Guinea pig wellness (Proceedings)

Guinea pigs belong to the family Cavidae. Four digits on the forepaw and three digits on the hindpaw characterize Cavidae. Guinea pigs originate from the high planes of South America therefore they tolerate cold better than heat. There are 3 original/standard breeds that were first recognized: American (English), Abyssinian, Peruvian; however there are now a total of 13 breeds recognized. Guinea Pigs make excellent pets. They are low cost, low maintenance, extremely docile, rarely bite, very social, and easy for small children to hold.

Housing

3 choices when choosing a house: Buy a commercially manufactured cage, have one custom built from a pet store or a feed-and-garden store, or build you own. Each guinea pig should have a minimum of 2 square feet in its cage. Most commercial cages are designed for 1 guinea pig. It is important to NOT house guinea pigs in a cage w/ a wire bottom as they very easily catch feet & legs on the mesh bottom and can lose toes or break legs. Large glass aquariums do NOT make good houses as they are difficult to clean, have very little air circulation (inc. ammonia), and retain heat. Guinea pigs do not handle heights well and if multiple levels are available they should be close together. Guinea Pigs prefer temperatures of 65-68°F, do not do well with colder drafts, and are very susceptible to heat stroke at >80°F. It is recommended to try to place cages away from heat vents and direct sunlight. Guinea Pigs should not be housed with rabbits, cats or dogs as they can carry Bordetella which can be very serious if transmitted to the guinea pig. The recommended bedding is the same as with other small mammals: Yesterday's news/Carefresh, Aspen wood shavings, Pine shavings, Timothy hay (No cedar shavings, No cat litters, No corn cob beddings, No straw). The bedding should be changed 2 times weekly. Water bottles are recommended as dishes can be overturned and soiled easily. Guinea pigs are notorious for playing with their water bottles. The food dish should be heavy/difficult to turn over and a hay rack is advisable to keep hay off cage floor. Cage furniture should consist of a variety of rocks, bricks, and tubes. These help to wear down claws, provide a hiding place, and help alleviate boredom. They should be checked routinely for signs of wear & tear.

Nutrition

Guinea pigs are strict herbivores and they digest fiber more efficiently than rabbits. In the wild they eat grasses, wild fruits & veggies. Guinea pigs need Vitamin C supplementation as they lack L-gulonolactone oxidase which is involved in synthesis of ascorbic acid from glucose therefore they are unable to manufacture or store vitamin C. Grass hay is one of the most important parts of the guinea pig diet (Timothy, Oat or Orchard grass hays are the best). Hay should be available at all times. Guinea Pig pellets are important but should be provided in proper amounts. They provide a proper balance of vitamins, minerals, and other nutrients. Pellets can lose Vit. C as it sits on the shelf so recommended to buy small amounts & make sure freshly milled (less than 90 days). Pellets however do not contain high enough fiber to regulate digestion and thus the importance of hay. The adult guinea pig should be fed 1-2 ounces per adult guinea pig. Fresh veggies & fruits are also an important part of the guinea pig diet. They help prevent boredom, makes diet complete/optimal. These should be introduced slowly in small amounts in order to prevent gastric upset & diarrhea. Feed veggies & fruits high in Vitamin C such as Broccoli, dandelion greens, cabbage, kale, mustard greens, parsley, green and red bell peppers, beet greens, Kiwi, apples, fresh tomatoes.

The ideal guinea pig diet:

Food consumption 6g/100g/day

Water consumption 10ml/100g/day or 100ml/kg/day

GI transit time 13-30 hours

Guinea pigs are social animals and live in family units centered around an alpha male and seek physical contact with other guinea pigs when housed together. However two adult males not brought up together may not tolerate each other's company and housing them together can lead to fighting, resource hoarding and eventually death for the submissive, weaker guinea pig. Guinea pigs do not groom one another so acts of hair pulling or ear nibbling are signs of aggression. The vocalizations of guinea pigs are well characterized (Whistle, purr, chutt, chutter, whine, tweet, drr, scream, squeal, chirp, grunt).

