Care of Guinea Pigs
The guinea pig, or cavy, is a docile rodent native to the Andes Mountain area of South America. They were first domesticated by the Andean Indians of Peru, who used them as a food source and as a sacrificial offering to the Incan gods. During the 16th century, Dutch explorers introduced guinea pigs to Europe, where they were selectively bred by fanciers. The guinea pig entered the research laboratory in the 18th century, and have since made significant contributions to the scientific community. To this day, the guinea pig remains a favorite pet among children due to their docile behavior, ease of handling, and clean, quite nature.
Through selective breading efforts, guinea pigs are found in any array of colors and coat types from which to choose. Five primary varieties are encountered in the pet industry. The Shorthair or English is characterized by having a uniformly short hair coat. The Abyssinian has whorls or rosettes in their short, rough, wiry coat. The Peruvian is recognized by its very long silky hair. These three types are most commonly kept as pets. The Silky and Teddy Bear varieties are encountered less frequently. The Silky is a large variety distinguished by its medium length silky hair. The Teddy Bear has medium length hair of normal consistency.
Diet
Good quality food and fresh, clean water must be readily available at all times. Commercially available pelleted chows provide all the essential nutrients required by guinea pigs, as long as the pellets are fresh when offered. These pellets contain 18-20% protein, 16% fiber, and approximately 1 gram of vitamin C per kilogram of ration. In general, adult guinea pigs should be limited to 1 tablespoon of pellets per day. Typically guinea pigs less than a year of age are offered a alfalfa based pellet. Guinea pigs over this age fare better on a grass-based pellet, most commonly timothy. Oxbow hay company is our preferred brand for reliable high quality pellets with stabilized vitamin C (which means the vitamin C in the pellet lasts more than twice as long as most store bought pellets. This extended shelf life for the vitamin C in Oxbow’s pellets gives them a six month shelf life before the vitamin C degrades. For more information on Oxbow products, go to oxbowhay.com.
Do not feed rabbit pellets as a substitute for guinea pig pellets. They are not equivalent in nutritive value. Unlike rabbit diets, guinea pig diets are uniquely formulated with specific requirements in mind.
Unlike most mammals, guinea pigs cannot manufacture their own vitamin C and therefore they must receive it from an outside source. Most store bought pelleted guinea pig diets are supplemented with necessary levels of this essential vitamin. Despite proper storage (i.e.- a cool dry area) pellets lose about half of their vitamin C due to degradation within six weeks of manufacture. For this reason we also recommend further vitamin C supplementation in the diet. Refer to the accompanying table for a list of greens, fruit, and vegetables with respective vitamin C levels. If in doubt, it is best to provide vitamin C in a tablet form at 50mg per day to an average sized adult pig. Water supplementation is not advised, as the vitamin C degrades in water within a few hours. Oxbow also makes a 50mg palatable vitamin C tablet that we stock in the hospital.
The guinea pig’s diet should be composed of a measured amount of fresh guinea pig pellets, fresh greens, and unlimited good quality timothy or other grass hay. As mentioned above, the pelleted diet should be restricted to one tablespoon daily (in order to prevent obesity). Guineas pigs less than 4 months old are allowed unlimited pellets. Fresh produce with a high Vitamin C content should be offered at 1/2 to one cup a day. The fresh items must be thoroughly washed to avoid exposing your pet to pesticide residues or bacterial contamination. The hay provides the necessary fiber for digestion. Any change in the guinea pig’s diet should be made gradually, as the digestive tract of this herbivore is very sensitive to rapid change in consumed items. Guinea pigs tend to be creatures of habit, and tolerate neither major changes in the presentation of their food or water, nor changes in the taste, odor, texture, or form of the food itself. Pet owners should avoid making radical changes with the food or water containers as well. Any sudden change in routine can result in the pet refusing its food and water, which can be ultimately dangerous.
All foods should be provided in heavy ceramic crocks that resist tipping and chewing. The crocks should be high enough to keep bedding and fecal pellets out of the food, but low enough for easy access by the animal.
Water is most easily accessible by the use of a water bottle equipped with a “sipper” tube. Guinea pigs tend to contaminate and clog their water bottles by chewing on the end of the sipper tube and “backwashing” food particles into it. For this reason, it is imperative that all food and water containers be cleaned and disinfected daily.
Handling
Generally, guinea pigs are docile, non-aggressive animals. They rarely bite or scratch when handled. They usually voice their protest simply by letting out a high pitched squeal. They may, however, struggle when being picked up or restrained. Extreme care should be taken not to injure them during handling. The guinea pig should be approached with both hands. One hand is placed under the guinea pig’s chest and abdomen, while the other hand supports its hindquarters. Adults, and especially pregnant females, should receive careful attention to gentle, yet firm and total support. This can also be accomplished by wrapping the guinea pig in a towel like a “burrito” before picking him/her up.
