Small Mammals - Rodents Flashcards

Question

Interesting fact need to do before surgery

Answer 1

1. Don't need to starve as have a high metabollic rate and relatively fast gut transit time. 2. poisons are good as once ingested are absorbed relatively quickly, and can't vomit!

Answer 2

1. Obligate nasal breathers 2. Lungs: 4 lobes Left lung ahs a single lobe, right 4 (cranial, middle, caudal, intermediate 3. but hamsters have an additional lobe caudal accessory (5 in total)

Answer 3

1. due to high larynx and long epiglottis | 2. means passage straight from trachea to nasal cavity, preventing mouth breathing in normal animal

Answer 4

o Short airways and increased respiratory rates (breath in faster) o More alveoli of thinner diameter (increased S.A for gas exchange) o High chest wall compliance = increase vital capacity (take in more air in each breath), decrease residual lung capacity (when breath out, everything taken out) o Optimised to expand lungs and efficiently expel air

Answer 5

Smaller animals move to right, harder for oxygen to bind but easy to release Hb releases O2 more readily at tissue level

Answer 6

Behavioural o Huddling, nest building, tunnelling underground where temp fluctuates less) • Shivering • Peripheral vasoconstriction (tails, ears, paws) keep heat in core • Non-shivering thermogenesis o Brown fat behind scapula, round neck and shoulders. Can persist for life

Answer 7

* Few sweat glands (minimal on feet) * Evaporation of saliva that is groomed over body (evaporative heat loss) * Arteriovenous shunts in ears, tails & feet

Answer 8

``` Myo 1. large litters 2. short gestation 3. Altricial young (blind deaf, no fur) Hystrico 1. Smaller litters 2. long gestation 3. precocial young (ready to go with fur) ```

Answer 9

1. all are polyoestrus sponstaneous | 2. apart from chinchillas whoa re poly oestrus seasonal - want young to be born at most optimal time

Answer 10

1. mice - 19-21 days 2. rate - 21-23 days 3. hamsters - 15-18 days 4. gerbils - 23-26 days 5. guinea pigs - 59-72 days 6. chinchillas - 111 days

Answer 11

mice, rate, hamsters, gerbils = 6-8 weeks Guinea pig = 4-6 weeks Chinchilla - 8 months

Answer 12

Bicornuate: guinea pig, ferret, dog, cat (single cervix, small body, long horns Duplex: hamster, rat, mouse, chinchilla, rabbit (2 cervix) If ever do a c section of a animal with duplate cervix you have to do 2 incisions, one on either horn as can't milk offspring from one side to other

Answer 13

Os penis like dog | 2. they have an open inguinal canal so can retract testes back into abdomen

Answer 14

1. testes are often inguinal unlike others that descend into scrotal sac following puberty

Answer 15

``` o Seminal vesicles o Prostate o Coagulating gland o Bulbourethral gland o Preputial gland o Mucous plug into vaginal to help with intromission ```

Answer 16

1. know that is is pretty stress inducing 2. Ano genital distance - longer in males than females 3. mice and rats - only females have nips Gerbils and hamsters both sexes have nips, but more obvious ones in females Guineapig both have obvious nips! 4. male gerbil has a much larger ventral scent gland (bald path on abdomen) 5. Male hamsters - lump 6. Male guinea pig (boars) looks like I and penis can be everted using gentle pressure 7. Female looks like a y 8. Chinchilla dont mistake clitoris for penis!

Answer 17

o Proestrus o Oestrus o Metoestrus o Dioestrus

Answer 18

* Found following copulation in most female rodent species * Thought to be congealed sperm, mucus and accessory ejaculatory fluids, which harden within the cervix * Remains in place for 8-12 hours * Often found on cage floor rather than in vagina! – hard waxy * Thought to seal vagina and make it more likely for mating to be successful

Answer 19

o Dehydration o Hypothermia o Hypoglycaemia o Have to consider when doing any procedure on them

Answer 20

o Increased O2 consumption and increased food intake | o Husbandry very important

Answer 21

o Susceptible to dental disease – obligate nose breathers – vitamin recycling

Answer 22

Naturally nocturnal Yellow incisors due to iron pigment – normal Prominent harderian gland o Red brown gland fills large part of orbit and lies behind the globe o Increased secretion when stressed or unwell o Looks like blood but NO! Venupuncture sites – take <1% bodyweight o Lateral tail vein o Lateral saphenous o Ventral tail artery No gall bladder Urethral orifice separates from vulva Extensive mammary tissue from axilla to groin in females o 6 pairs of mammary glands o Prone to tumour formation o Mammary fibroadenoma – benign, can remove and be successful o Mammary adenocarcinoma – malignant

Answer 23

• Naturally nocturnal, but can adapt to diurnal lifestyle o Need 12hr:12hr light dark periods o If cycle differs such, often get problems • Very dense fur – 50-60 hairs from each follicle o Tolerant of cold (but not wet) and sensitive to heat o Will ‘drop’ coat if stressed, careful handling required (fur slip) as a vet handle carefully o Dust baths help maintain coat condition • Long gestation period (111 days) o Young precocial  fully formed and ready to go • Blood sampling o Cranial vena cava and lateral saphenous

Answer 24

• Absolute requirement for vitamin C o 10mg/kg/day (3 times this so 30mg/kg/day if pregnant) o Scurvy can develop within 4 days of decreased intake • Males have prominent caudal sebaceous gland • Pubic symphysis dilates to allow parturition, important to breed females before age of 7-8 months to prevent fusion and subsequent dystocia. If want to breed older animal with no litter prior warn for dystocia • Blood sampling o No tail so o Cranial vena cava o Jugular o Femoral or lateral saphenous vein • Thymus is cervical o Often used in laboratory science • Young – precocial! Pregnant for 63-65, like dogs

Answer 25

• Form monogamous pairs o Dad helps with raising young o Post mating vaginal plug deep and not easily seen • Both sexes have large ventral midline sebaceous gland o Larger in males o Not a tumour, however, is a site for tumour formation • Drink very little (4ml/100g/day), are desert species and have excellent urine concentrating abilities. Popular pets as not too smelly • Avoid handling by tail – can slough, skin can just fall off • Absolute requirement for vitamin C o 10mg/kg/day (30mg/kg/day if pregnant) o Scurvy can develop within 4 days of decreased intake • Males have prominent caudal sebaceous gland • Pubic symphysis dilates to allow parturition, important to breed females before age of 7-8 months to prevent fusion and subsequent dystocia

Answer 26

Bilateral cheek pouches which can extend caudally as far as the shoulder blades - primary function storage adn transport food o Often site of impaction – you will need to go in and clear out o Lined with oral mucosa o Immunologically privileged site o can inflate - keep afloat • Stomach is compartmentalised into o Forestomach (like ruminants) o Glandular stomach • Sensitive to antibiotics due to bacterial population o Disruption of normal gut flora • Females have separate vaginal and urethral openings • Bilateral vaginal pouches internally making vaginal cytology hard to interpret o Vaginal plug deep and difficult to see o See post mating vaginal discharge • Shortest gestation of all eutherians o 15-18 days (Syrian) • Flank glands – androgen responsive. Litke ventral scent gland in gerbal, similar appearance o More obvious in males than females o Often mistaken for tumours • Blood sampling tricky o No tail vein! o Use jugular, cephalic, cranial vena cava • Will enter state of hibernation o If temperature drops below 5C • Nocturnal but very active during hours of darkness can travel around 5 miles in one night! • High water consumption o Up t0 20ml a day in some large adults