Health Care for Guinea Pigs

Introduction

Guinea pigs are rodents (related to chinchillas and porcupines) that originated from the Andes Mountains region of South America. In the 16th century, Dutch explorers introduced guinea pigs to Europe, at which time selective breeding and captive rearing began in earnest.

Guinea pigs are extremely popular pets today because of their availability, docile temperaments, tendency not to bite or scratch when handled, and because of their relatively clean habits. They are not terribly long-lived which can be disconcerting to owners (especially children).

In their natural habitat, guinea pigs live in open, grassy areas. They prefer to seek shelter in naturally protected areas or within burrows created and later deserted by other animals. Guinea pigs are sociable animals and tend to live in groups. They are strictly herbivorous (plant-eating) and do most of their foraging for grasses, roots, fruits, and seeds in the late afternoons and early evenings as the daylight wanes.

Handling-Restraint

Guinea pigs rarely violently struggle when they are being picked up but often make their “squeal of protest” which sounds pig-like to many. Nevertheless, great care should be taken not to injure them during this activity. The guinea pig to be lifted should be approached with two hands. One is placed under the guinea pig’s chest and abdomen and the other supports its hindquarters. Adults and those that are pregnant should receive careful attention.

One of the most desirable features of guinea pigs as pets is that the rarely bite when being handled or restrained.

Housing

Proper, adequate housing is a major factor in the maintenance of healthy guinea pigs. The well-being of the animals must be a primary consideration. Guinea pigs can be housed within enclosures made of wire, stainless steel, durable plastic or glass. The latter three materials are preferred because they resist corrosion. Wood and similar materials should not be included in the construction of enclosures because they are difficult to clean and these materials cannot withstand the destructive gnawing of the occupant(s). The construction and design of the enclosure must ensure that the resident(s) cannot escape. Furthermore, the enclosure must be free of sharp edges and other potential hazards.

The enclosure must be roomy enough to allow the resident(s) to pursue normal activities and breeding activity, if the latter is desired. One reference recommends at least 100 square inches of floor area per adult “pig”, whereas breeding guinea pigs should be allowed 180 square inches per animal.

The enclosure can be open at the top provided that the sides are at least 7 to 8 inches high. Male guinea pigs (especially breeding males) will require the sides of their enclosure to be at least 10 inches high. They tend to be more rambunctious.

Guinea pigs can be housed on wire mesh , but it is not recommended. Such material will allow urine and most fecal pellets to drop through, there by keeping the bedding and the resident “pig(s)” cleaner. Guinea pigs housed for long periods on wire, however, tend to develop serious injuries to the bottom of their feet. Furthermore, broken legs are quite common when guinea pigs fall through the mesh. This is most often a problem with guinea pigs that have not been reared on wire mesh, and occurs soon after they have been introduced onto it.

Enclosures that provide solid flooring and an adequate supply of preferred bedding are the best for pet guinea pigs. They should be easy to clean, well lighted and adequately ventilated. Bedding must be clean, non-toxic, absorbent, relatively dust-free and easy to replace. Shredded paper, wood shavings, and processed corn cob are preferred bedding materials. Sawdust should be avoided even though it meets the aforementioned criteria. This material tends to collect within the external genitalia of male “pigs”, forming an impaction. Rarely does this impaction interfere with urination, but it may inhibit successful breeding.

Guinea pigs seem most comfortable when they are spared exposure to excessive noise, needless excitement and confusion, and other similar or perceived stresses. Sudden environmental changes should also be prevented.

Guinea pigs exhibit two types of reactions when startled by a loud noise, sudden movement, or strange environment. They may “freeze” completely motionless (for up to 20 minutes) or panic. The latter reaction involves erratic running and leaping, often accompanied with shrill squealing. Groups of guinea pigs will stampede in a circle, often trampling the younger residents within the enclosure. A panic reaction will scatter bedding and food, fouling the food and water containers. Visual security (a place into or under which the resident(s) can retreat when frightened) should always be provided. Rectangular enclosures and the provision of barriers within them will also reduce the tendency to stampede and circle.

Hygiene

The frequency with which the enclosure is cleaned will depend on its design, the materials out of which it is made, and the number of guinea pigs that reside within it. As a general rule of thumb, the enclosure and all cage “furniture” should be cleaned and disinfected once a week. The food and water containers should receive cleaning and disinfection once a day. We suggest more than one set of containers. While one set is being “used” the other set can be disinfected. The containers can be put in the dishwasher, if possible. A vigorous scrubbing of the enclosure and “furniture” with hot water and soap and a thorough rinse should be followed by the disinfectant.

