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.
Investigating how worms spread between lambs and calves
Lambs and calves were treated against parasites and then infected with worm eggs. Infection status was monitored. This was repeated several times before all sheep were killed.
Testing a fertility treatment
Cows with fertility problems were treated with hormones for ten days or left untreated. All were then artificially inseminated.
Testing a supplement for more calcium intake
Pregnant cows were fed with or without a specific feed additive. After birth, all were fed the same diet. Blood samples were taken in the weeks around birth.
Checking endometritis rates in dairy herds
Some cows in several dairy herds were selected, and their vaginal discharge was measured and sampled. They were then impregnated as per standard agricultural practice.
Comparing weight gain with different diets
Newborn calves were raised on various milk, pasture, and pellets combinations. They were slaughtered at two years old, and their “quality” was measured.
Testing pain meds for disbudding
The horn buds of young calves who were slightly sedated were burned off with a hot iron. Half of them received pain meds beforehand, and blood samples were taken before and after. After 24 hours, the second group received pain meds, too.
Studying Ikeda infection and treatment
Regular blood samples were taken from cows on three different farms. Only some were treated against the parasite. Milk production and fertility were recorded.
Studying diarrhea infection
New mother cows had blood samples taken. If the sample was negative for a diarrhoea virus, they were sampled again after a while.
Studying genes for body size
Udders of dairy cows were slightly cut with a scalpel, and a tissue sample was taken with a biopsy needle.
Testing toxicity of a potential new fertiliser
Pigs were fed toxic bait and monitored until they died.
Studying stress around birth
Blood samples were taken from cows with a high or low risk of health concerns after birth.
Studying genetics of a missing tail
Cloned foetuses were implanted into female cattle to research taillessness. Some of them were killed during pregnancy to examine the foetuses. One tailless animal was killed at age 4, and one of the cloned calves died after birth.
Studying Ikeda (parasite) infection
Blood samples were taken from dairy cows and their calves directly after birth before separating them. After four months, the calves were sampled again.
Studying Osteoporosis in cows
Young female cattle who had given birth for the first time were sent to slaughter. Half of them had broken bones for between 2 and 10 days. Blood samples were taken before slaughter, and bones were collected after.
Testing a tuberculosis vaccine
Male calves were infected with bacteria. Two groups were vaccinated before or after the infection, and the third group was left untreated. All were killed and dissected 13 weeks later.
Testing feeding plans for better immunity after calving
Pregnant cows were fed either a bit too much or a bit too little. Blood samples were taken before, at, and after calving. Researchers also took liver samples with a 20-cm biopsy needle and vaginal samples with a small brush and a scoop at these dates, except for the date of birth.
Testing if blackcurrant extract is toxic for dogs
Dogs are given blackcurrant pills for several days. The number of pills increases over time up to 60 tablets. Their health is monitored.
Practising first aid on working dogs
The 2-day course involved training students with mannequins, placing an IV catheter in the handler's dogs (dogs were lightly sedated), a live demo and practical exercises on anaesthetised sheep that would killed afterwards.
Testing intermittent fasting
Dogs will be fed three different ways for one week each. A high carb diet twice a day, a high carb diet every two days, and a high fat, low carb diet every two days. Each dog will have 12 blood samples taken throughout the study.
Testing the fitness level of police dogs
Police dogs are fitted with a catheter for a whole week and get infused with a marker solution. They are fitted with an activity measuring collar and regularly have blood sampled.
Testing how sensitive some dog breeds are to pain
Dogs were tested for their pain threshold by having a disk the size of a coin placed onto one of their forelegs. This disc could be heated up remotely. Several tests with 10-minute breaks in-between were performed, where the disk temperature was raised until the dog showed signs of pain. Almost half the dogs showed burn marks after testing.
Testing what dogs prefer to eat
Dogs are fed three different diets (either high fat, high carb, or high protein) over 28 days once a day. The dogs are offered each of the three diets at once and in high quantities. Regular stool samples are taken. Blood samples are taken from dogs that have been fasted (18 hours with no food).
Studying how long morphine affects dogs
Dogs scheduled to have ovaries and uterus removed at a teaching clinic are used. Premedication, including morphine, is given 45min before the surgery. Dogs are fasted for 12 hours and water is withheld for about 1 hour before surgery. Blood samples are taken regularly for 4 hours.
Studying the influence of diet on working farm dogs
Dogs working on farms are fed either a premium diet or a standard "home-kill plus tux" diet. All dogs have a collar to measure activity. Body weight, condition, and blood samples are recorded regularly for a year.
Testing a new biomarker
For regular blood samples over nine weeks, dogs are fasted overnight at the lab and returned to their owners the next day until the following sampling.
