1. Chapter Nineteen Guinea Pigs

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3. (Images) Guinea Pigs

4. Guinea Pigs  Cavia porcellus or “cavies”  Extremely docile animals & rarely bite  Originated in Andes Mountains of South America  Related to chinchilla & porcupine  Used in nutrition (vitamin C), immune system function, infectious disease (TB) studies  Dunkin-Hartley outbred stock; albino  2 inbred strains available: Strain 2 and Strain 13

5. Handling & Restraint  Easy to restrain  Place 1 hand over shoulder area, w/ thumb & forefingers directly behind front legs.  Place other palm under hindquarters to support weight.  For greater control, with fingers supporting rump, grasp and restrain hind legs.

6. Physiological Data  Body temp: 37°-39.5°C (98.6°-103.1°F)  Heart rate: 230-320 per min  Respiratory rate: 42-104 per min  Weight: adult 500-800 gm, newborn 70-90 gm  Water: 50-80ml / day, or 10 ml / 100 gm body weight// day  Food: 30-48 grams / day, or 6 gm / 100 gm body weight /day  Feces: firm, dark pellet  Urine: yellow and slightly cloudy  Life span: 4-6 years

7. Sexing & Breeding  Penis felt under skin in inguinal area & protruded by manual pressure  Male = boar Female = sow  Special breeding considerations:  Bred at a weight of < 550 - 600 gms.  Usually ~ 12 wks. old  Female bred older than 7 mo. may have dystocia  Maintain pregnant sow on nutritious diet.  Keep a consistent roughage flow through intestines.  Estrous cycle varies w/ strain.  avg. 16 days; estrus lasts 6 - 11 hrs.  Has postpartum estrus.

8. Sexing & Breeding II  Gestation varies by litter size & strain.  Long gestation compared w/ other lab species.  avg. 63 days; range of 59 - 72 days  litter size 1 - 6, normally 2 - 4  Cannibalism of young is not serious problem.  Babies born precocious - fully furred, eyes open & they able to eat solid food.  still nurse until wean at 14 days (150-200 g).  Sexual maturity: 60-90 days  Estrous cycle: 16-18 days  Gestation: 60-65 days

9. Behavior  Cannot climb or jump well.  Louder vocalize volume than most rodents.  Loud squeal if in pain or distress.  Chorus of whistles w/ familiar feeding sounds.  Approach slowly to avoid startle & injury.  Waste large amounts of food.  Sit in feeder, urinate & defecate in it.  Blow partially chewed food into water sipper tubes.  Need to clean tubes & replace water more often.  Barbering common when housed together.  Dominant animal will chew subordinates hair, leaving bare patches; can be confused with a skin problem.

10. Husbandry  Group housed in contact bedding.  Suspended cage systems also used.  Cages do not normally require lids.  Large volume of urine and feces.  Sanitation several times per week, depending on density.

11. Diet  Need diet rich in vitamin C.  only use if milling date is less than 90 days  Microencapsulated ascorbic acid  new form of vitamin C used by food manufacturers  shelf life is extended to 180 days  Vitamin C deficient diet = scurvy, fatal if not treated  Commercial guinea pig & rabbit diets look similar.

12. Additional Reading Anderson, R.S. and A.T.B. Edney. Practical Animal Handling. Pergamon Press, Oxford, UK. 1991. Fox, J.G., B.J. Cohen, and F.M. Loew, (eds.) Laboratory Animal Medicine. Academic Press, Orlando, FL. 1984. Harkness, J.E. and J.E. Wagner. The Biology and Medicine of Rabbits and Rodents. Williams and Wilkins. 1995. Hrapkiewicz, Karen, Leticia Medina, and Donald D. Holmes. Clinical Laboratory Animal Medicine: An Introduction, 2nd Ed. Iowa State University Press, Ames, IA. 1997. Laber-Laird, K., M.M. Swindle, P. Flecknell, Handbook of Rodent and Rabbit Medicine. Pergamon Press, Oxford, UK. 1996. Terril, Lizabeth A., and Donna Clemens. The Laboratory Guinea Pig. CRC Press, Boca Raton, FL. 1998. Wagner, J.E. and P.J. Manning, (eds.) The Biology of the Guinea Pig. Academic Press, Orlando, FL. 1976.