Rats and mice are often the animals of choice to try and model human conditions, treatment and body functions - even though we know that the use of animals to try and model people fails over 90% of the time.
Mice and rats are commonly used due to their small size, low maintenance (i.e., they are easy to house and care for), short life cycle, and ability to breed quickly (allowing large numbers to be generated for studies quickly).
They also share many of our genes.1 But that's not surprising, even cats share many of our genes.2
Mice are also relatively easy targets for genetic manipulation, which is heavily used in cancer research.3 So it is not surprising, that over 95% of transgenic animals used in 2020 were mice (14,936 transgenic mice of 15,645 transgenic animals).4 Their small size also makes importing mice from other countries manageable.
Mice are mainly used for basic biological research, medical research, animal husbandry and testing in NZ. They are also used for veterinary research and the production of biological agents.
Mice in NZ have been used for:
- Drug research including safety and efficiency testing.
- For teaching purposes in schools, including observational activities and dissections.
- Disease research including research into the development of severe diseases (i.e., stroke, heart attack, cancer), modelling neurological disorders (i.e., Schizophrenia, Autism), modelling mood disorders (i.e., anxiety, and depression).
- Drug addiction research including research into the development and suppression of addictions and the impacts of drug use.
- Basic biological research into how parts of the brain work, damage affects the functions of the body, pregnancy changes body functions, wounds heal and how stress affects body and brain functions.
Places that use mice for science in NZ include crown research institutes, private companies and universities. Infact, most universities have their own breeding colonies. Otago University states on its website that they have a dedicated mouse testing room in the Behavioural Phenotyping Unit.5
Mice used for science in NZ are often sourced from breeding units at the respective institutions. Transgenic mice are sometimes imported from other countries like Australia, USA or Japan.
Discover real-life examples of how mice have been used in NZ below!
Studying selenium metabolism
Cats and dogs were fed diets with different selenium supplementation for three weeks in individual metabolic chambers. A liver biopsy was taken under anaesthesia.
Monitoring wild cats via GPS collar
Wild cats were caught and fitted with GPS collars. After an average of 9.75 days, there were recaptured to retrieve the collars.
Testing new toxin against stoats and wild pets
Dogs, cats and stoats were fed different versions of toxic bait. Symptoms and time of death were monitored. Four dogs and two cats survived, but their fate is not stated.
Testing the efficacy and shelf-life of a toxin
Captive wild cats were used to compare the efficacy of different toxin formulations and the effect of more extended bait storage. Cats were fed the toxin bait or pipette-fed toxin directly as control. Symptom onset and time of death were monitored.
Studying the genes for hairyness
The hairiness of male and female cattle was rated. Some animals had their rectal temperature taken repeatedly, and some were shut in a hot room for two hours to make them sweat. Eight calves were killed to take brain samples.
Optimising fertility treatment
Young female cattle were treated with different hormonal injections to control their fertility cycle. Around ten rectal ultrasounds were done on each of them within 11 days, and several blood samples were taken in the next month. All but nine were artificially inseminated. The nine animals showed no fertility signs and were therefore useless for the study and the industry.
Trying out a health test for breeding bulls
Breeding bulls were infected with a skin fungus that usually results in a dangerous build-up in the gall and eczema. Through a special diet, bulls can be tested for their reactions via repeated blood samples and ranked for their genetic quality.
Testing a vaccine against miscarriage
Younger and older pregnant cattle were injected with a new vaccine against a parasite or just control solution. Skin reactions to the injection were checked, and blood samples were taken. Farmers reported miscarriages when they happened, and dead foetuses were collected if possible. If female calves were born, blood samples were taken from them, too.
Studying Johne’s disease
Some female calves of a group were infected with bacteria causing life-threatening sickness. Poo samples were collected directly from the rectum of all calves every other month. Half were killed to be dissected at 7 months, the rest at 15 months.
Studying Johne’s disease bacteria
Blood samples were taken from sick dairy cows who were sent to slaughter to see if their immune system was even putting up a fight. After slaughter, organ samples were taken.
Finding a gene to increase casein in milk
Breeding bulls were evaluated on their quality by judging, breeding, and milking their daughters. No exact numbers are stated how many lived to the end of the study (5 lactations).
