Guinea Pigs


Cavia porcellus, better known as the Guinea Pig is a South American Rodent that has been domesticated for around 3,000 years.  They are used primarily for food in South America but are beloved as pets here in North America.  Guinea pigs are generally easy to handle, non-aggressive, come in a variety of coat types and colors and are a favorite small companion for children of all ages.

Guinea pigs live an average of 5 – 8 years.  Thick bodied with short limbs they can weigh anywhere from 700 to 1200 grams. Pigs are a social animal and prefer to have a housemate.  Females become sexually mature at the tender age of 6 weeks of age so if you have a mixed group, neuter your male. Gestation is about 4 weeks. Guinea pigs produce “precocious” young who are eating solid foods within 5 days of birth.  One important thing to know is that if females do not give birth before 6 months of age their pubic symphysis will mineralize rendering them unable to deliver a baby.

Guinea pigs can be kept in a wire cage with a solid bottom and shredded paper bedding.  Avoid wire bottom cages since they can cause injuries and other foot problems. The same goes for aromatic shavings which cause skin irritation and respiratory problems. Guinea pigs prefer to have a hiding place or hutch for privacy and an exercise area. Do not use an exercise ball. They are not climbers and do not need a cage top.  Just make certain that the sides are high enough to keep them in.  As their name suggests, Guinea pigs can be quite messy and should have their enclosure and feed dishes cleaned frequently. One final point to remember is that these mountain dwellers do not tolerate high temperatures or humidity.  Try to keep temperatures between 61 to 75 degrees.  Anything above 80 degrees can cause heat stroke.

Guinea pigs are vegetarians and need a diet comprised primarily of timothy hay, a commercial pelleted feed with added vitamin C and fresh vegetables such as dandelions, parsley and kale.  A small amount of fresh fruit is OK but only as a treat. Guinea pigs cannot synthesize vitamin C so great care must be taken to ensure that they receive an adequate (10mg/kg/day) amount in their feed.  Vitamin C tablets are also available.

The most common problem we see in Guinea pigs at the Animal Family is dental disease caused by malocclusion of the molars.  If your pig is not eating well or simply looks poor it is important to have the teeth checked. 

Guinea pigs are very sensitive to changes in diet and environment.  Because of this, they are prone to GI problems due to an over growth of “bad bacteria”.  Use of the wrong type of antibiotic can also cause GI problems in pigs.  Signs may include bloating, diarrhea and loss of condition.

We see urinary calculi and bladder infections more than we would like too.  It is more common in pigs on a high calcium diet like alfalfa, but some may simply be genetically predisposed to developing urinary tract problems. Signs may include, frequent urination, straining to urinate, blood in the urine and vocalizing while urinating.

Their small lungs and sensitivity to Bordatella bacteria make pneumonia a particular problem for Guinea pigs.  Stress, exposure to dogs and other Bordatella carriers and poor ventilation can all cause disease.  Signs include nasal discharge, sneezing, rapid respiration and lethargy.  Severe cases can cause death.

Bumble foot or Pododermatitis is seen in animals kept on wire flooring.  This problem can be quite severe if it goes untreated.  Swelling, ulceration and secondary infection can render your pig unable to bear weight.  If your pet develops this problem even though you have proper flooring, you may need to check your source of Vitamin C. 

Mites and ringworm are another common problem of Guinea pigs. You may see intense itching and hair loss.  The good news is both are also easily treated. Your pig will love for helping him with these nasty critters.

Our blog is only meant to be an introduction to Guinea pigs. More information is available through your veterinarian, the library or on-line.



Blastomycosis is a systemic fungal infection which causes illness when it is either inhaled into the lungs causing pneumonia or introduced into an open wound causing a localized skin infection.  Once the organism is in the body it transforms into yeast and can migrate to the lymph nodes, eyes, bones and central nervous system. The disease has a 1 to 3 month incubation period. Blastomycosis is common in the Great lakes and Mississippi river basin area and is found in sandy, acidic soil near water. We do see and treat cases at Animal Family.  There has recently been an uptick in cases in the greater Chicago area so it is worth familiarizing yourself with the symptoms of this disease.

 Dogs are the species most susceptible to Blastomycosis.  People and cats can become infected as well but with much less frequency.  In dogs, hunting breeds aged 2 – 4 years are the typical patient.  When cats do become infected they are generally young to middle aged.

Signs may include some but not all of the following:

  • Weight loss/depression
  • Fever up to 104 F (seen in 50% of cases)
  • Swollen Lymph nodes
  • Decreased appetite
  • Harsh, dry cough (pneumonia)
  • Enlarged testicles
  • Redness and discharge from the eyes (ocular)
  • Lameness (bone)
  • Draining skin lesions (cutaneous)
  • Fainting if the heart is affected
  • Seizures and dementia if the central nervous system is affected.

Diagnosis is made through:

  • Radiographs in cases of cough and pneumonia.
  • Cytology of lung/ lymph node aspirates and skin lesions.
  • Histopathology of bone lesions.Laboratory cultures of tissue samples.
  • Blood titers

Treatment with antifungal medications is successful in 75% of the cases. If antifungals are unsuccessful, surgical removal of lung abscesses may be required. In animals with severe breathing problems, supplemental oxygen may be required for up to a week. Even with treatment, animals with eye involvement may become permanently blind. Males with testicular involvement generally require castration. Early diagnosis improves the chance for survival.  About 20% of dogs may relapse and require a second course of treatment