Guinea Pigs in Research

What is the scientific name for guinea pigs?

Cavia porcellus

What are the breeds of guinea pigs?

Albino english or hartley (short haired) most common

Also abyssinian, peruvian, inbred strain 2 and 13

Describe the infraorbital foramen in chinchillas and guinea pigs?

Complete

What is the behavior of guinea pigs?

Docile, rarely bite, easily frightened, can be group housed

Very messy

Pinna reflex

Crepuscular

What happens when males are group housed?

Develop an hierarchy

What does it mean that guinea pigs are crepuscular?

Active at dusk and dawn but inside they do not follow this perfectly

Why are guinea pigs messy?

Regurg into sipper tubes

Lots of urine and feces

Feces in food bowls

What is the pinna reflex?

Will move their ears towards sound (used in research)

What happens when guinea pigs get out?

Freeze or flight behavior, do not tend to hide

What are the repro terms for guinea pigs?

Sow are females

Boar are males
Pups are young

Farrowing is parturition

How can you handle guinea pigs?

Hold close to chest and hold around the body

Football tuck is ok too

What husbandry should guinea pigs have?

Solid bottom cages

Elevates sipper tubes and J feeders

Avoid fine particle bedding because rooting will get dust in lungs and genitals

How do you wash their cages?

Acid wash

What do guinea pigs hate?

Changes, especially in temp/humidity

Why should you avoid fine particle bedding?

Dust can get in lungs and genitals

What enrichment can be given to guinea pigs?

Hides, balls etc but dont change things around

What is the diet of guinea pigs?

Strict herbivores needing 20-30% protein from plant origin and 10--18% fiber

What is the problem with guinea pig diet?

Can be very picky

What can stemy hays cause?

Oral lesions leading to abscesses and cervical lymphadenitis

Why do guinea pigs need specific chow different than other rodents?

Need need vitamin C supplementation because they lack L-gulonolactone oxidase

What is the shelf life of vitamin C post milling in guinea pig feed?

90 days, vitamin C can be microencapsulated in water to help with this but water cannot be chlorinated

What are the C/S of vitamin C deficiencies?

Anorexia, lethargy, increased susceptibility to infection, loose teeth, diarrhea, skin lesions, hemorrhage, lameness

How do you treat vit C deficiency?

50mg Vit C IM, IP or SQ until response and then give orally until C/S are gone

What identification tools can be used in guinea pigs?

Ear tag (can mess up pinna reflex), notch, or punch

Also tattoo

What digits do guinea pigs have?

4 on fore limbs

3 on rear

Describe repro in females?

vaginal membrane that is only open during estrus and parturition

What is the repro in males?

Inguinal rings open for life

How many mammae do guinea pigs have?

1 pair

T/F guinea pigs have a large tympanic bullae?

True

What is the dental formula for guinea pigs?

1/1 0/0 1/1 3/3 = 20 total

All are hypsodont

How do guinea pigs chew?

Grind food

What is the palatal ostium?

Oropharynx and pharynx communicate which makes intubation difficult

How do maxillary teeth grow?

Buccal or laterally

How do mandibular teeth grow?

Lungually or medially

Why is checking teeth difficult?

Big fleshy tongue, infolding of lips at diastema, and palatal ostium make it difficult

What happens if maxillary spurs extend bucally?

Lacerate cheek tissue

What are the C/S of malocclusion?

Anorexia, slobbering, halitosis, weight loss

How do you treat malocclusion?

Trimming during anesthesia

Overgrowth more common in premolars than molars

What can cause malocclusion?

Genetics or trauma

Describe the GI tract in guinea pigs?

Monogastric with a very large cecum 65% of GI content is that

Small intestine

Gallbladder

Coprophagic

Why is the size of the cecum important clinically?

If it is full and it messes up your dosage for drugs you can overdose

How do you sex male guinea pigs?

Visible testicles

Are larger

Penis that is easily extruded

Have a slit genital/anal opening

how do you sex female guinea pigs?

Smaller than males

y shaped genital opening

T/F male and female guinea pigs each have one set of inguinal mammae?

True

Why do you need to breed guinea pigs prior to 6 months old?

Fibrocartilaginous pubic symphysis fuses in sows and dystocia is a big risk

Describe the estrous cycle in guinea pigs

16 days

• proestrous for 1-1.5

• Estrus for 8-11 hours

• Metestrus for 3 days

• Diestrus for 11 days

Fertile postpartum estrus 2-10 hours after parturition

What is the copulatory plug in guinea pigs?

Indicates breeding but not pregnancy

What is the relationship between gestation period and litter size?

Larger litter causes a shorter gestational length

How do you diagnose pregnancy?

4-5 weeks via palpation

What is the gestation length of guinea pigs?

68 days

What do females do to prepare for farrowing in guinea pigs?

No nests, born precocious

What do pups do after being born?

Precocius

Can eat and use sipper by 48 hours, pups have voluntary micturation, easy to foster

When do you wean guinea pigs?

14-21 days but dietary introduction should begin prior so they are not as picky

Describe their urine

Very alkaline so need acid to clean

What are foa kurloff cells?

Lymphocyte of guinea pigs with intracytoplasmic inclusion

Found in the placenta and used to prevent maternal rejection

What makes guinea pigs hard to anesthetize?

Need to fast for 12 hours

Prone to salivation so need atropine/glycopyrrolate

Will self mutilate with ketamine IM

Avoid halothane due to hepatotoxicity

Iso has a lower MAC (1.15)

Difficult to intubate due to palatal ostium

What antibiotics should not be given to guinea pigs?

Gm+ spectrum like penicillins, ampicillin, lincomycin, clindamycin, erythromycin, bacitracin

What happens if you give improper antibiotics to guinea pigs?

Overgrowth of C. difficile and E. coli because lactobacillus will be wiped out

What antibiotics can you give guinea pigs?

Enrofloxacin

Chloramphenicol

Trimethaprim sulfas

What dosing should be avoided in guinea pigs?

PO antibiotics

How do you treat antibiotic associated enteropathies?

Fecal slurries

Yogurt with active cultures

Supportive care/fluids

Some researches will want to always give antibiotics after surgery, why should this have extra consideration in guinea pigs?

They do it to replace sterile technique, but dysbiosis can kill them after

What are guinea pigs used for in research?

Anaphylaxis

Asthma

Vit C deficiency

Serum complement source

Immunology (antibody production)

Otology (pinna reflex and large tympanic membrane)

Infectious like Tb, legionnaires

What are the research applications of vit C deficiency?

Wound healing/scar formation

Collagen formation

Nutritional

Tooth extraction healing

Calcification in human tissue

What are predisposing factors to pododermatitis in guinea pigs?

Wire bottom cages

Obesity

Lack of sanitation

What does pododermatitis lead to?

Secondary bacterial infections from S. aureus

How do you treat pododermatitis?

Change husbandry

Topical Ab with steroids

Bandaging