How to Breed Guinea Pigs
There is quite a lot to think about if you want to breed guinea pigs before you start, but the process itself is usually trouble free as guinea pig females make exemplary mothers and rarely hurt or abandon their young.
Another good thing with guinea pigs is that they generally don't turn up in big quantities in rescue centres, so if you breed responsibly you can do so without worrying that you are likely to be adding to the numbers of unwanted pets.
Like all babies, guinea pigs are very endearing and it is rewarding to watch them grow up under the gentle care of their mother.
Guinea Pig Reproductive Fact File
Capable of breeding from
Ideal age for 1st litter
Average litter size
Can breed as early as 8 weeks. So you must separate the male and female babies by this age.
Ideally the female should be 6 months - 1 year old. The male should be at least 6 months old.
Female guinea pigs come into heat for up to12 hours every 16 days throughout the year
Guinea pigs are pregnant for 9 - 10 weeks
Why do you Want to Breed Guinea Pigs?
You need to know what your goal is before you make a start breeding guinea pigs. These are some possible goals:
- To introduce the children to the reproductive cycle.
- My pet guinea pig has such a lovely temperament that I'd like to keep some baby guinea pigs from her.
- To show my home-bred guinea pigs in pedigree classes.
- To sell to local pet shops and other pet owners
- I'm interested in guinea pig genetics and want to try to breed a certain colour/coat combination.
There are different things to consider depending what your aim is.
Basics of Guinea Pig Breeding
If you decide to breed from your guinea pigs you must be prepared to keep and care for the young in the event that you are unable to sell the babies. They are your responsibility. As a responsible breeder you should also offer to take back any you sell if the new owners are no longer able to keep them.
1) Select a healthy well built boar (male) and sow (female). The ideal age is 6 -12 months for the sow's first litter. You can use a boar for breeding from 6 months. The boars and sows can breed when they are younger but it is advisable to let them mature and fill out before pairing them up. If your guinea pigs live outside don't breed from them in winter when it will be hard for the babies to stay warm.
2) Introduce the boar to the sow - there are rarely any problems, but it is worth keeping an eye on them to begin with to make sure they are getting on together. When the boar is interested in the sow he will often start making an excited chuntering sound and walk round her in a funny stiff legged way.
3) The pair can stay together for 17- 48 days. The sow will come on heat approximately every 16 days, so leaving them together for longer means that if she doesn't get pregnant in her first heat cycle, she might in the second or third one.
4) The boar should be taken away by day 48, although he probably won't hurt the babies if he stays with them, he will want to mate the mother straight away and you don't want her having two litters in close succession.
5) Usually it will be obvious whether the sow is pregnant - she will look ungainly and as though she's carrying a grapefruit inside her. However, if it is a small litter it can be hard to tell. If she usually lives with another female guinea pig you could put her back in with her friend. Other females are usually happy to be 'aunty' to the babies.
Although the sow won't make any sort of a nest for her babies it is worth making sure there is plenty of comfortable bedding for the pregnant sow. Hay is often recommended as bedding rather than straw for guinea pigs for being less likely to cause corneal ulcers (from bedding scratching the eye).
6) After 9-10 weeks gestation (pregnancy) the baby guinea pigs will be born, usually at night.
In all my time of breeding guinea pigs I only saw the babies being born once which was a rare occasion when the sow gave birth during the day. Guinea pigs usually have 3-5 babies and they rarely have any problems giving birth..
They don't make nests to have the babies in so will give birth anywhere in their hutch or pen. The babies are born covered in the birth sack which the sow will quickly clean off them, They are born with fur and their eyes open and will start to follow their mother around straight away.
It is fine to pick up the babies to check them over and make sure they are ok, but then leave them in peace with their mum so they can bond and suckle.
7) The baby guinea pigs will start to sample solid food from about 2 weeks old but they will continue to suckle from the sow for another 2 or 3 weeks. At this age you should be handling the babies regularly so that they are used to human contact.
They should be kept with their mother until they are 6 weeks old.
8) At 6 weeks old separate any male baby guinea pigs from their sisters and mother. They can become sexually mature as early as 2 months old and you don't want to risk them breeding at that age.
9) If you plan to sell the babies it is worth separating the females from their mother too at 6 weeks old and keep them for a further 2 weeks so that you know they are properly weaned from their mother and doing well before they go to their new homes at 8 weeks old.
Some Guinea Pig BreedsClick thumbnail to view full-size
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Breeding Pedigree Guinea Pigs
If you plan to show your guinea pigs in pedigree classes or just like the idea of breeding pedigree animals you will need to start off with stock which conforms to the breed standards of the 'Guinea Pig Council' in your country for example 'The British Cavy Council'. (Cavy is just another word for guinea pig.)
There are lots of breeds and colours to choose from. There are 4 main coat types: short coat, long coat, such as the sheltie and the Peruvian, rex and a similar gene known as teddy, which both give a hedgehog looking effect to the coat and Abyssinian which is also known as 'rosetted' because the hair grows in distinct rosettes over the guinea pigs' body. To make matters more complicated there is a long coated rex breed known as the texel and whilst Peruvians aren't long coated Abyssinian they do have two 'rosettes' over their haunches.
When you select your boar and sow for breeding, your aim is for them to produce babies which are as close to the breed standard as possible. So if your sow has good coat type and markings but a weak head shape you might look for a boar with an especially strong headshape to pair her with.
Guinea Pig Genetics
If you are breeding pedigree guinea pigs you might become interested in the genetics of different coat types and patterns, or you might just have an interest in it already and be curious as to how to breed a certain colour or coat in a guinea pig.
You might decide just to experiment with pairing different guinea pigs together and recording the results and then trying different combinations of boar and sow for your next litter.
Alternatively you might be interested to read this article on genetics from the British Cavy Council. It is astonishing how complicated even a single colour such as black is genetically. For example the black gene can be diluted by the pink eye dilution gene to produce a pale colour known as lilac. However if black is diluted by the partial pink eye dilution gene it produces a colour between lilac and black known as slate.
The genetics of guinea pig coat length and type is slightly easier to get to grips with. The Abyssinian (rough coat gene, denoted by R) is the dominant gene over r - normal coat. The coat length gene (denoted by L) produces LL - short coat Ll medium coat and ll long coat guinea pigs. Each guinea pig will carry two RR (or Rr or rr) genes and two LL (or Li or ii) genes. And the mix of those determines whether you have a sheltie, Peruvian, short coated or Abyssinian guinea pig.
There is currently a bit of craze for 'skinny pigs'. These are guinea pigs with a genetic mutation which are born with no hair and never grow it. These are expensive to buy and have some additional care requirements, so you should read up about them carefully if interested.
Breeding Guinea Pigs to Sell
If you have decided that you want to breed guinea pigs to sell you should get to know what your market wants first. If you plan to sell to pet shops you can ask them if they would be interested in buying baby guinea pigs from you and whether they have preferences for certain coat types or colours?
A lot of the guinea pigs that I have seen sold in pet shops are short coated or Abyssinian crossbreed guinea pigs.
If you plan to sell privately to other pet owners you could just ask around people you know as to what sort of guinea pig they are looking for. You might find that guinea pigs with coats of one colour - known as 'selfs' e.g. self black, are less popular in the pet market than guinea pigs with coats with 2 or more colours.
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