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!
Testing a new papillomavirus vaccine
Adult colony cats were injected with a new vaccine or a control solution. Regular skin swabs and blood samples were taken.
Testing the effect of dietary fibre in cat food
Cats received three diets for three weeks each. Food intake was measured daily, and urine and faeces were collected for the last 5 days each time.
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.
Tracking and killing wild cats
Wild-caught cats were used to train sedation and collar fitting before being killed. Another group of cats was fitted with GPS collars for one year before being tracked down and shot.
Scoring the body condition of colony cats
The body condition score of 101 cats was determined, adding to routinely collected body weight data from the breeding colony.
Testing new toxin at Ngatapa Station
Toxic bait traps were placed on a property in Hawke’s Bay. Cat population changes were monitored with stationary cameras.
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.
Testing new toxin at Toronui Station
Toxic bait traps were placed on a property in Hawke’s Bay. Cat population changes were monitored with stationary cameras.
Surveying caregivers on their cats’ personality
Cat caregivers in Australia and New Zealand filled in an online survey about their cats’ personality traits.
Training staff in wild cat handling
Wild cats are trapped and used to train staff in handling, sedation and collar fitting before they are killed.
Sampling cats’ saliva for feline autoimmune disease
Buccal swabs (inside the cheek) were collected from all cats in three British Shorthair breeding catteries.
Measuring vitamins in blood samples
Blood samples were taken from colony cats of different ages.
Collecting blood plasma for tests
Colony cats are switched from wet food to dry food for two days. Blood samples are taken before and after.
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.
Testing pain medication with lasers
Colony cats were put into small chambers, and a laser was pointed at a shaved skin patch. The influence of medication on their reaction time was measured.
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.
Analysing Greyhound race injury statistics
Historical data on Greyhound races between 2014 and 2019 were analysed. Injuries and deaths were investigated.
Using bones of euthanised shelter dog
Cadavers of dogs killed at an animal shelter were donated. Holes were drilled into leg bones and fitted with screws.
Investigating farm dogs for four years
Working farms dogs were examined regularly for four years. Health problems and fate were recorded.
Transplanting faeces as diarrhoea treatment
A dog with diarrhoea was treated with laxatives and warm water before a faeces sample from a healthy dog was inserted into his colon. Samples were taken before and after.
Testing the eyes of working dogs
Eye examinations were performed on working sheep dogs. Medication for pupil dilation was given, and faeces samples were taken from most dogs.
Analysing dog movements
Colony dogs were prepared with reflective markers and an activity collar. Their movements on a treadmill at various speeds were recorded.
Testing the effect of diet on farm dog performance
Working dogs were fed a diet very high or very low in carbohydrates. Their blood glucose and activity were monitored three times over four days each.
Testing a parasite treatment
After a pilot study with just one dog, six more were given an experimental parasitic treatment. Regular blood samples were taken through a catheter.
Teaching dogs to smell out catfish
Five pet dogs were trained over several months to identify catfish and goldfish smell in water samples.
Testing different combinations of pain meds
Eight dogs are treated with four different combinations of the test drugs in random order with two-week breaks in between. Two catheters are placed in leg veins (for drug injection and blood samples). For the test, dogs are fasted for 12 hours and anaesthetised. EEG is recorded with electrodes near the brain to measure response to electric shocks. Regular blood samples are taken for 8 hours.
Studying medical data of cat and dog CT-imaging
Medical data from cats and dogs were gathered, and animals that had been euthanised for other reasons were examined.
Teaching dogs to smell out koi carps (2019)
Three pet dogs were trained over several months to identify koi carb smell in water samples.
Testing working dogs for internal parasites
Faeces and blood samples were taken from working farm dogs.
Testing fluid management of dogs during anaesthesia
Dogs were anaesthetised. Their heart activity was measured while hey were injected with calculated amounts of fluid.
Trying to make rat poison unattractive for dogs
Dogs were fasted overnight and then given two food bowls with different kinds of repellent on one of them.
Surveying respiratory disease in racing Greyhounds
Laboratories sent in serum samples of dogs for analysis. Additionally, 17 racing Greyhounds were tested.
Using fish to study the impacts of Climate Change
Fish were either bought or caught and killed so that they could be dissected.
Overfeeding Zebrafish to learn about obesity
Normal and transgenic zebrafish were fed normally or way too much. The fish were taken out of the water for glucose tests and blood samples.