Food & Water

Good quality food and fresh, clean water must be readily available at all times. The exact nutritional requirements of the guinea pig are known and commercially available pelleted chows provide all of the essential nutrients, as long as the pellets are fresh and wholesome when offered. Some guinea pig owners will be tempted to feed rabbit pellets, assuming that they are roughly equivalent to guinea pig pellets. They are not equivalent. Unlike most mammals (including rabbits), guinea pigs require a high level of the vitamin C, folic acid. Unlike rabbits, guinea pigs cannot manufacture their own vitamin C and must receive it from an outside source. Pellets milled for guinea pigs take these special requirements into consideration and are appropriately fortified with these two nutrients, among many other essential ones.

Guinea pig chows generally contain 18 to 20% protein, 16% fiber, and approximately 1 gram of vitamin C per kilogram of ration. Even when the fresh pellets are properly stored in a cool, dry place, approximately one half of the vitamin C content is degraded and lost within six weeks of manufacture. Therefore, we recommend that the diet be supplemented with vitamin C as follows: 200 milligrams ascorbic acid (= vitamin C) added to approximately one quart of drinking water, make up fresh every 12 hours, or a single guinea pig should be offered one handful of kale or cabbage or one quarter of an orange daily.

All foods should be provided in heavy ceramic crocks that resist tipping over. The crocks should possess high enough sides to keep bedding and fecal pellets out of the food or the crocks should be elevated slightly above the bedding.

Water is most easily made available and kept free from contamination by providing it in one or more water bottles equipped with “sipper” tubes. Guinea pigs tend to contaminate and clog their water bottles more than other pet rodents 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.

Guinea pigs tend to be creatures of habit and do not tolerate changes in the presentation of their food and water or changes in the taste, order texture or form of the food itself. Pet owners should avoid making radical changes in the food and water containers used and changes in the food itself should be made gradually. Failure to do so usually results in guinea pigs refusing food and water, which can be disconcerting and dangerous.

Breeding Considerations

The guinea pigs heat cycle last 16 days. The actual period during which the female is receptive to the male and will allow breeding is approximately 8 hours. Female guinea pigs are capable of coming back into heat 6 to 15 hours after giving birth. This is called a “postpartum estrus” which means that they can be nursing a litter and be pregnant at the same time!

Pregnancy last an average of 63 to 68 days. The larger the litter size, the shorter the term and vice versa. The duration of pregnancy for guinea pigs is unusually long when compared with that of other rodents.

An uncomplicated delivery usually requires about ½ hour with an average of 5 minutes between babies. Litter size range from 1 to 6 young with 3 to 4 being average. Litters resulting from the first breeding are usually very small. Abortions and stillbirths are common occurrences with guinea pigs throughout their breeding lives.

The young are born relatively developmentally advanced. They are unusually large and fully-furred and capable of walking about. Furthermore, they possess teeth and open eyes at this time. Even though the newborn “pigs” are capable of eating solid food and drinking water from a container, it is recommended that they be allowed to nurse their mother for at least 2 weeks.

Medical Conditions Requiring Veterinary Attention

Non-Infectious Conditions

Malocclusion of Premolar Teeth (Slobbers)

A common problem of guinea pigs (especially those over two to three years old) results when the upper and lower premolar teeth (the most forward-positioned of the cheek teeth) meet improperly while chewing. In time, this problem results in abnormal wear of these teeth. This problem results in signs and symptoms that will surely be of concern to the guinea pig owner, desire to eat but inability to chew and swallow food, drooling resulting in a continually moist mouth and chin, and weight loss.

Correction of the problem involves general anesthesia and aggressive trimming or filling of the overgrown teeth, a most difficult procedure because of the guinea pig’s extremely small mouth opening. Forced feedings and antibiotics are usually necessary for a number of days before and after this procedure has been performed.

There is no permanent solution of correction for this problem. Periodic trimming/filling is almost always necessary. Guinea pigs with this problem should never be bred in order to prevent passing this most undesirable trait to their offspring.

Pregnancy Problems

Older or overweight guinea pigs can have difficulty delivering babies. It is best not to breed females that are over 7 months of age or are obese.

The guinea pig can be a very docile and easily cared for pet if it’s habitat is properly established and maintained.

This health care information was compiled by Marilyn Lieb, D.V.M.