Brachycephaly

Brachycephaly (Figures 3[a], [b]) describes a distortion of skull morphology resulting in a flattened face with a shortened muzzle with other linked changes such as a shallower eye socket and altered cranial cavity (Künzel et al. Reference Künzel, Breit and Oppel2003). Several cat breeds are considered brachycephalic (Table S1; Supplementary material), including British Shorthair, the most popular pure breed in the UK that makes up 8% of cats in the CATS Report 2024 (Cats Protection 2024) and 25% of all GCCF annual registrations (GCCF undated c). The distorted brachycephalic skull shape can cause painful conditions that may impact several of the welfare needs in Table 1, including ocular issues, such as entropion (Anagrius et al. Reference Anagrius, Dimopoulou, Moe, Petterson and Ljungvall2021; Demir Reference Demir2024) and conjunctivitis (Demir Reference Demir2024), which may also result in corneal ulcers. Brachycephalic cats may have dental issues, including malocclusions (Mestrinho et al. Reference Mestrinho, Louro, Gordo, Niza, Requicha, Force and Gawor2018) and crowding (Mestrinho et al. Reference Mestrinho, Louro, Gordo, Niza, Requicha, Force and Gawor2018; Sieslack et al. Reference Sieslack, Farke, Failing, Kramer and Schmidt2021), which negatively affect their ability to eat (Gleason et al. Reference Gleason, Phillips and McCoy2023). Ability to eat is an important aspect of a suitable diet (Table 1). Hypertype brachycephalic cats include Persians with ‘Peke’ faces that are flatter than the traditional ‘doll-faced’, longer-nosed Persian cats (Figure 1; Morel et al. Reference Morel, Malineau, Venet, Gaillard and Péron2024). Peke faces (Figure 3[b]) are likely to exacerbate dental and respiratory issues (Farnworth et al. Reference Farnworth, Chen, Packer, Caney and Gunn-Moore2016). Doll-faced Persians are sometimes known as ‘traditional’ Persians to highlight changing show trends whereby breed standards have moved from promoting the longer noses in the original Persian appearance in the 1950s towards now promoting a more extreme flat-faced appearance (Morris Reference Morris1999, cited in Schmidt et al. Reference Schmidt, Farke, Staszyk, Lang, Büttner, Plendl and Kampschulte2022).

As well as direct skeletal changes, brachycephalism may also cause respiratory problems stemming from relatively increased soft tissue in the shortened nose and also relative changes to the soft palate and larynx (Farnworth et al. Reference Farnworth, Chen, Packer, Caney and Gunn-Moore2016; Gleason et al. Reference Gleason, Phillips and McCoy2023) as well as stenotic nares (narrow nostrils; Razlighi et al. Reference Razlighi, Jahan and Jamshidi2022. Consequently, brachycephalic cats may be more reluctant to exercise, recover more slowly from activity and have shorter activity periods than non-brachycephalic cats (Gleason et al. Reference Gleason, Phillips and McCoy2023). This is likely to impact on the ability to show some of the normal behaviours identified in the welfare framework (Table 1). There is currently limited evidence on other negative impacts of brachycephaly in cats, including impacts on behaviour, but brachycephalic dogs are shown to also have neuropathic pain and pain from reflux in the oesophagus (Mitze et al. Reference Mitze, Barrs, Beatty, Hobi and Bęczkowski2022), as well as changes in their sense of smell (Polgar et al. Reference Polgar, Kinnunen, Újváry, Miklósi and Gácsi2016) and sight (McGreevy & Nicholas Reference McGreevy and Nicholas1999), and reduced sleep efficiency (Roedler et al. Reference Roedler, Pohl and Oechtering2013) so it is possible that similar effects could also occur in cats.

It is worth noting that some currently used methods of pain assessment based on facial expressions, including the feline grimace scale (FGS; Evangelista et al. Reference Evangelista, Watanabe, Leung, Monteiro, O’Toole, Pang and Steagall2019), did not include brachycephalic cats in their validation testing. As brachycephalic cats typically show greater pain-like features, especially Scottish Folds (Finka et al. Reference Finka, Luna, Brondani, Tzimiropoulos, McDonagh, Farnworth, Ruta and Mills2019), these pain scales may be unsuitable for pain assessment in brachycephalic cats, and consequently brachycephalic cat breeds may be at more risk of pain going undetected.

Folded ears

Folded or curled ears define breeds such as the American Curl, Scottish Fold (Figure 3[c]) and Highlander breeds. In Scottish Fold cats, this deformity results from defective cartilage which is unable to hold the ear pinna upright (Allan Reference Allan2000), with this defective cartilage also impacting bone development, termed osteochondrodysplasia (Chang et al. Reference Chang, Jung, Oh, Lee, Kim, Kim, Kweon, Yoon and Choi2007). Scottish Fold osteochondrodysplasia may present as musculoskeletal abnormalities, such as exostoses (bone swellings) in the feet (Takanosu & Hattori Reference Takanosu and Hattori2020), and short, misshapen limbs and tails (Malik et al. Reference Malik, Allan, Howlett, Thompson, James, McWhirter and Kendall1999; Chang et al. Reference Chang, Jung, Oh, Lee, Kim, Kim, Kweon, Yoon and Choi2007; Takanosu & Hattori Reference Takanosu and Hattori2020). As Scottish Fold osteochondrodysplasia is linked to the genetic variant which causes folded ears (Gandolfi et al. Reference Gandolfi, Alamri, Darby, Adhikari, Lattimer, Malik, Wade, Lyons, Cheng, Bateman, McIntyre, Lamandé and Haase2016), crossbred cats (e.g. cats with one Scottish Fold parent) with ear folds also have osteochondrodysplasia (Takanosu & Hattori Reference Takanosu and Hattori2020). Clinical signs of osteochondrodysplasia can begin as young as six months (Malik et al. Reference Malik, Allan, Howlett, Thompson, James, McWhirter and Kendall1999) and health status typically deteriorates with age (Malik et al. Reference Malik, Allan, Howlett, Thompson, James, McWhirter and Kendall1999; Allan Reference Allan2000). Treatment for osteochondrodysplasia is never curative and may include surgical procedures that themselves can be painful and stressful, exacerbating the overall welfare impact. As with all painful conditions, osteochondrodysplasia is likely to inhibit natural behaviours, such as the ability to jump or climb as seen in the welfare framework (Table 1). Osteochondrodysplasia can also cause osteoarthritis, which is associated with significant chronic pain and restrictions in movement, including lameness, crawling gait and a reluctance to perform normal behaviours (Malik et al. Reference Malik, Allan, Howlett, Thompson, James, McWhirter and Kendall1999; Allan Reference Allan2000). Osteoarthritis treatment and management is also not curative, and can include lifelong medication and environmental modification, such as steps or ramps, to enable cats to navigate their environment (Langley‐Hobbs Reference Langley‐Hobbs2023). Skeletal issues related to the ears in American Curls have not yet been reported (Takanosu & Hattori Reference Takanosu and Hattori2020) but further investigation is warranted.

