact dogs was 7.9 years versus a significantly older 9.4 years for altered dogs.

Another study, conducted by Banfield Pet Hospitals on a database of 2.2 million dogs and 460,000 cats reflected similar findings, concluding that neutered male dogs lived 18% longer and spayed female dogs lived 23% longer. Spayed female cats in the study lived 39% longer and neutered male cats lived 62% longer.

The reduced lifespan of unaltered pets can, in part, be attributed to an increased urge to roam. Such roaming can expose them to fights with other animals, resulting in injuries and infections, trauma from vehicle strikes and other accidental mishaps.

A contributor to the increased longevity of altered pets is their reduced risk of certain types of cancers. Intact female cats and dogs have a greater chance of developing pyometra (a potentially fatal uterine infection) and uterine, mammary gland and other cancers of the reproductive system. Neutering male pets eliminates their risk of testicular cancer and eliminates the possibility of developing benign prostatic hyperplasia which can affect the ability to defecate.

A handful of studies may appear to challenge the health benefits of widespread spaying/neutering of companion pets by raising concerns that these surgeries may predispose some altered dogs to certain orthopedic conditions and cancers. As a result, they have caused some pet owners to question altering their pets at an early age or altering them at all. However, on closer examination, the results of these studies pertain specifically to male dogs of certain giant breeds (dogs typically weighing 90-100 pounds or more) and their conclusions should not be generalized to other breeds of dogs, or to other species, including cats.

Studies on this subject are mostly retrospective in nature, meaning they are looking at existing research data. Therefore, while they evaluate for associations between a cause and an outcome, they cannot definitely establish causality. It’s also important to understand that while a study can find something to be statistically significant, it does not always mean there is a clinically significant difference. While all study designs have benefits and challenges, there is a need for repeatable prospective studies (new research) done by a variety of researchers in various geographic locations and with significant sample sizes to provide stronger data in all aspects of this subject.

Weight gain after spay/neuter can occur in both dogs and cats because of decreased metabolism and maturation. It is important to monitor a pet’s weight following surgery and adjust their diet appropriately with the help of a veterinarian to prevent weight gain.

These are the best general recommendations that can be drawn from a thorough analysis of research currently available:

  • Owned cats should be altered before they are 5 months old as they can become pregnant at 4 months of age and older.
  • Owned female dogs should be spayed before they are 5 months old.
  • Owned small, medium and large breed male dogs should be neutered before they are 5 months old.
  • Owned giant breed male dogs who are house pets should be neutered after growth stops, between 12 to 15 months of age due to orthopedic concerns.
  • Owned giant breed male dogs who roam freely should be neutered before they are 5 months old due to the population concerns of unintended breeding.
  • Shelter animals should be altered prior to adoption—ideally, as early as 6 weeks old; however, some states may require waiting until the animals are 8 weeks old.
  • Community cats should be altered via TNR (trap-neuter-return) at any age after 6 weeks old, although, again, some states may require waiting until the kittens are at least 8 weeks old.
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