Testing a new way to treat liver flukes
Young cattle were infected with liver flukes. They were treated with different medications or left untreated. Regular blood samples were taken from all animals for three weeks, and they were killed ten weeks later.
Studying effects of stunning before slaughter
Calves and sheep were anaesthetised. Some got 70-volt shocks to the shoulder. Others had a nerve exposed and stimulated before being stunned or cutting their throat.
Measuring brain reactions to stunning after killing
Calves were fasted for 24 hours and then anaesthetised. They were killed by their throats being cut, followed by stunning while measuring EEG/ECG (electronic heart and brain activity) and blood pressure.
Measuring brain reactions to stunning
Calves were fasted, anaesthetised and stunned with a non-penetrative bolt while being monitored for their response. After measurements were taken, they were killed.
Studying brain reactions to cutting blood vessels or neck tissue
Calves were anaesthetised, and their throat blood vessels exposed. While monitoring the brain“s activity (EEG) and blood pressure, either only the blood vessels or only the neck tissue was cut. The latter animals were then killed, too.
Measuring if being slaughtered is unpleasant
Calves were fasted, anaesthetised, and killed by cutting their throat. EEG and ECG (recording electronic heart and brain activity) were measured with electrodes in the head.
Measuring brain reactions to pain
Twenty calves were fasted and anaesthetised. Their horn buds were removed with a scoop, and pain response of the heart and brain with and without pain blockers.
Testing mastitis treatments
Dairy cows with an udder infection were treated with different antibiotic injections. Milk samples were taken to monitor results.
Trying to clone cows with more valuable milk protein
The genetic material of a cow foetus was manipulated and cloned into several cows. When they were less than one year old, they were injected with hormones to produce milk for sampling.
Testing dogs’ preception of time
Dogs were trained to press different levers based on their exposure to different types of light.
Testing working dogs for a gene mutation
Buccal swabs (inside the cheek) were collected from working dogs to analyse their DNA.</p><p id="">Procedure: Buccal samples were collected from 100 working farm dogs. Their owners were approached at gatherings such as Working Dog Trials, veterinary clinics and farms. Swabs were taken under the owner’s care. No adverse effects from the sampling were reported.
Determining how common E. coli is in pets
Rectal swaps were taken from cats and dogs presented at veterinary clinics, and their caregivers filled out a questionnaire.
Testing interest of dogs in different kiwi bird items
Dogs were taken to a small area to interact with different items that looked or smelled like kiwi bird. Some dogs had patches of hair shaved off to attach a heart rate monitor.
Teaching dogs to smell out koi carps (2018)
Five pet dogs were trained over several months to identify the smell of koi carb from water samples.
Measuring lean body mass of working dogs
Blood samples were taken from dogs, while they were deprived of water for 2 hours.
Testing a possum poison for other animals’ safety
Dogs were fed dead possum, either whole or minced. Once they got used to eating this, they were fed with possums killed with sodium nitrite, and signs for poisoning were monitored. In the end, all animals were killed and dissected.
Investigating separation anxiety in Greyhounds
The occurrence of separation anxiety with rehomed Greyhounds was investigated over one year.
Investigating a muscle weakness disease in dogs
Blood samples were taken from dogs with signs of myopathy within the regular veterinary treatment. A total of 22 of the 86 cases were euthanised.
Analysing CT scans of dogs
Veterinary data of German shepherd dogs were analysed; most were police dogs.
Testing if bone marrow is different in different body parts
Dogs were killed, and samples of their bone marrow were taken from different locations on their bodies.
Practising vet skills on different species
Students are taught anatomy, physiology, animal handling and basic clinical/husbandry skills. Dogs were used in for training in anaesthesia classes.
Assessing blindness in racing greyhounds
Greyhounds were treated with pupil dilation drops to examine their eyes. Some were brought to a vet clinic for further tests.
Testing a possum poison for other animals’ safety
Dogs, chickens and wild-caught cats were fed dead possum. Once they got used to eating this, they were fed possums killed with sodium nitrite, and signs for poisoning were monitored.
Testing nutritional value of new pet food
Cats and dogs were fed a test diet exclusively for several months. Some adults are kept in metabolic chambers for 10 days, and blood samples are taken at the end.
Scanning spines of dogs in CT
Police dogs and racing Greyhounds were sedated and computed tomography imaging was taken.
