ANIMAL HEALTH
AND OBSERVATION
MICE
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MICE
 Scientific Name – Mus musculus
 Over 100 recorded inbred strains of mice
 Only 7 or 8 are commonly used in research
 Variety of outbred mouse stocks are also
used in research.
MICE – USE IN RESEARCH
 Used in wide variety
of research
programs, including
genetics,
immunology and
infectious disease
studies.
MICE BEHAVIOR
 Normally keep all 4
feet on the floor and
when sleeping, will
curl its head under
its’ body.
 Usually, if housed
together in a group,
they will sleep
huddled together.
MICE BEHAVIOR
 Behaviorally
dominant mouse can
bite or chew fur off a
subordinate mouse,
usually in face region
 (see picture)
This is referred to as
barbering which is
usually harmless.
BEHAVIOR
 Barbering should not be
confused with fur loss
caused by skin or mite
problems.
 Females usually don’t
fight.
 Group housed males
often fight. Aggressive
mice should be housed
individually to avoid
potential injury to
cagemates.
Barbering
Fighting
IDENTIFICATION
 Required by most investigators in order
to provide a means of tracking history of
each animal throughout the study.
 Temporary ID may include
 Dye – applied to part of the body
 Clipped hair
 Use of a marking pen
IDENTIFICATION
 Permanent ID
 Ear tags sometimes used
 Small metal band with imprinted numbers that
are pierced through ear and locked in place
 Mice tend to catch these on things and rip them
out.
 Tattooing
 Generally done on the tail.
IDENTIFICATION
 Ear punch
 Small metal device which produces small,
permanent holes in the animals’ ear.
 Standardized number chart can be utilized.
 Should be noted that it can be somewhat difficult
to read another technicians’ ear notching as each
persons ear notches may vary slightly and can
be misread.
 See handout for ear notching examples.
IDENTIFICATION
 Computer chips can also be used.
 Cage cards should be used as well.
 Should have the following information
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Strain
Birth Date
Sex
Receiving Date
Source
Investigator name
Animal #
HANDLING AND
RESTRAINT
 May pick up by grasping the tail or the
skin over the shoulders with fingers OR
rubber-tipped forceps.
 When picking up by tail, avoid the last third
of the tail. Pick up by base of tail.
 If using forceps, remember to disinfect
between animals.
 Mice tend to urinate and excrete a fecal pellet
when you manipulate them. Be prepared!
RESTRAINT
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Start by placing the mouse on a
surface it can grasp (such as
cage top) while you hold near the
base of the tail with your
dominant hand.
Grasp the loose skin over the
shoulders by the non-dominant
hand between thumb and first
three fingers.
Mouse must be held firmly but
gently, so it does not have
difficulty breathing.
Note: The picture shown does not
accurately show an individual
wearing appropriate PPE. They
should be wearing gloves.
RESTRAINT
 Plastic restraint
devices can also be
used.
 Used to hold mice for
longer periods of
time.
 Device allows either
head or tail to
protrude for
procedures.
 Remember to
disinfect between
animals.
SEXING
 Males
 Have a greater
ano-genital distance
 Holds true for
neonates, juveniles
and adults.
Female
 Sexing in newborns is
best done by
comparing several
animals at one time.
Appropriate PPE is not shown in
these pictures.
Male
HOUSING
 May be housed in solid bottom shoe-box cages
with bedding, generally in groups.
 Solid bottom caging with bedding
recommended.
 Provide mice with warmth, security, and nesting
material.
 Lids rest on top of the cage with locks or clamps.
 Mouse lid wires placed closer together than rat
cages.
 Change bedding no less than twice a week.
HOUSING
 Cage and animal room sanitation are very
important.
 Need to follow SOPs per facility
 Examples  Solid bottom cages/accessories – 1-3 times
per week
 Cage shelving – At least once per month
 Wire bottom cages – At least once every 2
weeks
BEDDING
 Should be non-toxic,
non-nutritive,
unpalatable, nonabrasive, absorbent
and inexpensive.
 Processed wood
chips
 Corn cob products
 Shreddable paper
Alphi-Dri
(paper)
Wood
pellets
Carefresh (paper)
Aspen (hardwood)
Sanichip (hardwood)
Cellu-dri (paper)
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DIET
Normally provided in the
form of pellets.
 Pellets are firm and
require gnawing
 This helps keep their
continuously growing
incisors worn down.
 For programs which
require critical disease
control measures, diet
products which can be
sterilized are available.
 Diets already sterilized
by irradiation can also be
purchased.
Mouse with
normal incisors
Mouse with
overgrown
incisors and
malocclusion
DIET CONTINUED
 Rodents generally fed ad libitum – given
a continuous supply of food and water.
 Non-pelleted diets available – For use
when food intake being measured or
when substances are being added.
 Food consumption – 3-6 grams, or 1.5
grams per 10 grams of body weight, per
day
BREEDING INFORMATION
Sexual maturity – 40-60 days of age
Gestation – 19-21 days
Litter size – 6-12
Newborn litters should not be disturbed
for a few days to prevent cannibalism by
adults.
 Weaning – 21 days.
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DISEASE
 Tyzzer’s Disease
 Transmitted
 Fecal – oral route
 Symptoms
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Hunched
Unformed feces
Unkempt hair coat
Dehydration
Can by asymptomatic
FUR MITES
 Transmitted by direct contact
 Usually no clinical signs
 Alopecia may occur
 Pruritis
 Treatment
 Dusts
 Ivermectin