Cystic ovarian disease

Studies show that over 66%-75% of female guinea pigs over the age of 3 months will develop cysts on their ovaries, so it is quite a common disease in guinea pigs.

Ovarian cysts are fluid filled structures, which grow on the ovaries. Cysts will develop as the guinea pig goes through their normal reproductive cycle during life. The most common age at which they are detected is around 2-4 years of age.

As with many illnesses in guinea pigs they often show very few signs for this disease, often cysts are picked up on a clinical exam by your vet as an incidental finding in an apparently healthy guinea pig. Some signs which you may see in your guinea pig could include:

• A larger fuller abdomen (some people describe a pear shaped appearance)
• Hair thinning on both flanks/sides (this can be caused by other illnesses too)
• Decreased appetite
• Reluctance to exercise
• Pain on handling

During a full clinical exam your vet may be able to palpate (feel) the cysts if they are large. To confirm a diagnosis your vet will need to image the ovaries to confirm the presence of cysts. They will do this by ultra-sounding your guinea pigs abdomen. This can be done conscious without an anaesthetic.

The prognosis is generally a good one providing the guinea pig is well otherwise, and they are treated promptly. Without treatment ovarian cysts can cause pain to the guinea pig and potential peritonitis (abdominal infection) if the cyst bursts.

There are a couple of treatments available in guinea pigs with ovarian cysts:

• Spaying – this is the most common treatment as it will cure the disease by removing the ovaries. Some vets may be unfamiliar with neutering a female guinea pig so you may have to be referred to a more specialist or experienced exotics vet for the surgery, as all surgeries do it does carry some risk.
• Hormone treatment – this option either involves an implant being placed under the skin or a series of injections several days apart. This treatment does not always work depending on what type of cysts your guinea pig has and what injections are selected. in some cases there is also a risk of reaction to the injections. It is best to discuss this option with your vet.
• Draining the cysts – this is a temporary treatment which can be performed. This is usually done by sedating your guinea pig and then placing a needle directly into the cyst to drain it. This does not cure the disease as the cyst will refill and therefore should only ideally be done as a temporary relief for the guinea pig.

The only way to prevent guinea pigs from developing ovarian cysts is to have them spayed at a very young age (usually 4 months). This is not a routine procedure for most vets, so if you are considering this then you may wish to consult a small mammal or exotic specialist about performing this procedure.

There is sadly no other way of preventing your guinea pig from developing ovarian cysts. Ensure that you take your guinea pig for an annual health check so that any signs are detected in the early stages by your vet. Some people suggest that guinea pigs who have been pregnant in their life do not develop cysts, sadly this is not the case and even breeding sows can develop them.