Ears are important in feline communication: two cats meeting with both showing erect ears are significantly more likely to have positive interactions than those where either cat has non-erect ears (Deputte et al. Reference Deputte, Jumelet, Gilbert and Titeux2021). It has not yet been reported whether cats with folded or curled ears, who are unable to extend their ears to erect have significant impacts on their ability to interact with other cats (Table 1). While stronger evidence on the social behaviour of cats with curled ears is required, the concerns around the wider welfare of cats with folded ears should be enough reason to recommend avoiding breeding for this conformation at all in cats.

Dwarf breeds

Munchkin cats (Figure 3[d]) and their descendant dwarf breeds typically have short limbs (Struck et al. Reference Struck, Braun, Detering, Dziallas, Neßler, Fehr, Metzger and Distl2020), although some offspring from breeding between two dwarf cats may display normal limb length (Lyons et al. Reference Lyons, Fox, Chesney, Britt, Buckley, Coates, Gandolfi, Grahn, Hamilton and Middleton2019). Some genes that cause the shortening of limbs have been identified but are still under investigation (Lyons et al. Reference Lyons, Fox, Chesney, Britt, Buckley, Coates, Gandolfi, Grahn, Hamilton and Middleton2019; Buckley et al. Reference Buckley, Davis, Brashear, Farias, Kuroki, Graves, Hillier, Kremitzki, Li, Middleton, Minx, Tomlinson, Lyons, Murphy and Warren2020). Although dwarf cats do not appear to share the high predisposition to intervertebral disc disease seen in dogs (Lyons et al. Reference Lyons, Fox, Chesney, Britt, Buckley, Coates, Gandolfi, Grahn, Hamilton and Middleton2019), evidence is lacking as to whether the changes in skeletal morphology and resulting malalignment of limbs (Anderson et al. Reference Anderson, Fox, Chesney, Coates, Torres and Lyons2021) causes pain or predisposition to diseases such as the osteoarthritis seen in cats with dwarfism related to mucopolysaccharidosis (Allan Reference Allan2000). To date, research appears limited to a single case study describing a Minuet with pectus excavatum (sunken breastbone), which compressed the thoracic contents and caused respiratory issues (Kihara et al. Reference Kihara, Aikawa, Miyazaki, Nishimura and Muyama2024). Research is also lacking on the extent to which short limbs per se impair natural behaviours, such as jumping, climbing and grooming. While population-level studies to provide evidence on welfare impacts in dwarf cats are warranted, it is worth noting that dwarf cat breeds, such as the Munchkin, are not currently recognised by GCCF or FIFe due to welfare concerns.

Congenitally tailless or short-tailed cats

Cats deliberately bred to have no tail, or a very short tail, such as the Manx (Figure 3[e]), suffer from wider vertebral deformities linked to this phenotype (Leipold et al. Reference Leipold, Huston, Blauch and Guffy1974; Deforest & Basrur Reference Deforest and Basrur1979). Congenitally tailless or short-tailed cats carry a higher risk of spina bifida (Martin Reference Martin1971), which shortens the nerves and spinal cord. As well as consequent issues with reduced and altered mobility, including paresis (muscular weakness) and/or a hopping gait (Leipold et al. Reference Leipold, Huston, Blauch and Guffy1974; Deforest & Basrur Reference Deforest and Basrur1979), spina bifida in cats can also cause incontinence or other elimination problems (Leipold et al. Reference Leipold, Huston, Blauch and Guffy1974; Deforest & Basrur Reference Deforest and Basrur1979). The mobility and elimination problems impact on cat welfare through the need for protection from pain and suffering and the need for a suitable diet (Table 1). Although much of the research on Manx cats dates back to the 1970s, and failed to investigate pain levels, it has been recommended that Manx cats should routinely undergo consideration of pain management (Lyons Reference Lyons2024). Further assessment of pain in breeds of cats with no or short tails is warranted.

Cats use their tails for balance (Walker et al. Reference Walker, Vierck and Ritz1998). To our knowledge there has been no investigation as to whether having a short tail or no tail reduces a cat’s ability to balance and hence perform some of the natural behaviours in Table 1. Tails are also used in social interactions. The ‘tail up’ position for cats can be a friendly signal for an affiliative interaction, although it appears less important than the position of the ears as discussed above for cats with folded ears (Cafazzo & Natoli Reference Cafazzo and Natoli2009). Cats usually approach humans with their tail up, which may reflect the way that kittens approach their mothers. The tail up is suspected to be an important part of the cat-human interaction (Deputte et al. Reference Deputte, Jumelet, Gilbert and Titeux2021) and is theorised to be easily interpreted by humans as affiliative (Deputte et al. Reference Deputte, Jumelet, Gilbert and Titeux2021). The impact of not having a full tail on the human-cat bond has been poorly investigated but could be relevant for the social needs in Table 1.

