Guinea Pig (Cavia porcellus)
Natural history
The guinea pig is a native of Peru, Brazil, and Argentina that was domesticated by the Inca Indians. Guinea pigs are also known as “cavies”, a term derived from the South American vernacular. Male guinea pigs are called “boars” and females are “sows”.
Taxonomy
Class: Mammalia
Order: Rodentia
Suborder: Hystricomorpha
Family: Caviidae
Breeds
Over 20 breeds of guinea pig are recognized with the three most popular being:
| Peruvian: | Long hair |
| American or English: | Short hair |
| Abyssinian: | Whorled or rough hair |
Diet
Guinea pigs are strict herbivores. A sound diet consists of high-quality hay, fresh foods, and water. Offer unlimited grass hay, as guinea pigs eat small portions throughout the day. Alfalfa or clover hay should only be given to juvenile animals as the high calcium content can predispose adults to renal calcification. Fresh food can consist of grasses, herbs, leafy greens, peppers, and other vegetables. Avoid or limit fruits in the diet. Too many simple carbohydrates can lead to diarrhea and/or dysbiosis.
Guinea pigs of all ages require a dietary source of vitamin C (10-30 mg/kg per day). Fresh foods rich in vitamin C can provide sufficient levels of this nutrient. Additionally, commercial guinea pig pellets often contain vitamin C and small amounts of pellets (about ¼ cup a day) can be offered alongside hay and fresh food. Pellets should be fresh and relatively high in fiber, low in sugars and calcium, and grain free. The stability of vitamin C decreases over time and the vitamin C content of pellets is also reduced by exposure to dampness, heat, and light.
Husbandry
|
Normal physiologic values
| Temperature | 99-101.5ºF | 37.2-38.6ºC |
| Pulse | 230-380 | |
| Respiration | 40-100 | |
| Body weight | Adult male | 900-1200 g |
| Adult female | 700-900 g | |
| Mean life span | 6-8 y | |
| Sexual maturity | 2-4 months 2 months (F) 3 months (M) Males will exhibit mounting behavior as early as 1 month of age. Females can become pregnant as early as 4-5 weeks of age. |
|
| Breeding maturity | Male: 3-4 months Female: 6-8 months |
|
| Estrous cycle | 16-17 d, polyestrous | |
| Gestation | 59-72 days (average 68 days) | |
| Birth weight | 45-115 g (Inversely related to litter size) 70-100 g |
|
| Litter size | 1 to 13 (2 to 4 is the usual) | |
| Weaning age | 21 days (180 g) | |
| Target environmental temperature: | 65-79ºF 18-26ºC Avoid temperatures above 28°C (82°F) |
Anatomy / physiology
| Gastrointestinal Dental formula: | Incisors 1/1 Canine 0/0 PM 1/1 Molar 3/3All teeth are open-rooted and show lifelong growth.. The lower incisors are normally 3X longer than the upper incisors. |
Musculoskeletal: | Rodents have a distinctive masseter muscle. The zygomatic arch of the skull and the dental anatomy is related to their feeding habits.
Females must be bred before 6-9 months of age. Immature male s and females have a fibrocartilaginous pelvic symphysis fusion which becomes ossified over 1 year of age. The symphysis remains cartilaginous in primiparous sows so the pelvic canal can dilate allowing passage of the large fetus. |
| Special Senses: | Large ears with thin-walled pinnae and well-developed bullae. |
| Urogenital: | Males have lateral scrotal swellings on each side of the anus. Accessory glands include a prostate, coagulating gland, bulbourethral gland, and seminal vesicles. Seminal vesicles are large, yellow-white tubular structures which lie dorsal to the bladder. The seminal vesicles maybe confused with the uterus. |
| Respiratory: | All rodents are obligate nasal breathers. |
Restraint
Most pet guinea pigs are calm, gentle animals that rarely bite. To pick up a guinea pig, cup one hand gently under the thorax and use the other hand to support the hind end. Hold the rump lower than the rest of the body.
Large volumes: Jugular vein, cranial vena cava (only under sedation/anesthesia)
Small volumes: Cephalic vein or lateral saphenous vein
Fluid therapy
Administer warm fluids: 38-39°C (100-102°F).
Maintenance fluids are estimated as 50-75 ml/kg/day.
- Dehydration (%) x BW (kg) x 1000 ml/L = fluid deficit (ml)
- Correct fluid deficits over 12-24 hours
Subcutaneous (SC) fluids are indicated only for animals with a stable circulatory system and mild dehydration (max 5%).
- Administer SC fluids up to three times per day (give one-third of calculated fluid volume at a time)
- Infuse up to 150 ml/kg/day (average 40-60 ml/kg)
Intravenous or intraosseous fluid therapy is indicated in critical patients. Intravenous or IV catheters are placed with growing frequency in guinea pigs, but when IV catheterization fails or when veins are too small or too fragile, an intraosseous or IO catheter can be an excellent option.
| Catheter type | Recommended sites | Comments |
|---|---|---|
| Intravenous catheter | Cephalic or lateral saphenous vein | Slow bolus: 5-10 ml/kg IV every 8 hours |
| Intraosseus catheter | Proximal humerus, proximal tibia, proximal femur | 20-22 gauge (1-1.5 inch) spinal needle Local anesthesia with lidocaine Use survey radiographs to confirm placement |
Important medical conditions
- Bacterial pneumonia
- Fur mites
- Hypovitaminosis C or scurvy (can reportedly occur within 4 days of dietary decrease)
- Malocclusion
- Pododermatitis
Antibiotics to avoid
Avoid antimicrobials that attack only gram-positive bacteria such as beta-lactams.
P.L.A.C.E.:
- Penicillin
- Lincosamide, lincomycin
- Amoxicillin, ampicillin
- Cephalosporins, clindamycin
- Erythromycin
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References
References
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Pollock C. Basic Information sheet: Guinea pig. Feb 14, 2010. LafeberVet Web site. https://lafeber.com/vet/basic-information-for-guinea-pigs/