Responsible ownership and care of domestic cats in Scotland: report

3. How should responsible ownership and care of domestic cats be defined?

What constitutes responsible ownership and care of domestic cats depends on the level of interaction between people and cats, i.e. whether they are owned and to what degree they are under human control. Here we first review the different categories of domestic cat and their numbers in Scotland.

Categories of cats

It is clear that there can be different types of owned and unowned domestic cats (cats of the species Felis catus). Owing to the dynamic flows of cats between different ownership types, we have grouped these as pet cats (owned), farm cats (semi-owned/semi-feral) and feral (unowned, which may also include stray cats that have been previously owned).

In Table 1 we have classified the different types of cat ownership status and types (based on suggestions in the literature) and provide estimates of the numbers in Scotland. This may be useful in determining different actions to manage cat populations and different welfare risks experienced by different groups. The data suggest that there may be approximately one million domestic cats living in Scotland, with about 10% of these living in conditions where ownership and caring status may be limited, ad hoc or non-existent.

* As defined by Bradshaw et al. 1999^[2].

**Cats that are not actively managed (NAM) by their owners

Scottish owned cat population

Cats Protection reports suggest that there were an estimated 11 million owned cats in the UK in 2023^[3], with 830,000 of these animals living in Scotland^[1]. Figures from the UK Pet Food report suggest a higher UK cat population of 12.5 million pet cats living in 29% of UK households^[4], but do not give separate figures for Scotland. The numbers of Scottish cat owners increased slightly between 2021 (20%) and 2022 (24%) and reduced again slightly in 2023 (22%)^[1]. Levels of ownership in urban areas (22% of residents) and rural areas (21%) in Scotland were very similar. Of new cat owners in 2023, approximately a third of cats were bought, and 39% acquired from rescue or rehoming centres, or from friends and family; rehoming or acquiring a cat from abroad is relatively uncommon. Just under two-thirds of the Scottish pet cat population are classed as ‘moggies’ (non-pedigree or non-pure-breed cats), but there has been an increase in the number of pedigree or cross-breed, non-moggy cats acquired over the last two years (e.g., 40% of newly acquired cats are pedigree compared to 26% of the overall cat population)^[1].

Animal welfare, as defined by SAWC and others, is a property of the animal and based on the animal’s experiences^[5]. This can be considered to be the impact on the animal’s mental state, due to the integration of the impact of survival-critical factors (nutrition, health and environment) and situational factors (behavioural interactions)^[6]. This model situates welfare as the mental state of the animal, and thus is relevant to all sentient animals^[5], regardless of their legal status. Therefore, in this report we consider the welfare of all cats to be relevant, whether they fall under domestic animal legislation or not, but acknowledge that the different welfare issues, and methods to mitigate these issues, may differ depending on the category of cat under discussion.

The following actions and behaviours have been considered by SAWC to be part of responsible ownership and care of domestic cats. In this context we include not only the actions of owners towards their own pets, but also the activities of people who interact with free-roaming cats. In this section we also consider the frequency with which these actions are carried out by Scottish cat owners.

Microchipping and registration

Microchips are small Radio Frequency Identification (RFID) transponders that are implanted under the skin of companion animals (or mounted in ear tags in farm animals) that allow permanent identification of an individual. RFID chips can be read with a reader or scanner, and the unique identity number of the animal obtained. These allow the owner or keeper of an animal to be registered in a database and animals that have become lost, injured or abandoned can be reunited with their owners or identified, if stolen. In England it has been mandatory for cats over the age of 20 weeks to be microchipped from 10 June 2024. Scotland has not yet brought forward similar legislation, but 71% of cats were reported to be microchipped in 2023^[1].

The main benefits of microchipping are to ensure that lost, straying, injured or stolen animals can be reunited with their owners. Several studies have shown that microchipped cats and dogs are significantly more likely to be reunited with their owners and spend less time in shelters than animals without chips (e.g., in an Australian study 87% of microchipped cats were reunited with their owners compared to 37% of unchipped cats^[7]).

