How do I keep my guinea pig healthy?

What should I know about guinea pigs at a glance?

Guinea pigs (Cavia porcellus, "porquinho-da-índia" in Brazil) are social rodents first domesticated in the Andes. They usually live 5 to 8 years and weigh 700 to 1,200 g as adults. Their teeth never stop growing, and they can't make their own vitamin C.

What health problems do vets see most in guinea pigs?

Dental disease, vitamin C deficiency, chest infections, bladder stones, skin parasites and sore feet are among the common problems listed by the RVC's exotics service, which calls vitamin C deficiency very common.

• Dental disease: the back teeth often cause problems even when the front teeth look normal, as the Merck Veterinary Manual notes. Drooling, eating less and weight loss are common signs. Too little hay and too many pellets or treats are a usual cause.
• Vitamin C deficiency: guinea pigs need vitamin C from food every day. See the section on vitamin C below.
• Pneumonia: a leading cause of death, especially in young guinea pigs, according to Merck. Signs include runny eyes or nose, sneezing and trouble breathing.
• Bladder stones: VCA says guinea pigs are very prone to them. Blood in the urine, straining to urinate and crying out while urinating are signs, and they need a vet straight away.
• Sore feet (pododermatitis): pressure sores under the feet, which the RVC links to hard or wire floors and excess weight.
• Ovarian cysts: common in females over one year old, with hair loss, less appetite and low energy, according to Merck. VCA names spaying as the recommended treatment.
• Impaction in males: in males that aren't neutered, droppings can build up in the skin folds near the bottom. The RVC says it doesn't happen in neutered males, and the folds need gentle cleaning every day because the droppings attract flies. Ask your vet to show you how.

Do guinea pigs need vaccines or deworming?

No. "Guinea pigs don't need vaccinations," says the Merck Veterinary Manual, and the RVC adds that they need no yearly worming either. Parasites are treated when a vet finds them, and the skin is where guinea pigs usually get them.

• Mites: Trixacarus caviae, a mange mite, causes severe itching. Merck notes the scratching can be so intense that the guinea pig seems to be having a seizure.
• Lice: usually milder than mites, according to Merck. VCA says the eggs sit on the hairs, often around the face, behind the ears or over the shoulders.
• Ringworm: a fungal skin infection, not a worm, that can pass to people. VCA advises wearing gloves and washing your hands while it's treated.
• Mites and ringworm are most common in young, stressed or unwell guinea pigs, the RVC notes.
• Use only medicines your vet prescribed for guinea pigs, as the RSPCA advises.

Why does my guinea pig need vitamin C every day?

Guinea pigs, like people, can't make vitamin C and must get it from food, as the Merck Veterinary Manual explains. The RSPCA adds that they can only store it for a short time.

Without enough, a guinea pig can lose its appetite and get dental problems, swollen joints, a rough coat, lameness, bleeding under the skin and weight loss. It can die from it.

How much is not settled. Merck gives at least 10 mg per kg of body weight a day, and 30 mg per kg for pregnant females, while VCA gives 10 to 50 mg a day, depending on age, health, stress and pregnancy. Ask your vet what your guinea pig needs.

• Vegetables: bell pepper and parsley are on Merck's list of vitamin C sources and on the RSPCA's list of vegetables to offer often. Sources disagree on citrus: Merck, the RVC and VCA list oranges, while the RSPCA lists citrus fruit under what guinea pigs can't eat.
• Pellets: choose pellets made for guinea pigs and fortified with vitamin C. The vitamin breaks down with heat, light, moisture and time, so VCA advises using pellets within 90 days of the date of manufacture. The RVC notes that rabbits and guinea pigs have different dietary needs, and rabbit pellets aren't made with the vitamin C guinea pigs need.
• Vitamin C in the water: sources disagree. The RVC says drops or powders made for water should be changed daily, because vitamin C is unstable in water, and prefers a pinch of crushed vitamin C tablet on the food. VCA advises against adding it to water at all, because it breaks down fast and can change the taste.
• Supplements: ask your vet first. Merck notes multivitamins are usually not advised, because some added vitamins can harm guinea pigs.