Reproduction

     • Males = boar

     • Females = sow

     • Gestation 59-72 days (ave 63)

     • Females reach puberty at 6-8 weeks

     • Males reach puberty at 9-12 weeks

First breeding must be before 8 months b/c pelvic symphysis fusion. After mating, a vaginal/cervix plug will form and be shed the next day. Babies are born precocious with full body hair, open eyes, and ability to eat solid food w/in the first day.

Male guinea pigs have large scrotal sacs, and their penis can be easily extruded with gentle pressure. Females have a vaginal closure membrane that seals the vaginal orifice except during estrus and parturition.

Restraint

Most will sit quietly on table with a hand on the rump to prevent backing up. You can also pick up with one hand around the shoulder and the other to support the hindquarters. The "Guinea pig burrito" is another popular choice for restraint especially for examination of head and mouth. Many people find guinea pig dander to be severely allergenic and so gloves may be needed.

Physical examination

First observe in its cage the following: Movement, Mentation, Rate & rhythm of breathing. Healthy guinea pigs have an alert demeanor with clear eyes. They react to stimuli with vocalization or by moving and readily eat when offered treats or greens.

Life span 4-8 yrs (average 5)

Adult weight:

     •Male (boar) 900-1200 grams

     •Female (Sow) 700-900 grams

     •Temperature 99 - 103°F

     •Heart rate 230-380 beats/min

     •Respiratory rate 42-104/min

     •Dentition - All teeth open rooted 2(1/1,0/0,1/1,3/3)

     •Get weight of animal in grams

     •Follow with temperature before guinea pig gets excited

     •Look at fur coat, skin and mucous membranes

     •Sebaceous glands are abundant along the dorsal surface of the guinea pig and around the anal opening. These sebaceous glands are testosterone dependent and the sebaceous secretions can be excessive in the adult male.

     •Auscult heart and lungs

     •Palpate abdomen

     •Check rectal area for fecal impaction & observe genitalia

     •Examine oral cavity last using a speculum or otoscope -Healthy guinea pigs have a large amount of "green slime" in the back of their mouth on oral exam.

Preventive Medicine

Yearly wellness checkups are recommended to evaluate teeth, husbandry, diet, skin, ears and fecal material. After 3 years rec. semiannual visits and may include CBC/Chem, urinalysis, and radiographs. Spaying and neutering are recommended, especially if going to house with other guinea pigs. 80% of females can develop ovarian cysts which are very painful and can lead to early death.

Blood Collection can be difficult. The blood volume of guinea pigs is 7ml/100 grams of body weight. One can safely take 7-10% of the blood volume. Smaller samples can be obtained from the Lateral saphenous or Cephalic vein using a 27 or 25 gauge needle. Larger samples are best collected under general anesthesia from the cranial vena cava or jugular vein.

The Guinea pig has a unique leukocyte called the Kurloff cell. It is a mononeucular cell that resembles a lymphocyte. It contains round or ovoid inclusions termed Kurloff bodies. The origin of this cell is controversial, many think spleen or thymus. The number of these cells circulating in the blood is variable. This cell appears to be rare in very young animals, in low numbers in males, and the number in females is related to estrous cycle and highest during pregnancy. The Kurloff cell may play a role in creating a physiological barrier between fetus & mother.

Urine Collection can be obtained via a voided sample or cystocentesis. The cysto technique is similar as other small animals using a 25 gauge needle and anesthesia may be necessary for restraint. The normal pH of guinea pig urine is 9.0 and specific gravity is 1.045+.

Suggested Reading

1. Donnely T, Brown C: Guinea Pig and chinchilla care and husbandry In Vet Clinics of North American Exotic Animal Practice, Saunders, May 2004, 7:2, p351-372

2. Johnson-Delaney C: What veterinarians need to know about Guinea Pigs In Exotic DVM, volume 10 issue 3, p36-43.

3. Quesenberry K, Donnelly T, Hillyer E: Guinea pigs In Quesenberry KE, Carpenter JW (eds): Ferrets, Rabbits, and Rodents Clinical medicine and surgery 2nd ed. WB Saunders, 2004, p232-238.

4. American Cavy Breeders Association (ACBA) www.acbaonline.com