Studying if farm dogs are overworked
A glucose sensor is stuck between the dog's shoulder blades and sutured in place before a bandage is stapled over it. After being fasted, each dog is studied on glucose levels and activity for two days.
Testing different methods for skin sampling
Samples from the skin of dogs are taken in different ways: plucking hair with the roots, sellotape strips pressed down and ripped off several times, acetone-soaked cotton buds and solvent washes.
Testing nausea in dogs with different anaesthesia
Dogs who are about to have surgery are given different combinations of anti-nausea drugs to test the effects.
Testing a breathing mask on cats and dogs
Cats and dogs were held down tightly and fitted with face masks. Their breathing was measured for a while.
Learning when anaesthesia is lethal
The anaesthesia of pound dogs was gradually increased to dangerous levels. Students also practised taking blood samples, placing catheters and giving blood transfusions to the dogs, all while a teacher supervised.
Testing a gene therapy for Mucopolysaccharidosis
Newborn puppies are genotyped and divided into treatment groups. Some are left untreated. Some are injected with potential medication. The injection is into the neck vein or into the liver vein. For that, puppies are anaesthetised, have their belly cut open and the drug injected into the liver vein. All puppies are killed after regular blood and one spinal fluid sample.
Refining treatment for a (human) genetic disorder
Puppies with the genetic disorder MPS IIIA were treated with enzymes injected directly into the spinal fluid near the brain. Treatment was done until 22 -24 weeks old and varied in dose and frequency. In the end, the puppies were killed for dissection.
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.
Questioning vets on pain management
Veterinarians completed a questionnaire regarding pain and pain management in rabbits and guinea pigs.
Testing nerve reactions to electric stimulation
Young guinea pigs were bled to death. Specific nerves were removed and experimented on.
Studying short-sightedness
Guinea pigs had one eye covered for two weeks before increasing their eye pressure surgically and kill them.
Measuring nerve reactions to gases
Guinea pigs were anaesthetised, and their windpipe and blood vessels were cannulated. They were exposed to different gases and cyanide while measuring breathing and nerve activity.
Studying how anaesthesia affects breathing and heart
Guinea pigs were put in airtight chambers to test the effects of low oxygen. Some were surgically fitted with tubing so blood samples could be taken during the tests. In the end, all were killed.
Studying compensation after inner ear destruction
Guinea pigs were anaesthetised, and their inner ear was destroyed with a drill. Videos were made for over two days of their balance recovery.
Killing pregnant guinea pigs for tissue cultures
Pregnant guinea pigs were anaesthetised at specific time points of their pregnancy, including during labour, to then remove the uterus for tissue culture experiments.
Testing how oxytocin injections cause contractions
Pregnant guinea pigs were surgically implanted with electrodes on or near the uterus. They were injected with oxytocin in specific doses and timeframes, and the effects were measured.
Harvesting testicles for studies
Male guinea pigs were killed with CO2 to remove their testicles for experiments.
Testing a new tuberculosis vaccine
A new tuberculosis vaccine was tested by injecting guinea pigs with the bacteria, either with or without prior vaccination. After several weeks, all were killed.
Testing how heart calcium metabolism is different in species
Guinea pigs and rats were decapitated, and their hearts were quickly removed to study them.
Testing influences on the rate of a dissected heart
Albino guinea pigs were anaesthetised and dissected before they were killed.
Confirming the correlation of energy storage and stress in the inner ear fluid
Guinea pigs were anaesthetised and artificially ventilated. Ear fluid samples were taken through a hole in the skull, while exposing them to noise or lack of oxygen.
Comparing natural and genetically altered tuberculosis strains
Guinea pigs were infected with tuberculosis strains after being injected with bacterial proteins beforehand. In the end, all guinea pigs were killed and dissected.
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.
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.
Studying methane emission and meat quality
Sheep were bred for high and low methane emissions. Almost 2,000 were put through emission measurements. Over 17,000 were slaughtered.
Testing if anaesthesia affects the sleep–wake cycle
Mice were kept on a 12-hour light/dark cycle and then switched to total darkness. They were anaesthetised twice to see the effect on their activity cycles, and all were killed in the end.
Testing the influences on growth
Transgenic and "normal" mice were kept in small groups and killed at different ages. Fat and muscle tissue were dissected, and the hearts were taken.
Testing a new way to kill lab mice
Mice were fed cream cheese containing different amounts of a sedative. Behaviour was recorded during the sedation period and while gassing them with CO2.
Testing a possible cause for cataracts
Transgenic and "normal" mice were used to study the development of cataracts. They were anaesthetised, images of their eyes were taken, and then they were (likely all) killed.
Studying chronic stress
Mice were handled daily, had vaginal smears, and some were subject to the notorious Forced Swim Test. Half of them were additionally stressed daily in various ways to see the difference it makes.
