Rat & Mouse Husbandry and Diseases Flashcards
what order, suborder, family, and genus are RATS?
order: rodentia
suborder: myomorpha
family: muridae
genus: rattus
what species of RAT is most commonly seen as pets / brought into the clinic?
Rattus norvegicus
what order, suborder, family, genus, and species are MICE?
order: rodentia
suborder: myomorpha
family: muridae
genus: mus
species: musculus
A rat presents to your clinic because the owners noticed that one of the toes on the front feet must’ve fallen off since there are 5 toes on the back feet but 4 on the front. What is your presumptive diagnosis and plan?
nothing! this is normal anatomy.
T/F: mouse and rat incisors grow continuously throughout life
true
they can become maloccluded, which can lead to issues with eating. They require trimming if they present with this issue.
what is the purpose of brown fat deposits?
used to generate heat during exposure to cold environment. It is a form of non-shivering thermogenesis
T/F: rat and mice brains have ample gyri and sulci
false – lacks. smooth brains :/
What is the function of the harderian gland (a gland found below the eye)?
secretes porphyrin (iron-containing red pigment)
hypersecretion occurs under stressful conditions (red tears).
If a rodent presents to your clinic with a presenting complaint of “bleeding from the eyes/nose/legs” then you should consider this as a possibility and recommend stress reduction
how many lung lobes do rats and mice have?
4 (1 left, 3 right)
T/F: the mouse lacks a galbladder whereas rats have one.
false – rats lack one, mice have it.
what is the speculation about why rats canNOT vomit?
limiting ridge that separates the glandular and nonglandular portions of their stomach blocks the esophagus.
The cecum in rats and mice is large. What is the purpose of this organ?
contains resident microbes that aid in digestion of cellulose and other plant materials. Necessary for life.
You need to place a catheter in a rat. What is different about the urinary anatomy in rats and mice that you need to consider for ucath placement?
the urethra opens in the penis in males.
in females, the urethra opens in the genital papilla near the base of the clitoris (not in the vagina/vulva)
Secretions from what 4 glands in male rats/mice yields a sperm plug?
- vesicular glands / seminal vesicles
- coagulating glands
- prostate
- bulbourethral glands.
How is it possible that rats can draw their testicles into their abdomen?
they have open inguinal rings
pulling them into their body is beneficial during fights and/or cold weather
T/F: rats have 2 cervices
true
T/F: a vaginal closure membrane is present in immature female rats/mice but disappears prior to sexual maturity
true – this is different from guinea pigs.
Why would mammary tumor be one of your top differentials for a mouse/rat presenting with a mass under the arm pit or around the neck?
mice and rats have mammary tissue that is widely distributed and extends onto the lateral and dorsal areas of the abdomen and thorax
what are the lifespans of rats and mice?
rats – 2-3 years
mice – 1.5-3 years
Approximately how much urine do mice vs rats produce per day?
mice – 0.5-1.0 mL/day
rats – 3.3 mL/100g BW/day (A LOT)
Rats and mice are (nocturnal/diurnal/crepuscular)
nocturnal
T/F: male rats and mice are more aggressive than females
true
how is social dominance manifested in mice?
the dominant mouse exhibits barbering (excessive grooming/nibbling) of less-dominant individuals.
If you are looking at a group of individuals, the one that still has hair is likely the dominant individual who is barbering the others causing hair loss.
This is also known as trichotillomania and can be treated with N-acetylcysteine.
T/F: rats and mice need food and water available ad libitum
true
Mice and rats involved in nutritional and dosed feed toxicology studies are typically fed powdered mash feeds as opposed to pellets. What abnormality would you expect these animals to develop over time as a result of this diet?
incisor tooth overgrowth.
how long is the estrous cycle in rats? how about mice?
rats – 5 days; heat occurs on day 3
mice – 4-6days; heat occurs on day 3
females exhibit lordosis when in heat.
what is the most economical way to have rats/mice do natural breeding?
harem mating (one male to 2-4 females)
requires less males and less cost assoc with caging and husbandry than monogamous pairing
How can you confirm that successful mating has occured in rats and mice?
the presence of the sperm plug in the vagina.
In rats, tends to fall out easier than in mice.
You can also do vaginal lavage and exam for sperm microscopically.
what is gestation of rats and mice?
rats - 21 days
mice - 19 days
what is the consequence of humans intervening during parturition of rats/mice?
can delay delivery of entire litter by 4 hours and increase the incidence of stillbirths.
how long does weaning take in rats and mice?
21 days
how can you sex rats and mice?
assess anogenital distance
greater in males than females.