Studying fish behaviour in groups of multiple species
Mixed-species groups of fish (partly caught in the wild) were placed in a tank and fasted for 24 hours. Food was given and an artificial predator was used to study behaviour.
Studying food chains near CO2 vents
Fish and snails were observed and counted near CO2 vents and at control sites. Fish were also caught to examine their stomach content.
Studying fish behaviour in single-species groups
Young fish were caught in the wild and split into groups of 15, 75, and 150 animals. After being fasted for 24 hours, food was given and an artificial predator was used to study behaviour.
Testing the side-bias of fish (if they prefer to swim left or right)
Wild-caught fish were kept for 1.5 years before each fish was placed on a runway to observe their behaviour. Afterwards, fish were observed for schooling movements and some were killed to dissect their brains.
Studying effects of Climate Change on farming in damselfish
Fish were observed for their algae farming behaviour near CO2 vents and at control sites (Bay of Plenty). Small areas were covered to keep the fish away for a month and compare algae growths measured to compare.
Trying to estimate habitat quality from body condition
Snappers were hatched from eggs and raised on commercial food. They were kept in 800-litre flow-through tanks containing 170 to 260 fish each. At 80 days, they were fasted killed.
Trying different techniques for tagging fish
Fish were bait-trapped and treated for parasites. They were used to test different tagging methods. In the second part of the experiment, fish were caught with two different methods, after which injuries and survival over 12 days were monitored.
Studying fish near volcanic vents to learn about Climate Change
Fish near volcanic CO2 vents and at control sites were observed and counted. The reaction to baited underwater cameras and predator threats was filmed. Aquarium experiments were conducted with caught fish of different species.
Verifying “fish-friendly” flood pumps
Eels were caught, measured and tagged with transponders into the gut skin. They were later re-captured, observed for wounds and fungus and killed to examine internal damage.
Testing the temperature tolerance of Antarctic fish
Wild-caught fish were kept individually for months in tanks. During temperature experiments, fish of each group were tested for their breathing ability in small tubes before all fish were killed.
Slowly poisoning fish
Snappers were fasted for three days and then fed with toxic fish. Several died during feeding, and the rest were killed at the end.
Studying population changes in reef fish
Over 1,000 fish were caught by spearing at three NZ locations.
Testing the hearing of fish
Fish were anaesthetised and strapped to a plastic slide near an underwater speaker. Electrodes were placed in their head and gills to measure brain activity. For medical imaging, fish were restrained in a plastic tube with a sponge to keep them wet.
Developing a model for thermal stress in humans
Guinea pig pups were lightly anaesthetised, connected to devices measuring heart activity and breathing, and wrapped in a temperature-controlling blanket. Their body temperature was either forcefully raised or dropped.
Testing how too much fructose is bad during pregnancy
Female guinea pigs were mated; some were fed additional sugary water until birth. The pups were used for several glucose tolerance tests and X-rays. All pups were killed in the end.
Testing a seizure medicine for preterm babies
Pregnant guinea pigs were induced to give birth early, to test medication on their pups.
Testing the effects of sedatives
Young guinea pigs were treated with different sedatives. Their heart rate and blood pressure were measured before and during each treatment.
Testing an refined way of anaesthesia in guinea pigs
Guinea pigs were made to inhale anaesthetic gases. Different probes were inserted and attached to the animals to measure responses.
Studying the effect of fructose during pregnancy
Guinea pigs were fed either normally or supplemented with fruit sugar before and during pregnancy until birth. Mothers and pups were tested for glucose tolerance.
Studying the effects of meth
Guinea pigs were injected with sedatives, caffeine, and later meth. Under anaesthesia, their livers were cut out before they were killed.
Studying preterm birth effects on the brain
Pregnant guinea pigs were grouped to give birth normally or be induced early. The pups were put through behavioural tests and then killed for dissection.
Studying trauma and treatment of cochlear implants
After destroying their hearing with noise, guinea pigs were fitted with cochlear implants. Treatment success was tested before they were killed.
Testing the measurement of pupil reflexes in Alzheimer’s research
Guinea pigs were repeatedly flashed in the eyes with a phone light to record the pupil responses.
Teaching animal researchers
A range of animals is used to teach researchers handling and experimental methods.
Investigating mechanisms slowing down the heart rate
Young guinea pigs were injected with blood thinner before being anaesthetised and dissected.