Studying gut bacteria in fish
Nine fish were caught by underwater spearing and killed so that samples could be collected from their digestion tracts.
Studying the sleep of sharks
Sharks were caught and kept in outside tanks. For the experiments, they weren't fed for at least 4 days, of which they spent 3 days in a measuring chamber not much bigger than the shark. Oxygen consumption and behaviour were continuously recorded for the last 24 hours.
Infecting fish larvae as a potential model for humans
Zebrafish larvae were injected with bacteria to test how their immune system responds. This was repeated to test how well the immune system reacted and how long the effect lasts.
Finding a “growth gene” in snappers
Snappers were caught from the wild and bred. Around eighty-thousand of their offspring were hatched and raised. At regular “grading” events, injured and deformed fish were disposed of. At just under a year old, around twenty-two-thousand were left and transported to a sea pen, where they were raised to 17.5 months old before harvesting.
Testing how much fat you can feed fish
Fish in aquaculture were divided into groups and fed diets with different fat content. Fish were anaesthetised and faeces samples squeezed out of them.
Testing fish for mercury contamination
Wild fish were caught, measured and frozen to be analysed.
Measuring how stress affects fish
Fish were exposed to chronic stress for four weeks, while 57 non-stressed animals were kept as a control. Signs of stress were noted. At the end of the experiment, all were chilled to death.
Exposing fish to herbicides
Zebrafish were kept in tanks that were contaminated with different herbicide concentrations for 10 days. They were then mated to herbicide-exposed or control fish. Both generations were tested on behavioural changes at around 4 months of age. 24 fish per treatment were killed and dissected.
Testing supplements as protection from toxins in over 1,000 fish embryos
Embryos were harvested and kept in Petri dishes for toxicity and treatment tests. Embryos were treated with an antioxidant, a gold salt or both on the first day, and abnormal development was measured on day 5.
Studying effects of drying rivers on mudfish
Water depth and quality were measured at 24 different sites. Several traps for fish and invertebrates were set at 8 visits, sampling and mostly killing the caught animals (including 15 individuals of the endangered Kōwaro).
Studying bacterial spread in fish larvae
Bacteria were genetically modified and made fluorescent. Zebrafish were bred, and their larvae were infected with the bacteria. The fish were killed for analyses or used for live imaging under a microscope (and then killed, most likely).
Investigating effects of invasive fish removal
Using fyke nets and electrofishing, fish were caught on four occasions. Fish were marked with fin clippings around one big removal event where 3 tonnes of fish were caught. In recaptures a week after each marking event, invasive fish caught were killed after the examination.
Studying fish life cycles
Fish were sedated and their blood and ovarian tissue were sampled three times.
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 effect of certain lipids in formula on brain development
Piglets were kept individually and fed formula with different supplementation. After 18 days, they were killed.
Harvesting bladders to study contraction patterns
The bladders of six pigs were surgically removed under anaesthesia before the pigs were killed.
Testing the effect of a shot to the head
Pigs were anaesthetised and shot in the back of the head from different distances. Effects were recorded and analysed.
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.
Testing the viability of xenotransplantation using islet capsules
Newborn piglets were killed for their pancreas. Encapsulated pancreas cells were then implanted into young mice, who were killed later to retrieve the capsules.
Testing measurement of specific proteins
Pigs were surgically fitted with an outside access to their intestine and kept individually for eight weeks. Digestive matter was collected over ten hours on one day, while the pigs had no access to food or water.
Studying the spread of bovine tuberculosis in pigs
Pigs were bought, and wild pigs were captured and distributed through two studies over almost two years. Pigs were killed regularly to dissect them for tuberculosis signs.
Studying wound healing treatments
Pigs were anaesthetised and wounded in 20 places on their backs. The wounds were treated differently and sampled over a month before the pigs were killed.
Developing a model for varicose veins
Blood vessels in pigs' legs were surgically altered, and some pigs were fitted with devices to measure blood pressure. After weeks of regular examinations, all were killed.
Testing how long you have to wait to shoot and eat poisoned wild pigs
Piglets were fed different amounts of rat poison for longer or shorter periods before they were all killed.
Testing how many cancer cells spill out during colon surgery
Pigs were anaesthetised and injected with radioactive cancer cells. Different colon surgeries were performed.
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.
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.