Vaccination and prophylactic treatments

Considerable variation exists worldwide in feline vaccines, both from the perspective of the disease the vaccine protects against to the type of vaccine available. In the UK a range of vaccines has existed, but currently the main diseases vaccinated for are:

• Feline herpesvirus
• Feline calicivirus
• Feline panleucopaenia virus
• Feline leukaemia virus
• Feline chlamydia (Chlamydia felis)
• Terrestrial rabies virus (for cats travelling overseas or sourced outside the UK)

The World Small Animal Veterinary Association (WSAVA) 2024 guidelines for the vaccination of dogs and cats – compiled by the Vaccination Guidelines Group (VGG) of the WSAVA splits disease into those requiring core vaccination (should be given to all cats) and those that are non-core and may be required depending on the geographical location and lifestyle of the cat. Core vaccines in the UK are feline panleucopaenia, feline herpesvirus and feline calicivirus. Vaccination for feline leukaemia virus (if going outdoors) and terrestrial rabies (if travelling overseas) would also be considered core depending on lifestyle. Non-core vaccines include Chlamydia felis.

There are currently no vaccines available in the UK for feline coronavirus or feline immunodeficiency virus (FIV), although these are significant diseases of domestic cats and wildcats.

The available vaccines are predominantly modified live, attenuated viruses, often using a vector virus, such as canarypox, to deliver the antigens. Some are killed vaccines, such as the terrestrial rabies virus vaccine, and often feline chlamydia and feline leukaemia virus vaccines.

Responsible cat ownership includes protecting cats from serious infectious disease, where a threat exists. Various studies and reports have suggested that around three-quarters of cats are up to date with vaccines and so are fully protected^[3,8,9]. However, sales data of vaccines suggest a much lower rate of vaccination than these owner-reported statistics, potentially considerably lower than 50%. In Scotland owner-reported data suggest that 5% of cats have had no vaccinations at all and 13% were not up to date, although this is likely to be an under-estimation. Veterinary bodies in the UK recommend for outdoor cats that diseases 1-5 in the list above are vaccinated against, as the risk of exposure from other carrier cats is high. Rabies vaccine is generally only administered to cats that leave the UK, to accompany their owner on an overseas trip/export, as the UK is currently terrestrial rabies free.

For indoor cats, aerosol-spread diseases, such as feline herpes, calicivirus and the highly infectious feline panleucopaenia virus that may be transferred easily on the sole of a shoe from outside are typically recommended. Feline chlamydial disease can also be spread by aerosol over short distances and so may also be recommended in multi-cat environments, but feline leukaemia virus requires relatively close contact between an infected and susceptible cat, for it to be transferred, and so is less commonly recommended for indoor cats.

Vaccination schedules vary between brands of vaccine, but most require an initial primary course of two doses of the vaccine to be administered 3-4 weeks apart. Yearly booster vaccines are then recommended for diseases: such as feline herpes and feline calicivirus. WSAVA recommends revaccination every 3 years for low risk cats and annually for cats at higher risk. In practice in the UK, and in line with data sheet recommendations, cats are vaccinated annually against the flu viruses. Feline panleucopaenia virus vaccines provide long lasting protection and are administered every three years after an initial course. There is some evidence that in endemic areas, feline panleucopaenia virus may require an intermediate booster at six months of age, as immunity can wane quickly in young cats due to maternally derived antibodies transferred to kittens in maternal milk impacting the level and duration of immunity.

Terrestrial rabies vaccines are usually a single dose of vaccine, which can confer immunity against this devastating zoonotic disease. There is evidence that the immunity will slowly wane over time and so antibody levels against the virus are commonly measured, to assess whether booster vaccinations are required. However, the antibody test does not measure cell-mediated immunity so even animals with a lower antibody titre (0.5IU is the usual cut-off for a booster vaccination) may still have some ability to mount an immune response to the disease. Booster vaccinations must be kept up to date for animals to be exported out of, or imported into, the United Kingdom.

Cats are also susceptible to internal (worms and protozoa) and external (fleas, lice, ticks, mites, etc) parasitic infestations. Data in from 2023 suggest that less than two-thirds of Scottish owned cats are protected against fleas and worms (58%)^[1]. Veterinary advice currently argues against a blanket treatment with parasiticides, which can lead to issues with resistance and environmental concerns, and thus an assessment of individual risks depending on cat lifestyle, human and environmental risk factors should be implemented. The high number of indoor-only cats in Scotland may be a factor in the frequency of worming and flea treatments.