Housing
Housing accommodations provided for pet guinea pigs are limited only by one’s imagination, ingenuity, and budget. There is no single correct way to house your guinea pig as long as the well-being of your pet is considered. Adequate housing is a major factor in the maintenance of healthy pets.
Guinea pigs can be housed within enclosures made of wire, stainless steel, durable plastic, or glass. The latter three materials are preferred since they resist corrosion. Wood should not be used due to difficulty in cleaning and susceptibility to destructive gnawing. Many plastics are also easily destroyed by gnawing. Ideally the enclosure should have one more than one side open for adequate ventilation, so be careful when using aquariums. The design and construction of the enclosure must be escape-proof. In addition, the cage must be free of sharp edges and other potential hazards. The size of the enclosure should allow for normal guinea pig activity. Approximately 100 square inches of floor area per adult guinea pig is recommended. Breeding animals should be provided 180 square inches each. The enclosure can remain opened on the top if the sides are at least 10 inches high, provided other family pets such as dogs or cats are not a threat.
Cage flooring can be either wire or solid. Wire mesh flooring provides a cleaner environment and easier maintenance, but may result in injuries to the feet and hocks. Over extended periods of time this type of flooring can result in foot pad and hock infections, from abrasive rubbing on fecal-soiled wire. To reduce the incidence of these problems, provide an anchored solid platform as a resting place in one area of the cage. Broken legs are common in guinea pigs that fall through the wire mesh and panic to escape. Although solid flooring requires more effort to keep sanitary, it is safer for the guinea pig. Solid floored cages also tend to be more esthetically pleasing when appropriate bedding is used.
Bedding materials must be clean, non-toxic, absorbent, relatively dust-free and easy to replace. Cedar, redwood and chloroform impregnated pine shavings have been associated with respiratory difficulty and liver disease in some guinea pigs, and therefore should not be used. Corn cob bedding, walnut and other food byproduct materials are also not recommended as fungal spores and other contaminants are more likely. Saw dust should also be avoided since it tends to accumulate within the external genitalia of male guinea pigs potentially causing an impaction. Our preference is to use recycled newspaper beddings (such as Yesterday’s News) as these products are more hygienic, absorbent and less likely to be consumed or cause respiratory irritation. Aspen pine can also be used, although it tends to be less absorbent.
The environment in the vicinity of the pet’s cage is another important consideration. Because of their sensitive nature, guinea pigs are more comfortable and relaxed when housed in a quiet spot away from noise, excitement and other such stresses. Be sure to select a location away from direct sunlight, and avoid cold, damp areas. Guinea pigs thrive in a dry, cool environment with adequate ventilation. Drastic environmental changes should be prevented, especially high temperatures and humidity. As nocturnal pets (active at night), guinea pigs require quiet periods during the daylight hours in order to rest.
Since guinea pigs are social creatures, more than one animal may be safely housed together. In addition, males and females can remain in the same enclosure indefinitely. However, new males may occasionally fight if in the presence of a female. Older, dominant animals may also chew on the ears or hair of subordinate cage mates. If a males and females are to be housed together it is recommended to neuter the males in order to prevent breeding and undesired offspring.
Breeding
The single most important consideration regarding guinea pig breeding is that the female guinea pig (sow) should be bred between four and seven months of age if she is to be bred at all. If the first breeding is delayed much beyond this time, serious, and often fatal problems with delivery may result. The reason for this is that the pelvis of the guinea pig fuses at this early age which narrows the birth canal, preventing the babies from passing easily. Males (boars) should be at least four months of age before breeding.
The sow’s estrous cycle (“heat”) lasts 14 to 19 days. The actual period in which the sow is receptive to the boar for breeding is approximately eight to fifteen hours during this cycle. Sow’s often return to “heat” within a few hours after giving birth. This time is known as “postpartum estrus” which means that she can be nursing one litter while being pregnant with another.
Pregnancy lasts between 63 and 70 days. The gestation is shorter with larger litters, and longer with smaller litters. This duration of pregnancy is relatively long when compared to other rodents.
Pregnant sows exhibit a grossly enlarged abdomen during the later stages of pregnancy. Body weight may actually double during pregnancy. The time of delivery is difficult to assess in guinea pigs due to the relatively long gestation period and lack of nest building by the sow. Within a week prior to delivery, a slight widening of the pelvic area may be noted. This is the separation of the pelvis, which if does not occur, can cause the delivery problems mentioned previously. If this happens, delivery of the young may be impossible without cesarean section.