________ effect is characterized by grouping females, in the absence of males, will lead to estrus suppression and increased incidence of pseudopregnancy
lee-boot
________ effect is characterized by exposure of individuals or groups of females to a strange male will result in the induction of estrus and can be used to synchronize estrus in a group of females.
Whitten
______ effeect is characterized by exposing a female to a strange male BEFORE the ova implants in the uterus (0-4 days after breeding), causes the pregnancy to spontaneously terminate
Bruce
Grasping rats by the tip of their tail will cause …
degloving injurys
what type of restraint is best for rats versus mice?
rats – tail restraint (at base), thoracic encirclement,
mice –scruff hold > tail restraint
both- use rigid plastic containers or syringe cases.
what are the 4 injection sites of rats and mice?
- intramuscular (back leg)
- subcutaneous
- intraperitoneal
- intravenous (facial, submandibular, or tail vein)
what are things to NOT do when giving a rat/mouse an intraperitoneal injection?
dont insert to hub
dont use long needle
dont insert perpendicular to body wall
dont reuse needles
Do: inject within the cranial-midline portion of the caudal 2 quadrants; insert needle slow and at a shallow angle. only insert needle through skin and muscles. Dilute drugs if going IP.
what is the SAFE amount of blood you can collect from a mouse and rat?
mouse = 0.1-0.2 mL
rat = 1.6-3.3 mL
Note that if you are desiring to do diagnostics on serum, it will be only 55% of the blood volume collected (ex. collect 0.2 mL will have 0.1 mL serum). You may need to collect multiple samples and pool them for diagnostics.
what is different about an ovariectomy in mice/rats than in other species?
dorsal approach!
and you do not even need to place ligatures, just rip the ovaries out and close the skin.
what are ideal bedding characteristics for mice/rats?
- dry, should not cause injury, should not lead to ingestion by animal, should not interfere with research
Sawdust too fine –> ingested
corncob may contain pesticides
cedar affects CYTP450 and causes hair loss, itching, sneezing
hardwood chips, aspen, pine, and paper are much better options
what are potential causes of dental problems in rats/mice?
soft diets
injurys/fractures to teeth
calcium deficiency with loose sockets
what is the most common mammary tumor in rats/mice and what is the treatment?
fibroadenoma
surgical removal
what are the 3 viruses affect the digestive system and can cause stunting/runting, death of pups, and/or effects on the immune system and GI tract?
- mouse parvovirus 1
- mouse rotavirus (EDIM)
- reovirus type 3
dg by serology and tx supportively.
what are the 2 most common viruses that cause stunting/runting/death of pups, pneumonia, or death in immunocompromised mice?
- Pneumonia virus of mice (PVM)
- Sendai virus (highly infectious)
dg by serology
What bacterial organism causes weight loss, runting, perineal staining, and rectal prolapse. The organism cause the wall of the colon to become hyperplastic which blocks the passage of fecal material.
citrobacter rodentium
What is the CLASSIC sign of Clostridium piliforme (Tyzzers disease)?
white spots on the liver
impression smear looks like “pick-up sticks”
T/F: salmonellosis in mice causes white spots to develop on the liver
true – also causes anorexia, diarrhea, high mortality in weanlings.
What bacterial disease causes “spinner mice”?
pseudomonas aeruginosa
causes weight loss, hunched posture, and mice that spin when picked up by their tail.
what is the tx for pseudomonas auerginosa in mice?
water + acid (HCl)
or chlorinate their water.
which 2 bacterial organisms cause weight loss, hunched posture, and difficulty breathing in mice?
Klebsiella pneumoniae
Streptococcus pneumoniae
which 3 bacterial organisms cause skin disease in mice such as abscesses?
- pasteurella pneumotropica
- staphylococcus aureus
- corynebacterium spp.
A mouse presents to your clinic. the owner is worried that he hasnt gained a lot of weight since being born. She also states that he has some irritation around his anus. You suspect pinworms may be the problem. How can you detect pinworms?
tape test
What is sialodacryoadenitis virus?
a rat coronavirus that is highly contagious and causes dry eye/no tears/no saliva/anorexia/wt loss.
It resolves in 10 days, but rats can get corneal ulcers or glaucoma as a result.
What is a significant rat disease that causes head tilt, circling, dyspnea, chattering, and red tears as a result of proliferation f lymphoid tissue in the bronchi restricting air flow?
Murine respiratory mycoplasmosis
what bacterial organism would give rat lungs a cobblestone appearance?
corynebacterium kutscheri
what are the 7 zoonotic conditions of rats/mice?
- Rat bite fever (Streptobacillus moniliformis, spirillum minus)
- Hantavirus
- lymphocytic choriomeningitis
- leptosporosis
- plague
- campylobacter
- salmonella