Parasites or infections commonly carried by companion animals worldwide can be of zoonotic concern (i.e. can also cause disease in humans), including rabies virus; toxoplasmosis (infection with Toxoplasma gondii); cutaneous larval migrans due to roundworms, such as Toxocara species; mycobacterial disease (bovine and other tuberculosis); avian influenza; plague (Yersinia pestis infection); tularaemia (Franciscella tularensis infection) and murine/feline typhus (Rickettsia typhi and R. felis infection)^[10]. In Scotland, however, the most significant are Toxocara and Toxoplasma species infections. Although many people infected with Toxocara may be asymptomatic, more vulnerable groups may develop fever or pain, and ocular toxocariasis can cause vision loss, eye inflammation, and retinal damage. Cats are the main host for the protozoan parasite Toxoplasma gondii, which is transmitted through contamination by faeces or in undercooked meat (typically lamb) to other animals and humans^[11,12]. It infects about one third of people in developed countries and has life-long dormant stages in the brain and muscle, which are often regarded as asymptomatic and normally only considered a serious risk to pregnant or immunocompromised people. Vertical transmission from mothers to foetuses can result in spontaneous abortion and stillbirth, and even in surviving infants infection can result in craniocerebral, ocular and cognitive abnormalities as well as learning difficulties later in life^[13].

Ringworm is a contagious fungal infection that can cause hair loss, dry skin and variable levels of excessive grooming and scratching in cats. This condition is also zoonotic and the infection can be transferred to humans. Treatment of both infected cats / in-contacts and the environment is necessary.

Fertility control – neutering

Neutering is typically carried out to prevent unwanted breeding. However, this may also cause alterations in behaviour of male (e.g., less aggressive to other cats, less likely to engage in risky behaviours such as roaming, less likely to show territorial marking) and female cats (e.g., no longer display oestrus behaviours), which are often desirable for their owners. In addition, this may also benefit the cat by reducing the possible spread of diseases such as FIV. Neutering provides permanent cessation of breeding for individuals. Surgical methods, under general anaesthesia, include ovariectomy, ovariohysterectomy, or castration. Chemical / medical neutering is also possible.

For owned cats, up to 70.5% of litters may be unplanned^[14]. Various estimates of the unowned cat population (see Table 1 and below) suggest that this is considerable (for example, a modelling study suggests at least 1.5 million cats in GB^[15], and there is also a growing population of unowned cats in shelter accommodation. Supporting a large population of unwanted cats is a drain on resources and a huge economic burden, with £340 million estimated to have been spent by 519 registered UK rehoming centres in 2010^[16].

The increasing population of unowned cats is a concern for diverse stakeholders, and has implications for the environment, public health and welfare, and animal welfare^[17]. In Scotland 87% of cats are reported to be neutered^[1], a similar figure to the UK as a whole^[8], and higher than rates of neutering seen in dogs (68%). Cat owners are also reported to be more positive about routine neutering than dog owners^[18]. However, breeding in cats is not controlled by people to the extent seen in dogs, with most litters being accidental. This may be because most cats are not pedigree and of little monetary value, or because owners may not anticipate the earlier onset and more frequent oestrous cycling, and therefore fecundity, of cats compared to dogs^[19]. Cats are also more likely to be allowed free outdoor access than dogs. In Scotland 62% of cats are moggies (produced by non-selective breeding), which supports the view of cats not being pedigree or expensive^[1]. However, 40% of cats acquired in the last 12 months in Scotland were pedigree or pure breed, compared to 26% of the overall population, which may indicate a move towards more specific breeding of cats. Across the UK there has been a decline in the proportion of moggy-type cats being acquired and an increase in pedigree/ pure-breed cats over the last five years (an increase from 17% to 42% over the last five years for pure-breed cats)^[3].