Which signs in a guinea pig can't wait?

Guinea pigs hide illness until they are very sick, as the Merck Veterinary Manual notes, so by the time a sign shows the problem may be advanced. Call a vet who sees guinea pigs the same day for any of these.

• Not eating or not pooping: the RSPCA says to call your vet immediately if eating or drinking changes, or if droppings get fewer or stop.
• Trouble breathing: a guinea pig breathing with its mouth open needs a vet straight away, according to VCA.
• Straining to urinate or blood in the urine: this can mean bladder stones. The RVC adds producing no urine to the signs.
• Heatstroke: short quick breaths, drooling, struggling to breathe, a very sleepy guinea pig, collapse or fits. The PDSA says to call your vet right away, and never to put the guinea pig in cold water.
• A dirty bottom in warm weather: urine stains and stuck droppings attract flies. The RSPCA advises checking the rear twice a day in warm weather, because flystrike is often fatal. Call your vet if you see maggots.

Find a vet who sees guinea pigs before you need one. Don't give medicines at home unless a vet says so, because many common antibiotics are dangerous for guinea pigs.

How do I care for a guinea pig day to day?

Hay comes first. VCA advises unlimited timothy or another low-calcium hay all day, because it gives the fiber the gut needs and wears down teeth that never stop growing.

• Food: unlimited hay, fresh vegetables every day, a small amount of guinea pig pellets and fresh water. The RVC advises against alfalfa hay, which has too much calcium, and against muesli mixes. VCA adds no oats, seeds, nuts or dry cereals, and fruit only now and then.
• Changes: guinea pigs form food habits early and may stop eating after a sudden change, so VCA advises changing the diet slowly. Never give lawnmower clippings.
• Teeth, nails and weight: the RSPCA advises checking the front teeth and nails every week, and only a vet should correct overgrown teeth. Weight loss and drooling are among Merck's warning signs, so weigh your guinea pig regularly on a kitchen scale in grams.
• Company: at least one other friendly guinea pig. The RSPCA suggests a neutered male with one or more females, two females, or brothers raised together.
• Rabbits: don't keep them together. The RSPCA says rabbits may bully or injure guinea pigs, and the RVC warns that rabbits can carry Bordetella, a bacterium that can cause a fatal chest infection in guinea pigs.
• Housing: tall enough to stand up on the back legs, with one more hiding place than there are guinea pigs and no grid floors, which hurt their feet, according to the RSPCA. Dust-free hay makes good bedding, and pine shavings don't. Spot clean every day and clean the whole cage every week.
• Heat and cold: the RSPCA puts the ideal room at 17 to 20 °C, the RVC at 20 to 22 °C and Merck at 18 to 24 °C (65 to 75 °F). The RSPCA and the RVC both warn about heat above 26 °C, and the RSPCA says to bring guinea pigs indoors below 15 °C. Keep them out of direct sun, and ask your vet what suits your home and climate.
• Coat: baths only when soiled, and regular brushing for long-haired breeds, according to the Merck Veterinary Manual.
• Medicines: many common antibiotics are dangerous for guinea pigs, and VCA warns some can quickly cause fatal diarrhea. Give only what your vet prescribed, never pet shop antibiotics.

How do I keep my guinea pig's health record?

VetVitae, a free pet health record app for iPhone, Android and the web, keeps your guinea pig's weight in grams and warns you when it drops 10% in a month. It logs vet visits, mite and lice treatments, exams like skin scrapings and X-rays, and medicines, with no vaccination card, since guinea pigs don't need one.

It also suggests guinea pig routines like Fresh hay, Fresh vegetables and Fresh water. See small mammals in VetVitae and weight.

This guide is general information, not veterinary advice. Your vet knows your pet.

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