No hair coat or thin hair coat

Some cats have been deliberately selected to show genetic variants for hairlessness, such as Sphynxes (Figure 3[f]), or to have a very thin coat, such as Devon and Cornish Rexes. Cats with no or thin hair coats are reportedly prone to skin issues such as infection with the yeast Malassezia (Åhman & Bergström Reference Åhman and Bergström2009), which can lead to dermatitis, causing itchy and inflamed skin and necessitating lifelong treatment with anti-fungal baths. Cats with no or thin hair coats are reported to be prone to skin damage from the sun or exposure to cold (e.g. People’s Dispensary for Sick Animals [PDSA] undated a) although robust evidence here is lacking. Given this possibility, owners may choose to restrict hairless cats indoors, reducing opportunities to perform normal behaviours and not providing a suitable environment if there is no appropriate enrichment as listed in the welfare framework in Table 1. Based on comprehensive reviews elsewhere regarding the welfare impacts and suitability of indoor-only lifestyles for cats (Foreman-Worsley & Farnworth Reference Foreman-Worsley and Farnworth2019; Glanville et al. Reference Glanville, Hampton and Sandøe2025), we note that enforced indoor-only living for cats is commonplace and the need for appropriate enrichment is not limited to any specific breed or to purebred cats more generally (Herron & Buffington Reference Herron and Buffington2010).

Although there appears to be no published information regarding the impact of no or a thin hair coat on grooming, Sphynxes are anecdotally prone to greasy exudate that accumulates on the skin and in the claws and interdigital web (Åhman & Bergström Reference Åhman and Bergström2009). This may impact the need to be protected from pain, suffering, injury and disease as seen in the framework in Table 1. As a consequence to this exudate, the GCCF recommends regular bathing of Sphynxes (GCCF undated d), which itself can be a negative experience for cats (Rand et al. Reference Rand, Kinnaird, Baglioni, Blackshaw and Priest2002). There are alternative and potentially less stressful options to bathing for cats, for example, using wipes instead of water. We also note that recommendations for grooming and bathing are not exclusive to hairless cats, and that cats with long hair coats also require frequent grooming to prevent potentially painful matting and reduce hairballs. Cat conformations that carry a requirement for human grooming to maintain skin and hair health could be considered an extreme conformation whereby if the human husbandry input is inadequate, then these animals will not have their welfare needs met.

Multi-extreme cats

Some cat breeds typically display more than one extreme conformation trait. For example, Scottish Folds typically have both brachycephaly and folded ears. Experimental breeds are often created by crossing cats from established breeds, resulting in planned selection for new cat types with multiple extreme conformations. For example, the Minuet is a Munchkin and Persian cross, resulting in a cat affected with both brachycephaly and dwarfism (TICA undated c). Recently, the XL Bully cat, a cross between Sphynx and Munchkin resulting in a hairless cat with skin folds and dwarfism, has attracted interest from animal welfare organisations as a breed of concern, although the Bambino, a similar cross, appears to have escaped such welfare attention (Ahmed Reference Ahmed2024; The Cat Group 2024). Although the GCCF does not allow the registration of multi-extreme breeds, several are accepted by TICA (Table S1; Supplementary material).

Other conformational extremes in cats

In addition to the extreme conformations discussed above, humanity has selected for a wide range of other morphological changes in cats that do not commonly occur in natural cat populations, and which, as yet, have had very little research to establish their welfare impacts. These other phenotypes include polydactyly (extra digit[s] on the feet) and dolichocephaly, which refers to a longer face as seen in breeds such as Siamese. There is scant published research on polydactyly, but some lines of cats, including Maine Coons, are intentionally bred to maintain this trait (Hamelin et al. Reference Hamelin, Begon, Conchou, Fusellier and Abitbol2017). The extra digit causes changes in the carpal and tarsal bones in the foot, although the authors of that study concluded, based on their available evidence, that “polydactyly had no impact on cat welfare” (Hamelin et al. Reference Hamelin, Begon, Conchou, Fusellier and Abitbol2017). However, further research is warranted to better assess the impact of polydactyly on welfare, including analyses with larger samples with more lines of cats, more breeds, older study populations, and recognition of the diverse conformation polydactyly may take. Likewise, there is no evidence published to date on welfare impacts of dolichocephaly on health, behaviour or social signalling, including those with the extreme features of hypertypes, such as large ears (Morel et al. Reference Morel, Malineau, Venet, Gaillard and Péron2024), although this does not mean impacts do not exist.

Painful conditions

The need to be protected from pain is integral to the legally defined feline welfare needs. Indicators of pain in cats utilised in QOL assessment tools include yowling, changes in mobility and reluctance to jump (Table 1). Although acute and chronic pain can be managed to some degree with appropriate analgesia, pain itself can be difficult to detect in cats, and not all medications are highly effective with some potentially carrying serious side-effects (Taylor & Robertson Reference Taylor and Robertson2004). Chronic pain and its impact on mobility may also require management via environmental modifications, such as steps or changes to litter tray accessibility.

Painful conditions associated with purebred cat breeds include diseases of the urinary system such as urolithiasis that is predisposed in Bengals, Birmans, Egyptian Maus and Exotic Shorthairs, among others (Albasan et al. Reference Albasan, Osborne, Lulich and Lekcharoensuk2012). Skin issues, such as an increased incidence of atopic dermatitis in Abyssinians (Ravens et al. Reference Ravens, Xu and Vogelnest2014), may lead to painful lesions. Painful oral conditions, such as tooth resorptive lesions (Vapalahti et al. Reference Vapalahti, Neittaanmäki, Lohi and Virtala2024) and periodontal disease (Lund Reference Lund2012; O’Neill et al. Reference O’Neill, Blenkarn, Brodbelt, Church and Freeman2023a) are more common in various breeds, and may reduce appetite or the ability to eat, impacting on the welfare need for a suitable diet (Table 1).

Feline hip dysplasia is a rarer painful inherited condition defined by malformation of the coxofermoral (hip) joint (Keller et al. Reference Keller, Reed, Lattimer and Corley1999). Hip dysplasia in cats is poorly recognised and understood but appears to be more common in Maine Coons, Himalayans and Persians (Keller et al. Reference Keller, Reed, Lattimer and Corley1999; Loder & Todhunter Reference Loder and Todhunter2018). As well as causing primary pain, hip dysplasia can lead to further pain from secondary osteoarthritis (Allan Reference Allan2000). Hypertype Maine Coons may be larger-bodied than typical Maine Coons (Morel et al. Reference Morel, Malineau, Venet, Gaillard and Péron2024) with the potential to exacerbate the clinical signs of both hip dysplasia and osteoarthritis.