In Scotland, the main reasons given for not neutering cats were that the cat did not go outside (21%), the owner wanted kittens (13%), that the cat was too young (12%), and that the owner had not considered it or not got around to it (each 12%)^[1]. A common view of the public is that females should be allowed to have one litter and be allowed to experience mating and motherhood^[18]. The optimal age for neutering, traditionally deemed to be between five and eight months, is now questioned, as short- and longer-term studies demonstrate no significant behavioural and physical advantages conferred by traditional-age neutering. Furthermore, a number of safe anaesthetic and surgical protocols have been documented that produce lower morbidity and similar mortality rates in pre-pubertal neuters compared with traditional-age neuters^[20]. Age at which neutering should be carried out can be contentious, with nearly 30% of surveyed vets disagreeing with a policy of neutering at four months old (the British Veterinary Association and British Small Animal Veterinary Association recommend neutering from 16 weeks), although often opinions differed depending on whether these were the owned or unowned cat population (typically with better agreement that feral kittens should be neutered early)^[21]. A key concern, especially for those not practising four-month neutering, is the risk of anaesthesia and surgical complications in young cats, although a lower rate of postoperative wound infections has been documented following prepubertal compared with traditional-age neutering^[22]. However, many cat welfare organisations advocate for neutering at four months or earlier to reduce the risk of accidental litters in young cats. When rehoming kittens from a shelter, this is also seen to be desirable, as animals can be neutered before moving to their new homes.

Chemical / medical neutering : For many reasons, surgical sterilisation may not be effective as the sole method for population control. It requires anaesthesia, medical equipment, a sterile surgical suite, a trained veterinarian, recovery time, incision site observation, and it carries the risks inherent to other surgical procedures^[23,24]. Use of chemical or medical neutering has been advocated as an alternative method of achieving sterility.

Male Cats: Suprelorin^R is a sustained-release implant, containing 4.7mg deslorelin (a GnRH super agonist) for the induction of temporary infertility and suppression of urine odour and of sexual behaviours, such as libido, vocalisation, urine marking, and aggressiveness in intact male cats from three months of age. These benefits are achieved from six weeks post implant for 12 months. Increased food intake, transient heat and pain, and swelling at the implant injection site may be seen^[25]. Occasionally, infertility is not achieved with deslorelin treatment^[26].

In the USA zinc gluconate (Zeuterin^R) was licensed for use in dogs, and in other countries, also in cats. Injected into the testes, the product results in permanent infertility. This product is not currently available. Progestogens, synthetic analogues of progesterone, have anecdotally been used to induce sterility in male cats, but the evidence is largely anecdotal, and side effects likely to be seen if minimum doses exceeded^[26]. Products are given by injection.

Female Cats: The proligestone-containing Delvosteron^R suspension for injection, may be used for permanent postponement of signs of oestrus, with repeat injections given in 'anoestrus'/di-oestrus induced by the previous administration of the product. As with all progestogens, the possibility exists that the CEH (cystic endometrial hyperplasia)/pyometra complex may be seen as a side effect of the medication^[27]. However, this product is currently not available.

Products containing progestins, such as megestrol acetate and medroxyprogesterone acetate, continue to be used to prevent queens (breeding female cats) from cycling, and also as an adjunct or alternative to surgical sterilisation within trap–neuter–return (TNR) programmes^[28]. Given orally, low dosages can be used relatively safely in cats, while higher dosages increase the risk and severity of adverse reactions.

In trials on female cats a single injection of an anti-Müllerian hormone transgene can produce permanent sterility^[29]. This treatment is not available commercially.

GonaCon, a vaccine against gonadotrophin-releasing hormone, is also used in other species, but appears to be less effective in cats, resulting in effective contraception for one year of only 30% of vaccinated cats in a colony^[30].

Insurance and planning for veterinary care

Veterinary treatment can be expensive, as costly drugs, hospital stays and veterinary care are required for treatment of animal diseases or injuries. Many pet owners are unprepared for the costs of veterinary treatment and may not have factored this into planning for pet ownership. A survey of veterinary professionals suggests that a third consider that a lack of understanding of the costs of pet ownership and the costs of vet fees were among the top issues of concern^[8]. The rising costs of veterinary treatment are increasingly cited as reasons for not visiting veterinary clinics as often as the owner would like (at 27% of respondents in 2023, this has increased from 20% in 2022 and was the top reason given)^[3]. In addition, 56% of veterinary professionals say more clients are now unable to afford unexpected veterinary bills.