Testing a device to assess hearing
Young guinea pigs were anaesthetised, electrodes placed under their skin, and their brain's response to sound was measured. All guinea pigs had one ear damaged, some both ears, before all were killed.
Studying changes in the inner ear due to inflammation
Guinea pigs were injected into the ear with bacteria. Medical scans were done after injecting chemicals, and most were killed for dissection.
Studying the effects of medication on memory
Guinea pigs were force-fed different drugs and later tested in a water maze before some were killed. Another group was exposed to carbon dioxide and decapitated.
Studying how anaesthetics affect intestine movement
Guinea pigs and rats were anaesthetised, then dissected, and then killed, in that order.
Researching scoliosis genes
Transgenic mice with a specific gene defect were mated. Pregnant mice were at several time points. The unborn babies were taken, skinned, and gutted to stain their skeletons for better pictures.
Studying hormone influences on obesity and fertility
Transgenic mice were bred to have diabetes symptoms. Together with control mice, they were fed a normal or a high caloric diet and compared for their fertility over 150 days.
Testing a new stroke treatment
Mice were squeezed into plastic cones, and test drugs were dripped on their nose. An artificial stroke was caused by injecting a chemical into their brain. Before and after, mice had to perform behavioural tests. All were then killed to take their brains.
Testing another new stroke treatment
Mice were operated on several times. They were made to experience an artificial stroke, were later injected with a possible treatment, and then were injected with a marker. The mice had their memory tested before they were killed.
Testing prostate cancer drugs
Mice were anaesthetised, and their prostate was injected with cancer cells or a control solution. A 42-day treatment course started three weeks later with different treatment drugs and control solutions. In the end, all mice were killed.
Testing a heart attack treatment
Mice were trained to eat jelly and then subjected to an artificial heart attack. They received either a new drug or a control substance. Regular heart ultrasounds were performed before they were killed and dissected.
Studying ovary problems caused by testosterone
Transgenic mice were implanted with a capsule containing either hormones or not. Vaginal smears were done for several weeks, and serial blood tests were performed twice. In the end, all mice were killed.
Testing an Autism treatment on transgenic mice
Mice were genetically modified to show "autism-like" symptoms. Together with control animals, they were either fed normally or with a high-zinc diet. Invasive behavioural tests were performed. At least some, likely all, were killed.
Comparing transgenic mice and humans
Mice were anaesthetised, and their body composition was measured several times. Their grip strength and balance were tested with lab equipment. In the end, all mice were killed.
Testing a new stroke drug for better dexterity
Transgenic mice were anaesthetised, and an artificial stroke was caused. They then received either a test drug or a control solution. After recovery, their food was limited to test their fine motor skills every other week. After two months, they were killed.
Testing migraine drugs
Mice were injected with potential migraine drugs and anaesthetised. Ultrasound imaging of their ears was taken. One ear was rubbed with capsaicin to record the increased blood flow and compare different drugs, doses, and time points.
Killing rats and mice for tissue
Rats and mice were anaesthetised, and their necks were broken. Their tissue was then used for research.
Studying Alzheimer’s and stroke symptoms
One group of transgenic mice were bred and killed at either four or 12 months of age by flushing their hearts. Another group was anaesthetised and caused to have a stroke. They were killed the same way.
Testing Alzheimer’s treatment on mice
Transgenic and “normal” mice were injected with a special protein and a chemical to mark new brain cells that may have been produced.
Testing a new Alzheimer’s drug
Newborn mice were killed to collect brain tissue. Adult mice were used to test drug reactions. They were anaesthetised twice; to inject the drugs and to flush their hearts and take their brains.
Testing if anaesthesia affects the sleep–wake cycle when combined with light treatment
Mice were kept on a 12-hour light/dark cycle and then switched to total darkness. During this time, they were exposed to light once, either with or without anaesthesia. The effect on their activity cycles was monitored. In the end, all were killed.
Harvesting colon tissue for laboratory tests
Pigs were killed and their colon tissue was used for laboratory testing.
Testing if pigs can be fed by-products from biofuel and food processing
Pigs were fed a standard diet or a diet containing by-products from other industries. They were slaughtered to compare meat growth and quality.