Other breed predispositions

Hypertrophic cardiomyopathy (HCM) is the most commonly reported heart disease in cats and is more prevalent in Maine Coons, Persians, British Shorthairs and Ragdolls (Granström et al. Reference Granström, Nyberg Godiksen, Christiansen, Pipper, Willesen and Koch2011; Trehiou‐Sechi et al. Reference Trehiou‐Sechi, Tissier, Gouni, Misbach, Petit, Balouka, Carlos Sampedrano, Castaignet, Pouchelon and Chetboul2012; Casamian‐Sorrosal et al. Reference Casamian‐Sorrosal, Chong, Fonfara and Helps2014). HCM can occur from six months of age (Kittleson & Côté Reference Kittleson and Côté2021) but may have a later onset of 6–7 years (Kittleson et al. Reference Kittleson, Meurs, Munro, Kittleson, Liu, Pion and Towbin1999). In HCM, the heart muscles become thickened, reducing their efficiency. Although many cats with HCM can live an apparently normal life (Maron Reference Maron2018), clinically affected cats can show serious clinical signs including difficulty breathing, anorexia, hind leg paralysis and sudden death. A QOL assessment tool exists specifically for cats with cardiac disease (Table 1; Freeman et al. Reference Freeman, Rush, Oyama, MacDonald, Cunningham, Bulmer, MacGregor, Laste, Malakoff and Hall2012) which includes questions on breathing, collapse, increased drinking/urination, appetite changes, medications and veterinary visits, highlighting the wide spectrum of welfare impacts that cardiac disease may have on QOL. Variants responsible for HCM have been identified (Meurs et al. Reference Meurs, Norgard, Kuan, Haggstrom and Kittleson2009), with genetic testing for HCM as a familial trait available for certain breeds, such as Maine Coons and Ragdolls (Langford Vets undated). It is advised that breeding cats are screened using echocardiography (Häggström et al. Reference Häggström, Luis Fuentes and Wess2015), meaning potential stressful veterinary visits impacting on the welfare need to be protected from pain, suffering, injury and disease (Table 1).

Polycystic kidney disease (PKD) is a familial disorder identified in Persians (Biller et al. Reference Biller, DiBartola, Eaton, Pflueger, Wellman and Radin1996) and in breeds derived from Persians, including Exotic Shorthairs and Himalayans. A genetic test is available for the causative gene (Langford Vets undated) which has been identified (Lyons et al. Reference Lyons, Biller, Erdman, Lipinski, Young, Roe, Qin and Grahn2004). PKD is present at birth and progresses with age, with renal function deterioration generally resulting in clinical signs that typically appear at around seven years of age, although they can begin between three and ten years (Schirrer et al. Reference Schirrer, Marín-García and Llobat2021). Clinical signs include increase in thirst and urination, weight loss, vomiting/nausea and death which can impact on several welfare needs (Table 1). Treatment is palliative and might include fluid therapy, anti-nausea medications and dietary changes. In 2001, the prevalence of PKD in Persians in the UK was 49.2% (Cannon et al. Reference Cannon, Barr, Rudorf, Bradley, Gruffydd‐Jones and MacKay2001). To our knowledge, a more recent published estimate is not available and although the GCCF reports a decrease in PKD prevalence since the onset of the genetic test, it is not clear where those data were sourced (GCCF undated e). Widespread genetic testing is reported to have contributed to reduced prevalence of PKD in other countries such as Japan, although at this time these data are not yet peer-reviewed (Ukawa et al. Reference Ukawa, Kida, Ataka, Horie and Matsumoto2024). The causative PKD1 gene was not found in a more recent sample of 118 Persian cats from around the world (Anderson et al. Reference Anderson, Davison, Lytle, Honkanen, Freyer, Mathlin, Kyöstilä, Inman, Louviere, Chodroff Foran, Forman, Lohi and Donner2022). An updated investigation into the epidemiology of PKD in Persians and other breeds in the UK would be valuable.

Genetic testing of a large global sample of cats has indicated that several other genetic variants associated with disease have also decreased (Anderson et al. Reference Anderson, Davison, Lytle, Honkanen, Freyer, Mathlin, Kyöstilä, Inman, Louviere, Chodroff Foran, Forman, Lohi and Donner2022). Although the link between these decreases and the onset of genetic testing is not proven, it seems a likely explanation, and it has been postulated that many specific disorders could be reduced or even eradicated from pedigree lines if genetic testing were more widespread or even mandatory (Lyons Reference Lyons2024). To our knowledge there is no current evidence regarding the levels of genetic testing of cats in the UK, although it is mandatory for some breeds registering with the GCCF.

Diabetes mellitus is a chronic endocrine disease of relative insulin insufficiency that generally requires daily insulin injections for clinical management, although there is now an oral solution available for newly diagnosed cats. Diabetes predisposition is reported in Burmese and Russian Blue cats, among others (Öhlund et al. Reference Öhlund, Fall, Ström Holst, Hansson-Hamlin, Bonnett and Egenvall2015), and evidence supports a genetic predisposition (O’Neill et al. Reference O’Neill, Gostelow, Orme, Church, Niessen, Verheyen and Brodbelt2016). However certain purebreds, including Bengals, Persians, Ragdolls and British Shorthairs show a lower risk of developing diabetes mellitus compared with random-bred cats (Öhlund et al. Reference Öhlund, Fall, Ström Holst, Hansson-Hamlin, Bonnett and Egenvall2015). Random-bred related factors, such as age, obesity, being inactive and treatment with corticosteroids can also put cats at higher risk of developing diabetes (McCann et al. Reference McCann, Simpson, Shaw, Butt and Gunn-Moore2007; Öhland et al. 2015). There is a QOL tool specific to cats with diabetes mellitus, with questions regarding increased appetite, being unwell in general and pain from insulin injections (Table 1; Niessen et al. Reference Niessen, Powney, Guitian, Niessen, Pion, Shaw and Church2010).