Pet insurance can be one method to deal with the costs of veterinary care and may prevent difficult decisions around animal treatment, when cats are sick or injured. In 2023 45% of Scottish cat owners had insured their cats. This is higher than the UK as a whole, but remains lower than insurance for dogs (typically nearly twice as many dog owners insure their dogs compared to cats)^[8]. Cat insurance is highest in higher socio-economic groups (54% AB) and lowest in DE groups (33%).

Indoor cats and cat containment

Fertility control, and prevention of domestic cats interacting with wildlife and engaging in high-risk behaviours, can be achieved by containing cats permanently indoors and preventing free outdoor access. That the cat lives indoors is the most common reason cited by owners for not neutering their cat, and outdoor access is known to be a risk factor for increased rates of parasitic infections, including zoonotic disease^[31]. Scotland has the highest rates of indoor cat management in the UK (44%, down from 50% in 2022)^[1], although this is lower than reported in some other countries (e.g., USA, Japan), where cat containment is typically advocated^[32].

Allowing cats outdoor access is often considered to provide for better cat welfare to indoor management by cat welfare NGOs (e.g., Cats Protection, International Cat Care), as it allows cats to explore and engage with the environment. It may also allow cats in multi-cat households, to have opportunities for solitary behaviour and for cats to express behaviours associated with positive affective states, such as hunting, territorial patrolling, marking, roaming and climbing. Conversely, indoor only cats living in multi-cat households may experience significant social stress. A third of cats in Scotland live in multi-cat households^[1], although how many of these are also indoor only cats is not reported. Outdoor access is associated with lower rates of obesity, which is routinely cited as the most important welfare issue for domestic pet cats^[33].

The American Veterinary Medical Association and the Humane Society of the United States advise that cats should be kept indoors most or all of the time. However, nearly two-thirds of owners, who keep their cats indoors, reported that the cat engaged in at least one problem behaviour (aggression to humans or other cats, inappropriate urination or defaecation)^[34], and indoor cats are more at risk of stress-related disorders, such as lower urinary tract diseases. There is evidence that owner time investment in playing with their cat, such as encouraging hunting-like pursuit and pouncing games, reduced the incidence of problem behaviours. The indoor environment also needs to meet the cat’s physical and behavioural needs. These include provision of a ‘safe space’, where cats can retreat to and hide if they feel threatened, sufficient resources to allow cats to eat and toilet alone (particularly in multi-cat households), opportunities for cats to climb, scratch, explore and experience an unpredictable environment, to play and show predatory behaviours (such as playing with toys that resemble prey items), and an environment that respects the importance of the cats’ sense of smell^[35]. A survey of cat owners’ behaviour in relation to indoor or outdoor management in Brazil suggested that indoor-only cats receive a greater degree of owner attention and veterinary care compared to outdoor-managed cats, although obesity and destructive behaviours were more common with indoor management^[36].

Taken together, the data suggest that it is possible to provide a complex and enriched environment for indoor-only cats, but this requires significant owner investment and understanding of cat behaviour. However, this may be a potential approach to reduce the risks of cat predation on local wildlife, reduce the risks of some cat diseases and losses, and may be an alternative approach to cat neutering in some cases.

Stray cat management

Although not a direct component of responsible cat ownership, all unowned cats have originated at some point from owned domestic cats. The size and health of this population is of concern (see section 4), and many countries actively work to manage and reduce the size of the feral and stray cat population. As well as controlling breeding in owned cats, neutering may be incorporated into trap-neuter-release (TNR)/trap-neuter-vaccinate-release (TNVR) schemes, to control unowned cat populations. In free-roaming cats, annual euthanasia has been proposed as a more effective means of control than neutering, requiring euthanasia of at least 50% of the population^[37]. This is unlikely to receive favour as a method of population management, but highlights the magnitude of the control effort required^[20].

