Guinea pig breeding is something that should only be done with commitment, thought and responsibility. Nowadays, there are far too many people that breed guinea pigs without the knowledge and expertise that is required.
Really, you should only breed guinea pigs if you have arranged for a home for the new young, or you are keeping them yourself.
A guinea pig is best placed to breed at around 6 months of age. It's a good idea not to let a guinea pig breed if it's older than 12 months. Whilst it is quite capable of producing young, there is a likelihood of complications along the way.
In-breeding guinea pigs can sometimes lead to health problems. These problems might be poor imune systems and much shorter lifespans. In the wild, once a male guinea pig becomes fertile, he is driven out of their pack to stop them from in-breeding with their relatives! You should follow the same example.
You should consider both the temperament and appearance of the guinea pig when choosing a guinea pig to breed. Try and strike a balance - if one guinea pig is slightly bullish, then try and breed them with a more placid one. Again, do the same when choosing their looks and appearance.
Most boars when placed with a sow will try and mate with her straight away. You might find that the sow kicks up a bit of a squeaky fuss but don't be too worried about this. The sow can look after herself when she doesn't want to give the boar her attention!
Normally the sows deterrent is enough to tell the boar not to bother her again. On some occasions, the sow won't accept the boar at all. This is when things can get a bit tasty. The sow will probably attack the boar quite aggressively. Don't worry too much - the boar will very rarely get involved and retaliate.
If this happens, remove the boar. The sow will probably accept a different boar after a few days.
TIP! If you notice quite a lot of sexual activity between the guinea pigs, make a note of the date. This might be useful in planning when a litter is on it's way!
You can do some basic health checks on the sow and boar your are planning on breeding. Although it might be impossible, it is useful to find out if the guinea pigs you choose have have children before and if they have any health problems. Don't worry too much about it if they have, just do your research and ask your vet for advice if necessary.
If either the boar or sow seem to have hair loss problems, it's a good idea not to let them breed as it will be passed on to their young.
Most responsible breeders leave the sow and boar together to mate for around six weeks so as to increase the chance of the sow being caught in her oestrus cycle more than once.