Trialling cancer drugs in mice after similar drug failed in humans
Mice were force-fed daily with two new drugs in different dosages. Others were force-fed a control solution, and some were left untreated. In the end, the animals were killed with CO2 and dissected.
Testing if exercise influences treatment success with cancer
Mice were injected with cancer cells. When tumours reached an “ethical” limit, they were injected with a labelling agent, anaesthetised and killed to be dissected. This was repeated, while some mice received cancer treatment.
Testing if exercise influences muscle mass with cancer
Mice were injected with cancer cells, and some received immunotherapy once the tumour reached a specific size. When tumours reached an “ethical” limit, they were killed. Cancer-free control mice were killed simultaneously.
Studying the interaction of hormones and stress
Transgenic mice had their brains injected, some had their ovaries removed, and some were restrained for repeated blood samples. In the end, all mice were killed.
Studying movement processing in the brain
Transgenic mice were put through behavioural tests while half of them had a part of their brain-damaged. Some mice had a window put into their skull to take recordings of their brains while awake. They had limited access to water and were forced into a device that stopped them from moving their head. In the end, all were killed.
Testing seizure activity in transgenic mice
Mice with specific genetic limitations were bred. Some were killed for dissection, and others were injected with a gene activation drug before they were killed.
Testing a seizure treatment
Genetically modified mice had wires and a cannula implanted in their brains, and were injected to cause seizures. The next day, their genetic mutation was activated. The test was repeated before they were all killed.
Observing cancer growth with/without treatment
Mice were injected with human breast cancer cells. The growth was monitored and sampled (biopsy). Some were operated on to remove their ovaries and some were treated with drugs before all were killed.
Testing how hormones influence activity while pregnant
Transgenic and “normal” mice were used to test the influence of pregnancy and hormones on activity and anxiety. They were kept in single cages with running wheels and subjected to behavioural tests. The transgenic mice were killed in the end.
Studying the digestion of kiwifruit
Pigs were surgically fitted with an outside access to their intestine. Faeces were collected through anal stimulation, and samples were taken from the intestine for six-hour periods.
Testing feed supplements for their performance
Pigs were fed diets with different organic acids added. At a specific weight, they were slaughtered to collect samples.
Comparing the digestion of egg white in different forms
Pigs were acclimated to eating egg whites of different textures. After being deprived of water for two hours, they were fed again and then killed in intervals over six hours.
Testing ways of injecting nicotine
Pigs were anaesthetised and injected with nicotine through different methods. Blood samples were taken for two hours before the pigs were killed.
Measuring brain response to tail-docking
Piglets were bought at one to fifteen days old and anaesthetised. Their tails were cut off while measuring brain activity, and then they were killed.
Testing how cooking affects beef digestion
Pigs were fed ground beef for three days, either raw or cooked. They were then killed to cut out a part of their intestine.
Trialling a method to measure intestine fermentation
Young pigs were fed a test diet for two weeks while confined in metabolic chambers. After that, they were killed with an anaesthetic injected into the heart.
Testing how to gas piglets
Piglets were gassed plastic box to record their behaviour and vital signs.
Testing the accuracy of heart activity measurements
Pigs were anaesthetised, their open chests were equipped with electrodes and closed again. After measurements, the hearts were stopped, images were taken, and the hearts were removed.
Testing cholesterol absorption from baby formula
One-week-old piglets were kept in metabolic crates and fed baby formula for three weeks. They were then anaesthetised and killed to be dissected.
Studying the digestion of protein through serial slaughter
Ninety young pigs were housed individually for 13 days; their diet contained kiwi fruit and beef. All were killed to be dissected.
Studying the inner functions of the heart
Pigs were anaesthetised and their chests were cut open. Electrodes were inserted into their hearts so measurements could be taken before their hearts were removed.
Testing the effect of pain killers during tail docking
Piglets were anaesthetised and their tails were removed using different methods. During these procedures, the heart and brain activity of the pigs were measured.
Testing if pigs spread kauri tree sickness
A group of pigs was fed infected kauri roots for one day, and their faeces were collected for a week. Over 270 wild pigs were shot, and their stomach contents was sampled.
Trialing xenotransplantation for diabetes
Four pigs were used to harvest cells for transplantation into humans.
Studying sow and piglet behaviour in crates and pens
Sows and their newborn piglets were put in tightly confined crates or pens with slightly more room and their behaviour was observed.
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.
Investigating how worms spread between lambs and calves
Lambs and calves were treated against parasites and then infected with worm eggs. Infection status was monitored. This was repeated several times before all sheep were killed.
