The Medaille College Guide to the Guinea Pig
(by the students in VET 120 Spring 2003)

Five guinea pigs

  1. Taxonomy

    1. Scientific

      • Kingdom Animalia

      • Phylum Chordata

      • Class Mammalia

      • Order Rodentia

      • Suborder Hystricomorpha  (vaginal membrane opens during estrus & reseals)

      • Family Caviidae

      • Genus Cavia

      • Species  Cavia porcellus

    2. Breeds

      1. Used for research-

        • Dunkin-Hartley (albino shorthair)

        • Albino

        • English & American Shorthair

      2. Other breeds (pet GPs are often called "cavies")-

        • Abyssinian  (whorled hair-"rosettes")

        • Peruvian  (long silky hair parted in center of back)

        • Skinny pig  (hairless)

        • Silky or Sheltie  (longer hair but not parted)

        • Satin  (silky shiny fine short hair)

        • Teddy  (coarse kinked hair)

        • Crested  (single whorl on forehead)

        • Texel  (short hair on head with curly body hair)

  2. History

    1. Role in Research-  used since 1780

      1. Asthma & respiratory infections

      2. Nutritional studies, esp. vitamin C

      3. Immunology & antibody production

      4. Anaphylaxis  (severe & life-threatening allergic response)

      5. Schults-Dale technique-  histamine / antihistamine effects

      6. Analgesics

      7. Deafness/ear studies (ears sensitive & easily dissected)

      8. Ulcerative colitis / Crohn's disease

      9. Inflammatory bowel disease

      10. Gallstones

      11. Toxicology & teratology (birth defects) studies

      12. Wound healing

      13. Bone & tooth studies

      14. Diagnosis of tuberculosis

    2. Other Interesting Information (just for fun)

      1. Origin of Name

        1. Origin unknown

        2. Brought to Europe by way of Guinea by Spanish Conquistadors & Dutch traders

        3. Sold for a guinea (British coin)

        4. Squeal like a pig

      2. Natural History

        1. Domesticated by South American Incas  (@5000 BC)

        2. Used as food source & religious sacrifices

      3. Location of Origin

        1. Grassy plains, rocky areas, forest edges & swamps

        2. From northwestern Venezuela to central Chile  (esp. Peru)

      4. History in the US

        1. Brought to US in late 1700s

        2. Popular as pets

      5. Shown as main course meal in painting such as The Last Supper

  1. Anatomy and Physiology

    1. Data

      Criteria Guinea Pig
      Life Span 4 - 8 years
      Adult Size 700-900 g (F) to 900-1200 g (M)
      10 - 12"  long
      Temperature 103° F +/-1°
      Pulse 250-350 bpm
      Respirations 40-100 rpm
      Estrous Cycle Polyestrous; 15-17 days
      Estrus 8 hours
      Gestation 60-70 days
      Weaning Age 14-28 days

     

    1. Temperament

      1. Docile and rarely bite

      2. Easily stressed

      3. Vocal about any situation

      4. Stampede or freeze when frightened

      5. Popcorn jumping

    2. General appearance-

      1. Short legs

      2. Stocky body

      3. No tails

      4. Prominent hairless area just caudal to pinna of each ear

    3. Peculiarities of the Guinea Pig

      1. Herbivorous

      2. Open rooted teeth (dental formula  2(I1/1 P1/1 M3/3)

      3. Monogastric & cecotrophic hindgut fermenters

      4. Do not sweat (watch temperature extremes)

  2. Husbandry

    1. Bedding

      1. Type-

        • Direct (preferred)-  enrichment

        • Indirect-  be careful that legs don't get caught- foot damage may occur

      2. Materials-

        • Aspen or other hardwood, CareFresh (recycled paper), corn cobs

        • Bed thickly (2")

        • Never pine or cedar

  1. Temperature and Humidity

    1. Temperature:  70-75° F

    2. Humidity:  @50%

    3. More sensitive to changes than other species

    4. Prone to heat stress

  2. Cage, etc.

    1. Shoe-box type cage of plastic or stainless steel

    2. Urine is high in minerals;  crystals form scale on cage

    3. Cage sizes @ 2-4 ft2 /pig

    4. Cage can have open top, if sides are at least 7 - 8" high (pigs can't jump)

    5. Group housing recommended, but monitor males closely for fighting

  3. Food

    1. Commercial pellets (eat @ 6 g food/100 g bodyweight)

    2. Baby guinea pigs start eating solid food at 1-2 days old

    3. May be neophobic about food-  change foods gradually

    4. Food supplements-

      • Hay (keep GI tract moving)-  decreases barbering and boredom

      • Fresh veggies 

      • No nuts in potatoes, spinach, nuts in shells, iceberg lettuce, celery..

    5. Vitamin C-

      • Must be supplied in diet (cannot make their own)

      • Must use food containing vitamin C within 3 months

      • If insufficient C, may -> scurvy and decrease disease resistance

      • Approx. 10 mg is required per day

    6. Water-

      • Use bottle or automatic watering system

      • Play with sipper tube & stuff bedding in- watch for floods

    7. During pregnancy-

      • Feed additional hay and veggies

      • Double vitamin C

  4. Enrichment

    1. Not required, but good for GP welfare

    2. The best enrichment is another guinea pig

    3. Direct bedding

    4. Tunnels (ex. 4" PCV)

    5. Bird and chew toys

  5. Husbandry Predilections and Precautions

    1. GPs make lots of feces!!

    2. Pay attention to diet

    3. Watch that teeth & nails don't overgrow

  1. Reproduction

    1. Gestation-  60 - 70 days  (average 63 days)

    2. Weaning Age-  14 - 21 days

    3. Sexual Maturity-  females  (2-3 months) and males (3-4 months)

    4. Litter Size-  2-5  (some references list up to 14 babies at once!!)

    5. Pups weigh 600 - 115 gm at birth

    6. Type of Offspring-  precocial (but should nurse 3 weeks!)

    7. Offspring are pups, not piglets (go figure!)

    8. Mating System- 

      • Harem-  1 male to 3-10 females

      • Monogamous

      • Breeding often occurs at night

    9. Females-  

      • Sows

      • Spontaneous ovulators

      • Pelvis fuses after @8 months-  do not breed for first time after this age!