Feline infectious peritonitis (FIP) is a viral disease, with young and male cats overrepresented (Worthing et al. Reference Worthing, Wigney, Dhand, Fawcett, McDonagh, Malik and Norris2012), alongside several breeds, including Abyssinians, Bengals, Birmans, Himalayans, Ragdolls and Rexes compared to the random-bred cat population (Pesteanu-Somogyi et al. Reference Pesteanu-Somogyi, Radzai and Pressler2006; Worthing et al. Reference Worthing, Wigney, Dhand, Fawcett, McDonagh, Malik and Norris2012). Clinical signs are varied and can include abdominal effusion, fever, anorexia and neurological signs (Tasker et al. Reference Tasker, Addie, Egberink, Hofmann-Lehmann, Hosie, Truyen, Belák, Boucraut-Baralon, Frymus, Lloret, Marsilio, Pennisi, Thiry, Möstl and Hartmann2023). FIP carries a very poor prognosis, with one study reporting median survival times of 21–38 days after presentation (Tsai et al. Reference Tsai, Chueh, Lin and Su2011). Since 2021, antiviral medication has been legally available in the UK to treat FIP (Taylor et al. Reference Taylor, Tasker, Gunn-Moore, Barker and Sorrell2024). This is typically a 12-week course of tablets (Coggins et al. Reference Coggins, Norris, Malik, Govendir, Hall, Kimble and Thompson2023). During treatment cats may suffer pain, need fluid drained from the lungs and/or experience side-effects of medication, such as nausea (Taylor et al. Reference Taylor, Tasker, Gunn-Moore, Barker and Sorrell2024).

Cat-directed aggression

Appropriate application of the legal welfare need to be housed with or apart from other animals (Table 1) may vary between individual cats. Some breeds have been associated with higher levels of cat-directed aggression, such as Abyssinians, Tonkinese, Oriental Shorthairs (Wilhelmy et al. Reference Wilhelmy, Serpell, Brown and Siracusa2016) and Turkish Vans (Salonen et al. Reference Salonen, Vapalahti, Tiira, Mäki-Tanila and Lohi2019). If true, individual cats of these breeds may be better suited to single-cat households. Other breeds, such as Persians, show reportedly lower frequency and severity of cat-directed aggression (Salonen et al. Reference Salonen, Vapalahti, Tiira, Mäki-Tanila and Lohi2019) and therefore may more readily cohabit with conspecifics. However, as noted above, these studies are based on owner reports and are insufficient for making recommendations based on breed. Additionally, individual personality and socialisation should always be considered when assessing suitability for multi-cat households. Bengals, a hybrid breed, have been reported to not have an increased incidence of cat-directed aggression (Wilhelmy et al. Reference Wilhelmy, Serpell, Brown and Siracusa2016; Salonen et al. Reference Salonen, Vapalahti, Tiira, Mäki-Tanila and Lohi2019). However, hybrid cats generally are reported anecdotally as being more likely to have negative interactions with other cats, especially earlier hybrid generations which are closer to original wild cats (AAFP 2017). More robust behaviour studies incorporating more hybrid breeds would be valuable in decision-making around multi-cat households. There appears to be no evidence regarding whether any specific cat breeds are more or less amenable to living with other companion animals such as dogs.

Relationship with humans

Some individual cat breeds are also reported to show differing levels of human-directed aggression, although the literature lacks consistency regarding many of these associations. Birmans, Maine Coons and Turkish Vans have been reported to show higher levels of aggression towards familiar humans, while British Shorthairs, Maine Coons and Persians reportedly exhibited lower aggression (Wilhelmy et al. Reference Wilhelmy, Serpell, Brown and Siracusa2016; Salonen et al. Reference Salonen, Vapalahti, Tiira, Mäki-Tanila and Lohi2019). However, more generally, ‘mixed-breed’ (assumptively random-bred) cats were more likely to act aggressively towards humans than purebred cats in one study (Ramos & Mills Reference Ramos and Mills2009). All three of these studies are based on owner-reported behaviour. Desirable behaviour towards humans is important for cat welfare as a strong bond between owners and companion animals has been found to improve many indicators of good pet care, including a higher likelihood of seeking veterinary care (Lue et al. Reference Lue, Pantenburg and Crawford2008). Positive interactions with an owner (e.g. affectionate, relaxed behaviours) are often used as QOL indicators in assessment tools (Table 1).

Environmental needs

Environmental needs may vary predictably between breeds. Bengals, Birmans and Persians have been associated with higher incidences of inappropriate elimination, which might include urinating outside the litter tray and marking behaviour (Amat et al. Reference Amat, de la Torre, Fatjó, Mariotti, Van Wijk and Manteca2009; Wassink-van der Schot et al. Reference Wassink-van der Schot, Day, Morton, Rand and Phillips2016; Wilhelmy et al. Reference Wilhelmy, Serpell, Brown and Siracusa2016). The reasons for this association are unclear; underlying causes for not using the litter tray include litter type and location (Horwitz Reference Horwitz1997; Herron Reference Herron2010), multi-cat households and lack of outdoor access (Barcelos et al. Reference Barcelos, Kargas and Mills2024), as well as health issues such as cystitis which can be related to stress in cats (Buffington Reference Buffington2002). Urine marking, (also known as spraying), is a physiologically normal but unwanted behaviour linked with being entire, particularly in males (Pryor et al. Reference Pryor, Hart, Bain and Cliff2001), as well as the age and personality of a cat (Barcelos et al. Reference Barcelos, Kargas and Mills2024). Cats exhibiting inappropriate elimination may need environmental modification to address the underlying issue, such as alternative litter tray provisions and management of agonistic social interactions (Horwitz Reference Horwitz1997).

Individual cats of other breeds may also require specific environmental consideration to fulfil needs that are potentially more complex. Hybrid cats (Figure 1, Table S2; Supplementary material), are likely to retain strong natural hunting instincts and temperaments that require more mental and physical enrichment to fulfil. Although this has not been studied for all hybrids, Bengals have been reported to exhibit higher levels of hunting behaviour and are highly active (Wilhelmy et al. Reference Wilhelmy, Serpell, Brown and Siracusa2016; Salonen et al. Reference Salonen, Vapalahti, Tiira, Mäki-Tanila and Lohi2019). Many hybrids appear to have specific needs that often make them unsuitable for typical home environments, and therefore many UK cat welfare charities do not advocate their breeding (Cats Protection undated; International Cat Care undated). Despite these welfare considerations, Bengals are reported to be increasing in popularity in the UK (Cats Protection 2024), although the numbers of other hybrids kept as companion animals in the UK is unknown. More work is therefore needed to understand the behavioural traits and environmental needs of hybrids and whether these can be adequately met in the home as required by the framework in Table 1.

