Care of Guinea Pigs
Guinea pigs (Cavia porcellus) are rodents native to South America and were raised by the Incas for food and for use during religious ceremonies. Today, these animals are raised as pets and laboratory research animals. Guinea pigs are lively, interactive, gentle pets. They are somewhat messy but relatively easy to care for, and do not have a tendency to bite when frightened, making them good pets for children. There are three common types of domestic guinea pig in the pet trade: the short-haired English and American; the Abyssinian, whose hair is of intermediate length and grows in whorls or rosettes; and the long-haired (up to 15 cm) Peruvian.
Reproduction & Lifespan
Male guinea pigs are called boars, females are called sows, and babies are referred to as pups. Reproductive capability can begin as early as 2 months of age for females and 3 months of age for males. Gestation length is an average of 68 days with an average litter size of 2 to 4 pups. Weaning of pups occurs at about 21 days. The average life span of a guinea pig is 5 to 6 years. One important factor in reproduction is the age at which a female guinea pig is first bred. If a sow does not have her first litter before 6 months of age, her pubic bones may not be able to spread enough to allow the pups to pass through the birth canal. This can result in dystocia (inability to give birth). Cesarean section is often necessary to save the sow’s (and the pups’) life. Sexing should be done at an early age to prevent unwanted litters. Spaying and neutering is often performed, not just for population control, but to avoid future health problems.
Guinea pigs are social animals and should be housed together if possible. Cages can be constructed of metal, glass, or plastic and should be easy to clean and disinfect. Because guinea pigs do not jump or climb, a roof need not be provided but the sides of the enclosure should be at least 10 inches high. Bedding should be absorbent and dust-free and needs to be cleaned at least once weekly to keep feces and ammonia levels to a minimum. Cedar and other aromatic wood shavings should be avoided as they can damage the respiratory tract. Recycled paper products work well because they make it easier to spot clean the cage and are often more absorbent than wood shavings. We recommend Yesterday’s News cat litter. Food and water bowls need to be heavy enough that the guinea pig cannot tip them over. Water sipper bottles are preferred and should be disinfected weekly.
Nutrition is relatively easy but there are important considerations that, if ignored, can lead to serious health problems. Guinea pigs develop food preferences early in life and do not adjust well to sudden dietary changes. Thus, a variety of foods should be offered from a young age. Guinea pigs are herbivores and therefore have high fiber and low protein requirements. Commercial guinea pig pellets are readily available and should be fed sparingly to avoid obesity. Also, pelleted food should not contain other “junk foods” such as seeds, dried fruit and vegetables, and colored treats. Timothy or prairie grass hay should be available at all times to provide fiber which is important for gastrointestinal health. Alfalfa hay should be avoided because it has high levels of calcium which can lead to bladder stone formation. Guinea pigs are unable to synthesize vitamin C and are completely dependent on a dietary source (a trait shared only by humans and primates). Therefore, fresh vegetables should be offered daily to prevent vitamin C deficiency. Leafy greens such as kale, parsley, beet greens, and spinach, are good sources of vitamin C, as are red and green peppers and broccoli. One quarter of an orange can also be provided daily (with rind removed). Commercial pellets are manufactured with added vitamin C, but it degrades quickly making dietary supplementation a must. Another option for providing the vitamin is to put it in the drinking water (200 to 400 milligrams per liter of distilled water). Water should be mixed fresh on a daily basis to ensure activity of the vitamin. Careful monitoring of water intake is necessary because some pigs do not like the taste the vitamin imparts on the water. Oxbow Hay Company offers a full line of products and can be contacted at www.oxbowhay.com or 1-800-249-0366.
Diseases of Guinea Pigs
Parasites – External parasites are seen with relative frequency, the most
common of which are skin mites (mange). Depending on the type of mite present, the animal may or may not be itchy. Hair loss, dry, flaky skin, and self induced trauma from scratching can also be present. Confirming the presence of mites includes collecting skin and hair samples and observing the mites under a microscope. Fleas and lice are seen less commonly. Length and variety of treatment depends on the parasite but includes either topical or injectable parasiticides. None of these parasites are known to infect people.
Ringworm – This is not a worm but a fungus that infects the skin and hair. Affected animals may or may not be itchy and have localized areas of hair loss. Many guinea pigs are asymptomatic carriers and active disease often results from stress, poor husbandry, and underlying disease. Diagnosis is made by collecting hair and skin samples and performing a fungal culture. Treatment with either topical or oral medications is usually successful. Ringworm can be transmitted to and from guinea pigs, other pets, and owners.