The efficacy and appropriateness of TN(V)R schemes is debated. Returning recently neutered feral/stray cats to the site where they were captured can be problematic, as these animals will be newly recovering from surgery, and it may not be possible to provide effective pain management, if animals are returned too soon after surgery. In addition, although these animals are typically healthier than unneutered cats, they still compete for food and other resources and may still kill wildlife. Some studies advocate for a range of other measures to reduce the unowned cat population. For example, Crawford (2019)^[38] concluded that in Australia, targeted adoption, early-age neutering, community education initiatives and responsible pet ownership had greater potential to minimise euthanasia of unowned cats and reduce numbers rapidly. Rehoming young cats can be a suitable means of removing some animals from the population, accompanied by neutering of these animals, but older, unsocialised cats are unlikely to be suitable as pets and may lead to relinquishment to shelters at a later stage.

Isolated activities of collection and euthanasia are not effective for population control^[39]. Therefore, it is recommended to act on the cause of the problem, which is mainly the lack of responsible care of pet owners and the uncontrolled reproduction of pets. Feeding of feral and stray cats is sometimes carried out on an ad hoc basis in the UK and may be more formalised in some European cities with provision of feeding stations for cats. These can improve the welfare of stray and feral cats (see below), but need to be paired with neutering to prevent the improvements in nutrition leading to increased prolificacy in the cats and an increase in the numbers of kittens born. Well-meaning but short-term and uncontrolled feeding of stray and feral cats can improve welfare in the short term, but may increase welfare problems in the longer term through competition, disease transmission and an increase in population size. International rehoming of stray cats from other jurisdictions is to be discouraged. Cats are territorial in nature and subject to stress through movement and introduction. Additionally, they may contribute to further issues of cat population growth and the potential to introduce new infectious diseases.

Breeding issues and genetic deformities

Although the dominant type of domestic cat is still a ‘moggy’, which is defined as having no overall breed type or selective breeding, there is evidence of a recent increase in purchase of pure-breed cats in Scotland and the rest of the UK^[1,3]. Responsible breeding (of cats and other species, whether pure breed or not) involves a number of principles, including that the parents and offspring should be in good health and capable of normal species-specific behaviour, should not suffer from pain or injury/damage as a direct impact of breeding, avoid considerable deviations in morphology (such as lack of a tail, hairlessness, short legs, deafness, anatomical abnormalities of the face and mouth, etc.), inherited diseases and special requirements for housing in relation to breeding (such as naked animals or those with difficulties in thermoregulation)^[40]. The development of several cat breeds, where there may be excessive selection for traits considered aesthetically pleasing to humans, such as Scottish folds, Munchkin cats, Persian cats, Sphinx, Manx and bobtail cats, would all be examples where breeding is at risk of causing welfare harms to individuals.

Recently there has also started to be an increase in domestic cat-wild cat hybrids for the pet market. For example, hybridisation of the Asian leopard cat, Prionailurus bengalensis, with domestic shorthair cats produces ‘Bengal’ cats, which can be desirable for their spotted coats. Bengal cats are described as being more active and fearful than domestic cats, and to show more playfulness, be more vocal, show more predatory behaviour, higher aggression and territorial marking. Whilst these may not be interpreted as undesirable responses by their owners^[41], some of these traits can make the cats less successful as pet cats. Many other hybrids have occurred between Felis catus and other small wild cats, which can lead to problems with the wild cat parent (many of which are endangered in the wild), issues with (male) fertility, birth and neonatal survival, as well as behavioural problems, particularly aggression and high predatory responses^[42]. Accidental or deliberate release of these hybrids could also have a devastating impact on local fauna and could further compromise the genetics and welfare of the native wildcat, Felis silvestris. Anecdotal information (reported from a RZSS wildcat project manager) suggests that there may be cat owners living in wildcat release areas who would like to keep their domestic cats entire to be able to breed hybrids (with Felis silvestris) for future sale, which is a significant cause for concern.

Therefore, an element of responsible cat care is also related to assessing the suitability of the cat to the home environment that can be provided and ensuring that cats are acquired from responsible sources. Consideration of the potential for some breeds to have inherited diseases or painful disorders is also an important part of being a responsible cat owner.