Housing

The living conditions for breeding cats in the UK have not been reported. However, these conditions are important to consider carefully, given their ability to impact upon ability to fulfil the legal needs for a suitable environment, the need to be housed with, or apart from, other animals, and the need to be free from disease as listed in the framework (Table 1). There are no reliable data regarding how many cats reside in breeding catteries in the UK, nor how many cats are typically kept at any one site, although evidence from international studies suggests multi-cat breeding sites are common. In Sweden, the mean number of cats per breeding site was reported at six (Ström Holst & Frössling Reference Ström Holst and Frössling2009), while in Germany the reported median was 12 cats, with a range of five to 29 (Klein-Richers et al. Reference Klein-Richers, Hartmann, Hofmann-Lehmann, Unterer, Bergmann, Rieger, Leutenegger, Pantchev, Balzer and Felten2020). Many of these breeding cats cohabit, with 74% of Swedish breeding catteries housing their cats together (Ström Holst & Frössling Reference Ström Holst and Frössling2009). Enforced living in a multi-cat environment is recognised as a potential source of stress for cats in the framework in Table 1, although a recent review found that reported links between stress and multi-cat households vary considerably across studies (Finka & Foreman-Worsley Reference Finka and Foreman-Worsley2022).

Goericke-Pesch and Packeiser (Reference Goericke-Pesch and Packeiser2022) reported that breeding queens are often kept in the house as pets, with breeding tom cats kept individually in a room or in a ‘garden house’. Limited space and poor enrichment may restrict the natural behaviours listed in Table 1. Multi-cat environments are also linked with higher risks of infectious diseases, for example, Feline Calicivirus and Feline Herpesvirus appear to be more common in multi-cat than single-cat households (Binns & Dawson Reference Binns and Dawson1995) and in Sweden, 33% of breeders reported having a cat with conjunctivitis within the past year (Ström Holst & Frössling Reference Ström Holst and Frössling2009). Breeders may find it difficult to balance between hygiene to reduce the risk of infectious disease spread and complying with any licencing laws while still providing for the environmental needs of cats, such as consistent and predictable human-cat interactions (see Ellis et al. Reference Ellis Sarah, Rodan, Carney, Heath, Rochlitz, Shearburn, Sundahl and Westropp2013).

Pregnancy

Pregnancy itself can be a welfare concern. Dystocia, defined as an obstructed or difficult birth, appears to be significantly more common in some cat breeds, including Abyssinians and British Short Hairs, based on insurance data (Ström Holst et al. Reference Ström Holst, Axnér, Öhlund, Möller and Egenvall2017). Dystocia is likely to cause pain and distress, and can lead to the death of the queen, kittens or both (Ström Holst et al. Reference Ström Holst, Axnér, Öhlund, Möller and Egenvall2017; Černá et al. Reference Černá, Pugalendhi, Shaw and Gunn-Moore2024), impacting on the need to be protected from suffering, pain injury and disease in the welfare framework (Table 1). Dystocia may require a Caesarean section with associated risks of surgery and anaesthesia (Ström Holst et al. Reference Ström Holst, Axnér, Öhlund, Möller and Egenvall2017). In a 1994 study from one Swedish veterinary hospital, surgical intervention was undertaken in 79.4% of feline dystocia cases (Ekstrand & Linde‐Forsberg Reference Ekstrand and Linde‐Forsberg1994). There is also evidence that pelvic measurements are significantly smaller in brachycephalic cats in all dimensions, including a smaller pelvic canal (Monteiro et al. Reference Monteiro, Campos, Madeira, Silva, Freire, Pinto, De Souza and Da Silva2013), although the impact of this on the incidence of dystocia is not clear. Gunn-Moore and Thrusfield (Reference Gunn-Moore and Thrusfield1995) reported a higher incidence of dystocia in brachycephalic cats, while Ström Holst et al. (Reference Ström Holst, Axnér, Öhlund, Möller and Egenvall2017) found the incidence to be higher in some brachycephalic breeds, such as British Shorthairs, but lower in others, including Persians. It should also be noted that breeding cats must be left entire which can increase the risk of health issues including mammary cancer (Overley et al. Reference Overley, Shofer, Goldschmidt, Sherer and Sorenmo2005) or pyometra (Hagman et al. Reference Hagman, Ström Holst, Möller and Egenvall2014).

Socialisation

Effective socialisation of kittens in a breeding facility may be difficult, and in some cases neglected, although the evidence base on socialisation in breeding facilities is limited. The socialisation period of kittens is thought to be between two and seven weeks (Karsh & Turner Reference Karsh, Turner, Turner and Bateson1998) with kittens requiring exposure to experiences, including sights, sounds and interactions with other species, such as cats, dogs and humans, in their early life to ensure they develop the required skills to cope in domestic settings as they age (McCune Reference McCune1995; Casey & Bradshaw Reference Casey and Bradshaw2008; Campbell et al. Reference Campbell, Arnott, Graham, Niel, Ward and Ma2024). Where this socialisation does not take place adequately or at all, cats may struggle to cope later with household environments, impacting on the ability to provide a suitable environment and need to be housed with or apart from other animals (Table 1).