      • Nonseasonally polyestrous 

      • Breed first about 3-4 months old

      • May be bred during post-partum estrus  (approx. 15 hr after giving birth)

      • Pregnancy detection-  difficult  (double weight during last 2 weeks pregnancy)

      • Copulatory plug formed & lasts 1 - 2 days

      • Do not make a nest

      • Parturition takes approx. 30 min, with 5 minute interval between pups

      • Complications common  (stillbirth, abortion, dystocia, pregnancy toxemia)

      •  

    10. Males-

      • Boars

      • Breed at any age (once they reach sexual maturity)

    11. Sexing guinea pigs

      • Challenging-  

        • Cannot use anogenital distance  (similar)

        • Both sexes have mammary glands  (only 2 "spigots")

      • Female-  Y-shaped genital area

      • Male-  slit in genital area with penis that can be expressed

  2. Diseases

    1. Common Diseases

      1. Bordetella pneumonia

        • Bordetella bronchiseptica  (bacterium)

        • Can acquire from other species of animals (e.g. dogs & rabbits)

        • Asymptomatic-> respiratory disease-> death

        • Do not house GP with rabbits!

        • Worse in young pigs (up to 100% mortality)

      2. Tyzzer's disease (Clostridium piliforme)

      3. Salmonellosis  (Salmonella enteritidis)

      4. Cervical lymphadenitis (lumps)

        • Streptococcus zooepidemicus  (bacterium)

        • Enlarged cervical lymph nodes-> abscesses

        • May be associated to coarse food (-> injuries)

      5. Hypovitaminosis C  (scurvy or scorbutitis)-  

        • Must provide vitamin C!

        • GPs cannot manufacture vitamin C, so must be provided in diet

        • Signs:  anorexia, swollen painful joints, poor bone & teeth development

      6. Dystocia

        • Pelvic girdle fuses at about 8 months unless female is bred

        • Normally, hormones of parturition cause ligaments connecting pelvic girdle to become flexible, so that the pelvic hole enlarges during birth

        • Pups cannot be born naturally if sow is first bred when older- C-section is needed

        • Straining and uterine bleeding without producing young

      7. Pregnancy toxemia

        • Overweight or stressed sows

        • May occur last 2 weeks pregnancy & 2 weeks postpartum

        • Dyspnea, weakness, depression and death

        • Treatment usually futile

      8. Malocclusion (molars)-  slobbers

        • Hereditary

        • Common in older pigs

        • Signs:  drooling, anorexia, weight loss and tongue injury

        • Tx:  anesthetize & trim teeth

      9. Inclusion body conjunctivitis 

        • Chlamysia psittici

        • Reddened eyelids, chemosis, serous exudate & photophobia

      10. Antibiotic-induced enterotoxemia (hemorrhagic typhlitis)

        • Anorexia, weight loss, diarrhea, dehydrations, depression, death

        • Use oral antibiotics with caution

        • Can feed live yogurt cultures to try to prevent / treat

      11. Pododermatitis

      12. Heat stroke

      13. Cancer  (old pigs)

      14. Ectoparasites (lice and mites)

      15. Intestinal parasites, esp. coccidia

       

    2. Zoonoses

      1. Highly allergenic (dermal & respiratory)

      2. Ringworm  (Trichophyton mentagrophytes)

      3. Sarcoptic mange  (Trixocarus caviae)

      4. Salmonellosis

      5. Lymphocytic choriomeningitis

  3. Technical Procedures

    1. Handling and Restraint

      1. Restraint-  hold upper body in one hand & support hind end with other

      2. Easily frightened

      3. Socialization improves handling

      4. Minimal restraint

        • Escalate only if needed (gentle & do not bite)

        • Grasping thorax tightly interferes with breathing

      5. Commercial devices & towels-  be sure GP doesn't overheat

      6. Don't scruff  (hair pulls out and not enough skin)

    2. Identification-

      1. Physical appearance (markings)

      2. Markers-  temporary

      3. Ear tags or notching

      4. Tattooing

      5. Electronic transponders (microchips)

    3. Blood Collection  

      1. Auricular artery  (ear vein)

      2. Anterior vena cava & cardiac puncture-  anesthesia required

      3. Cephalic & lateral saphenous vein

      4. Orbital sinus venous plexus

      5. Toenail clip

      6. Lateral metatarsal vein

    4. Injection Sites

      1. IV-  ear vein or saphenous vein

      2. IP-  lower (R) quadrant of abdomen  (the usual site)

      3. IM-  lumbar muscles, semimembranosis/semitendonosis, quadriceps

      4. SC-  dorsal scapular area, flank

      5. Gavage (p.o.)

    5. Anesthetics

      1. Isoflurane (inhalant anesthetic)

      2. Pentobarbital  (rough induction & recovery)

      3. Ketamine/xylazine  (irritating)

      4. Ketamine/medetomidine

      5. Fentanyl

      6. Telazol