Using sheep to try and model how well humans will heal after dental surgery
Sheep were anaesthetised, three teeth were pulled, and the sockets were treated differently. For months, regular samples were taken from the healing wounds before all sheep were killed.
Preclinical testing of a gene therapy for Batten disease
Sheep with and without a specific gene mutation were checked and scanned regularly for nine months. Affected sheep received gene therapy at different ages. Treated sheep were killed.
Testing if blocking a cell signal can prevent foetal brain injury
Pregnant sheep were anaesthetised, and the foetuses fitted with electrodes. The umbilical cord was blocked for most of them, and half were treated with a test drug. Mothers and unborn lambs were killed three weeks later.
Testing the combination of drugs for congestive heart failure treatment
Sheep were anaesthetised and subjected to surgery. Electrodes were used to pace their hearts faster while testing the effect of different drugs.
Testing the best way to deliver gene therapy drugs
Sheep were anaesthetised. Their heads were drilled into, and their brains injected with test drugs. They were killed after three weeks.
Testing the potency of pneumonia vaccines for sheep
Lambs were vaccinated twice, and regular blood samples were taken for 34 weeks.
Testing the effects and wash-out of painkillers
Lambs were treated with different painkillers or not at all before tail docking and castration. Their behaviour was monitored.
Developing “hyperimmune” milk
Sheep were injected with Covid-19 vaccines, and regular blood samples were taken. Some were mated and gave birth to sample their milk, too.
Studying the genetics of Batten disease on chimeric lambs
Sheep foetuses were removed. After swapping cells between them, they were inserted into other ewes. Lambs born were subjected to X-rays and, at one to three years old, were bled out for dissection.
Testing pacemaker adjustments
After causing them heart failure, sheep were surgically fitted with pacemakers and measurement devices. Those who survived the procedures were killed after six months.
Studying methane emission and meat quality
Sheep were bred for high and low methane emissions. Almost 2,000 were put through emission measurements. Over 17,000 were slaughtered.
Studying the effect of chemicals in normal and high blood pressure
Sheep were surgically fitted with a clip around an artery, or they served as control. Measuring devices were added before injecting different chemicals into the hearts of the conscious sheep.
Comparing muscle repair success with and without weeks of delay
Ewes were anaesthetised, and one side of a pelvis muscle was detached. After several weeks, the muscle was repaired. Gait was evaluated before all were killed.
Comparing different designs of dental implants
Sheep were anaesthetised. One leg bone was exposed and fitted with several implants. After 12 weeks, all were killed.
Trying to model human brain injuries
To study changes in different areas of the brain after brain injuries. Sheep were used to study the effects of traumatic brain injuries in humans.
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.
Causing sinusitis in rabbits as a model
NZ White rabbits were anaesthetised, and a sinus tract in their nose was blocked for four weeks to cause sinusitis. After another ten weeks with regular samples, they were killed.
Testing a new vaccine
NZ White rabbits were injected with a new vaccine type several times before being killed.
Harvesting eyes for lab tests
The eyes of pigs and rabbits killed for experiments were used to analyse the structure of the cornea.
Testing the toxicity of some substances
Young NZ White rabbits were force-fed different doses of toxic substances. Blood samples were taken before and immediately after killing them at set time points (or to end their suffering).
Using a new imaging technology
One NZ White rabbit and rats were killed, and their eyes were removed to use for the study.
Measuring contractions in exposed rabbit uteruses
Pregnant rabbits were anaesthetised, and their uterus was exposed. Measurements were taken while contraction-inducing injections were given. Then they were all killed for dissection.
Mapping wave patterns of the small intestine
NZ White rabbits were anaesthetised, their intestines were used for electrode mapping, and then they were killed.
Studying presence of a virus in rabbits
Wild rabbits were shot, caught by dogs or trapped to test them for virus strains. The infectious solution was then fed to NZ White rabbits in a lab to kill them later.
Harvesting rabbit colons for lab tests
NZ White rabbits were anaesthetised, a part of their intestine was cut out, and then they were killed.
Harvesting rabbit bladders for lab tests
NZ White rabbits were anaesthetised, their bladder was cut out, and then they were killed.
Testing an antimicrobial eye medication
NZ White rabbits were treated with Manuka honey solution in one eye and a control solution in the other eye for five days. Different values like tearing and irritation were measured.
Using muscles of dead rabbits for imaging
Two NZ White rabbits were killed to use for detailed muscle imaging.
Measuring jaw bone growth in young rabbits
Young rabbits were anaesthetised and had holes drilled into their jawbones to implant small pieces of metal. X-ray scans were made, and the rabbits were killed.
Testing the welfare impact of pindone toxin
Three groups of young NZ White Rabbits received pindone-toxin pellets on different schedules. Any rabbit still alive after three weeks was killed.