Hybrid cats

Special consideration must be given to the deliberate breeding to produce hybrid cats (Table S2; Supplementary material). Breeding domestic cats with wild cats may risk severe injury or death to the domestic cat. Wild cats kept for breeding are often housed in unsuitable domesticated situations for extended periods and may have been removed illegally from the wild (AAFP 2017). First generation crossings can produce infertile males (Gershony et al. Reference Gershony, Penedo, Davis, Murphy, Helps and Lyons2014) that are unsuitable for breeding and likely unsuitable as companion animals. Although the welfare outcomes for these males are not reported, relinquishment or euthanasia seems likely. In some countries, concerns regarding hybrid cats have led to bans on their importation, for example, New Zealand only allows importation of Bengals of at least F5 or later, and no other hybrids are allowed to be imported (New Zealand Government 2024). Although not banned in the UK, any cat with a wild parent requires a licencing permit under the Dangerous Wild Animals Act 1976 (UK Parliament 2022). There is variation across UK cat registration bodies in the acceptability of hybrid cats. The GCCF does not allow registration of early generation (F1–F3) Bengals (GCCF 2017). The Toyger, which is derived from Bengals, is recognised as a preliminary breed (in the early stages of acceptance, see Table S1; Supplementary material). FIFe only allows registration of Bengals but do not allow breeding from generations F1–F4 (FIFe 2025), while TICA recognises four hybrids (Bengal, Chausie, Savannah and Toyger, see Table S2; Supplementary material), information on accepted generations could not be readily found. We note that the Highlander cat, recognised only by TICA, has been reported by some sources (e.g. Rare and Exotic Feline Registry undated) to be derived from hybrid cats although TICA describes them as being derived “from the domestic gene pool” (TICA undated d). Other hybrids (Table S2; Supplementary material) are not recognised by any UK registration body, nor are hybrids recommended as pets by many animal welfare organisations (e.g. Cats Protection undated; PDSA undated b).

Husbandry and management

It is likely that breed impacts on indoor-outdoor status, with one global study reporting ‘pedigrees’ (assumptively purebreds under the definition in Figure 1) were significantly more likely than ‘non-pedigrees’ to be enforced indoor-only, making up 16% of the indoor only population compared to 7.9% of the population allowed outside (Foreman-Worsley et al. Reference Foreman-Worsley, Finka, Ward and Farnworth2021). Crossbred cats were not reported but are likely to fall under the umbrella of ‘pedigree’ since they have purebred ancestry. Reasons for keeping their cats inside cited by owners of purebred cats included concerns about theft, stipulation from the breeder and impressions that their cat was not able to keep itself safe outdoors (Foreman-Worsley et al. Reference Foreman-Worsley, Finka, Ward and Farnworth2021). Although an indoor life provides some protection against outdoor hazards such as cat fights and road traffic collisions (Tan et al. Reference Tan, Stellato and Niel2020), outdoor access allows cats more space and access to resources that enable performance of natural behaviours, including hunting and ranging (Bradshaw Reference Bradshaw2018). Outdoor access also provides opportunities for exercise, which may explain higher levels of obesity seen in indoor-only cats than those with outdoor access (Buffington Reference Buffington2002; Rowe et al. Reference Rowe, Browne, Casey, Gruffydd-Jones and Murray2015; Wall et al. Reference Wall, Cave and Vallee2019). However, humans are more likely to provide indoor cats with better indoor enrichment such as toys and scratching posts (Lawson et al. Reference Lawson, Langford and Harvey2020; Machado et al. Reference Machado, Gonçalves, Vicentini, Ceballos and Sant’Anna2020; Tan et al. Reference Tan, Stellato and Niel2020) that may mitigate some of the welfare compromise. Across the spectrum of purebred cats, it is unclear whether some breeds are more affected by human decisions regarding cat lifestyle than others, although it may be rationalised that high-energy breeds and hybrid cats would benefit more from increased opportunities to be active and fulfil their natural instincts, such as through play. In the absence of literature in this area, it is important that owners understand the individual needs of their cat regardless of breed and are able to provide for them without unacceptably compromising welfare.

Travel

There is very scant evidence published on the frequency of travel and the distances undertaken for breeding purebred cats or displaying them at shows. In Sweden, most breeders (87%) reported showing a cat at least once in the previous year, with this extending up to 26 shows annually for some breeders, although it is not clear how many shows this is for each cat (Ström Holst & Frössling Reference Ström Holst and Frössling2009). Travel itself is a potential source of major stress to cats, although most research to date has focused on travel specifically for veterinary visits (e.g. Mariti et al. Reference Mariti, Guerrini, Vallini, Bowen, Fatjó, Diverio, Sighieri and Gazzano2017; Tateo et al. Reference Tateo, Zappaterra, Covella and Padalino2021). Mixing with other cats when breeding or at shows may also increase the spread of disease; 10.4% of Swedish breeders reported a cat having conjunctivitis after travelling to a show and 14.6% reported signs of upper respiratory tract disease (Ström Holst & Frössling Reference Ström Holst and Frössling2009). Additional issues for show cats may include the stress of encountering unfamiliar cats, being confined to a small crate for extended periods, limited hiding places, exposure to unfamiliar humans and handling, noise and unfamiliar odours (Stone Reference Stone2019). To our knowledge, only one study has investigated stress at cat shows, and although the authors of that study reported only low levels of behaviours that indicated stress, they noted that this was only a pilot study (Cannas et al. Reference Cannas, Alessi, Scarpazza and Palestrini2023). More robust work is needed to assess how showing of purebred cats impacts on the welfare framework in Table 1.

Veterinary care

Veterinary care is an important aspect of maintaining the welfare needs in the framework in Table 1. Given the increased risk of health and pain issues discussed above for some specific cat breeds, some purebred cats may require increased levels of veterinary care compared to random-bred cats. For this, owners must firstly be sufficiently aware of the status of their cat’s health. Unfortunately, normalisation of suffering related to breed-typical extreme conformation has been reported as widespread among owners of purebred dogs, with owners of brachycephalic dogs reported to often be unaware of the severity of their dog’s respiratory clinical signs, instead believing them to be ‘normal for breed’ (Packer et al. Reference Packer, Hendricks and Burn2012). It is likely that a similar cognitive dissonance and bias could prevail for owners of purebred cats. Once an awareness of disease has been reached, owners must then also be willing and able to obtain veterinary care and to undertake to administer any necessary treatments and make suggested changes to their cat’s environment.

