Dog Development - Embryology

YOUR DOG’S PREGNANCY WEEK BY WEEK

Female dogs (bitches) generally give birth around 63 days after conception, with a few variations between 56 and 70 days depending on the exact time of fertilisation in relation to mating. This step by step guide tells you what to expect during your dog’s pregnancy and gives you practical advice and important information to help things run smoothly.

Before considering pregnancy for your bitch there are a few important factors to consider.  It is recommended that all vaccinations should be up to date for the duration of the pregnancy and feeding (lactating) period, so check with your vet about this before you mate your bitch.  You should also not allow your bitch to have puppies until she is fully grown and mature herself.  For most breeds of dog, having a litter of puppies is not recommend until the bitch is at least 2 years of age.  Equally, it is inadvisable to breed from a bitch that is too mature and many vets recommend the ideal age for delivering a litter as being between 2 and 5 years old but the upper limit will depend on your dog, their breed and reproductive history and your vet’s specific advice.  You should also consult your vet, an experienced breeder of your breed of dog or the Kennel Club for advice on any screening schemes or precautionary measures that are advised for your particular breed of dog before you commit to breeding from your pet.

Week 1:   
 Mating

Mating between dogs is often preceded by a courting phase during which they play. Penetration can occur rapidly though, sometimes in under a minute. There may be a number of attempts, particularly if the partners are lacking in experience.

The male mounts the bitch and penetrates her, prompting a vaginal reflex that traps the male until the act of mating is complete. This lock phenomenon can keep the two dogs together for 15 to 30 minutes and may look odd to us, especially if the male does a 180 degree turn! It is important not to try separating them at this point by any means, as this could cause damage.

The mating process does not necessarily mean that fertilisation was successful; it may have taken place at a time when the bitch’s fertility had not yet reached its peak. Equally, the sperm can survive in the uterus for up to seven days, so fertilisation may take place several days after mating. To increase the chances of a pregnancy occurring, mating is often carried out twice, with a two day interval between the attempts.  Some breeders also use a series of progesterone blood tests for their bitch, (which are available at most veterinary surgeries), to identify the optimum window of fertility for their bitch before taking her for mating.

Fertilisationovulation_medium
Gestation begins when the female’s ova (eggs) are fertilised by the male spermatozoa (sperm). The fertilised egg is the first component of a new living being!

The embryos start off very high up in the uterus, but towards the end of the first week they migrate down towards the uterine horns. Here they float around within the uterine liquid.

Week 2:   
Maintenance 
When your dog’s heat has come to an end you may groom her as usual. The embryos are well protected in the uterus and gentle grooming (avoiding any stress) should not cause any concerns.

During this initial phase of gestation (from mating until around day 35) the goal is to maintain your dog’s ideal weight. Early weight gain is not recommended for optimal health. Weight gain during the first 42 days should not exceed 10% of the ideal weight. Your dog’s energy requirements remain stable at this point, the embryos do not develop greatly (in terms of their size) and no nutritional change is required, unless recommended by your vet.

If the bitch is being fed an appropriate, balanced and complete diet no vitamin or mineral supplements are required during gestation (unless your vet has specifically prescribed otherwise).

Week 3:  
Nidation

The embryos become embedded in the uterine lining where they will subsequently develop. They will be progressively enveloped in a protective membrane that provides them with the necessary supply of nutrients.

Week 4: 
 Confirm gestation (pregnancy)

Visit your vet around day 25, as they can perform an ultrasound to establish a reliable diagnosis of pregnancy. This will give you some idea of the size of the litter (although detecting exact numbers is often not possible), as well as potentially detecting any abnormalities. Alternatively, your vet can also diagnose gestation by doing a blood test to determine the level of relaxin, a hormone only created by the placenta. Whichever method your vet chooses, it is very useful to confirm your dog’s pregnancy as early as possible in order to properly monitor her condition.

Week 5: 
Foetal stage
Day 35 marks the end of embryogenesis (the first phase of gestation). The organs are now all beginning to form, and we now refer to the embryo as a foetus. During this foetal phase (and in particular from the 40th day onwards) the foetus’ weight will increase by around 75%.

Week 6 
 The turning point

From day 42 the pace changes, as your bitch enters the third and final phase of gestation. The foetus is developing fast now. Claws will be developing, the skeleton begins to solidify, and the foetus will gain weight rapidly.

As a result, your dog’s nutritional requirements will change, as she now requires a diet with higher energy, protein and mineral content. It may seem contradictory, but you may well observe a drop in her appetite as her distended abdomen may make eating normal meals harder for her. Getting her to eat the right food is essential and offering her several smaller meals throughout the day, instead of 2 larger meals, may also help if you find she is not eating enough to maintain a good body condition.