An uncomplicated delivery usually takes about ½ hour with an average of 5 minutes between babies. Litter sizes range between one and six, with an average of three to four. First time litters are usually very small. Unfortunately, abortions and stillbirths are not uncommon in guinea pigs.
The young are very well developed at birth. They weigh between 50 and 100 grams and have a full hair coat. Babies are even born with teeth and with their eyes open. Mothers are not very maternal in the raising of the offspring, in that they do not build a nest or even remains in a sitting position while nursing. The young can actually eat solid food and drink from a bowl shortly after birth, but it is recommended to allow them to nurse for three weeks before weaning.
NON-INFECTIOUS CONDITIONS
Slobbers/Dental Malocclusion
Slobbers is the condition where the fur under the jaw and down the neck remains wet from constant drooling of saliva. The primary cause for this condition is overgrowth of the premolars and/or molars. Most often this occurs in older (2-3 years of age) guinea pigs and usually involves the premolars (the most forward positioned cheek teeth). These teeth cannot be viewed without proper equipment as they are recessed deep within the oral cavity. The overgrowth is due to improper alignment of the teeth when chewing, but excess selenium in the diet has also been suspected as an underlying cause. The overgrown tooth causes injury to the guinea pigs tongue and gums resulting in an inability to chew and swallow food, drooling down the chin and neck, and weight loss (often severe). A veterinarian must be consulted as soon as this condition is suspected. The diagnosis is confirmed by visual examination of the mouth using special instrumentation and sometimes magnification. A thorough examination often requires general anesthesia. Correction of the problem involves trimming or filing of the overgrown teeth under general anesthesia. Dental work in the mouth of a guinea pig is difficult due to the extremely small mouth opening. A correction of the diet may also be in order. During the initial treatment period, force feedings and antibiotics may be necessary to aid in the recovery process. There is no permanent solution or correction to this problem. Periodic trimming or filing of the teeth is usually necessary (typically every 6-8 weeks). Guinea pigs with this problem should not be bred since dental malocclusion is often hereditary.
Scurvy (Vitamin C Deficiency)
As discussed, guinea pigs cannot manufacture Vitamin C and must receive an adequate supply from food sources. Lack of sufficient Vitamin C in the diet results in scurvy. The symptoms of scurvy include poor appetite; swollen, painful joints and ribs; reluctance to move; poor bone and teeth development, and spontaneous bleeding, especially from the gums, into joints, and in muscle. If left untreated, this disease can be fatal, especially to rapidly growing young and pregnant females. In addition, subclinical deficiencies often predisposes animals to other diseases. The mandatory level of vitamin C is supplemented in commercial guinea pig pelleted rations. However, with improper storage and handling these pellets lose their potency rapidly. For this reason, further supplementation is recommended (see diet section). Contact a veterinarian at the first sign of this condition for early diagnosis and treatment. These animals must be treated with supplemental vitamin C (given in food, water or injection) in order to reverse the symptoms.
Barbering (hair chewing)
Hair loss is a common problem in guinea pigs. “Barbering” is just one of many causes. This vice occurs when guinea pigs chew on the hair coat of other guinea pigs that are lower than them in the social “pecking order”. The dominant “pig” and main culprit, is identified by its normal , full hair coat, while others have areas of alopecia (hair loss). There is no treatment for this condition except separating the guinea pigs when necessary. Hair loss or hair thinning can occur for a number of other reasons as well. It is a common phenomenon among sows who are repeatedly bred or weakened, and newly weaned juvenile guinea pigs. Certain fungal diseases and external parasite infestations also can cause hair loss problems.
Heat Stress (Stroke)
Guinea pigs are very susceptible to heat stroke, particularly pigs that are overweight and/or heavily furred. Environmental temperatures above 85 F degrees, high humidity (above 70%), inadequate shade and ventilation, overcrowding, and other stresses are additional predisposing factors. Signs of heat stroke include panting, slobbering, weakness, reluctance to move, convulsion, and death. This is a treatable condition if recognized early. Heat stressed guinea pigs should be misted with cool water, bathed in cool water, or have rubbing alcohol applied to the foot pads for evaporative cooling. Once this first-aid measure is accomplished, veterinary assistance should be sought. Prevention of heat stoke involves providing adequate shade and proper ventilation. In addition a cool misting of water and/or a fan operating over a container of ice (frozen milk-jug) can be directed toward the pet’s cage. When indoors, air conditioning during the heat of the summer provides the best relief.
