Basic Biology and behavior Flashcards
Describe the oestrous cycle/ovarian cycle of rodent
The female mice can reproduce all year when housed at animal facilities (12:12 ligth:dark)- they will not in nature.
The female can get pregnant around 6 weeks of age
The female will only cycle if there is a male near by
Females will synchronize when housed together.
Anostrues if no male pheromones
Eustrus= will mate and get pregnant 12 hours
pregnant for 3 weeks
pups weaned at 3 weeks post partum
Lee-boot effect (no male)
How does pheromones affect the ovarian cycle and pregnancy in rodents?
If female mice housed together without the scent stimulation from a male, the oestrus cycle will become slower and will eventually stop completely in anoestrus.
The Whitten effect (synchronizing)
How does pheromones affect the ovarian cycle and pregnancy in rodents?
Used for synchronizing
If anoestral females are exposed to pheromones from male mice, their
oestrus cycle will start again
Anoestral females - male sent exposure –> 3 days post exposure male mates 75% of females
The Bruce effect (unfamiliar male)
How does pheromones affect the ovarian cycle and pregnancy in rodents?
If a pregnant female is exposed to scent stimulation (e.g. urine) from an unfamiliar male, this may result in insufficient implantation of the
fertilised egg or abortion
The Vanderberg effect (early mature female)
How does pheromones affect the ovarian cycle and pregnancy in rodents?
Young female mice appear to become sexually mature more quickly when a male mouse is nearby
Describe the rodents’ senses of hearing, vision and olfaction and discuss the importance of being aware of how these senses differ between rodents and humans
Hearing: Hear ultrasound and different wave lengths than human. Humans cannot hear their communication!
Vision: Blurry vision.
Can se ultraviolet (glowing mouse urine).
Can see green, but not red
Olfaction: Their hierarchy is based on smells (pheromones in urine and glands). Marking of their territory (dominent male all over the cage, subdominant in a corner)
Cage change: Take clean nesting material into the new cage = familiar sent.
We do not know how ultraviolet light and sounds affects the animals! and we are not able to recognize it when there.
Discuss what temperature is optimal for mice, how the preference for a specific temperature can be established and how mice can thermoregulate
EU-directive: 20-24 degrees Celsius
A proper nest can be used for thermo regulation in mice.
Mice nest: 32 degrees around the pups despite a surrounding temperature at -3 degrees Celcius
Mice prefer a warmer temperature (20/25/30 degrees) when being inactive (sleep) or eating/grooming/nest-building
Supply the mice with a sufficient amount of nesting material for giving them the possibility of thermoregulate.
Examples of stressors - external and internal
External stressors:
- Scent of a rat or cat for a mice – it is afraid of being eaten
- No place to hide
- No food
- Not being able to build a nest (mice)
- Being in a small space with multiple males in a new cage without pheromones –> the establishment of a dominant hierarchy
Internal stressors:
- Not being able to perform a behavior (dust bating in hens)
Discuss the physiological consequences and manifestations of stress in rodents
Physiological consequences:
- Stress response (adrenaline and noradrenaline): increased HR, BP, decreased digestion –> fight or flight reaction (or freeze)
- Glucocorticoid hormones: Increased blood glucose, metabolism, decreased effect of the immune system.
Manifestations:
The animal might cope with the stress by showing stereotypies – A repetitive behavior pattern with no obvious goal or function.
Discuss how different handling methods of mice can affect animal welfare and animal behaviour
Adverse handling induces the Fight and flight reactions! - mostly flight and freeze reactions
making the mice more difficult to handle, needing more training when being acclamitizied
Stressed animals
Gentle handling - tunnel/cupping:
not seeing the hand as a predator, being more willing to explore new surroundings
non-stressed animals results in more reliable research making it easier to reproduce the data.