ROYAL CANIN® has a range of diets specifically developed for optimal nutrition during pregnancy and lactation. Depending on the size of your dog’s breed you may choose Mini Starter, Medium Starter, Maxi Starter or Giant Starter. Starter Mousse is also available. Palatable, high in energy content and very digestible, Starter and Starter Mousse have been designed as a solution to all of her increasing needs during gestation. Remember to transition gradually (over at least 5 days) from one food to the next to minimise the likelihood of any digestive upsets.

Week 7:  
Hair

By day 45 the foetus’ first hairs will start to appear, and the skeleton begins to ossify (solidify). The coat and bones are some of the last areas to develop.

Worming
Parasites are a concern, as they have the potential to infect the puppies at birth. It is therefore essential to make an appointment with your vet to have your bitch wormed. The vet will advise you on which product to use.

Prepare for whelping
To avoid being caught by surprise, start preparing the place for your bitch to whelp as early as you can. The chosen place must be quiet and removed from the hustle and bustle of the household. Don’t forget that the room must be kept warm, as newborns need heat. The floor must be easy to clean. The mother and pups will need to use this place for a few weeks, well away from any excitement so as not to disturb suckling.


Week 8:  
X-ray
Around day 50 the foetus’ skeleton will have ossified, so you may choose to ask your vet whether they feel it is necessary to perform an x-ray. In many cases, an x-ray will confirm the number of foetuses; so when it comes to whelping this will reassure you that all puppies have been delivered.   Some vets may not feel an x-ray is necessary, however.

Check the bedding
Check that you have enough linen to change the bedding in the whelping area regularly. Linen must be completely dry when you use it. Make sure you have an extra heater available to provide a safe source of warmth, without risking burning the puppies or creating draughts but ensuring an ideal temperature when they are born.  The room should ideally be around 24-26°C during the first week, because puppies can’t regulate their body temperature at birth.  Adequate humidity levels should also be maintained.

Milk
Milk begins to flow from the bitch’s teats about one week prior to whelping. This is not, however, reliable in determining the date of whelping.

Even though it is comforting to see that your dog will be able to feed her puppies, make sure you have a tub of ROYAL CANIN Babydog Milk available too. This is specially developed to help you cope with any feeding problems or failure in milk production by the mother. Read the instructions and the advice on hygiene. Having milk in stock before the puppies arrive will make things a lot easier for you if you do have to feed the puppies yourself.




Week 9 

 Final countdown
By instinct, the bitch will seek out a quiet place to make her nest and may seem on edge; don’t be worried by this. If you haven’t done so already, set up the whelping nest in the selected place, well away from any excitement and somewhere that is easy for her to reach and get used to sleeping in. It’s a good idea to line a box with thick layers of newspaper so that she’s properly insulated from the floor. You can cover the papers with clean towels or sheets or any other material to make it comfortable; the linen and lining paper will have to be frequently changed once the pups are born.

Unless you think it will cause too much stress, it is advisable to ensure that the rear end and the teats of the bitch are clean and easily accessible so that she can give birth and feed her pups in the most hygienic conditions possible. If she has long hair, you can carefully clear the area around the vulva and teats using round tipped scissors.

To avoid being taken by surprise, take her temperature three times a day. A drop of around 1°C compared to the average of the previous day is often a sign that labour is about to start; as the drop typically occurs within 48 hours of whelping. 

Pre-birth checklist

• Whelping nest is set up in a quiet place in the house.
• Whelping room kept at around 24-26°C.
• Tin of puppy milk in stock, just in case.
• Clean linen and/or towels, to change the bed after whelping.
• Disposable gloves.
• Kitchen paper.
• Scales to weigh the puppies.

Note down the phone number of your vet.

Whelping (giving birth)
Generally, most bitches manage very well by themselves. Your role mainly consists of providing her with quiet surroundings and your comforting presence. But if you do have any concerns in advance, do ask your vet for advice.
Labour can last from just a few minutes to several hours. Check on your bitch every 15 minutes or so to make sure everything is going smoothly, taking care not to show her if you are worried.
Once the first puppy is delivered, if your bitch doesn’t tear open the foetal sack herself you can do it yourself wearing disposable gloves over clean hands. Subsequent puppies will be born within anything from a few minutes to four hours later. Typically, most puppies will be born within 1-2 hours of the last puppy, although greater variation can occur.  Remember it is normal for some of the puppies to be born with their back feet first, in what is often (incorrectly in dogs) described as the “breech” position (this is actually when the bottom is delivered first, with back feet tucked forwards).
Don’t worry if your bitch eats the placenta as soon as it is expelled, this is normal. 
 What to do

• Check progress regularly.
• Call your vet if the contractions are unproductive or if you are worried.
• If you need to invigorate a newborn puppy, rub it gently with a towel.

What NOT to do

• Never pull the puppies, especially by the paws, to help their expulsion, this could cause serious damage.
• Never put the puppies in cold water, it is unlikely you will need to use water for the puppies at all in the first few weeks, unless it has been recommended by your vet.
• Never use a hairdryer, as there is a real risk of burns and dehydration.