Pododermatitis – Often referred to as “bumblefoot”, foot infections generally result from poor husbandry practices. This disease is very painful and debilitating. Infection can progress quickly to involve not only the skin, but underlying tissues and bone. Treatment must be aggressive and involves antibiotic therapy, pain control, foot soaks, wound treatment, and frequent bandage changes. Even with the best efforts and intentions the prognosis is often grave, making prevention the key.
Cervical lymphadenitis – Also called “lumps”, this disease is characterized by bacterial infection of the lymph nodes in the neck. Infection often results from damage to oral tissues, allowing bacteria access to the lymph nodes. The hallmark sign is swelling under the chin which represents pus-filled nodes. Affected pigs are often depressed and painful. The most successful treatment is to surgically remove the affected nodes and initiate appropriate antibiotic therapy. Proper husbandry, diet, and a stress-free environment can aid in prevention.
Alopecia – Generalized hair loss can occur for a variety of reasons from parasitic disease to ringworm, vitamin deficiency to excessive grooming, and adrenal gland tumors to ovarian cysts. Diagnosis is made by excluding possibilities through appropriate testing. Treatment varies depending on the cause.
Scurvy – Vitamin C deficiency can occur quickly (within months) and can be quite severe. Guinea pigs require a dietary source of the vitamin as their bodies are unable to synthesize it. Deficiency results in defective collagen formation which is important in the proper function and integrity of blood vessels, bone and cartilage, and the ligaments which anchor the teeth their sockets. Signs of vitamin C deficiency include rough hair-coat, anorexia, diarrhea, loose teeth, delayed wound healing, lameness, and increased susceptibility to bacterial infections. Guinea pigs require 15 to 30 milligrams of vitamin C per day. Deficiencies require aggressive therapy.
Respiratory disease – Infections can affect any body system but are most common in the respiratory tract. Signs include nasal discharge, matted fur on the inside of the front legs (from grooming nasal discharge), sneezing, coughing, wheezing, and respiratory distress. Respiratory infections are almost always more advanced than they appear. Any suspicion of respiratory disease should be taken very seriously. Treatments are most successful when initiated early on in the course of the disease. Antibiotics and good nutrition are essential for recovery. There have also been reports of cancer of the respiratory tract.
Urinary tract disease – Guinea pigs are susceptible to urinary tract infections as well as bladder stones. Diagnosis is based on urinalysis and, occasionally, x-rays of the abdomen. Signs include straining to urinate, blood tinged or cloudy urine, pain on urination, and inability to urinate. Treatment involves antibiotics for infection, and surgery for removal of stones. Urinary tract obstruction from stones is a medical emergency.
Gastrointestinal disease – Intestinal parasites do occur in guinea pigs, although not commonly. Diarrhea may be due to parasites, bacterial, or viral infections and can occasionally be induced by prolonged antibiotic therapy. Dehydration can occur quickly so treatment should be initiated immediately. Type and success of treatment depends on the cause. Guinea pigs have been known to carry certain strains of Salmonella, usually a result of fecal contamination of feed. Always practice good hygiene, whether or not the guinea pig appears ill.
Dental disease – Improper jaw alignment, or malocclusion, can result in uneven wear of teeth. Guinea pig teeth grow continuously throughout life so complications of malocclusion can be severe. Oral erosions and tooth abcesses can occur leading to the inability to prehend and chew food properly. Anorexia, weight loss, and malnutrition follow. Sometimes the only sign is excessive salivation. Oral examination often requires sedation, as does trimming of the teeth. Malocclusion is a lifelong disorder requiring frequent attention.
Heatstroke – Guinea pigs are susceptible to heat stroke, even in moderate temperatures (70 to 80 ° F). High humidity levels make it more difficult for the animals to dissipate heat. Signs include panting, excessive salivation, disorientation, weakness, and even death. Prevention is aimed at maintaining appropriate temperature, humidity, and ventilation parameters. Heatstroke is a medical emergency.
Cancer – Cancer can occur in any body system at any age. Mammary gland tumors are most common, but liver, spleen, lungs, reproductive tract, and skin can be involved as well. Cancer can be either benign (not likely to spread) or malignant (easily spread).
* The above list of diseases is not intended to include every possible disease of guinea pigs, but to provide guinea pig owners information regarding common diseases and their symptoms.