Guinea Pig Breeding

Guinea Pig Breeding

Guinea Pig Breeding and Delivery can and will be difficult for the expecting sows. The babies are born large, fully furred and ready to run. The mother generally carries several pups and her weight may double, putting stress on her circulation system and other organs. Even with the best care, Sows can suffer from numerous problems which can include Dystocia, Hypocalcemia, A Prolapsed Uterus, or Pregnancy Toxemia. For the Health and well being of your beloved pet.


If you have accidentally purchased two miss sexed Guinea Pigs and the sow is pregnant remove the Boar immediately. The reason for this is a Pregnant Sow just given birth can become pregnant again and for this reason the Boar must not be present whilst the Sow is giving birth for that reason. Back-to-Back Pregnancies are extremely hard on a female Cavy and is Not Advised.

Normal Birth Weight70-100g
Typical Litter Size2-5 Pups
Gestation Period59-73 Days Depending on litter size
Weaning Age14-21 Days
(See Separation Dates)
Weaning Weight150-200g
Length Of Estrus Cycle15-17 Days
Milk Composition3.9% Fat, 8.1% Protein, 3.0% Lactose
Earliest Reproductive Age :- Female4 Weeks
Earliest Reproductive Age :- Male3 Weeks

Remember Female Guinea Pigs can be sexually mature at 4 weeks of age.

Given the early ages at which some males and females are sexually mature (Females have been reportedly been impregnated by 24 day old males) it is advised to remove the male young by the 3 week marker at the latest.

The earliest date of sexual maturity reported are as follows :-

  • Sexual Maturity Male : 3-5 Weeks
  • Sexual Maturity Female : 4-6 Weeks

While not all Males are always fertile it is still recommended that the safest action is to

Separate the Males from Females by 3-4 Weeks of age.

Pregnancies of very young sows are also difficult for the animal. Food for her developing and maturing body is diverted to the young foetuses. While intentional breeding is never Recommended, young cavies can successfully carry to term. To often Pet Stores mix sexes, Resulting in unintentional pregnancies.

Breeding after 8 months with a female that has not had a previous litter is Dangerous and Can lead to death due to Dystocia (a Fibrous Cartilage which firmly joins the two pubic bones) becomes less flexible upon reaching adulthood and may not separate properly making delivery difficult and can lead to hemorrhaging (Bleeding Out).

Should you believe that this is the case seek Emergency Help from your vet. A C-section may be necessary


It is stated in multiple sources that Estrus Cycle in Guinea Pig is 15 to 17 Days. Since most Sows will have an estrus cycle from 2 to 15 minutes immediately after giving birth, removing any boars from the cage as the delivery date approaches to prevent Back-To-Back Pregnancies. They claim that the estrus period occurs 24 to 48 hours, 6 to 11 hours of which the female will accept the male.

Multiple sources state “Your Pig is in Estrus when the Mucous Plug has dissolved”. The plug seal seals the vaginal opening when she is not in Estrus. The plug will dissolve approximately 10 to 21 days. To check if the plug has dissolved just see if the “y” is Separating to form an opening. It’s open for Approximately 24 hours then starts to seal itself.

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