DISEASE CONDITIONS
Pneumonia
Pneumonia is one of the most common bacterial diseases of the pet guinea pig. Respiratory infections are caused by a number of viral and bacterial agents including Streptococcal pneumoniae, Bordetella bronchiseptica, and a gram-positive diplococcus. Many of the disease causing organisms inhabit the respiratory tracts of clinically normal guinea pigs. Conditions of stress, inadequate diet, and improper husbandry will often predispose a pet to an opportunistic infection with one or more of these agents. Symptoms of pneumonia may include dyspnea (difficult breathing), discharge from the nose and eyes, lethargy, and decreased or no appetite. In some cases, sudden death will occur without any of these signs.
Occasionally, middle or inner ear infections accompany respiratory disease in guinea pigs. Additional symptoms in these cases include incoordination, torticollis (twisting of the neck), circling to one side, and rolling. Veterinary consultation should be sought when a guinea pig exhibits any of the above symptoms. A bacterial culture with antibiotic sensitivity of the throat and/or nasal discharge will assist the veterinarian in the selection of an appropriate antibiotic. Aggressive antibiotic therapy in addition to supportive care of the patient may be necessary to get the condition under control. Unfortunately, even though elimination of the symptoms is often possible with appropriate therapy, eradication of the causative bacteria is not.
Bacterial Enteritis (Intestinal Infection)
A number of bacteria are capable of causing infections of the gastrointestinal tract in guinea pigs. Some of these bacteria are introduced through contaminated greens or vegetables or in contaminated water. One of the most common bacteria that causes intestinal disease in guinea pigs is Salmonella spp. Other bacterial species that may cause diarrhea and enteritis are Yersinia pseudotuberculosis, E. coli, Arizona spp. and Clostridium spp. In addition to diarrhea, other common symptoms associated with intestinal disease are lethargy, anorexia, and weight loss. In other cases, however, sudden death may occur before expression of these signs. A veterinarian may elect to use aggressive antibiotic therapy and supportive care to treat this condition. A bacterial culture of the patient’s stool with antibiotic sensitivity will greatly assist the veterinarian in choosing an appropriate antibiotic to use.
Bacterial Pododermatitis (Footpad Infection)
Severe infections of the foot pads are very common among guinea pigs housed in cages with wire flooring. Fecal soiling of the wire potentiates the problem. The guinea pigs front feet are most susceptible to this condition. Symptoms of this condition include swelling of the affected feet, lameness, and reluctance to move. Improved sanitation and cage floor alterations are the initial steps in correcting the problem. In addition, the feet themselves should be treated by a veterinarian. Topical dressing with an antibiotic and periodic bandaging is often required. Depending on the severity of the damage, injectable antibiotics may also be necessary. Therapy may have to be carried out for a lengthy period of time to get full recovery. In severe cases, amputation may be necessary (a procedure that it not well tolerated in guinea pigs). A possible long term consequence of bacterial infections of the feet and hocks that have previously been treated is arthritis.
External Parasites (Lice and Mites)
Lice and mites are the most common external parasites of guinea pigs. Lice are tiny, wingless, flattened insects that live within the hair coats of infested animals. Both the adults and eggs are found attached to hair shafts of affected pets. Mites are microscopic, spider-like organisms that affect the top layers of skin in affected animals. Guinea pig lice and mites are not known to parasitize man.
Mite infestations are usually more severe than lice. A specific mite, Trixacarus cavie, causes serious infestations in pet guinea pigs. This sarcoptic mite lives in the outer layers of skin causing an intense itching and scratching with considerable hair loss. In some cases, they present without the itching and scratching, but only hair loss and crusting of the skin. In other cases, the infestation and irritation is so severe that the pet causes significant self-inflicted wounds and exhibits wild running and circling behavior, and may even appear to have “seizures”. A veterinarian can diagnose the mite infestation by performing skin scrapings of affected areas and viewing them under the microscope. Successful treatment consists of using anti-parasitic drugs at calculated intervals. Cages should be entirely leaned out, and disinfected with a one part bleach to 32 parts water solution. Cat/dog flea sprays can also be used to treat the environment. Make sure the cage is thoroughly rinsed and dried prior to returning the pet(s). If wood shaving are used as bedding or litter, they should be replaced with paper towels to make the pet more comfortable. Transmission of Trixacarus cavie mites occur only through the direct contact between infested and non-infested guinea pigs. Therefore, pet guinea pigs are not likely to harbor this parasite unless they are recent additions or had previous exposure to mite-infested guinea pigs. In some cases a solitary pet may show symptoms even if it was isolated for a long time. Most likely in these instances the pet has always had small numbers of mites, but stress or disease have allowed the parasites to flourish. For you pet’s sake, be sure that any guinea pig(s) that he/she comes into contact with is(are) healthy and free of this and other diseases.