Studying starch digestion in pigs to try and model humans
Pigs were fed different diets containing durum wheat or rice. Some had regular blood samples taken through a catheter. All the animals were killed at the end.
Validating a treatment for stomach muscle dysfunctions
Pigs were anaesthetised, their bellies were opened, and electrodes were placed on their stomach walls before and after damaging some stomach tissue with heat. All pigs were killed.
Assessing pigs as digestion models for humans
Titanium tubes were implanted into pigs’ intestines. Digested food was collected through the tube for 9 hours.
Testing the effect of different species’ milk on brain gene expression
Piglets were fed different kinds of milk from other species for 15 days. They were killed to dissect their brains.
Testing transmitter implantation on wild pigs
Wild pigs were captured, and three different tracking devices were fixed to or implanted into each one. After 104 days, they were tracked down and killed.
Investigating oxygen content in the gut
Pigs were fed diets with different or no protein sources as a control. After a week, all were killed.
Testing a UV treatment for bacterial eye infection
Pigs’ eyes were acquired for testing a new treatment, followed by tests on live mice, most of whom were killed.
Testing the effect of different species’ milk on protein digestion
Piglets were fed different kinds of milk from other species for 15 days. They were killed to dissect their stomachs.
Testing the strain on a temporary surgical implant
A surgical implant was screwed to a severed pig head, and measurements were taken via laser scanning.
Investigating intestine movements
Young pigs and NZ White rabbits were anaesthetised. A part of their intestine was pulled out far enough to record its movements and signalling.
Harvesting rabbit and pig eyes for lab tests
The eyes of slaughtered rabbits and pigs killed for experiments were used to analyse the structure of the cornea.
Harvesting eyes for lab tests
The eyes of pigs and rabbits killed for experiments were used to analyse the structure of the cornea.
Testing a treatment for stomach muscle dysfunctions
Pigs were anaesthetised, their bellies were opened, and electrodes were placed on their stomach walls before and after damaging some stomach tissue with heat. All pigs were killed.
Testing how electric stimulation affects stomach movements
Nine pigs were anaesthetised, their bellies were opened, and electrodes were placed on the stomach walls. Electric stimulation tests were performed before the pigs were killed.
Studying food intake in an autism "model"
Pregnant rats were injected to cause autism-like symptoms in their babies. The male babies were put through behavioural tests with control animals as well as a feeding study. Some were fasted for 16 hours and killed by flushing their hearts.
Testing the safety of a probiotic supplement
Rats were force-fed with a probiotic solution or control solution. After two weeks, they were killed for dissection.
Studying the effects of obesity and mussel powder on bone health
Rats were kept alone and fed different diets containing normal or high amounts of fat or sugar. Some were supplemented with Greenshell mussel powder. X-rays were done, and some rats' ovaries were removed. Ultimately, all were killed by bleeding them out.
Testing if a brain region controls memory
Some rats had their brains surgically heat-damaged. Electrodes were implanted to monitor brain activity and to stimulate the damaged parts with light. Rats then had to re-perform memory tests to see the impact before all were killed.
Studying the communication between inner ear and brain
Rats were anaesthetised, and their inner ear was partly removed, before parts of their brains were stimulated with wire electrodes. Reactions of the rat's eyes and brain were recorded. In the end, all rats were killed.
Testing a connection between tinnitus and brain function
Rats were anaesthetised and one ear was damaged with noise. Rats were taught that silence meant they would get electric shocks and freeze in fear. This was a test for tinnitus.
Testing diabetic rats’ hearts
Genetically diabetic fat rats and their lean littermates were anaesthetised. Ultrasound images were made from their hearts. All were killed and dissected.
Testing the effect of diabetes on pregnancy hormones
Rats were anaesthetised, and their brain was accessed through the mouth to measure reactions to stimulation. In the end, all rats were killed.
Trying to study schizophrenia
Half of a group of pregnant rats were injected to affect their babies' brain development. Some pups were allowed to grow up to test their behaviour.
Releasing a rat family into the wild to see where they go
A wild-caught rat was mated, fed a fluorescent dye, and released again with her pups. Traps, tunnels, and cameras were set up to track and eventually recapture the animals, which did not work 100%.
Comparing digestion of sheep versus cow milk yoghurt
Rats were fed cow milk, sheep milk, cow yoghurt or sheep yoghurt for two weeks. They were gassed with CO2 before their necks were broken.