There is some evidence suggesting that the owners of purebred cats provide more veterinary care than owners of random-bred cats. For example, in Denmark (Sandøe et al. Reference Sandøe, Nørspang, Forkman, Bjørnvad, Kondrup and Lund2017b) and Chile (Salgado-Caxito et al. Reference Salgado-Caxito, Benavides, Atero, Córdova-Bürhle, Ramos, Fernandez, Sapiente-Aguirre and Mardones2023), levels of vaccination were reported to be higher in purebred cats than in random-bred cats. Although there appears to be limited peer-reviewed studies in the UK, data collected by Cats Protection in 2024 as part of a survey of over 6,000 cat owners showed that purebred or pedigree cats had slightly higher levels of vaccination (80 vs 74%) than random-bred cats (unpublished data). There was no difference reported in the proportion of cats who were registered for veterinary care (both 92%), but more pedigree and purebred owners reported their cat having a regular check-up (70 vs 60%) and having their cat insured (62 vs 45%) than owners of random-bred cats (unpublished data). Whether these differences are statistically significant or impacted by other factors (for example, indoor-outdoor status) is unknown but it may also result from some purebred cats requiring increased healthcare. Insurance prices are generally higher for purebred cats, and this is often related to an increased need for healthcare (McEntee Reference McEntee2021; Go Compare 2024). More information on levels of veterinary care both needed by and provided to purebred cats is needed.

Diet

To achieve the welfare need for a suitable diet, cats are required to be provided with adequate food but also need to be able to eat normally and maintain a good appetite (Table 1). While there is limited published information regarding whether different breeds of cats have different nutritional needs, at least one cat food company markets breed-specific foods (Royal Canin undated). Although these breed-specific foods may, for example, claim to cater to the shape of a cat’s jaw, their hair coat type, or known health associations, such as cardiac issues, there is limited evidence on the specific benefits of these products. Additionally, it is unclear the extent to which catering to specific conformations perpetuates the normalisation of extreme traits.

There may be an association between purebred cats in general and the feeding of raw food diets (O’Halloran et al. Reference O’Halloran, Tørnqvist-Johnsen, Woods, Mitchell, Reed, Burr, Gascoyne-Binzi, Wegg, Beardall, Hope and Gunn-Moore2021). For example, an outbreak of Mycobacterium bovis was seen in 47 cats that had been fed a commercial raw diet, where 76% of the cats were purebred or crossbred cats of various breeds (O’Halloran et al. Reference O’Halloran, Tørnqvist-Johnsen, Woods, Mitchell, Reed, Burr, Gascoyne-Binzi, Wegg, Beardall, Hope and Gunn-Moore2021). Sarcocystis and toxoplasmosis have also been identified in raw food (van Bree et al. Reference van Bree, Bokken, Mineur, Franssen, Opsteegh, van der Giessen, Lipman and Overgaauw2018). Other issues with raw diets are a potential lack or imbalance of essential nutrients, such as taurine, which are typically supplemented in complete commercial diets. With little evidence on raw food diets, recommendations are difficult to make, although it seems reasonable to assume that commercial raw diets are more likely to have complete nutrients and higher health and safety standards than home-made diets.

Motivations behind purebred cat acquisition

A review of human behaviour would not be complete without mention of the motivations for owning a purebred cat and insight into the acceptance and desirability of extreme features of breeds like brachycephaly despite their negative impact on welfare. Personal justification and rationalisation for breed choice will likely vary across breeds as well as between individual humans, as seen with dogs (Sandøe et al. Reference Sandøe, Kondrup, Bennett, Forkman, Meyer, Proschowsky, Serpell and Lund2017a). However, there is some evidence that appears to show similar drivers of human choice for cat breeds as for dog breeds, with key human focus on perceptions around appearance (Plitman et al. Reference Plitman, Černá, Farnworth, Packer and Gunn-Moore2019) and personality (Berteselli et al. Reference Berteselli, Palestrini, Scarpazza, Barbieri, Prato-Previde and Cannas2023), while good health is deemed of less importance (Plitman et al. Reference Plitman, Černá, Farnworth, Packer and Gunn-Moore2019). Human social status may also be an influence for choice of cat breeds, as seen for dog breeds; owners of brachycephalic dogs are significantly younger, in the age groups 18–24 and 25–34 (Packer et al. Reference Packer, Murphy and Farnworth2017). For cats, reports similarly show that humans in the age group 18–34 are more likely to own a purebred or pedigree cat of any breed (Cats Protection 2024).

Packer et al. (Reference Packer, Murphy and Farnworth2017) hypothesised that a dependence on social media in younger age groups was a potential driver to own brachycephalic dogs. The same has been proposed anecdotally for an increase in purebred and pedigree cats by cat welfare organisations (Cats Protection 2023), as well as the use of particular cat breeds in advertising (International Cat Care 2023). Social media increases the visibility of purebred cats, it may also inspire the purchasing of a specific breed: 29% of pedigree cat owners in one survey chose the cat for ‘likes’ on social media, with 5% of non-purebred cat owners saying the same (Cats Protection 2023). Social media, along with other information dissemination networks, can spread misinformation on cat breeds, including perceived personality traits and also offer routes to buying and selling cats. With the internet and its trends constantly changing, research is lagging behind in multiple areas, including new breeds and acquisition trends and motivations.

Preference for individual breeds may also have a cultural influence. For example, respondents who lived in Asia completing a survey on breed preference were more likely to prefer brachycephalic and dolichocephalic cats than mesocephalic, compared with respondents in the rest of the world (Farnworth et al. Reference Farnworth, Packer, Sordo, Chen, Caney and Gunn-Moore2018). Similar to owners of brachycephalic dogs, owners of brachycephalic cats appear to be highly unaware of prevailing health issues in these cats (Berteselli et al. Reference Berteselli, Palestrini, Scarpazza, Barbieri, Prato-Previde and Cannas2023), and so increased public education around this may be a route to behaviour change. However, a survey found that almost one in seven owners of extreme brachycephalic dogs reported that nothing would dissuade them from owning a flat-faced dog (Packer et al. Reference Packer, Wade and Neufuss2024). In these cases, education alone would be unlikely to be a sufficient intervention and instead the powers of legislation or removal of the ‘social licence to own’ may need to be invoked to protect the welfare of these cats from well-meaning but misguided humans (Beban et al. Reference Beban, Korson, Reid, Procter, Halley and Mackenzie2024; LAGECDogs 2024). Whether owners of brachycephalic cats would report similar views is unknown.