Lice infestations often go undetected. However, heavy infestations are usually accompanied with excessive itching, scratching and some hair loss. Scabbing on or around the ears may also be evident. Guinea pigs have two types of biting lice that may parasitize them. Both irritate and abrade the skin surface and feed off the bodily fluids that exude through the superficial wounds that they create. A veterinarian can confirm the diagnosis of lice infestation by examination of the hair coat as well as microscopic examination of hairs from affected animals. There are several options for treatment which are prescribed by the veterinarian. As with mites, lice transmission occurs through direct contact with infested guinea pigs. Pet guinea pigs are not likely to have this parasite unless they had previous exposure to lice-infested guinea pigs. For your pet’s sake be sure that any guinea pig he/she comes in contact with is healthy and free of this and other parasites.
**Guinea Pig Sensitivity To Certain Antibiotics**
Guinea pigs are very sensitive to certain classes of antibiotics. For this reason, NEVER attempt treatment of your pet guinea pig at home without prior consultation with a veterinarian. Many antibiotics which are safe for other animals have been shown to be lethal to guinea pigs, whether given orally or by injection. In addition, even some topical antibiotic preparations can produce serious detrimental results. A partial list of potentially harmful antibiotics includes: ampicillin, vancomycin, penicillin, bacitracin, gentamicin, erythromycin, lincomycin, clindamycin, streptomycin, and sometimes tetracyclines. Even if an antibiotic is not on this list, it does not ensure that it is safe to use. When improperly administered, and antibiotic can produce detrimental and often lethal results. The primary mechanism behind this often lethal effect is a dramatic alteration of the normal microbial balance in the gastrointestinal tract. In addition to affecting the disease causing bacteria in the body, they also interfere with the normal beneficial bacteria in the guinea pig’s digestive system. Guinea pigs have very delicate digestive systems, so any alteration can produce a cascade of events leading to serious illness or even death. As well as causing disruption of the bacterial balance, these alterations also result in the production of harmful chemicals in the guinea pig’s body. Other antibiotics cause direct toxic effects to the guinea pig without initially disrupting the digestive system, often proving rapidly fatal. When an antibiotic is prescribed by a veterinarian, consider supplementing the guinea pig with about one-half teaspoon (2.5cc) of plain organic yogurt, twice daily. This therapy should continue for a couple of days past the antibiotic therapy. Although this is not absolutely critical, yogurt may help augment and replace the beneficial intestinal bacteria that are compromised by the antibiotic treatment. Pro-biotics can also be used for the same reason. A less common but potentially superior treatment would consist of feeding small amounts of feces from a healthy non-medicated guinea pig.
Guinea Pig Facts
Scientific name:……………………………………………………………. Cavia porcellus
Life Span:……………………………………………………………………. 4-5 years
Environmental temperature range:…………………………………… 65-75 degrees
Desired relative humidity range:……………………………………… 40-70%
Breeding age (first mating)……………………………………………… 3-4 months (male)
………………………………………………………………………….. 3-7 months (female)
…………………………………………………………………….. (dangerous if after 7 months for the first time)
Gestation Period…………………………………………………………… average 63-70 days
Litter Size……………………………………………………………………. 1-6 range, average of 3-4
Weaning Age………………………………………………………………… 2-3 weeks
Vitamin Content of Selected Foods
The following chart shows the vitamin C content in milligrams (mg) of 1-cup portions of selected foods.
Item Vitamin C (mg)
Turnip Greens……………………………………………………………………………. 260
Mustard Greens………………………………………………………………………….. 252
Dandelion Greens……………………………………………………………………….. 200
Kale………………………………………………………………………………………….. 192
Brussel Sprouts………………………………………………………………………….. 173
Parsley………………………………………………………………………………………. 140
Collard Greens……………………………………………………………………………. 140
Guavas……………………………………………………………………………………… 125
Broccoli Leaf*……………………………………………………………………………. 120
Beet Greens……………………………………………………………………………….. 100
Cauliflower………………………………………………………………………………… 100
Kohlrabi……………………………………………………………………………………. 100
Strawberries……………………………………………………………………………….. 100
Honeydew Melon……………………………………………………………………….. 90
Broccoli Florets*………………………………………………………………………… 87
Spinach……………………………………………………………………………………… 60
Raspberries………………………………………………………………………………… 60
Rutabaga……………………………………………………………………………………. 52
Orange………………………………………………………………………………………. 50
Cabbage (all leaves and Chinese cabbage also)………………………………… 50
*Broccoli stem has 0 mg of vitamin C