Testing a rat poison that is unattractive for dogs
Rats were kept in small cages and fasted overnight. Then, they were given two food trays. One of them was scented with lion, tiger, or dog faeces.
Comparing digestion of sheep versus cow milk
Rats were fed a test diet containing beef protein and received cow milk or sheep milk instead of drinking water. After 28 days, all were killed.
Testing medication after heart attack
Rats were anaesthetised, and their hearts were exposed. A heart attack was simulated by blocking an artery. Some had dye injected into their brains, and some were injected with test drugs. All animals were killed.
Testing a medicine against drug addiction
Mice's tails were dunked in hot water. Rats were put through cycles of drug-seeking and withdrawal using self-injection of cocaine. Other rats were injected, and their behaviour was tested (with the notorious Forces Swim Test, among others).
Studying cell death in breast tissue
Mother rats had some of their newborns taken away, and several of her teats were sealed off after two weeks. They were killed after different waiting times to analyse the dying tissue.
Testing out cloning as a breeding tool
Cloned embryos were implanted into 17 mother sheep but all the pregnancies failed.
Undernourishing sheep to test glucose metabolism of their babies
Sheep were fed normally or only every three days. Some were killed during pregnancy. Born lambs were subjected to repeated glucose tolerance tests and killed.
Testing a medication for vocal chord injuries
Sheep were anaesthetised, tissue samples were taken from their vocal folds, and most were treated with different medications. All were killed after one month.
Testing if pre-term birth injections compromise glucose metabolism
Pre-term and full-term lambs were subjected to glucose tests, regular blood samples and a constant glucose infusion. Some were killed at four weeks, the rest at one-year-old.
Studying the effect of Huntington’s disease on ageing
Transgenic sheep were produced through breeding, and blood samples were taken.
Testing a first aide drug for severe bleeding
Sheep were anaesthetised and 30% of their blood was drained. After being treated with different medications, the drained blood was returned, and the sheep were killed.
Studying ear posture while in pain
Lambs had their tails docked with a tight rubber band without pain relief. Their pain behaviour was recorded.
Teaching animal researchers
A range of animals is used to teach researchers handling and experimental methods.
Training students in surgical procedures
Pigs and sheep were used for training future surgeons.
Teaching students surgical techniques
Sheep and pigs were used and killed in teaching students.
Studying effects of stunning before slaughter
Calves and sheep were anaesthetised. Some got 70-volt shocks to the shoulder. Others had a nerve exposed and stimulated before being stunned or cutting their throat.
Questioning vets on pain management
Veterinarians completed a questionnaire regarding pain and pain management in rabbits and guinea pigs.
Testing immunity assays for RHD virus
Wild-caught rabbits were injected with Rabbit haemorrhagic disease (RHD). All that did not die were killed.
Testing treatments for another medication overdose
NZ White rabbits were anaesthetised, and catheters were placed in blood vessels and intestines. After poisoning them with an overdose of medication, different treatments were tested for one hour.
Testing treatments for anaesthesia overdose
NZ White rabbits were restrained, fitted with catheters and needle electrodes and then given an anaesthetic. Saline or lipid solutions were given, and the reaction was monitored.
Testing retention time of eye medication
NZ White rabbits were restrained, and medication was put into their eyes. The reaction was recorded.
Harvesting rabbit and rat hearts for lab tests
NZ White rabbits and rats were killed to use their hearts in lab tests.
Testing a treatment for medication overdose
Rabbits were anaesthetised, and devices measuring blood pressure and heart rate were placed. After testing a toxicity treatment, all were killed.
Testing different treatments for medication overdose
NZ White rabbits were anaesthetised, and devices to measure their circulation were placed. Their hearts were stopped, and “first aid” was performed before all were killed.
Testing a treatment combination for medication overdose
NZ White rabbits were anaesthetised devices to measure their circulation were placed. Their hearts were stopped, and “first aid” was performed before all were killed.
Studying rabbit eyes to learn about human glaucoma
Dutch black-belted rabbits were anaesthetised and killed. Their eyes were removed and studied.
Comparing effects of anaesthetics on breathing and heart rate
Guinea pigs, rabbits and rats were anaesthetised, and a tube was put into their windpipe through the neck. They were made to breathe anaesthetic gas.